• Geomechanics and Engineering
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• 제37권3호
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• pp.223-241
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• 2024

Evaluating the performance of Tunnel Boring Machines (TBMs) stands as a pivotal juncture in the domain of hard rock mechanized tunneling, essential for achieving both a dependable construction timeline and utilization rate. In this investigation, three advanced artificial neural networks namely, gated recurrent unit (GRU), back propagation neural network (BPNN), and simple recurrent neural network (SRNN) were crafted to prognosticate TBM-rate of penetration (ROP). Drawing from a dataset comprising 1125 data points amassed during the construction of the Alborze Service Tunnel, the study commenced. Initially, five geomechanical parameters were scrutinized for their impact on TBM-ROP efficiency. Subsequent statistical analyses narrowed down the effective parameters to three, including uniaxial compressive strength (UCS), peak slope index (PSI), and Brazilian tensile strength (BTS). Among the methodologies employed, GRU emerged as the most robust model, demonstrating exceptional predictive prowess for TBM-ROP with staggering accuracy metrics on the testing subset (R² = 0.87, NRMSE = 6.76E-04, MAD = 2.85E-05). The proposed models present viable solutions for analogous ground and TBM tunneling scenarios, particularly beneficial in routes predominantly composed of volcanic and sedimentary rock formations. Leveraging forecasted parameters holds the promise of enhancing both machine efficiency and construction safety within TBM tunneling endeavors.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2159-2163
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• 2003

Hand carried computing machinery and tools have been developed into an embedded system which the small footprint operating system is contained internally. Windows CE which is one of imbedded operating system is a lightweight, multithreaded operating system with an optional graphical user interface. Its strength lies in its small size, its Win32 subset API, and its multiplatform support. Therefore we choose to port this OS on Arm based board that is provided high performance, low cost, and low power consumption. In this paper, we describe the architecture of ARM based board, the feature of Windows CE, techniques and steps involved in this porting process.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.295-302
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• 2009

The flow in the draft tube cone of Francis turbines operated at partial discharge is a complex hydrodynamic phenomenon where an incoming steady axisymmetric swirling flow evolves into a three-dimensional unsteady flow field with precessing helical vortex (also called vortex rope) and associated pressure fluctuations. The paper addresses the following fundamental question: is it possible to compute the circumferentially averaged flow field induced by the precessing vortex rope by using an axisymmetric turbulent swirling flow model? In other words, instead of averaging the measured or computed 3D velocity and pressure fields we would like to solve directly the circumferentially averaged governing equations. As a result, one could use a 2D axi-symmetric model instead of the full 3D flow simulation, with huge savings in both computing time and resources. In order to answer this question we first compute the axisymmetric turbulent swirling flow using available solvers by introducing a stagnant region model (SRM), essentially enforcing a unidirectional circumferentially averaged meridian flow as suggested by the experimental data. Numerical results obtained with both models are compared against measured axial and circumferential velocity profiles, as well as for the vortex rope location. Although the circumferentially averaged flow field cannot capture the unsteadiness of the 3D flow, it can be reliably used for further stability analysis, as well as for assessing and optimizing various techniques to stabilize the swirling flow. In particular, the methodology presented and validated in this paper is particularly useful in optimizing the blade design in order to reduce the stagnant region extent, thus mitigating the vortex rope and expending the operating range for Francis turbines.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권1호
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• pp.76-80
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• 2008

제품 개발 기간을 단축하고 품질과 생산성을 향상시키기 위하여 설계/해석 프로세스의 자동화가 요구된다. 일반적으로 설계/해석 프로세스는 시간과 자원을 많이 필요로 하는 작업이기 때문에 분산 환경에서 다양한 엔지니어링 자원을 효과적으로 활용할 수 있어야 한다. 분산 환경에서의 유연한 엔지니어링 프로세스의 통합과 자동화를 가능하게 하기 위해 한국기계연구원에서는 SOA(Service Oriented Architecture)기반의 e-엔지니어링 프레임워크를 구축하였다. 본 논문에서는 한국기계연구원의 e-엔지니어링 프레임워크의 개념 및 구조를 설명한다. 또한 e-엔지니어링 프레임워크에서 발생할 수 있는 예외사항에 중점을 두고 이러한 예외사항에 대해서 엔지니어링 프로세스 측면과 태스크 측면으로 분류하여 장애진단 및 회복 기법을 제시한다.