• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.983-990
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• 2011

Universal Soil Loss Equation (USLE) has been used to estimate potential long-term soil erosion in the fields. However, the USLE does not estimate sediment yield due to lack of module considering sediment delivery ratio (SDR) for watershed application. For that reason, the Sediment Assessment Tool for Effective Erosion Control (SATEEC) system was developed and applied to compute the sediment yield at watershed scale. However, the R factor of current SATEEC Ver. 2.1 was estimated based on 5-day antecedent rainfall, it is not related with fundamental concept of R factor. To compute R factor accurately, the energy of rainfall strikes should be considered. In this study, the R module in the SATEEC system was enhanced using formulas of Williams, Foster, Cooley, CREAMS which could consider the energy of rainfall strikes. The enhanced SATEEC system ver. 2.2 was applied to the Imha watershed and monthly sediment yield was estimated. As a result of this study, the $R^2$ and NSE values are 0.591 and 0.573 for calibration period, and 0.927 and 0.911 for validation period, respectively. The results demonstrate the enhanced SATEEC System estimates the sediment yield suitably, and it could be used to establish the detailed environmental policy standard using USLE input dataset at watershed scale.

• Tunnel and Underground Space
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• v.32 no.3
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• pp.231-242
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• 2022

In this study, we developed a robot operating system (ROS)-based autonomous driving robot that estimates the robot's position in underground mines and drives and returns through multiple waypoints. Autonomous driving robots utilize SLAM (Simultaneous Localization And Mapping) technology to generate global maps of driving routes in advance. Thereafter, the shape of the wall measured through the LiDAR sensor and the global map are matched, and the data are fused through the AMCL (Adaptive Monte Carlo Localization) technique to correct the robot's position. In addition, it recognizes and avoids obstacles ahead through the LiDAR sensor. Using the developed autonomous driving robot, experiments were conducted on indoor experimental sites that simulated the underground mine site. As a result, it was confirmed that the autonomous driving robot sequentially drives through the multiple waypoints, avoids obstacles, and returns stably.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2802-2811
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• 2023

In a first-of-its-kind study, terrestrial radionuclide concentrations were measured in 35 topsoil samples from the outskirts of Dhaka using HPGe gamma-ray spectrometry to assess the radiological consequences of such a vast number of brick kilns on the plant workers, general as well as dwelling environment. The range of activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K is found at 19 ± 3.04 to 38 ± 4.94, 39 ± 5.85 to 57 ± 7.41, and (430 ± 51.60 to 570 ± 68.40) Bq/kg, respectively. ²³²Th and ⁴⁰K concentrations were higher than the global averages. Bottom ash deposition in lowlands, fly ash buildup in soils, and the fallout of micro-particles are all probable causes of the elevated radioactivity levels. ¹³⁷Cs was found in the sample, which indicates the migration of ¹³⁷Cs from nuclear accidents or nuclear fallout, or the contamination of feed coal. Although the effective dose received by the general public was below the recommended dose limit but, most estimates of hazard parameters surpass their respective population weighted global averages, indicating that brick kiln workers and nearby residents are not safe due to prolonged exposures to terrestrial radiation. In addition, the soil around sampling sites is found to be unsuitable for agricultural purposes.

• Steel and Composite Structures
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• v.44 no.6
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• pp.845-865
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• 2022

In this study, the performance of shear deficient reinforced concrete (RC) beams with rectangular cross-sections, which were externally bonded reinforced (EBR) with high strength CFRP and GFRP strips composite along shear spans, has been experimentally and analytically investigated under vertical load. In the study, the minimum CFRP and GFRP strips width over spacing were considered. The shear beam with turned end to a bending beam was investigated by applying different composite strips. Therefore various arising in each of strength, ductility, rigidity, and energy dissipation capacity were obtained. A total of 12 small-scaled experimental programs have been performed. Beam dimensions have been taken as 100×150×1000 mm. Four beams have been tested as unstrengthened samples. This paper focuses on the effect of minimum CFRP and GFRP strip width on behaviours of RC beams shear-strengthened with full-wrapping, U-wrapping, and U-wrapping+longitudinal bonding strips. Strengthened beams showed significant increments for flexural ductility, energy dissipation, and inelastic performance. The full wrapping strips applied against shear failure have increased the load-carrying capacity of samples 53%-63% interval rate. Although full wrapping is the best strengthening choice, the U-wrapping and U-wrapping+longitudinal strips of both CFRP and GFRP bonding increased the shear capacity by 53%~75% compared to the S2 sample. In terms of ductility, the best result has been obtained by the type of strengthening where the S5 beam was completely GFRP wrapped. The experimental results were also compared with the analytically given by ACI440.2R-17, TBEC-2019 and FIB-2001. Especially in U-wrapped beams, the estimation of FIB was determined to be 81%. The estimates of the other codes are far from meeting the experimental results; therefore, essential improvements should be applied to the codes, especially regarding CFRP and GFRP deformation and approaches for longitudinal strip connections. According to the test results, it is suggested that GFRP, which is at least as effective but cheaper than CFRP, may be preferred for strengthening applications.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.1
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• pp.62-74
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• 2002

The tracking of a reference temperature trajectory in a polymerization batch reactor is a common problem and has critical importance because the quality control of a batch reactor is usually achieved by implementing the trajectory precisely. In this study, only energy balances around a reactor are considered as a design model for control synthesis, and material balances describing concentration variations of involved components are treated as unknown disturbances, of which the effects appear as time-varying parameters in the design model. For the synthesis of a tracking controller, a method combining the input-output linearization of a time-variant system with the parameter estimation is proposed. The parameter estimation method provides parameter estimates such that the estimated outputs asymptotically follow the measured outputs in a specified way. Since other unknown external disturbances or uncertainties can be lumped into existing parameters or considered as another separate parameters, the method is useful in practices exposed to diverse uncertainties and disturbances, and the designed controller becomes robust. And the design procedure and setting of tuning parameters are simple and clear due to the resulted linear design equations. The performances and the effectiveness of the proposed method are demonstrated via simulation studies.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.101-108
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• 1999

In this paper, a real time diagnostic algorithm for estimating the impact location by loose parts is proposed. It is composed of two modules such as the alarm discrimination module (ADM) and the impact-location estimation module(IEM). First, ADM decides whether the detected signal that triggers the alarm is the impact signal by loose parts or the noise signal. Second, IEM by use of the arrival time method estimates the impact location of loose parts. In order to validate the application of this method, the test experiment with a mock-up (flat board and reactor) system is performed. The experimental results show the efficiency of this algorithm even under high level noise and potential application to Loose Part Monitoring System (LPMS) for improving diagnosis capability in nuclear power plants.

• Health Policy and Management
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• v.11 no.3
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• pp.71-88
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• 2001

The purpose of this study is to analyze the cost-effectiveness of four medications for treating and preventing osteoporosis -HRT therapy(conjugated equine estrogen 0.625mg for 25 days and medroxyprogesterone acetate 5mg for 01112 days), Alendronate(10mg and 5mg), Active Vitamin D(Calcitriol), and Calcium. Total costs include the direct medical cost -examination fee, consultation fee, prescription fee, fee for preparing medications, and the price of pharmaceuticals- and the indirect cost of patients such as traffic expenses and time cost. In addition, the costs of monitoring in adverse reactions are added. The effects of four medications are expressed as BMD(Bone Mineral Density) percent change measured by DEXA(Dual Energy X-ray Absorptiometry) in lumbar spine(L2-L4) and femoral neck site. A mixed model based on meta analysis provides the estimates of effectiveness, which are then appled to the hypothetical cohort consisting of postmenopausal women at the age of 50-59. HRT therapy is the most cost-effective medication at 172,433.64 won (lumbar spine site) and 546,328.28 won (femoral neck site) per BMD percent change for osteoporosis. Alendronate 10mg is more cost-effective than Alendronate 5mg as 345,971.23 won and 378,441.63 won per lumbar BMD percent change at 0.991ｇ/$cm^2$, respectively. Alendronate 10mg is more cost-effective than Alendronate 5mg as 1,329,257.89 won and 1,467,291.23 won per femoral neck BMD percent change at 0.834ｇ/$cm^2$, respectively.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.15 no.3
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• pp.223-231
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• 2011

During spray coating, especially in an air plasma spray (APS), pores, cracks, and splat boundaries are developed and those factors exert influence on thermomechanical properties such as elastic modulus, thermal conductivity, and coefficient of thermal expansion. Moreover, the thermo mechanical properties are crucial elements to determine the thermoelastic characteristics, for instance, temperature distribution, displacements, and stresses. Two types of thermal barrier coating (TBC) model, the dense and porous microstructures, are taken into account for the analysis of microstructural characterizations. $TriplexPro^{TM}$-200 system was applied to prepare TBC samples, and the METECO 204 C-NS powder is adopted for the relatively porous microstructure and METECO 204 NS powder for the dense microstructure in the top coat of TBCs. Governing partial differential equations were derived based on the thermoelastic theory and approximate estimates for the thermoelastic characteristics were obtained using a finite volume method for the governing equations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.649-664
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• 2011

Cooperative spectrum sensing (CSS) with decision fusion is considered as a key technology for tackling the challenges caused by fading/shadowing effects and noise uncertainty in spectrum sensing in cognitive radio. However, most existing solutions assume an error-free decision transmission, which is obviously not the case in realistic scenarios. This paper extends the general decision-fusion-based CSS scheme by considering the fading/shadowing effects and noise corruption in the common control channels. With this more practical model, the fusion centre first estimates the local decisions using a binary minimum error probability detector, and then combines them to get the final result. Theoretical analysis and simulation of this CSS scheme are performed over typical channels, which suggest some performance deterioration compared with the pure case that assumes an error-free decision transmission. Furthermore, the fusion strategy optimization in the proposed cooperation model is also investigated using the Bayesian criteria. The numerical results show that the total error rate of noisy CSS is higher than that of the pure case, and the optimal values of fusion parameter in the counting rule under both cases decrease as the local detection threshold increases.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1368-1375
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• 2013

The Smart Grid, which can monitor or diagnose the power grid in real time to operate efficiently, has been pushed ahead systematically as one of alternatives to solve these issues by combining the advanced Information Communication Technology and the electrical network. Hence, the electric company which introduces smart grid technology can read remotely the electrical meter readings by means of two-way communication between the meter and the central system. This enabled the customer and the utility to take part in reasonable electrical energy utilization. AMI became one of the core foundations in realizing the Smart Grid. It is hard to test the entire process of AMI system before the full deployment because it covers the broad objects from the customer to the utility operation system and requires mass data handling and management. Therefore, we design an efficient AMI network model and a simulator for performance evaluation required to simulate the network model similar to the real environment. This tool supports to evaluate the efficiency of the AMI network equipments and deployment. Additionally, it estimates the appropriate number of deployments and the proper capabilities.