• Journal of Korean Society on Water Environment
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• v.31 no.6
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• pp.715-722
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• 2015

Four major river basin in Korea has been managed with Total Maximum Daily Load(TMDL) System. Water quality indicators as targeted pollutants for TMDL were BOD and TP. In order to satisfy water quality criteria, government allocation using public treatment facilities and its action plan has been used. However, the role to improve water quality were recently faced to its limitation. It is time to require the role of non-government allocation in private discharge facilities to control good water quality. This study investigated three different scenarios in reduction demands of non-government allocations about industry and private sewages. The three different scenarios were discharge under 1) legal water quality standard, 2) water quality level in 2011 and 3) current water quality level with maximum value in group. The results showed that reduction potential in water discharge for TP indicator was 1,118kg/day, under second scenario with 20% of deduction. This results arrived at 42% of whole reduction potential costs and 0.012mg/L improvement in water quality. In conclusion, to intrigue voluntary participation in non-government allocation, various benefits such as tax reduction, tax exemption, and water quality trading should be provided.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.1
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• pp.52-59
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• 2006

Purpose: The purpose of this study was to evaluate the influence of apical-coronal implant position on the stress distribution after occlusal and oblique loading. Materials and Methods: The cortical and cancellous bone was assumed to be isotropic, homogeneous, and linearly elastic. The implant was apposed to cortical bone in the crestal region and to cancellous bone for the remainder of the implant-bone interface. The cancellous core was surrounded by 2-mm-thick cortical bone. An axial load of 200 N was assumed and a 200-N oblique load was applied at a buccal inclination of 30 degrees to the center of the pontic and buccal cusps. The 3-D geometry modeled in Iron CAD was interfaced with ANSYS. Results: When only the stress in the bone was compared, the minimal principal stress at load Points A and B, with a axial load applied at 90 degrees or an oblique load applied at 30 degrees, for model 5. The von Mises stress in the screw of model 5 was minimal at Points A and B, for 90- and 30-degree loads. When the von Mises stress of the abutment screw was compared at Points A and B, and a 30-degree oblique load, the maximum principal stress was seen with model 2, while the minimum principal stress was with model 5. In the case of implant, the model that received maximum von Mises stress was model 1 with the load Point A and Point B, axial load applied in 90-degree, and oblique load applied in 30-degree. Discussion and Conclusions: These results suggests that implantation should be done at the supracrestal level only when necessary, since it results in higher stress than when implantation is done at or below the alveolar bone level. Within the limited this study, we recommend the use of supracrestal apical-coronal positioning in the case of clinical indications.

• Transactions of the KSME C: Technology and Education
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• v.5 no.2
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• pp.115-126
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• 2017

This paper proposes an accelerated life evaluation of drive shaft for the power train parts of special purpose vehicle. It is necessary the real load data of usage level driving load condition for life evaluation of power train parts, but we can't get the load spectrum data for evaluation in many case of special purpose vehicle. So, in this paper, the road load spectrum data for evaluation is created by modeling and simulation based on vehicle data and special road condition. The inverse power model is used for accelerated life test. The equivalent torque of load spectrum is achieved using the Miner's Rule. This paper also proposes the calibrated acceleration life test method for drive shaft. The fatigue test is performed through three stress levels. The lifetime at normal stress level is predicted by extrapolation, and is verified through comparison of experimental results and load spectrum data.

• Journal of Biomedical Engineering Research
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• v.43 no.1
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• pp.52-60
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• 2022

Purpose: For now, cognitive load is assessed based on survey-based methods, which can be difficult to track the amount of cognitive load in real-time. In this study, we investigated the difference in electrophysiological activation due to different levels of cognitive load not only at sensor-level but also at source-level using electroencephalogram that might be potentially used for quantitative cognitive load evaluation. Materials and Methods: In this study, ten healthy subjects (mean age 24.3 ± 2.1, three female) participated the experiment. All participants performed 4 sessions of n-back task in different difficulties: 0-, 1-, 2-, and 3-back during electroencephalogram recording. For sensor-level analysis, we calculated the event-related potential and event-related spectral perturbation while low resolution brain electromagnetic tomography (LORETA) to estimate the source activation. Each result was compared between different workload conditions using statistical analysis. Results: Statistical results revealed that the accuracy of the task performance was significantly different between different cognitive loads (p = 0.018). The post-hoc analysis confirmed that the accuracy of the 3-back task was significantly decreased compared to 1-back condition (p = 0.018), but not with 2-back condition (p = 0.180). ERP results showed that P300 target amplitude between 1-back and 3-back had a marginal difference in Cz (p = 0.059) and Pz(p = 0.093). A significant inhibition in Cz high-beta activation (p = 0.017) and decrease in source activation of right parahippocampal gyrus was found in 3-back condition compared to 1-back condition (p < 0.05). Conclusion: In this study, we compared the sensor- and source-level differences in electroencephalogram between different levels of cognitive load, that were found to be in line with the previous reports related to cognitive load evaluation. We expect that the outcome of the current study can be used as a feature to establish a quantitative cognitive load assessment system.

• Journal of Mechanical Science and Technology
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• v.16 no.8
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• pp.1095-1101
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• 2002

The load characteristics of engine main bearing are very important in the design of crankshaft and engine block. The stiffness of crankshaft and block, or the optimal dimension of the bearing can be determined according to the load level. This paper presents the load characteristics of engine main bearing. Two components of the main bearing load are measured during engine firing and motoring. The vertical and horizontal load components are measured by using the dynamic load cell mounted in each main bearing cap bolt. The measured main bearing loads are compared with calculated results by using the statically determinate method. The theoretical results, provided in this study, agreed well with the experimental results. The presented results are very useful for achieving optimal design of engine.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1156-1163
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• 2010

The bi-directional high pile load test(BDH PLT) does not have weaknesses found in the existing bi-directional low pile load test(BDL PLT); it has strong economics, is unbound by load capacity limit and secures quality stability of working piles. In this study, Verification the field found a very high capacity level of stability and reliability of the BDH PLT, as well as outstanding field applicability. Field verifications reaffirmed the advantage of the BDH PLT device, which was capable of loading 90 MN capacities as maximum. It was also found to be durable enough to load high capacity with ease.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.6
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• pp.334-339
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• 2004

In this study, a new UC (Unit Commitment) algorithm is proposed to consider the uncertainty of a daily load profile. The proposed algorithm calculates the UC results with the lower load level than the one generated by the conventional load forecast and the more hourly reserve allocation. In case of the worse load forecast, the deviation of the conventional UC solution can be overcome with the proposed method. The proposed method is tested with sample systems, which shows that the new UC algorithm yields completely feasible solution even though the worse load forecast is applied. Also, the effects of the uncertain hourly load demand are statistically analyzed especially by the consideration of the average over generation and the average under generation. Finally, it is shown that independent power producers participating in electricity spot-markets can establish bidding strategies by means of the statistical analysis. Therefore, it is expected that the proposed method can be used as the basic guideline for establishing bidding strategies under the deregulation power pool.

• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.16-21
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• 2005

In this study, a new Unit Commitment (UC) algorithm is proposed to consider the uncertainty of a daily load profile. The proposed algorithm calculates the UC results with a lower load level than that generated by the conventional load forecast method and the greater hourly reserve allocation. In case of the worst load forecast, the deviation of the conventional UC solution can be overcome with the proposed method. The proposed method is tested with sample systems, which indicates that the new UC algorithm yields a completely feasible solution even when the worst load forecast is applied. Also, the effects of the uncertain hourly load demand are statistically analyzed, particularly by the consideration of the average over generation and the average under generation. Finally, it is shown that independent power producers participating in electricity spot-markets can establish bidding strategies by means of the statistical analysis. Therefore, it is expected that the proposed method can be used as the basic guideline for establishing bidding strategies under the deregulation power pool.

• Proceedings of the KIEE Conference
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• 2006.10b
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• pp.141-146
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• 2006

According as level of industry develops day after day, electricity load system of industry requires high level control, effectiveness and high efficiency. Among supply and control unit of suitable power supply in these load characteristic, inverter systems of constant current regulate is used widely control of lighting and electric heating system. Therefore, in this paper proposed an inverter systems with constant current regulation and power factor correction (PFC) circuit for Lighting and Beaconing of Aerodromes. The effectiveness of the proposed system confirmed through experimental results of CCR.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.98-101
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• 1988

A non load level decomposition algorithm is presented for power system reactive source planning. The fuel cost is introduced to performance index in optimal operation problem. The investment variables are all reactive sources such as capacitance or inductance. Experiment showed a desirable result and the computation time reduced considerably.