• Title/Summary/Keyword: stability evaluation

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6$\sigma$를 이용한 정밀 저항 용접기의 출력 안정성 평가 (Application of 6$\sigma$ for Output Stability Evaluation of the Micro Spot Welding Machine)

  • 홍성준;박정규;홍순국;조성우;조상명
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2003년도 추계학술발표대회 개요집
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    • pp.147-149
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    • 2003
  • Many factors, such as welding current, welding time, force, electrode shape, the output stability of a welding machine, are closely related with micro spot series welding. Of those factors, the output stability evaluation of the welding machine would be checked first. in this study, we applied 6$\sigma$ to evaluation for the output stability of the welding machine. We estimated output stability and control stability of the welding machine by using Cp(process capability), Ppk and 4-block diagram. Therefore the problem as solved in micro spot series welding process and the problem of output control in welding machine by 6$\sigma$ tool.

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이동형 수상부유식 가두리의 저항성능과 복원성능 평가 (Resistance and stability evaluation of mobile fish-cage)

  • 김효주;정성재
    • 수산해양기술연구
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    • 제52권2호
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    • pp.79-87
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    • 2016
  • Mobile fish-cage was developed assuming a cage net with an enclosed area, which and estimated the hydrodynamic characteristics of the cage through the model experiment. Flux-shielding plates, installed in the bow were compared with the resistance test carried out by making a hole, bilge keel and stud, and basic block flow rate consisting of the results to a flat surface plate. The experimental results confirmed the improved resistance performance effect of 3~6% in the bilge keel and the stud form. To assess the stability of the fish-cage, evaluation of the stability in accordance with the stability criteria for determining the floating docks had confirmed that it satisfied the static stability performance under operating conditions at sea.

Development of stability evaluation system for retaining walls: Differential evolution algorithm-artificial neural network

  • Dong-Gun Lee;Sang-Yun Lee;Ki-Il Song
    • Geomechanics and Engineering
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    • 제34권3호
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    • pp.329-339
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    • 2023
  • The objective of this study is to develop a Stability Evaluation System for retaining walls to assess their safety in real-time during excavation. A ground investigation is typically conducted before construction to gather information about the soil properties and predict wall stability. However, these properties may not accurately reflect the actual ground being excavated. To address this issue, the study employed a differential evolution algorithm to estimate the soil parameters of the actual ground. The estimated results were then used as input for an artificial neural network to evaluate the stability of the retaining walls. The study achieved an average accuracy of over 90% in predicting differential settlement, wall displacement, anchor force, and structural stability of the retaining walls. If implemented at actual excavation sites, this approach would enable real-time prediction of wall stability and facilitate effective safety management. Overall, the developed Stability Evaluation System offers a promising solution for ensuring the stability of retaining walls during construction. By incorporating real-time soil parameter analysis, it enhances the accuracy of stability predictions and contributes to proactive safety management in excavation projects.

브리넬 경도 표준 시험기 및 압입자국 자동 측정 장치의 장기 안정도 평가와 최적 시험조건에 관한 연구 (A Study on the Evaluation of Long Term Stability of Brinell Standard Hardness Tester and Automatic Indentation Measurement System and Optimum Test Condition)

  • 방건웅;탁내형;황농문
    • 열처리공학회지
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    • 제13권1호
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    • pp.10-15
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    • 2000
  • Evaluation of long term stability of the Brinell standard hardness tester was carried out to secure its application as a national standard in Brinell hardness. Accuracy and repeatability in load application were tested through evaluating errors in hardness measurement of certified reference blocks. All of those requirements in KS as well as ISO specifications were satisfied by this standard hardness tester. In addition to this, long term stability test of automatic indentation measurement system was carried out. The scattering range was almost the same with its error range. To figure out an optimum test condition for better repeatability and long term stability, the effect of load variation, load application speed and time have been studied using orthogonal array experimental plan. It was found that the best combination is $30{\mu}m/s$ of load application speed and 25 seconds of load application time.

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지진진동수에 따른 콘크리트 중력댐의 내진성능에 대한 해석적 사례연구 (Numerical Study on Earthquake Performance of Gravity Dam Considering Earthquake Frequencies)

  • 채영석;민인기
    • 한국안전학회지
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    • 제31권4호
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    • pp.64-74
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    • 2016
  • Recently, the seismic stability evaluation of concrete gravity dams is raised due to the failure of dams occurred by the Izmit, Turkey and JiJi, Taiwan earthquake in 1999. Dams failure may incur loss of life and properties around the dam as well as damage to dam structure itself. Recently, there has been growing much concerns about "earthquake - resistance" or "seismic safety" of existing concrete gravity dams designed before current seismic design provisions were implemented. This research develops three evaluation levels for seismic stability of concrete gravity dams on the basis of the evaluation method of seismic stability of concrete gravity dams in U.S.A., Japan, Canada, and etc. Level 1 is a preliminary evaluation which is for purpose of screening. Level 2 is a pseudo-static evaluation on the basis of the seismic intensity method. And level 3 is a detail evaluation by the dynamic analysis. Evaluation results on existing concrete gravity dams on operation showed good seismic performance under designed artificial earthquake(KHC earthquake).

인공신경망을 활용한 급경사지 붕괴유발인자 평가 (Assessment of Factors affecting Steep-slope Failure using Artificial Neural Network)

  • 송영갑;오정림;박덕근;손영진
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2010년도 춘계 학술발표회
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    • pp.1342-1348
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    • 2010
  • Currently available evaluation checklists are developed for specific purposed using different parameters and items determined by different weighting factors. Those items with different weighting are sometimes said that they are based on the engineering judgement and leap of faith and, therefore, there is a limitation to adapt those checklists for slope-stability evaluation in the field. This study reviews factors affecting slope stability, analyze the relationship between those factors and slope failures using artificial neural network, and proposed a slope-stability evaluation model for adequate weighting for the factors.

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리어뷰 미러의 실차 동특성 및 주행시 동적 안정성(회전각)에 대한 평가 (On the Evaluation of In-Vehicle Dynamic Characteristics and On-Road Dynamic Stability(Angle of Rotation) of Rearview Mirror)

  • 정승균;이근수;김증한
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2008년도 추계학술대회논문집
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    • pp.385-386
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    • 2008
  • Dynamic stability of the vehicle rearview mirror is an important factor for the driver's visual perception (image blur) when driving down the road and regarded as one of the vehicle level N&V performance of visible component vibration. Several projects within GM identified a set of objective metrics and validation methods that can replace current existing subjective evaluation of mirror stability. This paper presents objective evaluation results for assessing dynamic stability (angle of rotation) of the vehicle rearview mirrors using both in-lab FRF measurements and on-road testing.

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HUMAN-IN-THE-LOOP EVALUATION OF A VEHICLE STABILITY CONTROLLER USING A VEHICLE SIMULATOR

  • Chung, T.;Kim, J.;Yi, K.
    • International Journal of Automotive Technology
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    • 제5권2호
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    • pp.109-114
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    • 2004
  • This paper presents a closed-loop evaluation of the Vehicle Stability Control (VSC) system using a vehicle simulator. Human driver-VSC interactions have been investigated under realistic operating conditions in the laboratory. Braking control inputs for vehicle stability enhancement have been directly derived from the sliding control law based on vehicle planar motion equations with differential braking. A driving simulator has been validated using actual vehicle driving test data. Real-time human-in-the loop simulation results in realistic driving situations have shown that the proposed controller reduces driving effort and enhances vehicle stability.

Stability evaluation of a double-deck tunnel with diverging section

  • La, You-Sung;Kim, Bumjoo
    • Geomechanics and Engineering
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    • 제21권2호
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    • pp.123-132
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    • 2020
  • Due to the various restrictions and problems related to the construction of new roads in urban areas, underground road construction has been receiving a great deal of attention in the field of tunnel engineering. In this study, a double-deck road tunnel with a diverging section was analyzed for the evaluation of its stability. Both numerical analysis and scale model tests were performed, the results were used to develop a stability evaluation method for double-deck tunnels with diverging sections constructed in rocks by NATM. From regression analyses conducted on the results of the numerical analysis, an equation and a chart were derived, these tools allow us to obtain the strength/stress ratio (SSR) for double-deck road tunnels with a diverging tunnel in various diverging conditions quickly and accurately. These tools have great potential to help engineers evaluate the stability of double-deck tunnels in the preliminary design stage.