摘要：In the era of Big Data, typical architecture of distributed real-time stream processing systems is the combination of Flume, Kafka, and Storm. As a kind of distributed message system, Kafka has the characteristics of horizontal scalability and high throughput, which is manly deployed in many areas in order to address the problem of speed mismatch between message producers and consumers. When using Kafka, we need to quickly receive data sent by producers. In addition, we need to send data to consumers quickly. Therefore, the performance of Kafka is of critical importance to the performance of the whole stream processing system. In this paper, we propose the improved design of real-time stream processing systems, and focus on improving the Kafka's data loading *** use Kafka cat to transfer data from the source to Kafka topic directly, which can reduce the network transmission. We also utilize the memory file system to accelerate the process of data loading, which can address the bottleneck and performance problems caused by disk I/O. Extensive experiments are conducted to evaluate the performance, which show the superiority of our improved design.

摘要：In this paper, a hexagonal shape photonic crystal fiber （H-PCF） has been proposed as a gas sensor of which both micro-structured core and cladding are organized by circular air cavities. The reported H-PCF has a single layer circular core which is surrounded by a five-layer hexagonal cladding. The overall pretending process of the H-PCF is completed by using a full vectorial finite element method （FEM） with perfectly matched layer （PML） boundary condition. All geometrical parameters like diameters and pitches of both core and cladding regions have fluctuated with an optimized structure. After completing the numerical analysis, it is clearly visualized that the proposed H-PCF exhibits high sensitivity with low confinement loss. The investigated results reveal the relative sensitivity of 56.65% and confinement loss of 2.31×10^-5 dB/m at the 1.33%tm wavelength. Moreover, effective area, nonlinearity, and V-parameter of the suggested PCF are also briefly described.

摘要：A trajectory generator based on vehicle kinematics model was presented and an integrated navigation simulation system was *** that the tight relation between vehicle motion and topography,a new trajectory generator for vehicle was proposed for more actual ***,a vehicle kinematics model was built based on conversion of attitude vector in different coordinate ***,the principle of common trajectory generators was ***,combining the vehicle kinematics model with the principle of dead reckoning,a new vehicle trajectory generator was presented,which can provide process parameters of carrier anytime and achieve simulation of typical actions of running ***,IMU(inertial measurement unit) elements were simulated,including accelerometer and *** setting up the simulation conditions,the integrated navigation simulation system was verified by final performance *** result proves the validity and flexibility of this design.

摘要：Cloud Computing is an emerging technology for processing and storing very large amounts of data. Sometimes anomalies and defects affect part of the cloud infrastructure, resulting in a performance degradation of the cloud. This paper proposes a performance measurement framework for Cloud Computing systems, which integrates software quality concepts from ISO 25010.

摘要：The standard software development life cycle heavily depends on requirements elicited from stakeholders. Based on those requirements, software development is planned and managed from its inception phase to closure. Due to time and resource constraints, it is imperative to identify the high-priority requirements that need to be considered first during the software development process. Moreover, existing prioritization frameworks lack a store of historical data useful for selecting the most suitable prioritization technique of any similar project domain. In this paper, we propose a framework for prioritization of software requirements, called Re Pizer, to be used in conjunction with a selected prioritization technique to rank software requirements based on defined criteria such as implementation cost. ReP izer assists requirements engineers in a decision-making process by retrieving historical data from a requirements repository. Re Pizer also provides a panoramic view of the entire project to ensure the judicious use of software development resources. We compared the performance of Re Pizer in terms of expected accuracy and ease of use while separately adopting two different prioritization techniques, planning game（PG） and analytical hierarchy process（AHP）. The results showed that Re Pizer performed better when used in conjunction with the PG technique.

摘要：It is widely acknowledged that Requirements engineering (RE) has an important implication for the overall success of software or system development projects. As more and more organizations consider RE as the principal problem areas in the projects, improving RE process therefore appears critical for future business success. Moreover, nowadays there are evidences that support improving RE process maturity can contributes to improved business performance. There exist generic software Process Improvement (SPI) standards, specialised RE process improvement models as well as guidance and advices on RE. However, they suffer from various issues that limit their adoption by organizations that are interested to assess and improve their RE process capability. Therefore, the research presented in this paper proposes a new RE process improvement model. The model is built by adapting and expanding the structure of the continuous representation of the formal maturity framework Capability Maturity Model Integration for Development (CMMI-DEV) developed by the software engineering Institute (SEI) through three rounds of development and validation stages, which involved RE and CMMI expert panel in the software industry. This paper aims to provide an overview on what, why and how we build the maturity model for RE. The intention is to provide a foundation for future development in the area of RE process improvement.