采用Scheduled Thread Pool Executor执行定时重试任务时内存溢出的分析及解决

开发Java Web项目中发现服务之间的调用存在超时情况,由于涉及的处理逻辑全部是异步,引入定时重试的机制,重试工具选择了JDK自带的Scheduled Thread Pool Executor。当A服务依赖B服务,B服务由于在业务高峰期处理能力降低,导致大量A服务过来的请求超时,A加入了超时重试机制,间隔时间根据重试次数的多少来决定,次数越多,两次重试之间间隔的时间越多,此时的业务高峰也会给A带来大量请求,大量的超时会导致重试队列迅速堆积,直到内存溢出。该文从线程池工作机制、Scheduled Thread Pool Executor实例的创建,获取重试任务的过程以及提交任务的过程角度分析,并通过源代码的剖析和测试工具My Eclipse进行演示测试内存泄露的情况,得出避免内存泄露的解决方案。

Energy-efficient Traffic Grooming Under Sliding Scheduled Traffic Model for IP over WDM Optical Networks

In this paper,we investigate on the problem of energy-efficient traffic grooming under sliding scheduled traffic model for IP over WDM optical networks,so as to minimize the total energy consumption of the core network.We present a two-layer auxiliary graph model and propose a new energyefficient traffic grooming heuristic named Two-Dimension Green Traffic Grooming(TDGTG) algorithm,which takes both space and time factors into consideration for network energy efficiency.We compare our proposed TDGTG algorithm with the previous traffic grooming algorithms for scheduled traffic model in terms of total energy consumption and blocking probability.The simulation results in three typical carrier topologies show the efficiency of our proposed TDGTD algorithm.

基于Scheduled Sampling的种群活动区域动态仿真优化模型

针对元胞自动机(CA)模型在迭代过程中误差不断累积的问题,提出了一种基于时间序列分析及Scheduled Sampling的优化CA模型(CC-TAS)来仿真种群活动区域。为克服传统CA模型固定化参数的局限,采用时间序列分析来预测参数,并利用Scheduled Sampling优化方法在实际值与模型上一阶段输出值中进行随机选择,避免误差在模拟过程中不断累积,修正了模型仿真的结果。实验结果表明:CC-TAS模型峰值误差仅为19.4%,其综合准确率达93.4%,显著改进了CA模型的相应结果。

基于Scheduled Sampling采样机制的人体行为预测

针对循环神经网络存在的预测误差累积问题,提出了融合Scheduled Sampling采样机制的序列预测算法。该算法选用较大概率p作为选择使用真实值或是前一帧预测数据作为当前时间步输入依据,并随着时间的推移p值逐渐变小,使解码器更倾向于使用预测序列作为输入,以此增加模型的健壮性。实验结果表明:该算法能够将Human3.6M数据集中绝大多数动作短期预测误差降低到0.5 dm左右,相比原方法降低了0.2~0.4 dm,在行为预测上表现良好。

Determination of Scheduled Travel Time for a Fixed Transit Route Based on Multistate Model

In order to provide the guideline for bus drivers to adjust speed to minimize scheduled deviation,the method for setting bus scheduled travel time is proposed. Firstly,multistate model is introduced to fit historical travel time data and identify different service states. Based on the calibrated travel time distribution parameters,an optimization model is proposed,followed by a Monte Carlo( MC) simulation based genetic algorithm( GA)procedure to obtain the optimal scheduled time. A case study from a fixed bus route from Shenzhen is used to demonstrate the model applicability. The sensitivity analysis is conducted to study the effects of parameters setting on optimal slack time for each segment. The results show that multistate model fits travel time under peak hours better than Lognormal distribution,and the length of scheduled travel time basically reflects travel time reliability.

Experimental study on human umbilical cord blood scheduled transplanta-tion in severe combined immunodeficient mice

Objective: To explore a new way for developing the human umbilical cord blood (CB) engraftment with high efficiency and in further understand the homing potentiality of hematopoietic stein/progenitor cells (HSC/HPC). Method: Sub-lethally irradiated severe combined immunodeficient (SCID) mice were transplanted i. v. with CB which was cryopre- served at - 80℃. Human cells in recipient mice were detected by flow cytometry and CFU-GM assay for each host organ. Results: In contrast with the single transplantation, scheduled engraftment of the identical numbers of CB cells resulted in an obvious increase of CD45+ and CD34+ cells produced in SCID mouse bone marrow (BM). While the donor cells were reduced by 5 times, the similar reconstitution of both hematopoietic fumctions and part of immunologic fumctions was ob- tained.Conclusion:Scheduled engraftment can improve repopulating of the HSC, which provides a novel way for clinical cord blood engraftment into adults.

Interior-Point Methods Applied to the Predispatch Problem of a Hydroelectric System with Scheduled Line Manipulations

Transmission line manipulations in a power system are necessary for the execution of preventative or corrective main- tenance in a network, thus ensuring the stability of the system. In this study, primal-dual interior-point methods are used to minimize costs and losses in the generation and transmission of the predispatch active power flow in a hydroelectric system with previously scheduled line manipulations for preventative maintenance, over a period of twenty-four hours. The matrix structure of this problem and the modification that it imposes on the system is also broached in this study. From the computational standpoint, the effort required to solve a problem with or without line manipulations is similar, and the reasons for this are also discussed in this study. Computational results sustain our findings.

A Gain Scheduled Method for Speed Control of Wind Driven Doubly Fed Induction Generator

This paper proposes a gain scheduled control method for a doubly fed induction generator driven by a wind turbine. The purpose is to design a variable speed control system so as to extract the maximum power in the region below the rated wind speed. Gain scheduled control approach is applied in order to achieve high performance over a wide range of wind speed. A double loop configuration is adopted. In the inner loop, the rotor speed is used as the scheduling parameter, while a function of wind and rotor speed is used as the scheduling parameter in the outer loop. It is verified in simulations that a high tracking performance has been achieved.

Ling'ao Nuclear Power Plant is progressing as scheduled

Construction of Ling’ao Nuclear Power Plant in Guangdong Province, the country’s second-largest nuclear power project between 1996-2000, chalked up notable progress this year. On July, 15, all foreign suppliers in the project were given official notice that both sides should start to implement the contracts. "The move marked a significant step forward in the project’s construction," said Zeng Wenxing, General Manager of Ling’ ao Nuclear Power Co Ltd, set up in

China Scheduled to Accredit its Own Innovative Products from 2007

China will begin accrediting its own innovative products from this year. It plans to complete the Catalog of China's Independent Innovation Products by 2007 for future reference of government procurement. The products in the catalog shall enjoy preferential policies. According to the Ministry of Science and Technology of the People's Republic of China, the accreditations shall be made based on Measures for the Administration of the Accreditation of National Independent Innovation Products (for Trial Implementation), which was jointly launched on December 31, 2006, by the Ministry of Science and Technology, the National Development and Reform Commission (NDRC), and the Ministry of Finance of the People's Republic of China.

Three Gorges ready to be dammed in 1997 as scheduled

A year from now, dam builders will have blocked the mighty Yangtze River at the Three Gorges, marking the start of the second phase of the gigantic water harnessing and developing scheme.

Subsea Maintenance Service Delivery:Mapping Factors Influencing Scheduled Service Duration

The oil and gas （O＆G） industry on the Norwegian continental shelf （NCS） leads the world in terms of the number of subsea O＆G installations. Ensuring the dependability of these assets is critical. Non-intrusive inspection, maintenance and repair （IMR） services are therefore needed to reduce risks. These services are planned and executed using a mono-hull offshore vessel complete with remotely operated vehicles （ROVs）, a module handling system and an active heave compensated crane. Vessel time is shared between competing jobs, using a prioritized forward-looking schedule. Extension in planned job duration may have an impact on O＆G production, service costs and health, safety, and environmental （HSE） risks. This paper maps factors influencing the job schedule efficiency. The influence factors are identified through reviews of literature as well as interviews with experts in one of the large IMR subsea service providers active on the Norwegian Continental Shelf. The findings show that the most obvious factors are weather disruption and water depth. Other factors include job complexity, job uncertainty, IMR equipment availability, as well as the mix of job complexity.

Performance deterioration modeling and optimal preventive maintenance strategy under scheduled servicing subject to mission time

Servicing is applied periodically in practice with the aim of restoring the system state and prolonging the lifetime. It is generally seen as an imperfect maintenance action which has a chief influence on the maintenance strategy. In order to model the maintenance effect of servicing, this study analyzes the deterioration characteristics of system under scheduled servicing. And then the deterioration model is established from the failure mechanism by compound Poisson process. On the basis of the system damage value and failure mechanism, the failure rate refresh factor is proposed to describe the maintenance effect of servicing. A maintenance strategy is developed which combines the benefits of scheduled servicing and preventive maintenance. Then the optimization model is given to determine the optimal servicing period and preventive maintenance time, with an objective to minimize the system expected life-cycle cost per unit time and a constraint on system survival probability for the duration of mission time. Subject to mission time, it can control the ability of accomplishing the mission at any time so as to ensure the high dependability. An example of water pump rotor relating to scheduled servicing is introduced to illustrate the failure rate refresh factor and the proposed maintenance strategy. Compared with traditional methods, the numerical results show that the failure rate refresh factor can describe the maintenance effect of servicing more intuitively and objectively. It also demonstrates that this maintenance strategy can prolong the lifetime, reduce the total lifetime maintenance cost and guarantee the dependability of system.

Synthesizing Scheduled Robust Model Predictive Control with Target Tracking

Systems with large operating regions and non-zero state target tracking have limited the industrial application of robust model predictive control (RMPC) with synthetic action. To overcome the problem, this paper presents a novel formulation of synthesizing scheduled RMPC for linear time varying (LTV) systems. Off-line, we compute the matrix that transforms target output into steady state first. Then a set of stabilizing state feedback laws which are corresponding to a set of estimated regions of stability covering the desired operating region are provided. On-line, these control laws are implemented as a single scheduled state feedback model predictive control (MPC) which switches between the set of local controllers and achieve the desired target at last. Finally, the algorithm is illustrated with an example.

Factors associated with non-adherence to scheduled medical follow-up appointments among Cameroonian children requiring HIV care: a case-control analysis of the usual-care group in the MORE CARE trial

Background:A better understanding of why HIV-exposed/infected children fail to attend their scheduled follow-up medical appointments for HIV-related care would allow for interventions to enhance the delivery of care.The aim of this study was to determine characteristics of the caregiver-child dyad(CCD)associated with children’s non-adherence to scheduled follow-up medical appointments in HIV programs in Cameroon.Methods:We conducted a case-control analysis of the usual-care group of CCDs from the MORE CARE trial,in which the effect of mobile phone reminders for HIV-exposed/infected children in attending follow-up appointments was assessed from January to March 2013.For this study,the absence of a child at their appointment was considered a case and the presence of a child at their appointment was defined as a control.We used three multivariate binary logistic regression analyses.The best-fit model was the one which had the smallest chi-square value with the Hosmer-Lemeshow test(HLχ^(2)).Magnitudes of associations were expressed by odds ratio(OR),with a p-value<0.05 considered as statistically significant.Results:We included 30 cases and 31 controls.Our best-fit model which considered the sex of the adults and children separately(HLχ^(2)=3.5)showed that missing scheduled medical appointments was associated with:lack of formal education of the caregiver(OR 29.1,95%CI 1.1-777.0;p=0.044),prolonged time to the next appointment/follow-up(OR[1 week increase]1.4,95%CI 1.03-2.0;p=0.032),and being a female child(OR 5.2,95%CI 1.2-23.1;p=0.032).One model(HLχ^(2)=10.5)revealed that woman-boy pairs adhered less to medical appointments compared to woman-girl pairs(OR 4.9,95%CI 1.05-22.9;p=0.044).Another model(HLχ^(2)=11.1)revealed that man-boy pairs were more likely to attend appointments compared to woman-girl pairs(OR 0.23,95%CI 0.06-0.93;p=0.039).There were no statistical associations for the ages of the children or the caregivers,the study sites,or the HIV status(confirmed vs.suspected)of the children.Conclusion:The profile of children who would not attend follow-up medical appointments in an HIV program was:a female,with a caregiver who has had no formal education,and with a longer follow-up appointment interval.There is a possibility that female children are favored by female caregivers and that male children are favored by male caregivers when they come to medical care.

Tiandilong Group 250,000-ton Copper Rod Production Line Scheduled for Production in May

It is reported from Tiandilong Group that its 250,000-ton 8mm copper rod production line is scheduled to put into production this May. It

China National Gold Group Corporation’s 100,000 tonnes Copper Smelting Project is scheduled

The 100,000 tonnes copper smelting project is one of the key industrial projects of Manzhouli in 2013, the project uses Xiqi tungsten and molybdenum mine resource for copper downstream processing, China National Gold Group Corporation Inner Mongolia Mining Co., Ltd

500,000 Tonnes Ferro Alloy Project Landed in Huade,Scheduled to Produce 100,000 Tonnes of Nickel Each Year

On July 20,Huade County People’s Government signed agreement for 500,000tonnes ferro alloy project with Zhongtian Xinrun Holdings Co.,Ltd.This project involves a total investment of 1.2 billion yuan,scheduled to be completed in three stages.Construction of Phase I project is from August2015 to May 2016,with staged fund investment of 500 million yuan,which is for completion