• 한국도로학회논문집
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• 제15권3호
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• pp.37-44
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• 2013

PURPOSES: This study is to develop the deduct value curves for the calculation of pavement condition index of asphalt airfield pavement. METHODS: To develop the deduct value curves of asphalt airfield pavement, panel rating was conducted to decide the pavement condition based on pavement distress type, severity, and density. RESULTS: Results show that standard deviation of deduct values by panel rating is increased at higher severity level and as damage density increases. The deduct value of alligator cracking show the highest. CONCLUSIONS: The deduct value curves based on panel rating could be used without existing problems which were occurred in Shahin's method.

• Industrial Engineering and Management Systems
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• 제4권2호
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• pp.192-197
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• 2005

Among many amplitude parameters, Kurtosis (4-th normalized moment of probability density function) is recognized to be the sensitive good parameter for machine diagnosis. Kurtosis has a value of 3.0 under normal condition and the value generally goes up as the deterioration proceeds. In this paper, simplified calculation method of kurtosis is introduced for the analysis of impact vibration with one sided affiliated impact vibration which occurs towards the progress of time. That phenomenon is often watched in the failure of such as bearings’ outer race. One sided affiliated impact vibration is approximated by one sided triangle towards the progress of time and simplified calculation method is introduced. Varying the shape of one sided triangle, various models are examined and it is proved that new index is a sensitive good index for machine failure diagnosis. Utilizing this method, the behavior of kurtosis is forecasted and analyzed while watching machine condition and correct diagnosis is executed.

• 한국토양비료학회지
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• 제16권2호
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• pp.106-111
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• 1983

토양유실량 여측(予測)을 위해서는 강우인자(降雨因子)(R치(値))를 구(求)하여야 되며 이를 종뢰사용해오던 방법(方法)으로 구(求)할 경우 계산과정(計算過程)이 복잡(複雜)하고 어려워 실제 이용(利用)하기가 곤란(困難)하였다. 본(本) 연구에서는 이러한 불편(不便)한 점(点)을 고려(考慮)하여 간편(簡便)하고 실용적인 새로운 강우인자(降雨因子) 추정방법(推定方法)으로 IA-S Index을 제안(提案)하였다. IAS Index에 의(依)한 강우인자(降雨因子)의 추정(推定)은 연중(年中) 강우량(降雨量)이 최대(最大)가 되는 2개월간(個月間) 강우량(降雨量)의 총합으로 하였다. 이와 같이 추정(推定)된 강우인자(降雨因子)의 적용성(適用性)을 검토하기 위하여 우리나라 12개(個) 도시(都市)의 강우성적(降雨成績)을 토태(土台)로 기존방법(旣存方法)($EI_{30}$)과 상호(相互) 비교(比較)해 본 결과(結果) 7~8월에 집중(集中) 호우(豪雨)가 있는 지역(地域)에서는 제안(提案)된 방법(方法)인 IAS Index에 의(依)하여 강우인자(降雨因子)의 추정(推定)이 가능(可能)하였다.

• 한국농공학회지
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• 제37권6호
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• pp.103-111
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• 1995

Drought index calculation based on the principal hydrological parameters, such as rainfall and reservoir storage, can estimate the duration and intensity of drought in irrigation reservoirs. It is difficult to build up a drought criteria since the conditions change variously by the reliability of rainfall. Because of the increasing water demands, it is urgent to prepare a generalized positive countermeasure to overcome drought. Water demands can at calculated but the estimation of drought characteristics, and the effective water management method can be established. The purpose of this study is to obtain a drought index and build up a data-base on the reservoir basins for establishing the fundamental hydrological data-base. This Index can observe the behavior of the WSI(Water Supply Index) and the component indices. The results summarized through this study are as follows. 1. WSI value of zero does not correspond to 100% in average due to the skewness in the probability distributions. 2. WSI is not a linear index; that is, given change in terms of water volume or percentage of average does not result in a proportional change on the WSI scale. 3. WSI is not always between the reservoir and the rainfall index in magnitude. This is only true if the component indices are of opposite sign. If they are of the same sign, the SWSI will often have a mangitude greater than either of the component indices. This is easily understood, because the concurrence of extreme values of the same sign for the two components is rarer than the occurrence of extreme values for either of the two components individually.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.246-259
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• 2021

IMO stability regulations include various stability parameters such as GM values. To assess the stability of the ships, we should check all stability parameters of the IMO requirements. However, since this process is complex, a more convenient way to evaluate stability performance is required. In this research, the index for marine ship intact stability assessment (IMSISA) model was developed to solve these problems. The IMSISA model consists of a stability index calculation module and a stability assessment module. In the stability index calculation module, ten stability parameters, including GM, were used to develop the stability index, which has the advantage of being able to quantify the ship stability. The stability assessment module uses the stability index value to determine the stability status of the ship and provides the captain with stability management guidelines. To verify the proposed model, the basic stability calculations were performed for two model ships in 32 loading situations. The proposed model was found to provide better performance in the stability assessment than the previous study. By applying the IMSISA model to the ships, the captain can assess the ship stability more quantitatively and efficiently.

• 한국도로학회논문집
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• 제19권5호
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• pp.89-96
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• 2017

PURPOSES: This study aims to develop a rational procedure for estimating the pavement roughness index considering vehicle wandering. METHODS : The location analysis of the passing vehicle in the lane was performed by approximately 1.2 million vehicles for verification of the wandering distribution. According to verification result, the distribution follows the normal distribution pattern. The probability density function was estimated using each lane's wandering distribution model. Then the procedure for applying a weighted value into the lane profile was conducted using this function. RESULTS : The modified index, MRIw, with consideration towards applying the wandering weighted value application was computed then compared with MRI. It was found that the Coefficient of Variation for distribution of lateral roughness index in the lane was high in the case of a large difference between each index (i.e., MRIw and MRI) observed. CONCLUSIONS : This result confirms that the new procedure with consideration of the weight factor can successfully improve the lane representative characteristics of the roughness index.

• Safety and Health at Work
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• 제12권4호
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• pp.452-461
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• 2021

Background: The prevailing global work scenario and deteriorating health facilities in economies indulge the risk perspective in the labor market model. This is the reason that the risk factor is cautiously attributed to wages and labor market efficiencies specifically in developing and emerging economies. In this respect, Occupational Injuries of Workers (OIW) is considered essential to demonstrate the risk and Occupational Health and Safety (OHS) setups given the constraints of the labor. Intuitively, the prime objective of this study is to make an assessment of the labor market considering the OIW through the indicators of industry division, employment status, occupational distribution, adopted treatment, gender and regionality. Methods: The assessment strategy of the study has been categorized into trend analysis and Index Value Calculation (IVC) segments employing the data from 2001 to 2018. Results: The pattern of the selected indicators of the OIW has been observed in the available data while the IVC estimations are considered through time and reference categories. The findings of both exercises revealed absolute and relative heterogeneities at both industry and occupational levels. Conclusion: The consistency for gender and regional distribution of both assessments points out the need for effective policy initiatives. The study suggests separate analyses of industry and occupations for a better understanding of the OHS setups and up-gradation in Pakistan.

• 한국항공운항학회지
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• 제13권3호
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• pp.61-72
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• 2005

The main purpose of this study is to develop air transportation cultural index which is able to estimate the level of them. Generally Speaking, air transportation cultural, a compound word of 'air transportation' and 'culture', is a substantial entity consisting knowledge, art, morality, legality, cultivation, customs, and etc, which comes from aircraft operation sector, airport operation/management sector and user sector. They are classified in a primary scope, as aircraft operation sector relating to flight operation, airport operation/management sector and user sector. The research and analysis were taken approximately 4 months, from June 2004 to October 2004. To evaluate the index, the detailed item for three categories were chosen and quantified. The grades for each items were induced from calculation formula for air transportation cultural index by applying weight values. The final grade of Korea's air transportation cultural index recorded 63.19 points.

• Geomechanics and Engineering
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• 제30권6호
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• pp.503-515
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• 2022

The permeability coefficient is an essential parameter for the study of seepage flow in fractured rock mass. This paper discusses the feasibility and application value of using readily available RQD (rock quality index) data to estimate mine water inflow and grouting quantity. Firstly, the influence of different fracture frequencies on permeability in a unit area was explored by combining numerical simulation and experiment, and the relationship between fracture frequencies and pressure and flow velocity at the monitoring point in fractured rock mass was obtained. Then, the stochastic function generation program was used to establish the flow analysis model in fractured rock mass to explore the relationship between flow velocity, pressure and analyze the universal law between fracture frequency and permeability. The concepts of fracture width and connectivity are introduced to modify the permeability calculation formula and grouting formula. Finally, based on the on-site grouting water control example, the rock mass quality index is used to estimate the mine water inflow and the grouting quantity. The results show that it is feasible to estimate the fracture frequency and then calculate the permeability coefficient by RQD. The relationship between fracture frequency and RQD is in accordance with exponential function, and the relationship between structure surface frequency and permeability is also in accordance with exponential function. The calculation results are in good agreement with the field monitoring results, which verifies the rationality of the calculation method. The relationship between the rock mass RQD index and the rock mass permeability established in this paper can be used to invert the mechanical parameters of the rock mass or to judge the permeability and safety of the rock mass by using the mechanical parameters of the rock mass, which is of great significance to the prediction of mine water inflow and the safety evaluation of water inrush disaster management.

• 로봇학회논문지
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• 제15권3호
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• pp.212-220
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• 2020

This paper deals with a strategy of gain optimization for the kinematic control algorithm of a wire-driven surgical robot. The proposed controller consists of the closed-loop inverse kinematics with the back-calculation method. The closed-loop inverse kinematics has 18 PID control gains, and the back-calculation method has 6 gains. An efficient strategy is designed to optimize 18 values first and then the remaining 6 values. The optimal gain sets are searched under the step input with performance indices. In this gain optimization, the objective function is defined as the minimum value of signal-to-noise ratio of the performance indices for 6 DoF (Degree-of-Freedom) motion that is based on the Taguchi method, and the constraints are applied to obtain stable responses for each motion evenly. The gain sets obtained are verified by simulations using the test trajectories. In comparative results, the optimal gain value based on the performance index combined with ISE (integral of square error) and settling time showed the best control performance.