Optimal design of main girder structure of bridge crane based on equal life concept driven by data

Yannan Yu,Zhiping Liu,Yao Lu,Peng Zhang,Hui Liu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.9

In traditional structural crane design, the fatigue strength of the structure is qualitatively evaluated, only depending on the steel type, working level and joint form, which leads to the excessive service life of some parts of the existing main girder structure, resulting in a waste of industrial resources and manufacturing costs. Based on the concept of equal life design, this paper obtained the service information of the crane in the scheduled inspection period through the rapid prediction method of "field collection+machine learning." Combined with the bearing capacity evaluation method and the fatigue life assessment method of "S-N curve+ fracture mechanics," a nonlinear mixed integer equal life optimization model of crane girder structure was established, and the multi-specular reflection optimization algorithm was used to optimize the life distribution at different positions and overall weight of the main girder. The structural design parameters of the crane main girder which meet the bearing capacity and have the characteristics of "equal life+lightweight" were obtained. The performance of the optimized main girder structure was verified by finite element simulation. The results show that this method can realize the quantitative control of the life distribution of each position of the crane main girder structure and the lightweight design of the whole structure, and provides a scientific reference for the equal life and lightweight design of large construction machinery products.

Dynamic Seal Friction Heat Characteristics Analysis of Hydraulic Servo Swing Motor

Yannan Zhu,Qiang Zhang,Jianfeng Tao,Dun Tan,Xuyong Wang 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.3

Hydraulic swing motor’s dynamic seal friction heat is a direct factor leading to motor’s temperature rise. To study the key factors in motor’s dynamic seal friction heat, therefore, reducing motor’s temperature rise, the contact stress model and friction model were established. Based on the swing motor of a three-axis turntable system, the relationship between three key factors was analyzed. Motor’s friction heat characteristics in two conditions were simulated, and simulation results show that with the increase of three factors, the friction heat increases obviously. Further experimental research validated the theoretical analysis and indicated that friction heat can be significantly reduced when reducing combined gasket’s compression ratio, motor’s working pressure and spindle’s speed appropriately. Furthermore, improving the machining precision of motor’s seal structure and combined seal’s installation precision also work.

Depth Up-Sampling via Pixel-Classifying and Joint Bilateral Filtering

( Yannan Ren ),( Ju Liu ),( Hui Yuan ),( Yifan Xiao ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7

In this paper, a depth image up-sampling method is put forward by using pixel classifying and jointed bilateral filtering. By analyzing the edge maps originated from the high-resolution color image and low-resolution depth map respectively, pixels in up-sampled depth maps can be classified into four categories: edge points, edge-neighbor points, texture points and smooth points. First, joint bilateral up-sampling (JBU) method is used to generate an initial up-sampling depth image. Then, for each pixel category, different refinement methods are employed to modify the initial up-sampling depth image. Experimental results show that the proposed algorithm can reduce the blurring artifact with lower bad pixel rate (BPR).

PP-TABLF Based Adaptive Command Filter Control for Fully Actuated MSVs with Unknown Uncertainties and Multiple Constraints

Yannan Bi,Zhipeng Shen,Qun Wang,Haomiao Yu,Chen Guo 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.12

This article investigates the adaptive tracking control problem for the marine surface vessels (MSVs) with unknown uncertainties and multiple constraints. Firstly, a novel prescribed performance-based time-varying asystematic barrier Lyapunov function (PP-TABLF) is proposed to control the MSVs to navigate in a variable narrow waterway and to improve the transient performance of MSVs. Secondly, the predictor-based radial basis function neural networks (P-RBFNNs) are developed to approximate the system uncertainties and external disturbances. Specifically, the tracking errors of the RBFNNs are estimated in advance, and the prediction errors are utilized to update the RBFNNs and improve the estimation precision. The command filter and the idea of the recursive sliding mode are integrated with the control law to limit the amplitude of the virtual control signals and to reduce the computational burden. With the proposed control scheme, tracking errors will not override the prescribed performance ranges, and the control force will not be violated in the presence of total unknown uncertainties. Finally, the semi-global uniformly ultimate boundedness of the system is guaranteed by the proposed control scheme, and the simulation results are given to further demonstrate the effectiveness of the proposed approach.

Research on College Students Who Participate in Volunteer Activities that Affect the Physical Development of Their Future-Take Finish the Course of Sports Welfare Projects as an Example

( Yannan Liu ) 한국체육학회 2015 국제스포츠과학 학술대회 Vol.2015 No.1

[중국언론시리즈 Ⅱ] 중국 텔레비전산업의 구조조정 연구

류연남(Liu Yannan) 서울대학교 언론정보연구소 2002 언론정보연구 Vol.39 No.-

본문은 세기의 교차시기에 중국 텔리비전산업의 구조조정이 왜 일어났으며, 구조조정의 주요내용과 현황을 소개하고, 구조조정의 특징을 분석하고, 이와 관련된 문제에 대해 토론해보았다.

Privatization-related Subsidies under SCM Agreement : Focusing on Subsidies Countervailed by the United States

Lee, Eun Sup;Sun, Yannan 법무부 2011 통상법률 Vol.- No.100

There have been growing interests among the WTO member countries in the issue whether it is reasonable under WTO subsidy rules to impose countervailing duties on those goods imported from the privatized company based on the pre-privatization subsidies, even when the company was privatized at arm's length. This paper suggests the proposal for more reasonable interpretations and application of the SCM Agreement to avoid the abuse of the countervailing measures under the current WTO Agreement. For the applicable suggestion, it reviews the problems exposed through the enforcement of the United States subsidy-relating policy and irrational methodology in treating with the privatization-related subsidies, and the WTO's judicial decisions on them. With regard to the privatization-related issues, the United States attempted to impose countervailing measures on products imported from privatized companies, for which the U.S. made amendment to the countervailing duties law and tried to apply various methodologies in the countervailing investigation. Such efforts of the U.S., however, were criticized severely by the trading partner countries and also judged to be in breach of the SCM provisions of the WTO. The United States laws and the Department of Commerce's enforcement would impede the effect of the several salient U.S. trade policies and threaten the credibility in its efforts to pursue a trade policy toward liberalization and open markets. Such an approach would be harmful to the U.S. consumers and industry, foreign industries, and free trade in general. Since the United States has maintained ideological and pragmatic interests in promoting privatization in the word markets, its legislative and administrative approach to the privatization-related subsidies should conceptually be reframed to be well-grounded in economic principles, and compatible with the U.S. trade policy goals and, at the same time, the WTO spirit and principles. 1990년대 이후 개발 도상국뿐만 아니라 선진국에서도 철강 등 주요산업부문의 국가 또는 공영기업의 민영화가 적극적으로 추진되면서, 미국의 민영화 된 기업으로부터의 수입 물품에 대하여 부과하는 상계관세에 대하여 국제적인 우려가 점증되어 왔다. 사회주의 경제체제로부터 자본주의의 체제로 변경 되는 과정에서 이루어진 특수한 민영화를 제외하면 대부분의 선진국에서 이루어진 공영기업들은 시장가치에 따라 민영화가 이루어져 왔다. 그럼에도 불구하고 미국의 상무 부는 민영화된 기업으로부터 수입한 물품에 대해서 상계관세를 부과하여 왔다. 이러한 미국의 상계관세부과는 WTO보조금과 상계조치 협정을 위반한 것으로 상소기구는 결정을 내린 바 있다. WTO 협정하에서 민영화된 물품에 상계관세를 합법적으로 부과하기 위하여 미국은 국내 상계조치 관련법을 개정하였으며 여러 가지의 효과적인 접근 방법을 모색하여 왔으나 시장원리에 따라 민영화 된 기업으로부터의 수입에 대하여 여전히 상계관세를 부과하여 오고 있다. 이런 미국의 상계조치는 미국이 추구하는 대외통상 정책과 상충될 뿐만 아니라 무역 자유화와 시장 개방을 추구하고자 하는 WTO체제의 노력을 방해할 것이다. 미국은 앞으로 미국 통상정책 및 통상법의 취지와 WTO 협정상의 기본 정신에 부합하는 상계조치 관련법과 시행 절차를 마련해야 할 것이다.

Seismic Behavior of Assembly Joint with CFST Column and H-shaped Steel Beam

Xiushu Qu,Yannan Xie,Guojun Sun,Qingwen Liu,Hui Wang 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.2

Existing concrete-filled steel tubular (CFST) structures are mostly based on cast-in-situ concrete construction technology. The beam-column joint emphasizes the horizontal connection, while the vertical connection of columns is mostly based on a steel tube connection instead of a precast CFST column connection; this is detrimental to the control of the concrete pouring quality and the full assembly of the structure. Thus, the investigation of an assembly joint that enables the full connection between the beam and CFST column is the key to the improvement of the construction quality and the promotion of the development of the assembled structure. This work proposes an assembly joint between an H-shaped steel beam and a CFST column, and the seismic behavior of the joint was investigated by low-cycle loading experiment. The finite element model of the joint was then established by the numerical analysis method. After verifying the rationality of the finite element model, the influences of both the endplate thickness and the bolt diameter on the energy dissipation performance of the joint were investigated via parametric analysis. The results reveal that with the increase of the endplate thickness and the bolt diameter within a certain range, both the bearing capacity and energy dissipation capacity of the joint will be improved. Moreover, the cooperative bearing mechanism of the column connector and concrete can be fully exerted. Thus, these conclusions indicate the feasibility of the use of the proposed assembly joint in practical engineering applications. Finally, the mechanical mechanism of the assembly joint was studied, and the calculation formula of the joint bending capacity was proposed.

Stable Microbial Community and Specific Beneficial Taxa Associated with Natural Healthy Banana Rhizosphere

( Lin Fu ),( Yannan Ou ),( Zongzhuan Shen ),( Beibei Wang ),( Rong Li ),( Qirong Shen ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.10

Banana planting altered microbial communities and induced the enrichment of Fusarium oxysporum in rhizosphere compared with that of forest soil. Diseased plant rhizosphere soil (WR) harbored increased pathogen abundance and showed distinct microbial structures from healthy plant rhizosphere soil (HR). The enriched taxon of Bordetella and key taxon of Chaetomium together with some other taxa showed negative associations with pathogen in HR, indicating their importance in pathogen inhibition. Furthermore, a more stable microbiota was observed in HR than in WR. Taken together, the lower pathogen abundance, specific beneficial microbial taxa and stable microbiota contributed to disease suppression.

Managerial Mechanism Design Theory:The Concept and Framework with Applications in Emergency Management

An Chen,Yannan Wu,Ning Chen 위기관리 이론과 실천 2012 Journal of Safety and Crisis Management Vol.2 No.2

Mechanism design theory (MDT) which gained Nobel Prize in 2007 provides a formal way to mechanism design in Economics. It not only emphasizes on the phenomenon of modern economics, also gives an idea on the engineering side of economic theory, in particular, the implications for economic policy making. Despite the success of MDT in economics, it is difficultly migrated to management field. In managerial practices, especially emergent situation, people cannot make free choice and voluntary exchange due to the fact that some policies are sing-directed or half-compulsory. While the managerial mechanism is actively investigated for specific usages, a less studied issue is to study the unified framework of managerial mechanism which is of major importance to managers. This paper aims to provide a unified framework of managerial mechanism with an attempt to provide some insights into the fundamental of managerial mechanism design. Firstly, we discuss the difference between economical and managerial mechanism design from the perspectives of background, basic hypothesis, and weak obligation characteristic. Afterwards, we propose a unified framework of managerial mechanism design theory, composed of an order seven-tuple and some fundamental design modes. Lastly, we give a case study to show the applicability of the proposed mechanism design theory in emergency management.