A review on queueing network models with finite capacity queues for software architectures performance prediction

A review is carried out on how queueing network models with blocking have been applied so far into the performance evaluation and prediction of Software Architectures (SA). Queueing network models with finite capacity queues and blocking have recently been introduced and applied as more realistic models of systems with finite capacity resources and population constraints. Queueing network models have been often adopted as models for the evaluation of software performance. Starting from our own experience, we observe the need of a more accurate definition of the performance models of SA to capture some features of the communication systems. We consider queueing networks with finite capacity and blocking after service (BAS) to represent some synchronization constraints that cannot be easily modeled with queueing network models with infinite capacity queues. We investigate the use of queueing networks with blocking as performance models of SA with concurrent components and synchronous communication. Queueing theoretic analysis is used to solve the queueing network model and study the synchronous communication and performance of concurrent software components. Our experience is supported by other approaches that also propose the use of queueing networks with blocking. Directions for future research work in the field are included.     

A carboxyalkanethiol monolayer modified electrode for blocking of ascorbic acid oxidation and its application to a biosensor

Upon the application of amperometric biosensor to the biological fluid, ascorbic acid interferes the amperometric determination of analytes, because the oxidative potential of ascorbic acid is lower than that of electro active substances such as H₂O₂ produced by the enzymatic reaction. In this study we propose a method to block ascorbic acid based on the electrostatic interaction with self-assembled monolayer (SAM) and its application of the surface modified electrode to biosensor. In order to form SAM on the gold electrode with carboxyl group, 7-carboxy-heptanethiol (7-CHT) was used. The 7-CHT modified electrode did not show anodic response to ascorbic acid, but oxidized phenanthroline cobalt complex [Co(phen)₃²⁺], which can be used as a mediator of biosensor. Thus, the 7CHT-modified electrode was applied to biosensor mediated with Co(phen)₃²⁺. Fructose dehydrogenase (FDH) was immobilized to the 7-CHT modified electrode. Fructose was determined selectively with the FDH/7-CHT modified electrode at the range of 0.2-2 mM.     

柳州,云浮,宣化三厂预热分解系统技术改进经验引起的思考

本文分析了柳州、云浮、宣化三厂预分解系统粘结堵塞、难以稳定生产和不能“达产达标”的原因,逐一介绍了三厂预分解系统技术改进的措施和效果,并就其技改工程经验进行了分析总结和探索思考.     

New integer linear programming approaches for course timetabling

The most complete form of academic timetabling problem is the population and course timetabling problem. In this problem, there may be multiple classes of each subject, and the decision on which students are to constitute each class is made in concert with the decision on the timetable for each class. In order to solve this problem, it is normally simplified or decomposed in some fashion. One simplification commonly used in practice is known as blocking: it is assumed that the classes can be partitioned into sets of classes (or blocks) that will be timetabled in parallel. This restricts clashing to occur only between classes in the same block, and essentially removes the timetabling aspect of the problem, which can be carried out once the blocks are constituted and the classes populated. The problem of constituting the blocks and populating the classes, known as the course blocking and population problem, is nevertheless a challenging problem, and provides the focus of this paper. We demonstrate, using data provided by a local high school, that integer linear programming approaches can solve the problem in a matter of seconds. Key features include remodelling to remove symmetry caused by students with identical subject selection, and the observation that in practice, only integrality of the block composition variables needs to be enforced; the class population aspects of the model have strong integrality properties.     

Human visual sensitivity based optimal local backlight dimming methodologies under different viewing conditions

An adaptive local backlight dimming algorithm is proposed considering human visual sensitivities under various viewing conditions. Local dimming amount is maximized based on contrast sensitivity function and local image characteristics to minimize perceived luminance and contrast losses maintaining image qualities. Average luminance, contrast and spatial frequency are evaluated as local image characteristics. As dimming based on local characteristics has blocking artifacts, a compensation method using edge luminance difference is proposed considering human responses. The proposed algorithms reduce backlight power consumption by 39.69% on average, with an average SSIM of 0.995. It can be increased by 5.66% with varying viewing conditions, resulting in a 45.35% power consumption reduction on average. The outperformances of the proposed algorithm in power consumption reduction and maintaining image quality are verified with various image quality metrics compared to recent dimming algorithms.     

On hypercube packings,blocking sets and a covering problem

Consider sets S of hypercubes of side 2 in the discrete n-dimensional torus of side 4 with the property that every possible hypercube of side 2 has a nonempty intersection with some hypercube in S. The problem of minimizing the size of S is studied in two settings, depending on whether intersections between hypercubes in S are allowed or not. If intersections are not allowed, then one is asking for the smallest size of a non-extensible packing S  ; this size is denoted by f(n)$f(n)$. If intersections are allowed, then the structure S is called a blocking set. The smallest size of a blocking set S   is denoted by h(n)$h(n)$. By computer-aided techniques, it is shown that f(5)=12$f(5)=12$, f(6)=16$f(6)=16$, h(6)=15$h(6)=15$ and h(7)≤23$h(7)\le 23$. Also, non-extensible packings as well as blocking sets of certain small sizes are classified for n≤6$n\le 6$. There is a direct connection between these problems and a covering problem originating from the football pools.     

实体分辨研究综述

实体分辨是数据集成、信息检索等领域的重要研究内容,目的是发现数据集合中的不同实体和同一实体的不同描述。将实体分辨过程划分为数据分块、记录比较和匹配决策等3个主要步骤。从记录聚集方式的角度介绍了实体分辨的数据分块方法;从字符串划分粒度的角度分析了实体分辨的记录比较方法;从记录关联方式的角度阐述了实体分辨的决策模型。最后对实体分辨研究下一步需要解决的问题进行了展望。     

频谱可用性和保护带宽共享度感知的弹性光网络生存性多路径策略

针对弹性光网络频谱利用率降低和带宽阻塞率高等问题,该文提出一种频谱可用性和保护带宽共享度感知的生存性多路径策略(M-SDSAA)。首先,该策略对业务采用单路径路由,通过区分业务的持续时间,分别采用首次命中和末端命中的工作路径频谱分配方式,并且为不同大小共享频谱块设定不同链路权重值。若单路径路由或频谱分配失败,引入多路径传输策略,自适应选择消耗频隙数少的策略,并且引入共享保护机制,提高保护带宽共享度。最后,当业务阻塞时,且存在单路径业务的保护路径预置在频隙消耗次优的路径,则启动重配置机制进一步降低阻塞率,将该业务重配置到保护频隙消耗最少的路径。仿真结果表明所提算法能有效地提高频谱利用率,降低网络的带宽阻塞率。     

兰尖矿粉矿通过溜井的堵塞和跑矿事故分析与处理

该文对兰尖铁矿粉矿通过溜井运输过程中出现的事故进行了分类，通过实例说明其危害。对事故原因进行分析，提出了具体处理办法和预防事故的措施。     

回转式空气预热器堵塞的探讨

介绍了改进空气预热器吹灰及清冼装置,减少或防止低温腐蚀的发生,加强燃烧调整,维持最佳的燃烧工况,完善吹灰及碱冼的操作方法,为防止空气预热器堵塞提供借鉴.