• Title/Summary/Keyword: Controlled models

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Numerical simulations of fracture shear test in anisotropy rocks with bedding layers

  • Haeri, Hadi;Sarfarazi, Vahab;Zhu, Zheming;Nejati, Hamid Reza
    • Advances in concrete construction
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    • v.7 no.4
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    • pp.241-247
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    • 2019
  • In this paper the effect of bedding layer on the failure mechanism of rock in direct shear test has been investigated using particle flow code, PFC. For this purpose, firstly calibration of pfc2d was performed using Brazilian tensile strength. Secondly direct shear test consisting bedding layer was simulated numerically. Thickness of layers was 10 mm and rock bridge length was 10 mm, 40 mm and 60 mm. In each rock bridge length, bedding layer angles changes from $0^{\circ}$ to $90^{\circ}$ with increment of $15^{\circ}$. Totally 21 models were simulated and tested. The results show that two types of cracks develop within the model. Shear cracks and tensile cracks. Also failure pattern is affected by bridge length while shear strength is controlled by failure pattern. It's to be noted that bedding layer has not any effect on the failure pattern because the layer interface strength is too high.

Maintaining the close-to-critical state of thorium fuel core of hybrid reactor operated under control by D-T fusion neutron flux

  • Bedenko, Sergey V.;Arzhannikov, Andrey V.;Lutsik, Igor O.;Prikhodko, Vadim V.;Shmakov, Vladimir M.;Modestov, Dmitry G.;Karengin, Alexander G.;Shamanin, Igor V.
    • Nuclear Engineering and Technology
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    • v.53 no.6
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    • pp.1736-1746
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    • 2021
  • The results of full-scale numerical experiments of a hybrid thorium-containing fuel cell facility operating in a close-to-critical state due to a controlled source of fusion neutrons are discussed in this work. The facility under study was a complex consisting of two blocks. The first block was based on the concept of a high-temperature gas-cooled thorium reactor core. The second block was an axially symmetrical extended plasma generator of additional neutrons that was placed in the near-axial zone of the facility blanket. The calculated models of the blanket and the plasma generator of D-T neutrons created within the work allowed for research of the neutronic parameters of the facility in stationary and pulse-periodic operation modes. This research will make it possible to construct a safe facility and investigate the properties of thorium fuel, which can be continuously used in the epithermal spectrum of the considered hybrid fusion-fission reactor.

Analysts' Cash Flow Forecasts and Accrual Anomaly (재무분석가의 현금흐름예측과 발생액 이상현상)

  • Kim, Jong-Hyun;Chang, Seok-Jin
    • Asia-Pacific Journal of Business
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    • v.11 no.3
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    • pp.137-151
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    • 2020
  • Purpose - The purpose of this study is to investigate whether financial analysts' cash flow forecasts mitigate the accrual anomaly. In addition, we examine whether the more accurate analysts' cash flow forecasts are the greater the decline of the accrual anomaly. Design/methodology/approach - Data used in the empirical tests are extracted through KIS-VALUE and FN-GUIDE, and the sample consists of firms listed on Korea Stock Exchange for 7 years from 2005 to 2011. We test the hypotheses using multiple regression analysis and we also estimate the regressions with the decile ranks of the explanatory variables to minimize the influence of outliers. Findings - We have failed to capture evidence that the provision of financial analysts' cash flow forecasts itself reduces the accrual anomaly. However, we find the accrual anomaly to be less severe when financial analysts provide more accurate cash flow forecasts. The findings are consistent in the regression models with the decile ranks as well as in the robustness tests that controlled the accruals quality. Research implications or Originality - This study contributes to the expansion of related studies in the Korea by providing empirical evidence partially that the financial analysts' cash flow forecasts mitigate the accrual anomaly.

Bank Capital and Lending Behavior of Vietnamese Commercial Banks

  • DANG, Van Dan;LE, Thi Tuyet Hoa;LE, Dinh Hac;NGUYEN, Hoang Dieu Hien
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.2
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    • pp.373-385
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    • 2021
  • The objective of the study is to empirically investigate the impact of bank capital on the lending behavior of Vietnamese commercial banks from 2007 to 2019. Lending behavior is captured by two dimensions, including the quantity (loan growth) and quality (credit risk) of loans. Instead of investigating loan growth and credit risk separately, we combine these two aspects in our study and further develop the interaction term between capital buffers and credit risk to capture the asymmetric impact. We apply the dynamic model (regressed by the generalized method of moments) and the static models (regressed using the fixed effects, random effects, and the pooled regression approach) to perform regressions. The results show that banks with higher capital ratios tend to expand lending more, while the risk of credit portfolios is controlled at lower levels at these banks. Further analysis reveals that credit risk mitigates some aspects of the relationship between bank capital and loan expansion. The patterns remain robust across alternative measures and econometric techniques. The study provides insightful policy implications for bank managers and regulators in the process of upgrading capital resources to ensure the safety and soundness of the banking industry in an emerging country.

Analysis of BIM Technology Structure and Core Technology Using Patent Co-classification Network Analysis (특허 동시분류 네트워크 분석을 활용한 BIM 기술구조와 핵심기술 분석)

  • Park, Yoo-Na;Lee, Hye-Jin;Lee, Seok-Hyoung;Choi, Hee-Seok
    • Journal of KIBIM
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    • v.10 no.2
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    • pp.1-11
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    • 2020
  • BIM(Building Information Modeling) is a salient technology for influential innovation in the construction industry. The patent network analysis is useful for suggesting the direction of technology development and exploring the research and development field. Therefore, the purpose of this study is to analyze the BIM technology structure and core technologies according to the convergence of BIM technology and market expansion. In this study, social network analysis was conducted by establishing a co-classification IPC network for the United States BIM patent. In particular, the characteristics of the major technical areas in the BIM technology network were identified through centrality analysis. G06F017/00, digital computing or data processing method, is a core technology field in the BIM network. Arrangements, apparatus or systems for transmission of digital information, H04L029/00 is an influential technology across the network. B25J009/00 for program controlled manipulators is an intermediary technology field and G06T019/00, manipulating 3D models or images for computer graphics, is an important field for technological development competitiveness.

Wastewater Treatment Plant Control Strategies

  • Ballhysa, Nobel;Kim, Soyeon;Byeon, Seongjoon
    • International journal of advanced smart convergence
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    • v.9 no.4
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    • pp.16-25
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    • 2020
  • The operation of a wastewater treatment plant (WWTP) is a complex task which requires to consider several aspects: adapting to always changing influent composition and volume, ensuring treated effluents quality complies with local regulations, ensuring dissolved oxygen levels in biological reaction tanks are sufficient to avoid anoxic conditions etc. all of it while minimizing usage of chemicals and power consumption. The traditional way of managing WWTPs consists in having employees on the field measure various parameters and make decisions based on their judgment and experience which holds various concerns such as the low frequency of data, errors in measurement and difficulty to analyze historical data to propose optimal solutions. In the case of activated sludge WWTPs, parts of the treatment process can be automated and controlled in order to satisfy various control objectives. The models developed by the International Water Association (IWA) have been extensively used worldwide in order to design and assess the performance of various control strategies. In this work, we propose to review most recent WWTP automation initiatives around the world and identify most currently used control parameters and control architectures. We then suggest a framework to select WWTP model, control parameters and control scheme in order to develop and benchmark control strategies for WWTP automation.

Wellness Prediction in Diabetes Mellitus Risks Via Machine Learning Classifiers

  • Saravanakumar M, Venkatesh;Sabibullah, M.
    • International Journal of Computer Science & Network Security
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    • v.22 no.4
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    • pp.203-208
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    • 2022
  • The occurrence of Type 2 Diabetes Mellitus (T2DM) is hoarding globally. All kinds of Diabetes Mellitus is controlled to disrupt over 415 million grownups worldwide. It was the seventh prime cause of demise widespread with a measured 1.6 million deaths right prompted by diabetes during 2016. Over 90% of diabetes cases are T2DM, with the utmost persons having at smallest one other chronic condition in UK. In valuation of contemporary applications of Big Data (BD) to Diabetes Medicare by sighted its upcoming abilities, it is compulsory to transmit out a bottomless revision over foremost theoretical literatures. The long-term growth in medicine and, in explicit, in the field of "Diabetology", is powerfully encroached to a sequence of differences and inventions. The medical and healthcare data from varied bases like analysis and treatment tactics which assistances healthcare workers to guess the actual perceptions about the development of Diabetes Medicare measures accessible by them. Apache Spark extracts "Resilient Distributed Dataset (RDD)", a vital data structure distributed finished a cluster on machines. Machine Learning (ML) deals a note-worthy method for building elegant and automatic algorithms. ML library involving of communal ML algorithms like Support Vector Classification and Random Forest are investigated in this projected work by using Jupiter Notebook - Python code, where significant quantity of result (Accuracy) is carried out by the models.

Numerical analysis of embankment primary consolidation with porosity-dependent and strain-dependent coefficient of permeability

  • Balic, Anis;Hadzalic, Emina;Dolarevic, Samir
    • Coupled systems mechanics
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    • v.11 no.2
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    • pp.93-106
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    • 2022
  • The total embankment settlement consists of three stages: the initial settlement, the primary consolidation settlement, and the secondary consolidation settlement. The total embankment settlement is largely controlled by the primary consolidation settlement, which is usually computed with numerical models that implement Biot's theory of consolidation. The key parameter that affects the primary consolidation time is the coefficient of permeability. Due to the complex stress and strain states in the foundation soil under the embankment, to be able to predict the consolidation time more precisely, aside from porosity-dependency, the strain-dependency of the coefficient of permeability should be also taken into account in numerical analyses. In this paper, we propose a two-dimensional plane strain numerical model of embankment primary consolidation, which implements Biot's theory of consolidation with both porosity-dependent and strain-dependent coefficient of permeability. We perform several numerical simulations. First, we demonstrate the influence of the strain-dependent coefficient of permeability on the computed results. Next, we validate our numerical model by comparing computed results against in-situ measurements for two road embankments: one near the city of Saga, and the other near the city of Boston. Finally, we give our concluding remarks.

Fractal kinetic characteristics of uranium leaching from low permeability uranium-bearing sandstone

  • Zeng, Sheng;Shen, Yuan;Sun, Bing;Tan, Kaixuan;Zhang, Shuwen;Ye, Wenhao
    • Nuclear Engineering and Technology
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    • v.54 no.4
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    • pp.1175-1184
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    • 2022
  • The pore structure of uranium-bearing sandstone is one of the critical factors that affect the uranium leaching performance. In this article, uranium-bearing sandstone from the Yili Basin, Xinjiang, China, was taken as the research object. The fractal characteristics of the pore structure of the uranium-bearing sandstone were studied using mercury intrusion experiments and fractal theory, and the fractal dimension of the uranium-bearing sandstone was calculated. In addition, the effect of the fractal characteristics of the pore structure of the uranium-bearing sandstone on the uranium leaching kinetics was studied. Then, the kinetics was analyzed using a shrinking nuclear model, and it was determined that the rate of uranium leaching is mainly controlled by the diffusion reaction, and the dissolution rate constant (K) is linearly related to the pore specific surface fractal dimension (DS) and the pore volume fractal dimension (DV). Eventually, fractal kinetic models for predicting the in-situ leaching kinetics were established using the unreacted shrinking core model, and the linear relationship between the fractal dimension of the sample's pore structure and the dissolution rate during the leaching was fitted.

Control Strategies for Landing Quadcopters on Ships with Legged Platform Based on Impedance Control (선박 위 착륙을 위한 임피던스 제어기반 쿼드콥터 족형 랜딩플랫폼 제어 전략)

  • Hwang, Seonghyeon;Lee, Seunghyeon;Jin, Seongho;Lee, Inho
    • The Journal of Korea Robotics Society
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    • v.17 no.1
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    • pp.48-57
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    • 2022
  • In this paper, we propose a legged landing platform for the quadcopter taking off and landing in the ship environment. In the ship environment with waves and winds, the aircraft has risks being overturned by contact impact and excessive inclination during landing on the ship. This landing platform has four landing legs under the quadcopter for balancing and shock relief. In order to make the quadcopter balanced on ships, the position of each end effector was controlled by PID control. And shocks have mainly happened when quadcopter contacts the ship's surface as well as legs move fast. Hence, impedance control was used to cope with the shocks. The performance of the landing platform was demonstrated by a simulation and a prototype in three sea states based on a specific size of a ship. During landing and tracking the slope of the ship's surface, oscillations of rotation and translation from the shock were mitigated by the controller. As a result, it was verified that transient response and stability got better by adding impedance control in simulation models and prototype experiments.