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Analyses on schedule-cost coefficient correlation of spaceflight project based on historical statistics and its application

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Journal of Systems Engineering and Electronics 2006年第4期17卷 769-774页

作者： Liu Yanqiong Chen Yingwu Information System and Management School National Univ. of Defense and Technology Changsha 410073 P.R.China

When analyze the uncertainty of the cost and the schedule of the spaceflight project, it is needed to know the value of the schedule-cost correlation coefficient. This paper deduces the schedule distribution, considering the effect of the cost, and proposes the estimation formula of the correlation coefficient between the in（schedule） and the cost. On the basis of the fact and Taylor expansion, the relation expression between the schedule-cost correlation coefficient and the in-schedule-cost correlation coefficient is put forward. By analyzing the value features of the estimation formula of the in-schedule-cost correlation coefficient, the general rules are proposed to ascertain the value of the schedule-cost correlation coefficient. An example is given to demonstrate how to approximately amend the schedule-cost correlation coefficient based on the historical statistics, which reveals the traditional assigned value is inaccurate. The universality of this estimation method is analyzed.

关键词： cost schedule correlation coefficient spaceflight project management risk.

Kronos:towards bus contention-aware job scheduling in warehouse scale computers

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Frontiers of Computer Science 2023年第1期17卷 1-14页

作者： Shuai XUE Shang ZHAO Quan CHEN Zhuo SONG Shanpei CHEN Tao MA Yong YANG Wenli ZHENG Minyi GUO Shanghai Jiao Tong University Shanghai 200240China Alibaba Group Hangzhou 311121China

While researchers have proposed many techniques to mitigate the contention on the shared cache and memory bandwidth, none of them has considered the memory bus contention due to split lock. Our study shows that the split lock may cause 9X longer data access latency without saturating the memory bandwidth. To minimize the impact of split lock, we propose Kronos, a runtime system composed of an online bus contention tolerance meter and a bus contention-aware job scheduler. The meter characterizes the tolerance of jobs to the “pressure” of bus contention and builds a tolerance model with the polynomial regression technique. The job scheduler allocates user jobs to the physical nodes in a contention aware manner. We design three scheduling policies that minimize the number of required nodes while ensuring the Service Level Agreement (SLA) of all the user jobs, minimize the number of jobs that suffer from SLA violation without enough nodes, and maximize the overall performance without considering the SLA violation, respectively. Adopting the three policies, Kronos reduces the number of the required nodes by 42.1% while ensuring the SLA of all the jobs, reduces the number of the jobs that suffer from SLA violation without enough nodes by 72.8%, and improves the overall performance by 35.2% without considering SLA.

关键词： bus contention split lock schedule high performance cloud

Analysis of Multi-AGVs Management System and Key Issues: A Review

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Computer Modeling in Engineering & Sciences 2022年第6期131卷 1197-1227页

作者： Wenhao Lu Shuai Guo Tao Song Yuwen Li Shanghai Key Laboratory of Intelligent Manufacturing and Robotics School of Mechatronic Engineering and AutomationShanghai UniversityShanghai200444China National Demonstration Center for Experimental Engineering Training Education Shanghai UniversityShanghai200444China

Multiple Automatic Guided Vehicle(multi-AGVs)management systems provide an effective solution to ensuring stable operations of multi-AGVs in the same scenario,such as flexible manufacturing systems,warehouses,container terminals,etc.This type of systems need to balance the relationship among the resources of the system and solve the problems existing in the operation to make the system in line with the requirement of the administrator.The multi-AGVs management problem is a multi-objective,multi-constraint combinatorial optimization problem,which depends on the types of application scenarios.This article classifies and compares the research papers on multi-AGVs management in detail.Firstly,according to the different dimensions of the problem,the multi-AGVs management system is analyzed from three perspectives,namely,1)task dimensiondispatch,2)spatial dimension-path,and 3)time dimension-scheduling.The detailed comparison between the three dimensions and their respective solutions are discussed in detail as well.Secondly,according to their utility,the multi-AGVs management problems are divided into three categories:1)cost reduction,resource-oriented,2)efficiency improvement,problem-oriented,3)personalized demand,goal-oriented.The algorithm and methods of the different utility-oriented are analyzed and discussed.The related literature is summarized and corresponds to the composition of the multi-AGVs management system and the multi-AGVs management problems.Finally,according to the literature review,suggestions are made for further research.

关键词： Multiple automatic guided vehicle dispatch route schedule

Research on throughput prediction of 5G network based on LSTM

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Intelligent and Converged Networks 2022年第2期3卷 217-227页

作者： Lanlan Li Tao Ye Purple Mountain Labs Nanjing 210000China China Communications Construction Second Harbor Engineering Company Ltd. Wuhan 430040China

This paper proposes a wireless network traffic prediction model based on long-term and short-term memory cyclic neural networks.Through simulation experiments,the throughput prediction of 5G wireless networks using different scheduling algorithms for many different types of services is studied.The results verify that the long short-term memory prediction model has acceptable prediction accuracy and algorithm training speed,meets the needs of wireless network traffic prediction,and has a good application prospect.

关键词： wireless network flow forecast long short-term memory(LSTM) schedule throughput

schedule-Aware Power Management for Energy-Efficiency Improvement in 802.11u WLAN

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Communications and Network 2013年第3期5卷 455-460页

作者： Di Zhang Qinghe Du Pinyi Ren Li Sun School of Electronic and Information Engineering Xi’an Jiaotong University Xi’an China School of Electronic and Information Engineering Xi’an Jiaotong University Xi’an China National Mobile Communications Research Laboratory of Southeast University Nanjing China

Mobile stations supporting the 802.11u standard can access WLAN automatically when they are within the coverage of the network service provided by this WLAN. To achieve this goal, the stations need to keep “on” states includingidleandactiveall the time. However, studies have noted that the idleness of stations often lead to considerable power consumption. Although the conventional power saving mode (PSM) can provide energy saving effect to some extent, its own disadvantage leads to lower energy efficiency when the number of stations accessing the target WLAN. In this paper, we propose a schedule-Aware PSM (S-PSM), which can improve the energy efficiency in 802.11u WLAN. Particularly, we use the Generic advertisement service (GAS) defined in 802.11u standard to broadcast the transmission schedule information and all stations switch off their radios based on this information accordingly. We introduce the Respond Contention Window to reduce the collision probability of competition channel. When there is no packet in the access point (AP), AP broadcasts the GAS frame and actives the Idle Timer. All stations will turn into sleep and AP will not send GAS frame until Idle Timer expires. Simulations have shown that our proposed scheme can significantly reduce power consumption compared with the conventional PSM.

关键词： 802.11u Standard Power Saving Transmission schedule Generic Advertisement Service (GAS)

schedule Control of Coal Mine Construction Projects Based on Factor Analysis

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Geomaterials 2013年第3期3卷 67-70页

作者： Lingling Fan Hui Zhang Xiao Li China Shenhua International Engineering Co. Ltd. Beijing China Department of Safety Engineering Shijiazhuang Railway University Shijiazhuang China School of Mechanics Architecture and Civil Engineering China University of Mine and Technology Beijing China

schedule management is the crucial capability for large-scale coal mining investors to successful finish the construction project, which could get by the accumulation of the long-time institutional executive force and ability training. By using factor analysis and validation analysis, extracted control factors of schedule management from data have been made in large coal mine construction companies. Some control factors have a greater influence on the schedule management which are the system factor, measures factor, economic controlling factor, behavioral factor, process factor, organization factor, thus the enterprise schedule management system should include the terms of the above factors.

关键词： schedule Management Factor Factor Analysis Validity Analysis

Estimation Method of schedule-cost Correlation Coefficient of Spaceflight Project

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工程科学（英文版） 2007年第3期5卷 69-75页

作者： Liu Yanqiong(Humanity and Social Science School,National University of Defence Technology,Changsha,410073,China)

To evaluate the cost risk and the schedule risk of the spaceflight project,the schedule-cost(S-C) correlation coefficient is directly appointed according to the experts' experience usually.This paper deduces SDMCU(the schedule distribution model considering the effect of the cost uncertainty),and then proposes the approximate formula to estimate the ln(S)-C correlation coefficient based on the models of SDMCU and CDMSU(the cost distribution model considering the effect of the schedule uncertainty).Furthermore,an approximate relationship expression of the S-C and the ln(S)-C correlation coefficients is put forward according to general facts and the Taylor expansion,and advanced by means of mass numerical validation is the general rule of obtaining the estimation value of the schedule-cost correlation coefficient based on the historical data.

关键词： spaceflight project risk cost schedule correlation coefficient

Understanding the Occurrence of Two Total Floats in One Activity and schedule Crashing Approaches for That Situation

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Journal of Building Construction and Planning Research 2013年第3期1卷 67-74页

作者： Boong Yeol Ryoo Mike T. Duff Department of Construction Science Texas A&M University College Station USA

Critical Path Method (CPM) Scheduling has proven to be an effective project management tool. However, teaching the topic has proven difficult to include all elements of CPM yet keep it simple enough for students to understand. In an effort to simplify the teaching of critical path method scheduling, the issue of two total floats in an activity does not get the attention necessary to address its occurrence. The objective of this paper is to present a mathematical method to show multiple total floats are possible for an activity. Also presented are suggestions for schedule crashing when multiple total floats are found. Two totals floats can be found if constraints (Lag or Lead) or non-Finish-to-Start (FS) relationships, or both are used in a network diagram. Situations are possible where an activity may have a start total float (STF) of zero but have a finish total float (FTF) greater than zero, or vice versa. Because the critical path generally follows the zero total float, these situations, where either the STF or the FTF is critical while the other is not, determines how the critical path activity must be controlled and crashed. This paper will present approaches of how to crash the schedule when a portion of the activity, either start or finish, is critical. Also presented will be methods to teach the subject matter with or without the use of scheduling software. Critical Path Method was revisited to see what the minimal conditions are needed to have activities with two total float. Generalized crashing methods were studied to see if the methods can be used when two total floats exist.

关键词： Critical Path Method Multiple Total Floats schedule Crashing Constraints Lag/Lead

The Relation between the Initial Type of schedule Used to Administer Doxorubicin and Long-Term Doxorubicin Cardiotoxicity

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Journal of Cancer Therapy 2014年第12期5卷 1145-1152页

作者： Arthur J. Weiss Irwin L. Stoloff Antonio C. Simoes Richard D. Lackman Division of Medical Oncology Thomas Jefferson University Hospital Philadelphia PA USA North Penn Hospital Landsdale PA USA Division of Orthopedic Oncology Cooper University Hospital Camden NJ USA

Background: As more patients survive cancer chemotherapy, problems associated with the late complications of therapy have become increasingly apparent;late doxorubicin cardio-myopathy being one of the most pressing. The relationship between initial dose, schedule employed, and etiology are still not well defined. This study attempts to clarify some of these issues. Methods: Patients receiving large total doses of doxorubicin by schedules designed to minimize peak drug levels were monitored in regard to their cardiac status for up to 31 years following completion of doxorubicin therapy. A computer program predicting the amount of doxorubicin retained by the heart vs. schedules employed was devised with the predictions of the computer program being compared to the clinical findings. Results: 1365 patients receiving doses of doxorubicin greater than 610 mgm./M2 were monitored for up to 31 years following completion of such therapy. No patient developed unequivocal clinical and pathologic evidence of a doxorubicin related cardiomyopathy. Knowing that human cardio-myocytes contain enzymes capable of neutralizing doxorubicin, a computer program predicted that by increasing their efficiency, the schedules employed substantially l decreased the relative amount of drug retained by the heart, findings compatible with both animal experiments and clinical results. Conclusions: administration of doxorubicin by schedules in which peak plasma levels of drug were minimized resulted in marked decreases in both acute and long-term cardiac toxicity;believed to be due to potentiation of myocardial enzymes capable of inactivating the drug.

关键词： Late Doxorubicin Cardiotoxicity Initial Type of Doxorubicin schedule