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Stress distribution rule of roadway affected by overhead mining in gently inclined coal seams group

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中国有色金属学会会刊：英文版 2011年第S3期21卷 529-535页

作者： KANG Qin-rong1, 2, TANG jian-xin1, 2, HU Hai1, 2, ZHANG Wei-zhong1, 3.1. College of Resource and Environmental Sciences, Chongqing university, Chongqing 40003., china 2. State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing university, Chongqing 40003., china 3. school of Safety Science and Administration, Zhongnan university of economics and Law, Wuhan 43.074, china [a] College of Resource and Environmental Sciences Chongqing University Chongqing 400030 China [b] State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Chongqing 400030 China [c] school of Safety Science and Administration Zhongnan University of Economics and Law Wuhan 430074 China

In light of the severe deformation and destruction of the district raise tunnel in the mining area at the northern part of the Lubanshan colliery, by the theoretic analysis and numerical simulation, both the mining stress distribution in seams group and the deformation and destruction mechanism of floor district raise were investigated. The results show that, at the maximum vertical distance of 40 m, the abutment stress has an influence on the recovery of 2# and 3. coal seam and 8# coal seam at distance of 3. m. As a result, the recovery of 8# is rather than those of 2# or 3. coal seam, which contributes to the deformation and destruction of the district raise surrounding rock. The major factors affecting the abutment stress include the mining depth, mining height, residual gob space, adjacent working faces and short spacing coal seam recovery.

关键词： coal seams group stress distribution district raise surrounding rock deformation and destruction abutment stress

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虚拟企业中核心能力的定性与定量识别

系统工程理论与实践 2002年第5期22卷 48-54页

作者：冯蔚东陈剑清华大学经济管理学院北京100084 清华大学现代管理研究中心北就100084

首先对企业核心能力的概念进行了辨析和界定 ,给出了一个识别核心能力的定性框架 .进一步地 ,根据虚拟企业组建过程的需要 ,提出了一个基于模糊聚类的伙伴企业核心能力的定量识别方法 .最后 ,给出了一个简化的仿真算例。

关键词：虚拟企业核心能力定性定量识别

Technical Notes:STUDIES ON THE VALUE OF SECONDARY MARKET TO THE SUPPLY CHAIN

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Systems Science and Systems Engineering 2003年第3期12卷 360-371页

作者： Ju-liang ZHANG jian chenDepartment of management Science and Engineering{3. of economics and management tsinghua university, beijing 100084, china. tsinghua university Department of Management Science and Engineering School of Economics and Management Beijing China (GRID:grid.12527.33) (ISNI:***)

This paper investigates the impact of a secondary market, where retailers can buy and sell excess inventories, on the supply chain. We develop a two-period model with a single manufacturer and two retailers. At the beginning of the first period the retailers order and receive products from the manufacturer, but at the beginning of the second period, they can trade surplus products between themselves in the secondary market. We investigate the impact of the correlated dependence of retailers' demand on both the quantity effect and the allocation effect under the secondary market. Lastly, we study potential strategies for the manufacturer to increase sales with the existence of the secondary market.

关键词： Supply chain secondary market exchanges market equilibrium

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基于凸情形下在线设备更新问题的竞争分析

系统工程理论与实践 2009年第11期29卷 145-151页

作者：辛春林陈剑刘天亮北京化工大学经济管理学院北京100029 清华大学经济管理学院北京100084

市场以在线的方式给出新设备,决策者必须决定是否更新现有的设备,并确定何时更新?即在已知现在和过去的设备信息和订单信息而对未来信息一无所知情况下,决策如何更新设备完成陆续达到的订单需求.优化目标是使设备更新投资成本与设备运... 详细信息

市场以在线的方式给出新设备,决策者必须决定是否更新现有的设备,并确定何时更新?即在已知现在和过去的设备信息和订单信息而对未来信息一无所知情况下,决策如何更新设备完成陆续达到的订单需求.优化目标是使设备更新投资成本与设备运行成本总和最小.首先讨论了离线设备更新问题,给出了两种算法并分析了算法复杂度.其后,讨论了凸情形下在线设备更新问题,给出了临界值策略,得出了竞争比为6,证明该策略要优于原有的策略.

关键词：在线问题设备更新竞争分析竞争比

基于Swarm的供应链多主体聚集模型及其仿真

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系统仿真学报 2004年第6期16卷 1308-1313页

作者：周庆陈剑清华大学经济管理学院北京100084

供应链是一类典型的复杂适应系统,本文采用一种高级Petri网方法建立基于多主体的供应链模型,着重论述通过子主体代换建立多主体聚集模型的方法与步骤,并给出多主体聚集模型实例。最后,建立了供应链配送渠道系统简化模型,设计了相应的仿... 详细信息

供应链是一类典型的复杂适应系统,本文采用一种高级Petri网方法建立基于多主体的供应链模型,着重论述通过子主体代换建立多主体聚集模型的方法与步骤,并给出多主体聚集模型实例。最后,建立了供应链配送渠道系统简化模型,设计了相应的仿真参数,通过Swarm仿真平台模拟了供应链配送渠道系统的动态组合行为,并对仿真结果进行了分析。

关键词：聚集模型多主体复杂适应系统供应链 Swarm仿真平台

Quantifying the impacts of COVID-19 on Sustainable Development Goals using machine learning models

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Fundamental Research 2024年第4期4卷 890-897页

作者： chenyang Shuai Bu Zhao Xi chen jianguo Liu Chunmiao Zheng Shen Qu jian-Ping Zou Ming xu school of management Science and Real Estate Chongqing UniversityChongqing 400044China bschool for Environment and Sustainability University of MichiganAnn ArborMI 489United Stats Michigan Institute for Computational Discovery&Engineering University of MichiganAnn ArborMI 48109United States College of economics and management Southwest UniversityChongqing 400044China Center for Systems Integration and Sustainability Department of Fisheries and WildlifeMichigan State UniversityEast LansingMI 48824United States Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control School of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China school of management and economics Beijing Institute of TechnologyBeijing 100081China Center for Energy&Environmental Policy Research Beijing Institute of TechnologyBejing 100081China Key Laboratory of jiangxi Province for Persistent Plutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China Department of Civil and Environmental Engineering University of MichiganAnn ArborMI 48109United States

The COvID-19 pandemic has posed severe threats to global sustainable ***,a comprehensive quantitative assessment of the impacts of COVID-19 on Sustainable Development Goals(SDGs)is still *** research quantified the post-COVID-19 SDG progress from 2020 to 2024 using projected GDP growth and population and machine learning models including support vector machine,random forest,and extreme gradient *** results show that the overall SDG performance declined by 7.7%in 2020 at the global scale,with 12 socioeconomic SDG performance decreasing by 3.0%-22.3.and 4 environmental SDG performance increasing by 1.6%-9.2%.By 2024,the progress of 12 SDGs will lag behind for one to eight years compared to their pre-COVID-19 trajectories,while extra time will be gained for 4 environment-related ***,the pandemic will cause more impacts on countries in emerging markets and developing economies than those on advanced economies,and the latter will recover more quickly to be closer to their pre-covID-19 trajectories by ***-COVID-19 economic recovery should emphasize in areas that can help decouple economic growth from negative environmental *** results can help government and non-state stakeholders identify critical areas for targeted policy to resume and speed up the progress to achieve SDGs by 203..

关键词： Sustainable development goals COVID-19 Machine learning Global development Sustainable development assessment

FEEDBACK OF CONTRACTS EFFORTS IN THREE TIERS SUPPLY CHAINS

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FEEDBACK OF CONTRACTS EFFORTS IN THREE TIERS SUPPLY CHAINS

Spatiotemporal Evolution and Linkage Analysis of Mutton Price in Xinjiang

The Fourth International Conference on Systems Science and Systems Engineering(ICSSSE’03.

作者： Ding Ding school of economics and management {3. beijing 100084,P.R.china jian chen school of economics and management {3. beijing 100084,P.R.china

We address three tiers supply chains selling short-life cycle products which consisting of a supplier,a manufacturer (or distributor) and a retailer facing uncertain price-dependent *** first,the wholesale price from the supplier to the manufacturer is *** manufacturer chooses his sales price to the retailer and the retailer need to decide his order quantity and sales prices to the final ***,the manufacturer can introduce contracts to coordinate the two tiers supply chain contained himself and the retailer to improve their *** retailer will order more when the contract goes into ***,the supplier can sale more products (or components) and benefits from the external effort of the contracts in which he does not *** the business cycle repeated,the supplier will attempt to change his wholesale price to maximize his own profit,which contrary affects the contracts effort to the downstream *** phenomena are called feedback of contracts efforts in this paper,which is seldom studied in the former contracts literatures as most of them only consider two tiers supply *** develop models to analyze such feedback in this paper.

关键词： Supply Chain Contracts Coordination Feedback

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Journal of Systems Science and Information 2024年

作者： Yulin YANG jian xu Lean YU school of economics and management University of Chinese Academy of Sciences Business school Sichuan University school of Business Shenzhen Institute of Technology

The mutton industry plays a pivotal role in the animal husbandry industry of Xinjiang Uygur Autonomous Region. To better monitor the volatility movement and risk warning of mutton price, the fluctuation characteristics of mutton prices and the future trend of prices are analyzed systematically. On the one hand, the Hodrick Prescott(HP) filter method is used to analyze the longterm trends and cyclical characteristics of mutton prices in Xinjiang and explored the spatial evolution characteristics of mutton price fluctuations in various regions of Xinjiang. On the other hand, the Threshold Auto-Regressive(TAR) model is used to analyze the linkage relationship between mutton prices and the prices of other livestock products. The empirical results show that(1) the overall volatility of mutton price in Xinjiang is high, showing a trend of rising first, then falling and then rising from the temporal perspective.(2) At the regional level, the price in the south is higher than that of the north, showing a decreasing trend from south to north on the whole from the spatial viewpoint.(3. From the linkage relationship perspective, mutton and beef are complementary in the short term,but they are substitutes each other in the long term. This paper explores the characteristics of mutton price fluctuations in Xinjiang from the single time series of mutton prices and the linkage with other livestock products, which provides a reliable basis for the monitoring and risk warning of mutton price fluctuation.

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Research on the Technology of Virtual Data Private Network Based on 3. Network

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Research on the Technology of Virtual Data Private Network B...