Applied Mechanics and Materials Vol. 742

Abstract: It is extremely urgent to study on the scientific and reasonable evaluation index system in this field when small and medium-sized enterprises start turning to purchase cloud services instead of IT hardware. By making use of analytic network process, based on characteristics of cloud services, referring to common QoS properties in cloud service evaluation, 11 cloud service evaluation indexes are established in this paper and each index is quantified.

Abstract: Cloud Foundry is the industry's first open source PaaS cloud platform, it supports a variety of framework, language, runtime cloud platform and application environment, the service that allows developers to make applications in a few seconds the deployment and expansion, there is no need to worry about any infrastructure problems. This paper introduces the main steps to build the PaaS service platform: Cloud Controller、 Health Manager、 stager、 service, and discusses the matters needing attention in construction process.

Abstract: In application-layer DoS/DDoS attacks, malicious users attack the victim server by sending lots of legitimate requesting packages, which overwhelm the server bottleneck resources. Normal user’s request thus may not be satisfied. The traditional intrusion detection systems for network-layer cannot effectively identify this attack, and recent researches on this kind of attack are mainly for Web servers. This paper proposed a new defense algorithm based on user activity for topic-based Pub/Sub communication servers in mobile push notification systems. Users consuming system bottleneck resources the most can get high scores and thus are considered overactive. With some resource retaken strategy, overactive users’ connections will be dropped according to system performance level. Therefore, the system can get rid of latent threatens. Experiments indicated that this algorithm can identify normal and abnormal users well.

Abstract: Using advantages of PLC, SCADA, inverter, bus and internet in industrial production, in order to cope with the characteristics of large number of motor, complex sequential logical, high drive control demanding and distributed in different territory, it designs a configuration monitoring system for motor group integrative management and control network system, which uses PPI protocol and USS protocol and fieldbus technology, configuration monitoring technology and network technology, etc. It can realize the effective management of large number of motor driving and control. Due to its function quite similar, S7-200 and S7-300 and MM440 in the paper can be replaced by other kinds of PLC and inverter on the market. So the control scheme proposed by this paper is more practical and universal. Application in textile printing and dyeing institutions multi-cell motor driving, it shows that the designed system can drive and control the motor group with high efficiency and reliable.Keyword: large number of motor; motor group network; drive and control; inverter; PLC-SCADA.

Abstract: The Internet of Things (IoT) technology has been extending its applications in the electric power system since the very beginning of the construction of the smart grid in China. Under such a background, this paper first discusses the technical principles and development goals of the IoT for the electric power system, which can also be called the “power grid IoT” in brief. And then, according to the technical principles mentioned above and the common guidance released by the power grid authorities, this paper presents an IoT technology based Supervisory Control And Data Acquisition (SCADA) system for substations. The key technologies, functions and applications of the system are described respectively. The design of an extremely long-life and stable wireless temperature sensor is presented in detail. The functions of the SCADA system include substation equipment status monitoring, 3D-visualization, environment monitoring, spare parts location, asset management and so on. The applications of such a system can be regarded as efficient methods for substation intelligent operation and maintenance.

Abstract: The virtual cable television network is a cable television system with virtual assets, users in the network may have different authentication mechanisms. In order to meet corporate users across heterogeneous virtual, trusted domain request service is required. This paper proposes a bill based on the access authorization authentication scheme across heterogeneous domains. The scheme is based on VCA certification model, the Kerberos AS and the PKI domain as the domain where the CA Enterprise Domain external authentication node, generate its extracellular domain users access, the domain resources authorization bill and the session key, and then realize PKI and Kerberos cross-domain authentication ,domain user and session key agreement. Article on the safety and efficiency of the program are analyzed. Analysis shows that this scheme can resist various attacks, with high security, and higher than the efficiency of alternative solutions for virtual cable television network, efficient resource sharing of cross-domain security provides an effective solution.

Abstract: With fast development and deep appliance of the Internet, problem of mass image data storage stand out, so the problem of low management efficiency, low storage ability and high cost of traditional storage framework has appeared. The appearance of Hadoop provides a new thought. However, Hadoop itself is not suit for the handle of small files. This paper puts forward a storage framework of mass image files based on Hadoop, and solved the internal storage bottleneck of NameNode when small files are excessive through classification algorithm of preprocessing module and lead-in of high efficiency and first-level of index mechanism. The test manifests that the system is safe, easy to defend and has fine extension quality; as a result, it can reach to a fine effect.

Abstract: This paper presents a lightweight index does not suspend services online update program, and demonstrate the performance of the index update program from the theoretical analysis and experimental data in two ways. A new method of MapReduce existing index methodology based on this design and further discussion are done in the paper, in the index MapReduce and Hadoop MapReduce feasibility aspects, the design flaws through experimentation.

Abstract: This paper presents a collision algorithm based on frame slots RFID tag identification and prevention, algorithms on performance is more stable, less total cost of the number of time slots. For the anti-collision algorithm for the simulation, the average number of searches were simulated contrast of the number of tags and the number of slots and different algorithms collision situations relations, research results show that this type of algorithm is effective in reducing the identification number of the reader's request to reduce the energy consumed by the reader, particularly suitable for applications in handheld reader today.

Abstract: Reactive power compensation is one of the effective means to improve the quality of voltage, reduce loss and save energy. How to make full use of the inductance converter and capacitance banks and to make them cooperative run, is the key of industrialization for the dynamic reactive power compensator for the composite power load. Therefore, a novel parameter optimization platform of the dynamic reactive power compensator for the composite power load is designed in this paper. The following works have been done in the study: reactive power variation characteristic of the composite power load and power factor requirements, capacity calculation and parameter adjusting method of the dynamic reactive power compensator, and a novel parameter optimization platform of the dynamic reactive power compensator for the composite power load. The research has laid a theoretical foundation for this dynamic reactive power compensator in industrial applications.