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施工进度 3

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Schedule Compression Impact on Construction Project Safety

Curt Webb,Lu Gao,Ling-guang Song

《工程管理前沿（英文）》 2015年 第2卷 第4期   页码 344-350 doi: 10.15302/J-FEM-2015059

摘要： Many construction projects are met with stringent timelines or the threat of exorbitant liquidated damages. In addition, construction schedulers are frequently forced to incorporate aggressive schedule compression techniques. As already discussed by previous researchers, these schedule compression techniques have direct impacts on project productivity and quality defects. Researchers have also pointed out that schedule compression will affect safety incidents such as Occupational Safety & Health Administration recordable injuries and near misses over long project durations. However, most of the existing studies treated safety as a subcategory of project productivity and project quality, and minimal research has been done to directly quantify the effect of schedule compression on safety at the project level. Therefore, in this research, we conducted a survey and statistical analysis to investigate the relationship between schedule compression and safety in construction projects. We interviewed various members of the Houston construction community from both industrial and non-industrial roles. Statistical analysis was used to identify factors that have significant impacts on the occurrence of safety incidents at an industry specific level.

关键词： construction safety     schedule compression     overtime     work shift     Hurdle model    

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Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1415-1425 doi: 10.1007/s11709-021-0786-9

摘要： To study the behavior of coral aggregate concrete (CAC) column under axial and eccentric compression, the compression behavior of CAC column with different types of steel and initial eccentricity (ei) were tested, and the deformation behavior and ultimate bearing capacity (Nu) were studied. The results showed that as the ei increases, the Nu of CAC column decreases nonlinearly. Besides, the steel corrosion in CAC column is severe, which reduces the steel section and steel strength, and decreases the Nu of CAC column. The durability of CAC structures can be improved by using new organic coated steel. Considering the influence of steel corrosion and interfacial bond deterioration, the calculation models of Nu under axial and eccentric compression were presented.

关键词： coral aggregate concrete column     axial compression     eccentric compression     steel corrosion     calculation model    

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Behavior of dam concrete under biaxial compression-tension and triaxial compression-compression-tension

WANG Huailiang, SONG Yupu

《结构与土木工程前沿（英文）》 2008年 第2卷 第4期   页码 323-328 doi: 10.1007/s11709-008-0043-5

摘要： In order to meet the requirement for nonlinear analysis and design of mass concrete structures, the deformation behavior and strength of three-graded concrete specimens 250 mm × 250 mm × 400 mm with a maximum aggregate size of 80 mm and the corresponding wet-screened concrete specimens 150 mm × 150 mm × 300 mm with a maximum aggregate size of 40 mm were studied experimentally. Specimens subjected to biaxial compression-tension (C-T) and triaxial compression-compression-tension (C-C-T) stress states. Test data indicate that both the deformation and strength of the mass concrete specimens are lower than those of the corresponding wet-screened concrete small specimens, but the initial tangent modulus of the stress-strain curve of the former is greater than that of the latter. Test results show that the wet-screened effect and size effect of the specimens under complex stress states are obvious such that these should be considered in the design of mass concrete structures. In addition, respective failure criteria for mass concrete in principal stress space and octahedron stress space are proposed.

关键词： requirement     wet-screened concrete     compression-tension     maximum aggregate     principal    

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The origins of schedule management: the concepts used in planning, allocating, visualizing and managing

Lynda M. BOURNE, Patrick WEAVER

《工程管理前沿（英文）》 2018年 第5卷 第2期   页码 150-166 doi: 10.15302/J-FEM-2018012

摘要： Getting the in the at the has always been a major organizational challenge. In ancient times this process seems to have been accomplished based on the scheme of arrangements being contained in the leader’s mind and instructions communicated verbally. Modern approaches to solving the twin challenges of first thinking through the ‘plan’ and then communicating the plan to the people who need to do ‘ ’ use sophisticated graphics, charts, diagrams, and computations. This paper traces the development of the concepts most project managers take for granted including bar charts and critical path schedules from their origins (which are far earlier than most people think) through to the modern day. The first section of the paper looks at the development of concepts that allow the visualization of time and other data. The second looks at the shift from static representations to dynamic modeling through the emergence of computers, dynamic calculations and integrated data from the 1950s to the present time.

关键词： time management     scheduling     CPM     PERT     Gantt     Critical Path     bar chart    

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Detection of schedule delay risk of empirical construction projects

Tsegay GEBREHIWET, Hanbin LUO

《工程管理前沿（英文）》 2018年 第5卷 第2期   页码 251-267 doi: 10.15302/J-FEM-2018086

摘要： In Ethiopian construction projects, schedule delay risk is a predominant issue because it is not properly addressed. Although several studies have been focused on the various effects of risk in construction projects, limited efforts have been made to investigate the typical and the overall schedule delay risk. In this study, our aim is to detect the typical and overall schedule delay risk throughout the construction project lifecycle, which consists of the pre-construction, construction, and post-construction stages, and compare the stages with each other. Common criteria, sub-criteria, and attributes were developed for all alternatives for the purpose of making a risk decision. The methodology that was followed integrated the multiple-criteria decision-making (MCDM) model of fuzzy analytic hierarchy process comprehensive evaluation (FAHPCE) and the relative important index (RII). Data were collected from 77 participants, who were selected through purposive sampling from different contracting organizations in Ethiopian construction projects by means of questionnaires that were distributed to experienced experts. The findings showed that there is a typical delay risk either in the type or in the level of the different construction activities. Consequently, the most influenced alternative is the construction stage because of the high-risk responsibility, resource, and contract condition related criteria. The post-construction stage was the second most influenced stage because of the high-risk responsibility-related criteria. The pre-constructed stage was the least influenced stage that consist high-risk criteria of responsibility, resource, and contract condition related. These differences provided noteworthy information about risk mitigation in construction projects by identifying the exact risk level on specific activity to make appropriate decision.

关键词： fuzzy analytic hierarchy process comprehensive evaluation     construction project     detection of delay risk     relative important index    

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Effects of compression ratio on the combustion characteristics of a homogeneous charge compression ignition

SONG Ruizhi, ZHOU Longbao, LIU Shenghua, LI Wei, HU Tiegang

《能源前沿（英文）》 2007年 第1卷 第4期   页码 463-467 doi: 10.1007/s11708-007-0068-0

摘要： The effects of homogeneous charge compression ignition (HCCI) engine compression ratio on its combustion characteristics were studied experimentally on a modified TY1100 single cylinder engine fueled with dimethyl ether. The resul

关键词： homogeneous     cylinder     combustion     compression     dimethyl    

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Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

《能源前沿（英文）》 2009年 第3卷 第4期   页码 432-439 doi: 10.1007/s11708-009-0050-9

摘要： A detailed chemical dynamical mechanism of oxidation of n-heptane was implemented into kiva-3 code to study the ignition mechanism of a high-temperature, high-pressure, three-dimensional-space, transient turbulent, non-homogeneous, mono-component fuel in the engine. By testing the quantity of the heat released by the chemical reaction within the cylinder cell, the elementary reaction showing an obvious increase in the cell temperature was defined as ignition reaction and the corresponding cell as ignition position. The main pathway of the ignition reaction was studied by using the reverse deducing method. The result shows that the ignition in the engine can be divided into low-temperature ignition and high-temperature ignition, both of which follow the same rule in releasing heat, called the impulse heat releasing feature. Low-temperature ignition reaction, whose ignition reaction is c5h9o1-4=ch3cho+c3h5-a, follows the oxidation mechanism, while high-temperature ignition reaction, whose ignition reaction is c2h3o1-2=ch3co, follows the decomposition mechanism. No matter which ignition it is in, the chemical reaction that restrains the ignition reaction from lasting is the deoxidization reaction of alkylperoxy radicals.

关键词： compression-ignition engine     ignition mechanism     elementary reaction     n-heptane    

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Three-dimensional numerical simulation for plastic injection-compression molding

Yun ZHANG, Wenjie YU, Junjie LIANG, Jianlin LANG, Dequn LI

《机械工程前沿（英文）》 2018年 第13卷 第1期   页码 74-84 doi: 10.1007/s11465-018-0490-1

摘要：

Compared with conventional injection molding, injection-compression molding can mold optical parts with higher precision and lower flow residual stress. However, the melt flow process in a closed cavity becomes more complex because of the moving cavity boundary during compression and the nonlinear problems caused by non-Newtonian polymer melt. In this study, a 3D simulation method was developed for injection-compression molding. In this method, arbitrary Lagrangian-Eulerian was introduced to model the moving-boundary flow problem in the compression stage. The non-Newtonian characteristics and compressibility of the polymer melt were considered. The melt flow and pressure distribution in the cavity were investigated by using the proposed simulation method and compared with those of injection molding. Results reveal that the fountain flow effect becomes significant when the cavity thickness increases during compression. The back flow also plays an important role in the flow pattern and redistribution of cavity pressure. The discrepancy in pressures at different points along the flow path is complicated rather than monotonically decreased in injection molding.

关键词： injection-compression molding     simulation     injection molding     melt flow     cavity pressure    

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基于4D CAD的大型桥梁施工进度系统仿真研究

张正峰,付金强,吴康新,张发瑜

《中国工程科学》 2006年 第8卷 第1期   页码 63-66

摘要：

随着桥梁建设的发展，传统横道图与网络图已成为施工管理水平提高的制约因素。将面向对象的复杂工程系统仿真方法与CAD数字建模方法相结合，将桥梁的3D整体模型和施工进度相链接，提出了基于4D CAD的桥梁施工系统仿真思想，使施工过程的动态可视化与直观分析优化后的施工进度成为可能。以Visual C++作为仿真平台，设计编制了桥梁施工4D CAD可视化仿真软件。研究成果在某斜拉桥工程施工组织设计中得到成功应用，验证了基于4D CAD的大型桥梁可视化仿真方法在斜拉桥施工进度分析与优化方面的实用性和优越性。

关键词： 施工进度     系统仿真     4D CAD     斜拉桥    

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Improvement of engine performance with high compression ratio based on knock suppression using Miller

Haiqiao WEI, Jie YU, Lei ZHOU

《能源前沿（英文）》 2019年 第13卷 第4期   页码 691-706 doi: 10.1007/s11708-019-0621-3

摘要： In theory, high compression ratio has the potential to improve the thermal efficiency and promote the power output of the SI engine. However, the application of high compression ratio is substantially limited by the knock in practical working process. The objective of this work is to comprehensively investigate the application of high compression ratio on a gasoline engine based on the Miller cycle with boost pressure and split injection. In this work, the specific optimum strategies for CR10 and CR12 were experimentally investigated respectively on a single cylinder DISI engine. It was found that a high level of Miller cycle with a higher boost pressure could be used in CR12 to achieve an effective compression ratio similar to CR10, which could eliminate the knock limits at a high compression ratio and high load. To verify the advantages of the high compression ratio, the fuel economy and power performance of CR10 and CR12 were compared at full and partial loads. The result revealed that, compared with CR10, a similar power performance and a reduced fuel consumption of CR12 at full load could be achieved by using the strong Miller cycle and split injection. At partial load, the conditions of CR12 had very superior fuel economy and power performance compared to those of CR10.

关键词： high compression ratio     knock     Miller cycle     split injection     engine performance    

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Efficient controller area network data compression for automobile applications

Yu-jing WU,Jin-Gyun CHUNG

《信息与电子工程前沿（英文）》 2015年 第16卷 第1期   页码 70-78 doi: 10.1631/FITEE.1400136

摘要： Controller area networks (CANs) have been designed for multiplexing communication between electronic control units (ECUs) in vehicles and many high-level industrial control applications. When a CAN bus is overloaded by a large number of ECUs connected to it, both the waiting time and the error probability of the data transmission are increased. Thus, it is desirable to reduce the CAN frame length, since the duration of data transmission is proportional to the frame length. In this paper, we present a CAN message compression method to reduce the CAN frame length. Experimental results indicate that CAN transmission data can be compressed by up to 81.06% with the proposed method. By using an embedded test board, we show that 64-bit engine management system (EMS) CAN data compression can be performed within 0.16 ms; consequently, the proposed algorithm can be successfully used in automobile applications.

关键词： Controller area network (CAN)     Electronic control units (ECUs)     Data compression     Signal rearrangement    

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Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

《能源前沿（英文）》 2019年 第13卷 第1期   页码 185-192 doi: 10.1007/s11708-017-0452-z

摘要： Solar absorption-subcooled compression hybrid refrigeration system is a new type of efficient and economical solar refrigeration device which always meets the demand of cooling load with the change of solar irradiance. The performance of the hybrid system is higher due to the improvement of evaporator temperature of absorption subsystem. But simultaneously, the variation of working process as well as performance is complicated since the absorption and compression subsystems are coupled strongly. Based on the measured meteorological data of Guangzhou, a subtropical city in south China, a corresponding parametric model has been developed for the hybrid refrigeration system, and a program written by Fortran has been used to analyze the performance of the hybrid system under different external conditions. As the condensation temperature ranges from 38°C to 50°C, the working time fraction of the absorption subsystem increases from 75% to 85%. Besides, the energy saving fraction also increases from 5.31% to 6.02%. The average COP of the absorption subsystem is improved from 0.366 to 0.407. However, when the temperature of the absorption increases from 36°C to 48°C, the average COP of hybrid system decreases from 2.703 to 2.312. Moreover, the working time fraction of the absorption subsystem decreases from 80% to 71.7%. The energy saving fraction falls from 5.67% to 5.08%. In addition, when the evaporate temperature increases from 4°C to 14°C, the average COP of the absorption subsystem decreases from 0.384 to 0.365. The work of the compressor decreases from 48.2 kW to 32.8 kW and the corresponding average COP of the absorption subsystem is improved from 2.591 to 3.082.

关键词： solar     absorption-subcooled     compression hybrid     dynamic simulation     performance analysis    

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Primary spinal epidural non-Hodgkin’s lymphoma presented with spinal cord compression syndrome

Chunquan CAI MD, PhD, Qingjiang ZHANG BM, Changhong SHEN MD, PhD,

《医学前沿（英文）》 2009年 第3卷 第4期   页码 499-502 doi: 10.1007/s11684-009-0075-9

摘要： The spinal epidural space is an uncommon presenting site in primary non-Hodgkin’s lymphomas, especially for children. A boy suffered spinal cord compression syndrome caused by primary spinal epidural non-Hodgkin’s lymphoma. Thoracolumbar magnetic resonance imaging (MRI) demonstrated an intraspinal mass. An operation was performed with gross total tumor removal. Histological examination revealed a non-Hodgkin’s B-cell lymphoma. Bone marrow aspiration was negative for lymphoma involvement. No other therapies (chemotherapy and/or radiotherapy) were performed according to the parents’ opinion. The patient died approximately one year after the operation due to brain metastases. The clinical course and imaging features were discussed with a review of literatures.

关键词： non-Hodgkin’     s lymphoma     primary     spinal cord compression syndrome     epidural space    

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Schedule refinement for homogeneousmulti-core processors in the presence of manufacturing-caused heterogeneity

Zhi-xiang CHEN,Zhao-lin LI,Shan CAO,Fang WANG,Jie ZHOU

《信息与电子工程前沿（英文）》 2015年 第16卷 第12期   页码 1018-1033 doi: 10.1631/FITEE.1500035

摘要： Multi-core homogeneous processors have been widely used to deal with computation-intensive embedded applications. However, with the continuous down scaling of CMOS technology, within-die variations in the manufacturing process lead to a significant spread in the operating speeds of cores within homogeneous multi-core processors. Task scheduling approaches, which do not consider such heterogeneity caused by within-die variations, can lead to an overly pessimistic result in terms of performance. To realize an optimal performance according to the actual maximum clock frequencies at which cores can run, we present a heterogeneity-aware schedule refining (HASR) scheme by fully exploiting the heterogeneities of homogeneous multi-core processors in embedded domains. We analyze and show how the actual maximum frequencies of cores are used to guide the scheduling. In the scheme, representative chip operating points are selected and the corresponding optimal schedules are generated as candidate schedules. During the booting of each chip, according to the actual maximum clock frequencies of cores, one of the candidate schedules is bound to the chip to maximize the performance. A set of applications are designed to evaluate the proposed scheme. Experimental results show that the proposed scheme can improve the performance by an average value of 22.2%, compared with the baseline schedule based on the worst case timing analysis. Compared with the conventional task scheduling approach based on the actual maximum clock frequencies, the proposed scheme also improves the performance by up to 12%.

关键词： Schedule refining     Multi-core processor     Heterogeneity     Representative chip operating point    

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基于工期可控性的网络进度计划仿真评价方法研究

潘菲菲,王仁超,曹永雷

《中国工程科学》 2015年 第17卷 第1期   页码 143-150

摘要：

针对工程建设过程中常常通过资源重新配置或提高资源利用率来应对风险事件可能引起工期延迟的问题，提出了基于工期可控性的网络进度计划随机仿真评价方法，以资源配置和利用裕度作为活动的可控性衡量指标，同时考虑了风险事件发生时间不同导致的风险应对措施的可实施性不同的问题，通过对各个风险事件发生时间及其引起的活动持续时间延误、风险应对效果等进行随机仿真，从而对整个项目的工期分布进行模拟，评价编制的网络进度计划的合理性。算例表明：相对于传统的基于工期和基于因素的Monte-Carlo仿真评价方法，基于工期可控性的仿真评价方法得到的结果更为合理。

关键词： 网络进度计划；随机仿真；风险应对；工期可控性；评价    

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标题 作者 时间 类型 操作

Schedule Compression Impact on Construction Project Safety

Curt Webb,Lu Gao,Ling-guang Song

期刊论文

Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete

期刊论文

Behavior of dam concrete under biaxial compression-tension and triaxial compression-compression-tension

WANG Huailiang, SONG Yupu

期刊论文

The origins of schedule management: the concepts used in planning, allocating, visualizing and managing

Lynda M. BOURNE, Patrick WEAVER

期刊论文

Detection of schedule delay risk of empirical construction projects

Tsegay GEBREHIWET, Hanbin LUO

期刊论文

Effects of compression ratio on the combustion characteristics of a homogeneous charge compression ignition

SONG Ruizhi, ZHOU Longbao, LIU Shenghua, LI Wei, HU Tiegang

期刊论文

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

期刊论文

Three-dimensional numerical simulation for plastic injection-compression molding

Yun ZHANG, Wenjie YU, Junjie LIANG, Jianlin LANG, Dequn LI

期刊论文

基于4D CAD的大型桥梁施工进度系统仿真研究

张正峰,付金强,吴康新,张发瑜

期刊论文

Improvement of engine performance with high compression ratio based on knock suppression using Miller

Haiqiao WEI, Jie YU, Lei ZHOU

期刊论文

Efficient controller area network data compression for automobile applications

Yu-jing WU,Jin-Gyun CHUNG

期刊论文

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

期刊论文

Primary spinal epidural non-Hodgkin’s lymphoma presented with spinal cord compression syndrome

Chunquan CAI MD, PhD, Qingjiang ZHANG BM, Changhong SHEN MD, PhD,

期刊论文

Schedule refinement for homogeneousmulti-core processors in the presence of manufacturing-caused heterogeneity

Zhi-xiang CHEN,Zhao-lin LI,Shan CAO,Fang WANG,Jie ZHOU

期刊论文

基于工期可控性的网络进度计划仿真评价方法研究

潘菲菲,王仁超,曹永雷

期刊论文