Satisfying quality requirements in the design of a partition‐based,distributed stock trading system

Although quality requirements (QRs) have become a major drive in today's software development, there have been very few real‐world examples in the literature that demonstrate how to meet these requirements. This paper presents such an example. Specifically, the paper describes the design of a partition‐based distributed stock trading service system that satisfies a set of QRs related to resource utilization, performance, scalability and availability. The paper evaluates this design through detailed experiments and discusses some design alternatives and the lessons learned. Central to this design are a static load distribution strategy and a dynamic load balancing strategy. The first strategy is to achieve an initial balanced workload on the system's server cluster during the system initialization time, whereas the second strategy is to maintain this balanced workload throughout the system execution time. Together, these two strategies work in unison to ensure that the server resources are efficiently utilized; the user requests are processed with the required speed; the application is partitioned with sufficient room to scale; and the system is highly available. Copyright © 2011 John Wiley & Sons, Ltd.     

基于DSP的地源热泵中央空调控制器设计与实现

为了提高地源热泵中央空调控制器电路设计的合理性和变频控制的实时性,使空调系统运行稳定性更高、节能效果更明显,设计以TMS320LF2407为主控芯片的空调系统控制器。控制器采用优化的电源电路方案、可靠的外围电路信号处理方式、节能效果良好的组合模糊PID算法、控制量稳定的控制策略。硬件测试与软件仿真结果表明,该控制器电源信号完整性符合电路设计要求,电路运行稳定可靠,软件算法实时跟踪效果良好。     

Event‐based modelling,analysis and testing of user interactions: approach and case study

With the growing complexity of computer‐based systems, their graphical user interfaces have also become more complex. Accordingly, the test and analysis process becomes more tedious and costly. This paper introduces a holistic view of fault modelling that is carried out as a complementary step to system modelling, enabling a scalability of the test process, and providing considerable potential for automation. Event‐based notions and tools are used to generate and select test cases systematically. The elements of the approach are illustrated and validated by a case study. This paper does not claim to introduce a novel theoretic approach; rather, it makes use of graph‐theoretic results for a practical and simple, but nevertheless powerful, view of modelling, analysis and testing of graphical user interfaces. Copyright © 2005 John Wiley & Sons, Ltd.     

Faults diagnosis of a centrifugal pump using multilayer perceptron genetic algorithm back propagation and support vector machine with discrete wavelet transform‐based feature extraction

This paper presents a comparative study of two artificial intelligent systems, namely; Multilayer Perceptron (MLP) and support vector machine (SVM), to classify six fault conditions and the normal (nonfaulty) condition of a centrifugal pump. A hybrid training method for MLP is proposed for this work based on the combination of Back Propagation (BP) and Genetic Algorithm (GA). The two training algorithms are tested and compared separately as well. Features are extracted using Discrete Wavelet Transform (DWT), both approximations, details, and two mother wavelets were used to investigate their effectiveness on feature extraction. GA is also used to optimize the number of hidden layers and neurons of MLP. In this study, the feature extraction, GA‐based hidden layers, neurons selection, training algorithm, and classification performance, based on the strengths and weaknesses of each method, are discussed. From the results obtained, it is observed that the DWT with both MLP‐BP and SVM produces better classification rates and performances.     

A new digital watermarking evaluation and benchmarking methodology using an external group of evaluators and multi‐criteria analysis based on ‘large‐scale data’

Digital watermarking evaluation and benchmarking are challenging tasks because of multiple evaluation and conflicting criteria. A few approaches have been presented to implement digital watermarking evaluation and benchmarking frameworks. However, these approaches still possess a number of limitations, such as fixing several attributes on the account of other attributes. Well‐known benchmarking approaches are limited to robust watermarking. Therefore, this paper presents a new methodology for digital watermarking evaluation and benchmarking based on large‐scale data by using external evaluators and a group decision making context. Two experiments are performed. In the first experiment, a noise gate‐based digital watermarking approach is developed, and the scheme for the noise gate digital watermarking approach is enhanced. Sixty audio samples from different audio styles are tested with two algorithms. A total of 120 samples were evaluated according to three different metrics, namely, quality, payload, and complexity, to generate a set of digital watermarking samples. In the second experiment, the situation in which digital watermarking evaluators have different preferences is discussed. Weight measurement with a decision making solution is required to solve this issue. The analytic hierarchy process is used to measure evaluator preference. In the decision making solution, the technique for order of preference by similarity to the ideal solution with different contexts (e.g., individual and group) is utilized. Therefore, selecting the proper context with different aggregation operators to benchmark the results of experiment 1 (i.e., digital watermarking approaches) is recommended. The findings of this research are as follows: (1) group and individual decision making provide the same result in this case study. However, in the case of selection where the priority weights are generated from the evaluators, group decision making is the recommended solution to solve the trade‐off reflected in the benchmarking process for digital watermarking approaches. (2) Internal and external aggregations show that the enhanced watermarking approach demonstrates better performance than the original watermarking approach. © 2016 The Authors. Software: Practice and Experience published by John Wiley & Sons Ltd.     

The Mediatization of E‐Campaigning: Evidence From German Party Websites in State,National, and European Parliamentary Elections 2002–2009

The rise of e‐campaigning is often associated with its ability to circumvent journalistic principles of news selection and presentation. By this, parties and candidates are said to free themselves from the discretionary power of the mass media and to reach voters in an unfiltered way. This conventional wisdom is tested through a comparative content analysis of German party websites in state, national, and European parliamentary elections between 2002 and 2009. The results show that e‐campaigns in all elections adhere in their messages to the media logic. Specifically, they replicate those patterns of offline coverage that have been held accountable for rising political alienation and civic apathy. Moreover, the mediatization of German e‐campaigning grows over time.