一种可调节的多级颜色量化算法

针对当量化图像的颜色数量较少时如何调节颜色层次和微弱颜色,本文提出了一种新颖的多级颜色量化算法.根据Kohonen自组织神经网络和线性像素置换计算第一级调色板;然后多次迭代找出最相似的颜色对,删除其中的一个,得到第二级调色板;最后根据调色板中颜色的像素数量和与基色距离的加权和,选出最终的代表颜色.实验结果表明,该算法能够通过设置适当的像素取样率、像素数量权重和与基色的距离权重而有效地选择满足不同需要的量化结果,并且保持较好的量化图像质量.     

一种支持实时集群系统的双层调度机制

提出一种集群环境下的实时调度机制,它通过前端负载机平衡调度、后端机区分实时和非实时任务队长差调度而提供实时优先服务,有效提高了以往前端机单点调度模式下的集群节点利用率和实时任务响应性.对比实验表明,在保证吞吐率的情况下,实时任务的响应时间明显减少,为分布式实时调度提供了一种可行的设计参考.     

Linux中一种改进的实时调度算法及其应用

在实时操作系统中,调度算法起着关键性的作用,然而调度算法的开销与系统的调度性能之间经常是一对矛盾.就此问题,结合最新版Linux2.6内核任务调度的特点,提出了一种改进的最小裕度优先(LSF)算法.针对LSF算法中因任务间的频繁切换造成系统开销增大的缺点,通过采用适当的抢占阚值策略减少"颠簸"现象,提高了Linux2.6内核的实时性.     

解决矩阵链相乘处理器调度问题的一种新算法

本文介绍了矩阵链相乘处理器分配问题和离散处理器分配算法,描述了Lee Heejo等人提出的解决MCSP的处理器分配算法,提出了一种解决MCSP的时间复杂度更低的算法,使处理器能尽量被充分利用,并对三种分配算法进行了比较分析.     

一种基于改进的贝叶斯投票算法的服务评估技术

现有的Web服务体系架构缺少服务质量与优选方面的有效支持,如何动态地选择、绑定并调用最适合用户需求的Web服务受到研究领域的关注.本文基于对"可信服务测试中介"模型的研究,提出了一种基于改进的贝叶斯投票算法的服务评估技术--把每一个测试评估结果作为对测试对象的一次投票,通过对协同服务测试数据的收集和分析,最终计算出同类服务的加权通过率,并在同类服务中进行排行,体现了Web2.0的技术特点.     

一种异构传感器网络的能量有效路由算法

无线传感器网络设计能量有效的路由算法是至关重要的.对于不同类型的传感器节点传输不同大小数据包信息以及拥有不同初始能量的异构传感器网络,本文提出了一种适合此传感器网络的D-REECR路由算法,此算法是在之前提出的REECR算法上改进而来.基于REECR没有考虑簇头在选择时的分布不均匀性,D-REECR将簇头闻的距离作为选择簇头的因素之一,与节点的剩余能量及能量消耗率一起作为选择簇头的依据.这样使各个簇大小基本一致,从而平衡各个节点的能量消耗,达到延长网络生命的目的.仿真结果显示,改进后的D-REECR算法比REECR算法在能量效率上大约提高5%～10%.     

一种基于分簇结构的无线传感器网络混合调度MAC协议

针对突发和周期信号并存的应用场景,提出了一种基于分簇结构的无线传感器网络混合调度MAC协议--CBPMAC/TFC(A Cluster-based Wireless Sensor Network MAC Protocol for the System with Burst and Periodic Signals/ Based on TDMA,FDMA,CSMA).簇间采用基于FDMA的调度机制,簇内采用基于TDMA和CSMA的联合调度机制.提出了以簇头为基准的相对时间同步机制,同步精度为一个帧周期的时钟漂移.给出了基于能量阈值的簇头轮换策略和基于侦听的故障处理策略.理论分析和实验结果表明:CBPMAC/TFC协议在响应实时性和能量有效性方面介于CSMA和TDMA之间,与CSMA相比,在损失一定突发信号响应实时性的情况下,节省能耗18.7%;与TDMA相比,在改善突发信号响应实时性的情况下,损失能耗23.6%.     

PGA:一种基于最优路径的Ad Hoc网络地理路由算法

本文提出了一种基于最优路径的Ad Hoc网络的地理路由算法PGA及其改进算法H-PGA,该算法在路径的构造、路由、路由恢复各个方面都应用了最优路径路由的概念,较好地解决了地理路由算法中的凹节点问题.在网络节点数n较大的情况下,依然保持很高的报文投递率(n=400、网络度为4时,报文投递率为96%),且实际路径很接近最短路径路径.同时H-PGA路由表的大小与平方根√n成线性关系,单个节点的协议带宽消耗也为O(平方根n),这使得H-PGA可以适用于较大的应用范围.     

Multi-stage carcinogenesis in the urinary bladder

Sodium saccharin has been shown to be a promoting substance for urinary bladder carcinogenesis in the rat following initiation with N-methyl-N-nitrosourea, N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT), or N-butyl-N-(4-hydroxybutyl)nitrosamine. It has been shown to have many of the properties of promoting substances in other animal models, such as the mouse skin; it lacks mutagenic activity, induces hyperplasia in the target tissue, and does not bind DNA. It has recently been demonstrated to be co-carcinogenic for the rat bladder. It has also been shown that the administration of sodium saccharin during the regenerative hyperplasia observed after freeze ulceration or cyclophosphamide administration resulted in the induction of bladder tumours, even without pre-initiation with FANFT or other known initiating substances. This model appears to be analogous to the administration of sodium saccharin to animals with a rapidly proliferating bladder mucosa as occurs in utero during the two-generation carcinogenesis experiments and in the pellet-insertion experiments in which a cholesterol pellet containing sodium saccharin is inserted into the bladder. To enhance our understanding of the complex interaction of the many variables involved in two-stage bladder carcinogenesis, a stochastic model has been formulated based on long-term carcinogenicity and in vivo tissue kinetic studies. This model indicates the importance of cell proliferation and the development of hyperplasia in carcinogenesis.     

基于反馈控制的开放式实时系统自适应调度算法设计与实现

对于负载不可预测且资源受限的开放式实时系统,传统"开环"调度算法不能根据系统负载情况调整调度策略,影响系统实时性能或造成资源浪费.采用双闭环反馈控制方法,改进目前开放式实时系统常用的时限驱动总带宽利用率服务器.本方法根据负载情况,动态地为不同实时性能需求的任务分配资源,保证硬实时任务满足时限要求并且提高资源利用率.实验表明,系统负载存在突发的情况下,算法既很好地控制了任务的时限错过率,又得到了较高的资源利用率.     

基于性能量化矩阵的计算网格作业调度算法研究

提升计算网格系统运行效率的关键在于作业调度算法,如何综合各种因素使得调度策略更为全面是一个有挑战性的问题.通过建立网格资源性能量化矩阵,构建了一个作业调度模型,并基于此模型给出了一个具体的作业调度算法.通过性能分析和实验仿真,该算法在运行时间、占用资源等方面都有较大的改善,能较好地适应网格系统的动态性和可扩展性特点,提高了作业调度效率.     

移动实时数据库QoS管理和更新事务调度算法

分布式环境下的移动实时数据库服务应用逐渐广泛,但系统负载的不可预测甚至可能的超载使得应用受到限制.系统中事务在低带宽移动环境下竞争有限的系统资源导致重启或夭折,从而给系统带来损失甚至灾难.通过结合时间有效性和值域的有效性提出基于的一种新的衡量系统性能的参数标准,如错过截止期事务的比率、数据新鲜度、CPU利用率去保证QoS,同时提出一种更新事务调度新算法和基于反馈控制的架构去实现.通过仿真实验评估,算法可以从稳定性能和暂态性能保证系统的性能指标不会超过由数据库管理员事先提出的QoS规范.     

Switching approach in the management of schizophrenia patients

Atypical neuroleptics combine efficacy with good tolerability. As a result, prognosis and quality of life may improve when patients receiving treatment with traditional agents are switched to an atypical compound. Major indications for switching are lack of or incomplete response to classical neuroleptic treatment, and/or the occurrence of extrapyramidal symptoms. The previous treatment should be discontinued, preferably progressively, and the new one started, overlapping the previous treatment. Caution is advised in patients who have suffered a recent relapse, a severe psychotic episode or who are being treated as outpatients. Anticholinergic medication, if needed, should be continued for 2-4 weeks after the switch has been made. The physician should be aware of the potential drug interactions leading to increased sedation or hypotension. Patient education is vital when switching medications. Treatment should be individualized. Patients who have gained weight on previous therapy, or who have negative symptoms of schizophrenia and depressive symptoms, are particularly likely to benefit from amisulpride. Furthermore, the highly selective affinity of amisulpride for dopaminergic receptors with its lack of interference with other neurotransmitter systems facilitates the change in treatment.     

罐组式动态逆流提取工艺在丹参提取酚酸类成分中的应用

目的:采用罐组式动态逆流提取工艺提取丹参中酚酸类成分。方法:分别用罐组式动态逆流提取与传统单罐煎煮提取工艺进行丹参提取,测定提取液中丹参酚酸B的含量,比较各项工艺的能耗。结果:罐组式动态逆流提取工艺与传统单罐煎煮提取工艺比较,减少了有效成分的降解,节省了能源,缩短了生产周期。结论:罐组式动态逆流提取工艺适用于丹参工业生产。     

Switching to tianeptine in patients with antidepressant-induced sexual dysfunction

Sexual side effects are frequent and are recently being considered as effects of antidepressant treatment. One method to improve the sexual dysfunction associated with the use of antidepressants is to change to another antidepressant. In the present work, the consequences of switching to tianeptine in patients with antidepressant-induced sexual dysfunction were studied. The study group comprised 23 patients with major depressive disorder who experienced antidepressant-induced sexual dysfunction. These antidepressants were stopped and switched to tianeptine (12.5mg x 3/day). All patients were screened by using the clinical global impression-improvement scale (CGI-I), the Hamilton depression rating scale (HAM-D) and the Arizona sexual experience scale (ASEX) at the beginning of the study, and at weeks 4 and 8. No patient failed to tolerate 37.5mg of tianeptine or to complete the study except for one patient becoming pregnant. Paired t-tests revealed a significant difference between baseline and week 4 or week 8 in scores on both the HAM-D and ASEX. At 8 weeks, six patients were rated as very much improved (CGI-I=1) and ten patients were rated as much improved (CGI-I=2). Thus, with a CGI-I score of 2 or less used to indicate a positive response, 72.7% of the patients were responders. The results suggest that switching to tianeptine appears to be useful for alleviating sexual dysfunction caused by other antidepressants.     

Switching strategies in the recent era of antiretroviral therapy

Introduction: Although antiretroviral therapy is highly effective, many patients may benefit from switching strategies. Rapid advances in the development of new antiretroviral drugs could enhance the success of these approaches. In this review, we build on a previous review from 2014 and summarize the current options for switching strategies in virologically suppressed HIV-infected patients.

Areas covered: We conduct a critical analysis of scientific evidence for various switching strategies used in the modern era of antiretroviral therapy, as well as reasons for these approaches, other considerations to be taken into account, and alternative strategies.

Expert opinion: Current antiretroviral regimens are effective and well tolerated in HIV patients. A number of options may provide benefit to patients, even virologically suppressed patients, possibly enhancing adherence and avoiding adverse effects and toxicities. Cost reduction may also be an important goal of switching strategies. The present scenario is excellent, as many good antiretroviral compounds and regimens allow clinicians to further improve on effective treatments now used in routine practice. Even the current paradigm of triple-drug regimens as the standard of care could change, at least in some patients.