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Relative Performance Evaluation of Competing Crude Oil Prices’ Volatility Forecasting Models: A Slacks-Based Super-Efficiency DEA Model
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作者 Jamal Ouenniche Bing Xu Kaoru Tone 《American Journal of Operations Research》 2014年第4期235-245,共11页
With the increasing number of quantitative models available to forecast the volatility of crude oil prices, the assessment of the relative performance of competing models becomes a critical task. Our survey of the lit... With the increasing number of quantitative models available to forecast the volatility of crude oil prices, the assessment of the relative performance of competing models becomes a critical task. Our survey of the literature revealed that most studies tend to use several performance criteria to evaluate the performance of competing forecasting models;however, models are compared to each other using a single criterion at a time, which often leads to different rankings for different criteria—A situation where one cannot make an informed decision as to which model performs best when taking all criteria into account. In order to overcome this methodological problem, Xu and Ouenniche [1] proposed a multidimensional framework based on an input-oriented radial super-efficiency Data Envelopment Analysis (DEA) model to rank order competing forecasting models of crude oil prices’ volatility. However, their approach suffers from a number of issues. In this paper, we overcome such issues by proposing an alternative framework. 展开更多
关键词 Forecasting CRUDE Oil Prices VOLATILITY performance evaluation Slacks-Based Measure (SBM) Data Envelopment Analysis (DEA) COMMODITY and Energy Markets
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System-Level Performance Evaluation of Very High Complexity Media Applications : A H264/AVC Encoder Case Study 被引量:1
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作者 Hajer Krichene Zrida Abderrazek Jemai +1 位作者 Ahmed C Ammari Mohamed Abid 《International Journal of Communications, Network and System Sciences》 2011年第7期436-446,共11页
Given the substantially increasing complexity of embedded systems, the use of relatively detailed clock cycle-accurate simulators for the design-space exploration is impractical in the early design stages. Raising the... Given the substantially increasing complexity of embedded systems, the use of relatively detailed clock cycle-accurate simulators for the design-space exploration is impractical in the early design stages. Raising the abstraction level is nowadays widely seen as a solution to bridge the gap between the increasing system complexity and the low design productivity. For this, several system-level design tools and methodologies have been introduced to efficiently explore the design space of heterogeneous signal processing systems. In this paper, we demonstrate the effectiveness and the flexibility of the Sesame/Artemis system-level modeling and simulation methodology for efficient peformance evaluation and rapid architectural exploration of the increasing complexity heterogeneous embedded media systems. For this purpose, we have selected a system level design of a very high complexity media application;a H.264/AVC (Advanced Video Codec) video encoder. The encoding performances will be evaluated using system-level simulations targeting multiple heterogeneous multiprocessors platforms. 展开更多
关键词 System-Level performance evaluation Embedded Systems DESIGN Space Exploration Tools the Sesame/Artemis DESIGN Tool a Parallel H.264/AVC Video ENCODER
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Analysis of Office-Teaching Comprehensive Buildings Using a Modified Seismic Performance Evaluation Method
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作者 Hanbo Zhu Changqing Miao Meiling Zhuang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2019年第3期471-491,共21页
Current building design codes allow the appearance of structural and nonstructural damage under design basis earthquakes.The research regarding probabilistic seismic loss estimation in domestic building structure is u... Current building design codes allow the appearance of structural and nonstructural damage under design basis earthquakes.The research regarding probabilistic seismic loss estimation in domestic building structure is urgent.The evaluation in this paper is based on a 11-story reinforced concrete office building,incremental dynamic analysis(IDA)is conducted in Perform 3D program using models capable to simulate all possible limit states up to collapse.Next,the probability distribution of post-earthquake casualties,rebuild costs repair costs and business downtime loss are calculated in PACT software for the studied building considering the modified component vulnerability groups and population flow models.The evaluation procedure can also shed light on other types of buildings in China.For non-typical functional building structures,this article proposes to build a finite element model of structural components and to classify the vulnerability groups based on the construction drawings,and to supply and improve the vulnerability library of appendages in FEMA P-58 according to the actual situation.In this way,the application scope of building seismic performance evaluation can be expanded. 展开更多
关键词 A MODIFIED SEISMIC capacity ASSESSMENT method frame-shear wall structure incremental dynamic analysis(IDA) SEISMIC performance ASSESSMENT ANALYSIS software(PACT)
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Establishment and application of performance evaluation model for collection and transportation system of municipal solid waste
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作者 彭绪亚 林晓东 +2 位作者 贾传兴 王渝昆 黄媛媛 《Journal of Central South University》 SCIE EI CAS 2009年第S1期351-356,共6页
On the basis of analyzing the typical waste collection and transportation mode,the evaluation index system for performance of the waste collection and transportation system was proposed with three grades,which related... On the basis of analyzing the typical waste collection and transportation mode,the evaluation index system for performance of the waste collection and transportation system was proposed with three grades,which related to six factors,such as economic evaluation,high efficient evaluation,environmental impact assessment,resource evaluation,evaluation of security and emergency,evaluation of management and society. With the performance evaluation theory,the performance evaluation model of waste collection and transportation system was constructed,which quantified the grading standard of index and determined the index weight in analytic hierarchy process (AHP). After evaluating the waste collection and transportation system of the main districts of Chongqing city,the results show that the it has an excellent performance evaluation grade with very high performance level of three indices involving evaluation of management and society,environmental impact assessment,evaluation of security and emergency and quite low performance level of two indices that include high efficient evaluation and economic evaluation. 展开更多
关键词 MUNICIPAL solid waste COLLECTION and transportation SYSTEM performance evaluation index SYSTEM ANALYTIC HIERARCHY process
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Development of Performance-Based Tunnel Evaluation Methodology and Performance Evaluation of Existing Railway Tunnels
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作者 Sadao Kimura Takashi Kitani Atsushi Koizumi 《Journal of Transportation Technologies》 2012年第2期113-128,共16页
The concept of performance-based design, which mainly focuses on mechanical performance, has become the international standard, as in the case for ISO. The standardization of tunnel design has not been achieved becaus... The concept of performance-based design, which mainly focuses on mechanical performance, has become the international standard, as in the case for ISO. The standardization of tunnel design has not been achieved because it requires integration of separate specialized fields, such as geotechnical engineering, structural engineering and concrete engineering. It is also required to clarify performance-based criteria for tunnel structures to suit specific use purposes (objectives), establish the concept of survey, planning, design, construction and maintenance based on such criteria, and develop proper management systems for operation and maintenance to suit specific tunnel use purposes. To this end, it is vital to develop a methodology for evaluating and verifying the performance of existing tunnels. This paper presents a new concept of performance requirements for tunnel structures and describes the method of quantitatively evaluating the total performance of existing tunnels in relation to the required performance, assuming the total performance to be based on the Analysis Hierarchy Process. 展开更多
关键词 TUNNEL performance CRITERION Life CYCLE DESIGN performance-Based DESIGN ASSET Management Maintenance Analysis HIERARCHY Process
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Moving Personal-Cell Network: Characteristics and Performance Evaluation
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作者 Syed Tariq Shah Minsu Shin +3 位作者 Young Min Kwon JaeSheung Shin Ae-Soon Park Min Young Chung 《China Communications》 SCIE CSCD 2018年第12期159-173,共15页
Recent years have witnessed a huge demand for ubiquitous communications services from continuously moving users. In order to provide seamless network services to high-mobility users, one of the promising solution prop... Recent years have witnessed a huge demand for ubiquitous communications services from continuously moving users. In order to provide seamless network services to high-mobility users, one of the promising solution proposed by 3 GPP is the deployment of moving-relays. In this article, we introduce the concept of Moving-Personal-Cell(mPC), which is a type of moving-relays. mPC is a user-centric network, which aims to provide reliable network services to moving users. A mPC receives data-traffic from eNB and its neighboring mPCs via wireless backhaul and sidehual links respectively and forwards the received data to its serving users. In addition to this, mPC can also increase the network capacity by caching and distributing the popular contents to its serving users. Besides these pros, the mPC also has some limitations, as its performance is highly affected by cross-tier and co-tier interferences. In this article, we analyze the effect of these interferences on mPCs performance. Our results show that the performance of mPC network is equally affected by the capacity of wireless backhaul, sidehaul, and access links. Moreover, since mPCs accommodate data traffic from wireless backhaul, sidehaul links, and content cache, their performance is also affected by the ratio of data-traffic delivered via these links. 展开更多
关键词 heterogeneous NETWORKS MOVING SMALL CELLS fixed SMALL CELLS MOVING cache NETWORK performance evaluation next generation NETWORKS
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Efficient structural seismic performance evaluation method using improved endurance time analysis 被引量:3
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作者 Li Shuang Liu Kun +2 位作者 Liu Xiangyang Zhai Changhai Xie Fengwei 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第4期795-809,共15页
Evaluation of structural performance under seismic excitations from low intensity to high intensity is essential to verify the seismic resistant capacity of a structure, and usually carried out by the incremental dyna... Evaluation of structural performance under seismic excitations from low intensity to high intensity is essential to verify the seismic resistant capacity of a structure, and usually carried out by the incremental dynamic analysis (IDA) method or pushover method. The recently developed endurance time (ET) method is another method that uses dynamic pushover excitations, i.e., endurance time acceleration function, to obtain results similar to those obtained by IDA or pushover methods with low computational cost and acceptable accuracy. This study proposes an improvement on the ET method by considering more restrictions for both the elastic and inelastic response spectra in the generation procedure, and by specifying a target duration. Four reinforced concrete frame structures with 4, 8, 12, and 16 stories are adopted to verify the accuracy of the improved method. Comparison of the results obtained by the proposed method, the ET method and the IDA method shows that the improved method has a higher accuracy than the ET method. For evaluation of structural responses under specifi c ground motion intensity, which is typically required in seismic design codes, the results obtained by the proposed method are compared with fi ve commonly used ground motion selection methods, and shows the proposed method provides acceptable accuracy for engineering applications. 展开更多
关键词 SEISMIC performance evaluation ENDURANCE TIME method INELASTIC response spectra target DURATION
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Public Transit Performance Evaluation Using Data Envelopment Analysis and Possibilities of Enhancement
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作者 Sunil Sujakhu Wenquan Li 《Journal of Transportation Technologies》 2020年第2期89-109,共21页
This study evaluates the operational performance of all routes of Sajha Bus Yatayat operating inside Kathmandu valley using Data Envelopment Analysis (DEA) in terms of efficiency and effectiveness score. This approach... This study evaluates the operational performance of all routes of Sajha Bus Yatayat operating inside Kathmandu valley using Data Envelopment Analysis (DEA) in terms of efficiency and effectiveness score. This approach allows us to access the relative performance of transit system in absence of historical data and research to compare with. To explore the possibility of enhancing the performance, scenarios were created for relatively underperforming routes and long route problem by changing the most important input variable and output variables accordingly with regression model where it was relevant. Partial Least Squares (PLS) regression was used to determine the most influential input variables to the output variables. DEA was conducted to access the performance of all routes under these scenarios. Underperforming routes except the longest route under the first set of scenarios, emerge to be better performing efficiently without considerable negative deviation in effectiveness. The result of second set of scenarios for long route problem suggests that the longest route’s performance can be enhanced significantly upon proper route alignment. Scenarios development and evaluation can help lead transit companies to explore the strategies to facilitate operational performance enhancement. 展开更多
关键词 PUBLIC TRANSIT System Data Envelopment Analysis performance Evalua-tion Partial Least SQUARES Regression
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Test Apparatus for Performance Evaluation of Compressed Air End-Use Applications
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作者 Vishal Sardeshpande Vijay Patil Cherat Murali 《Open Journal of Energy Efficiency》 2013年第1期29-33,共5页
Compressed air is an integral utility part of industrial utility systems. Any improvement in compressed air system will lead to reduction in utility cost. The effectiveness of utilization side of compressed air is usu... Compressed air is an integral utility part of industrial utility systems. Any improvement in compressed air system will lead to reduction in utility cost. The effectiveness of utilization side of compressed air is usually dependent upon operator’s discretion. There are no performance testing methods available for testing existing end use equipments. A test apparatus for estimation of compressed air flow based on measurement of pressure reduction in a fixed volume cylinder in a given time is developed. The test apparatus is easy to build and simple to operate in an industrial environment. This can be used for measuring performance of any pneumatic end-use equipment and for benchmarking the performance. The test apparatus was used in a foundry for quantifying the performance of the old and new blow guns. 展开更多
关键词 Compressed Air UTILIZATION SIDE Test Apparatus performance Estimation PNEUMATIC Equipment PNEUMATIC BLOW GUN
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Enterprise Service Bus: A Performance Evaluation 被引量:1
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作者 Sanjay P. Ahuja Amit Patel 《Communications and Network》 2011年第3期133-140,共8页
The flexibility offered by an Enterprise Service Bus (ESB) in enabling various applications to exchange data makes it a very important middleware layer that is responsible for transporting data in a Service-Oriented A... The flexibility offered by an Enterprise Service Bus (ESB) in enabling various applications to exchange data makes it a very important middleware layer that is responsible for transporting data in a Service-Oriented Architecture (SOA). The popularity of the ESB has given rise to a number of commercial off the shelf (COTS) products as well as open source ESBs. In this study, we evaluated three open source ESBs and compared them both qualitatively and quantitatively. The empirical results were statistically tested to determine the statistical significance of the results. 展开更多
关键词 ENTERPRISE SERVICE BUS SERVICE Oriented Architecture Web SERVICE MULE WSO2 APACHE SERVICEMIX performance
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Synthesis of new EVA graft copolymer and its pour point depressant performance evaluation for Daqing crude oil 被引量:4
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作者 伍丽娟 张帆 +1 位作者 关中原 郭淑凤 《Journal of Central South University》 SCIE EI CAS 2008年第S1期488-491,共4页
EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar ... EVA was widely used as the pour point depressant for waxy oil.In order to improve its effect,some graft copolymerization methods should be used to modify EVA's property.EVA has long side chains and nitrogen polar groups to enforce its adaptability and effect of waxy oil.The pure amine,maleicanhydride and their reaction product were tested using infrared spectra and the NMR spectral.The results show that when the modified EVA is added into oil,the wax deposits not only on the main chain but also on the side chains.And the polar groups have the function to avoid and resist the wax crystals connection each other to form the net.Using the reaction product of maleicanhydride and high carbonic amine(C12,C16,C18 amine) as the graft component,the toluene as the solvent and BPO as the initiator,the series of new EVA graft copolymer with special side chains are prepared under controlled condition.A series of cylmaleimide exist indeed in modified EVA and the highest grafted percentage is 18.8%.EVA-16,the new graft copolymer,is better than EVA about 3 ℃ more in depressant the pour-point of Daqing waxy crude oil. 展开更多
关键词 MODIFICATION EVA COPOLYMER POUR POINT depressants performance evolution DAQING crud
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Simplified stiffness-based approach for seismic performance evaluation of moment-resisting frame
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作者 于琦 孟少平 +1 位作者 吴京 孙巍巍 《Journal of Southeast University(English Edition)》 EI CAS 2009年第2期241-246,共6页
Based on the concept of stiffness degradation, a damage index of the whole frame and the storey is proposed for the frame seismic performance evaluation. The index is compatible with the non-linear static analysis (e... Based on the concept of stiffness degradation, a damage index of the whole frame and the storey is proposed for the frame seismic performance evaluation. The index is compatible with the non-linear static analysis (e. g. the pushover analysis), and the structural damage is considered via plastic hinges. Simultaneously, a practical approach is developed to obtain the relationships between the proposed index and earthquake intensities based on the capacity spectrum method. The proposed index is then illustrated through two low-rise reinforced concrete frames, and it is also compared with some other indices. The results indicate that the proposed index is on the safe side and not sensitive to the lateral load pattern. The storey index is helpful to reflect the storey damage and to uncover the position of the weak storey. Finally, the relationship between performance levels and damage index values is also proposed through statistical analysis for the performance-based seismic evaluation. 展开更多
关键词 damage index seismic evaluation capacity spectrum method FRAME lateral load pattern pushover analysis performance level stiffness degradation
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Waste Biomass Gasification Simulation Using Aspen Plus: Performance Evaluation of Wood Chips, Sawdust and Mixed Paper Wastes 被引量:3
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作者 Sahar Safarian Christiaan Richter Runar Unnthorsson 《Journal of Power and Energy Engineering》 2019年第6期12-30,共19页
Biomass is one of the most widely available energy sources and gasification is a thermal conversion process where biomass is transformed into a fuel gas with a gasifying agent. In this paper by using ASPEN Plus, a new... Biomass is one of the most widely available energy sources and gasification is a thermal conversion process where biomass is transformed into a fuel gas with a gasifying agent. In this paper by using ASPEN Plus, a new steady state simulation model for down draft waste biomass gasification was developed. The model that is stoichiometric equilibrium-based is proposed to be used for optimization of the gasifier performance. Prediction accuracy of the model is validated by comparing with available experimental and modeling results in other literature. Then the model is used for comparative analysis of the gasification performance of sawdust, wood chips and mixed paper wastes. In the model, the operating parameters of temperature and equivalence ratio (ER) have been varied over wide range and their effect on syngas composition, syngas yield, low heating value (LHV) of syngas and cold gas efficiency (CGE) has been investigated. Raise in temperature increases the production of CO and H2 which leads to higher syngas yield, LHV and CGE. However, increasing ER decreases the production of CO and H2 which results lessens in LHV and CGE but syngas yield continuously increases because more oxygen is available for biomass reactions at high ER. The optimal values of CO and H2 mole fraction and CGE of sawdust, wood chips and mixed paper wastes are located at 900&degC, 1000&degC and 1000&degC, respectively and ER range is between 0.20 - 0.35 regardless of the kind of biomass which is used as the feedstock. 展开更多
关键词 WASTE Biomass GASIFICATION SIMULATION Model GASIFIER performance WASTE to Energy
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Hardware Performance Evaluation of SHA-3 Candidate Algorithms 被引量:1
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作者 Yaser Jararweh Lo’ai Tawalbeh +1 位作者 Hala Tawalbeh Abidalrahman Moh’d 《Journal of Information Security》 2012年第2期69-76,共8页
Secure Hashing Algorithms (SHA) showed a significant importance in today’s information security applications. The National Institute of Standards and Technology (NIST), held a competition of three rounds to replace S... Secure Hashing Algorithms (SHA) showed a significant importance in today’s information security applications. The National Institute of Standards and Technology (NIST), held a competition of three rounds to replace SHA1 and SHA2 with the new SHA-3, to ensure long term robustness of hash functions. In this paper, we present a comprehensive hardware evaluation for the final round SHA-3 candidates. The main goal of providing the hardware evaluation is to: find the best algorithm among them that will satisfy the new hashing algorithm standards defined by the NIST. This is based on a comparison made between each of the finalists in terms of security level, throughput, clock frequancey, area, power consumption, and the cost. We expect that the achived results of the comparisons will contribute in choosing the next hashing algorithm (SHA-3) that will support the security requirements of applications in todays ubiquitous and pervasive information infrastructure. 展开更多
关键词 INFORMATION SECURITY SECURE HASH Algorithm (SHA) HARDWARE performance FPGA
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Management Performance Evaluation Model of Korean Construction Firms
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作者 Donghoon Lee Manki Kim Sunkuk Kim 《Journal of Building Construction and Planning Research》 2013年第2期27-38,共12页
Corporate management performance evaluation currently focuses on financial aspects;however, it is necessary to identify and manage elements that contribute to increased economic values in the long run. When it comes t... Corporate management performance evaluation currently focuses on financial aspects;however, it is necessary to identify and manage elements that contribute to increased economic values in the long run. When it comes to construction firms, most previous research did not cover weighting and estimation approaches for non-financial elements that ultimately influence financial status. In this research, the objective is to develop a management performance evaluation model for Korean construction firms. The model includes financial factors and non-financial factors. This research investigated actual data from Korean construction firmsandclassifiedtheir characteristics. This study is performed in two steps. First, this study derives KPIs for performance measurement techniques and weights the KPIs. And then, it applies the performance data of construction firms to the technique. The findings of this study show that Korean construction firms consider customers to be the foremost priority, converse to previous research which argued that the internal business process was the top priority. The performance measurement results can be fed back into strategies and plans to shed light on issues, reflect on management plans for subsequent years and modify mid to long-term strategies. Therefore, the developed model can help decision-makers effectively revise their management plans. 展开更多
关键词 Management performance evaluation KEY performance INDICATORS BALANCED SCORECARD AHP Fuzzy
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Research on the Internal Talent Training Path and Performance Evaluation Mechanism of New R&D Institutions in Zhejiang Province
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作者 Xiangjiang Li 《Proceedings of Business and Economic Studies》 2024年第2期100-105,共6页
New research and development(R&D)institutions are an important part of the national innovation system,playing an important role in promoting the transformation of scientific and technological achievements.In recen... New research and development(R&D)institutions are an important part of the national innovation system,playing an important role in promoting the transformation of scientific and technological achievements.In recent years,new R&D institutions have gradually become the driving force of innovation-driven development in China.Taking new R&D institutions in Zhejiang Province as the research object,this paper studies the internal talent training path and performance evaluation mechanism of new R&D institutions in Zhejiang Province by using the literature research method,comparison method,case verification method,and other methods.The investigation results show that there are problems such as lack of material and spiritual support and neglect of the absorption of local talents in the internal talent training,and there are problems such as unclear standards,insufficient data,and opaque processes in the performance evaluation mechanism,which greatly affect the establishment and improvement of the performance evaluation mechanism.Given the above problems,this paper puts forward a forward-looking,oriented,flexible,and compatible talent training path and performance evaluation mechanism,hoping to optimize the effective internal talent training path of new R&D institutions,improve the evaluation performance,and promote healthy development of new R&D institutions in Zhejiang Province. 展开更多
关键词 INNOVATION New R&D institutions Zhejiang Province Talent cultivation performance evaluation mechanism
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Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams
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作者 Zahra Ramezandoust Abbas Tajaddini Panam Zarfam 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第3期691-712,共22页
Replaceable flexural and shear fuse-type coupling beams are used in hybrid coupled shear wall(HCSW)systems,enabling concrete buildings to be promptly recovered after severe earthquakes.This study aimed to analytically... Replaceable flexural and shear fuse-type coupling beams are used in hybrid coupled shear wall(HCSW)systems,enabling concrete buildings to be promptly recovered after severe earthquakes.This study aimed to analytically evaluate the seismic behavior of flexural and shear fuse beams situated in short-,medium-and high-rise RC buildings that have HCSWs.Three building groups hypothetically located in a high seismic hazard zone were studied.A series of 2D nonlinear time history analyses was accomplished in OpenSees,using the ground motion records scaled at the design basis earthquake level.It was found that the effectiveness of fuses in HCSWs depends on various factors such as size and scale of the building,allowable rotation value,inter-story drift ratio,residual drift quantity,energy dissipation value of the fuses,etc.The results show that shear fuses better meet the requirements of rotations and drifts.In contrast,flexural fuses dissipate more energy,but their sectional stiffness should increase to meet other requirements.It was concluded that adoption of proper fuses depends on the overall scale of the building and on how associated factors are considered. 展开更多
关键词 hybrid coupled shear wall steel fuse coupling beam shear and flexural fuse nonlinear dynamic analysis seismic performance
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Research on Scientific Research Performance Evaluation in Colleges and Universities Based on Malmquist Index
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作者 Guopeng Wang Chun Wang 《Review of Educational Theory》 2019年第4期25-31,共7页
Scientific research is of vital importance to the development of colleges and universities.Scientific evaluation of the scientific research performance of colleges and universities,especially the study of their dynami... Scientific research is of vital importance to the development of colleges and universities.Scientific evaluation of the scientific research performance of colleges and universities,especially the study of their dynamic performance in different time ranges,can not only promote the progress of scientific research in colleges and universities,but also contribute to the rational allocation of national educational resources.Based on the Malmquist index,using the panel data of the five-year period from 2012 to 2016,this paper evaluates the changes in the research performance of China’s colleges and universities,analyzes the influencing factors of total factor productivity changes from three perspectives of time series,comparison of colleges and universities,and regional analysis,and proposes countermeasures and suggestions. 展开更多
关键词 COLLEGES and UNIVERSITIES SCIENTIFIC RESEARCH Efficiency evaluation MALMQUIST INDEX
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Development and Performance Evaluation of Self-Generating Enhanced Foam Water Plugging System 被引量:1
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作者 Jiexiang Wang Chang Liu Guoyu Chu 《Journal of Power and Energy Engineering》 2019年第11期47-54,共8页
For the waterflooding of late development on an offshore oilfield has become worse, and some wells group has entered into high water cut-off period, water plugging work becomes particularly important. Due to the limit... For the waterflooding of late development on an offshore oilfield has become worse, and some wells group has entered into high water cut-off period, water plugging work becomes particularly important. Due to the limited construction of offshore oilfield, space water supply difficulties, and stability of plugging agent, self-generating enhanced foam has been designed as the aimed block plugging system. The formula is determined as: 23.25% of NH4Cl + 30% of NaNO2 + 0.1% of catalyst + 0.6% of COSL-3 foaming agent + 0.25% of HS-type HPAM foam stabilizer. Measurement point of pipe with permeability of 0.5 μm2 and 2 μm2 has been used in the plugging and EOR experiments. The experiments show that this system has the selective plugging effect for the heterogeneous formation, especially for middle and posterior part of high permeability formation, and the recovery rate of low permeability pipe is enhanced up to 32.15%. 展开更多
关键词 Self-Generating ENHANCED Foam BLOCKING LOCATION Plugging performance WATER Plugging
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Reservoir water effects on earthquake performance evaluation of Torul Concrete-Faced Rockfill Dam
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作者 Alemdar BAYRAKTAR Murat Emre KARTAL Hasan Basri BASAGA 《Water Science and Engineering》 EI CAS 2009年第1期43-57,共15页
This study presents earthquake performance analysis of the Torul Concrete-Faced Rockfill (CFR) Dam with two-dimensional dam-soil and dam-soil-reservoir finite element models. The Lagrangian approach was used with fl... This study presents earthquake performance analysis of the Torul Concrete-Faced Rockfill (CFR) Dam with two-dimensional dam-soil and dam-soil-reservoir finite element models. The Lagrangian approach was used with fluid elements to model impounded water. The interface elements were used to simulate the slippage between the concrete face slab and the rockfill. The horizontal component of the 1992 Erzincan earthquake, with a peak ground acceleration of 0.515g, was considered in time-history analysis. The Drucker-Prager model was preferred in nonlinear analysis of the concrete slab, rockfill and foundation soil. The maximum principal stresses and the maximum displacements in two opposite directions were compared by the height of the concrete slab according to linear time-history analysis to reveal the effect of reservoir water. The changes of critical displacements and principal stresses with time are also shown in this paper. According to linear and nonlinear time-history analysis, the effect of the reservoir water on the earthquake performance of the Torul CFR Dam was investigated and the possible damage situation was examined. The results show that the hydrodynamic pressure of reservoir water leads to an increase in the maximum displacements and principal stresses of the dam and reduces the earthquake performance of the dam. Although the linear time-history analysis demonstrates that the earthquake causes a momentous damage to the concrete slab of the Torul CFR Dam, the nonlinear time-history analysis shows that no evident damage occurs in either reservoir case. 展开更多
关键词 earthquake performance evaluation concrete-faced rockfill dam dam-soil-reservoir interaction Drucker-Prager model interface element Lagrangian approach nonlinear time-history analysis
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