• Geomechanics and Engineering
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• 제38권3호
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• pp.215-229
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• 2024

Because of the various patterns of deep-water inrush and complicated mechanisms, accurately predicting mine water inflows is always a difficult problem for coal mine geologists. In study presented in this paper, the water inrush channels were divided into four basic water diversion structures: aquifer, rock fracture zone, fracture zone and goaf. The fluid flow characteristics in each water-conducting structure were investigated by laboratory tests, and multistructure and multisystem coupling flow analysis models of different water-conducting structures were established to describe the entire water inrush process. Based on the research of the water inrush flow paths, the analysis model of different water inrush space structures was established and applied to the prediction of mine water inrush inflow. The results prove that the conduction sequence of different water-conducting structures and the changing rule of permeability caused by stress changes before and after the peak have important influences on the characteristics of mine water-gushing. Influenced by the differences in geological structure and combined with rock mass RQD and fault conductivity characteristics and other mine exploration data, the prediction of mine water inflow can be realized accurately. Taking the water transmitting path in the multistructure as the research object of water inrush, breaking through the limitation of traditional stratigraphic structure division, the prediction of water inflow and the estimation of potentially flooded area was realized, and water bursting intensity was predicted. It is of great significance in making reasonable emergency plans.

• 한국음향학회지
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• 제21권2호
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• pp.134-141
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• 2002

본 연구에서 곡선 와동 요소와 CVC (Constant Vorticity Contour) 후류 모델이 수평축 풍력 터빈의 공력 성능 및 소음을 예측하기 위해 사용되었다. 또한 2차 회귀에 근거하여 회전수의 예측을 하였다. 광대역 소음을 예측은 경험식에 근거한 방법을 사용하였다. 직선 와동요소 대신에 BCVE (Basic Curved Vortex Element)와 SIVE(Self Induction Vortex Element)를 사용하는 곡선 와동 요소를 사용하였으며 CVC 후류 모델에서 와동의 강도는 블레이드의 스팬방향 및 와동을 따라서 일정하다고 가정하였다. 이렇게 만들어진 자유 후류는 와동 격자를 대치한다. 본 방법은 여타의 방법에 비해 휠씬 적은 계산 시간을 요구하며 후류의 정확한 구조를 모사할 수 있었다. 검증을 위해서는 김준모의 실험과 Zond사의 Z-40FS의 모델을 성능 예측 결과와 WTS-4와 USWP를 소음 예측 결과와 비교하였다. 계산 결과는 실제의 실험치와 잘 일치하는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.846-849
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• 2004

It is important to decide the precise chloride diffusion coefficient in order to predict the durability plan of concrete structure chloride and prediction of remaining lifetime. However, the inland references are limited to the rapid test in laboratory. The purpose of this study is to examine and analyze the established data, which are restricted by chloride diffusion coefficient, and to examine the prediction of the concrete structure durability by an FEM interpretation and the chloride diffusion coefficient as a variable.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.51-56
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• 2017

This paper presents an approach of predicting the radiated noise due to the structural vibration by internal harmonic forces using the doubly asymptotic approximation (DAA). Acoustic transfer vector is derived from the Helmholtz integral equation and the fluid-structure interaction relation of DAA. Numerical results and analytical results of radiated noise for a cylindrical shell were compared and showed that they were consistent in most of frequencies and radiation directions, but showed errors in some radiated directions in the mid-frequency region. Despite these errors, the prediction method will be suitable for practical radiated noise prediction.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.115-116
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• 2006

In these days, almost urban railway vehicle has been serviced under the random load application. But it is very important that fatigue lift prediction fur structures is major factor of safety. So do this, it is required that fatigue assessment method for cumulative damage approach while Korea domestic regulations only has endurance limit approach. With this endurance limit approach, fatigue lift prediction is impossible. In this research, it will be present that fatigue assessment for urban transit structure by using of cumulative damage approach method and related theories.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1998년도 The Korea Society for Simulation 98 춘계학술대회 논문집
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• pp.101-105
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• 1998

A large system predictor, which can perform prediction of sales trend in a huge number of distribution centers, is presented using neural predictive model. There are 20,000 number of distribution centers, and each distribution center need to forecast future demand in order to establish a reasonable inventory policy. Therefore, the number of forecasting models corresponds to the number of distribution centers, which is not possible to estimate that kind of huge number of accurate models in ERP (Enterprise Resource Planning)module. Multilayer neural net as universal approximation is employed for fitting the prediction model. In order to improve prediction accuracy, a sequential simulation procedure is performed to get appropriate network structure and also to improve forecasting accuracy. The proposed simulation procedure includes neural structure identification and virtual predictive model generation. The predictive model generation consists of generating virtual signals and estimating predictive model. The virtual predictive model plays a key role in tuning the real model by absorbing the real model errors. The complement approach, based on real and virtual model, could forecast the future demands of various distribution centers.

• KCI Concrete Journal
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• 제11권3호
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• pp.99-107
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• 1999

In designing the Prestressed concrete box-girder bridge. dead load, prestressing force, creep and shrinkage of concrete are the main factors which influence the camber and deflection of segmental concrete structure under construction. Among these factors the creep and shrinkage are the functions of the time-dependent property which. therefore, must be considered with time. The prediction model for estimating creep and shrinkage of concrete has been suggested by ACI, CEB/FIP, JSCE and KSCE design code and EMM, AEMM, RCM, IDM and SSM has been suggested for analytical method in consideration of time-dependent characteristics. In this study the creep test was carried out for four different curing ages of concrete which were applied to the Prestressed concrete structure at the construction site, and the results of test were compared with the values of creep prediction proposed by the design code. Also the creep test was performed with step-wise incremental stresses and the results were compared to the analytical values.

• Journal of Information Processing Systems
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• 제19권1호
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• pp.130-138
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• 2023

The traffic flow in an urban area is affected by the date, weather, and regional traffic flow. The existing methods are weak to model the dynamic road network features, which results in inadequate long-term prediction performance. To solve the problems regarding insufficient capacity for dynamic modeling of road network structures and insufficient mining of dynamic spatio-temporal features. In this study, we propose a novel traffic flow prediction framework called shared spatio-temporal attention convolution optimization network (SSTACON). The shared spatio-temporal attention convolution layer shares a spatio-temporal attention structure, that is designed to extract dynamic spatio-temporal features from historical traffic conditions. Subsequently, the graph optimization module is used to model the dynamic road network structure. The experimental evaluation conducted on two datasets shows that the proposed method outperforms state-of-the-art methods at all time intervals.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3612-3624
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• 2021

At present, in the case of pump fast optimization, there is a problem of rapid, accurate and effective prediction of cavitation performance. In "A Cavitation Performance Prediction Method for Pumps PART1-Proposal and Feasibility" [1], a new cavitation performance prediction method is proposed, and the feasibility of this method is demonstrated in combination with experiments of a mixed flow pump. However, whether this method is applicable to vane pumps with different specific speeds and whether the prediction results of this method are accurate is still worthy of further study. Combined with the experimental results, the research evaluates the sensitivity and accuracy at different flow rates. For a certain operating condition, the method has better sensitivity to different flow rates. This is suitable for multi-parameter multi-objective optimization of pump impeller. For the test mixed flow pump, the method is more accurate when the area ratios are 13.718% and 13.826%. The cavitation vortex flow is obtained through high-speed camera, and the correlation between cavitation flow structure and cavitation performance is established to provide more scientific support for cavitation performance prediction. The method is not only suitable for cavitation performance prediction of the mixed flow pump, but also can be expanded to cavitation performance prediction of blade type hydraulic machinery, which will solve the problem of rapid prediction of hydraulic machinery cavitation performance.

• 한국정보통신학회논문지
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• 제16권4호
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• pp.765-770
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• 2012

본 논문에서는 인트라 모드 결정으로 인해 발생되는 연산 복잡도 문제를 줄이기 위해 DCT 기반 인트라 예측을 사용하는 효율적인 하드웨어 구조를 제안한다. 제안된 하드웨어 구조는 처음 입력 블록에 대해 DCT를 수행하고 DCT 계수의 특성을 이용하여 에지 방향성을 예측한다. 그리고 예측된 에지 방향에 해당하는 모드에 대해서만 화면 내 예측을 수행함으로써 복잡도 문제를 해결하였다. DCT 하드웨어 구조는 4개의 덧셈기와 4개의 뺄셈기, 2개의 쉬프트 연산기로 구성된 Transform_PE를 이용하여 Multitransform_PE를 구현하였고 $4{\times}4$ 블록 DCT를 1 사이클에 계산한다. 또한, 15개의 덧셈기, 15개의 쉬프트 연산기로 구성된 Intra_pred_PE를 통해 2 사이클에 하나의 화면 내 예측을 수행한다. 따라서 하나의 매크로블록을 인코딩할 때 517 사이클을 소요하며 기존의 하드웨어 구조 보다 수행 사이클 수에 있어서 17%의 성능이 향상됨을 보였다. 본 논문의 하드웨어 구조는 DCT 기반 인트라 예측 알고리즘을 사용하며 Verilog HDL을 이용하여 구현되었고, 매그나칩 공정 $0.18{\mu}m$ 셀 라이브러리로 합성 결과 최대 125MHz에서 동작함을 확인하였다.