Formal specification of non-functional properties of component-based software systems

Component-based software engineering (CBSE) is viewed as an opportunity to deal with the increasing complexity of modern-day software. Along with CBSE comes the notion of component markets, where more or less generic pieces of software are traded, to be combined into applications by third-party application developers. For such a component market to work successfully, all relevant properties of components must be precisely and formally described. This is especially true for non-functional properties, such as performance, memory foot print, or security. While the specification of functional properties is well understood, non-functional properties are only beginning to become a research focus. This paper discusses semantic concepts for the specification of non-functional properties, taking into account the specific needs of a component market. Based on these semantic concepts, we present a new specification language QML/CS that can be used to model non-functional product properties of components and component-based software systems.     

最优中值滤波跨度计算及其应用

为提高地震资料的信噪比（Signal Noise Ratio，SNR），通过对地震模型纹理进行中值滤波实验分析，研究最优中值滤波跨度与波长、道间时差或频率、视速度之间的关系，推导最优跨度的计算公式，并以理论模型和实际数据进行验证，得到较为满意的中值滤波结果．     

Software quality, non-functional software requirements and IT-business alignment

‘High quality’ might seem an obvious requirement for any piece of software, but do the different stakeholder groups involved in its production and use conceptualize this requirement in the same way? Many existing models refine the broad concept of quality into a number of well-defined and measurable attributes related to the software product itself and the development process which produced it. But despite growing awareness of the importance of achieving cultural alignment between holders of different business and IT groups, little attempt has been made to empirically examine the requirements for software quality held by different groups involved in the development process. We conducted a survey of more than 300 current and recently graduated students of one of the leading Executive MBA programs in the United States, asking them to rate the importance of each of 13 widely-cited attributes related to software quality. The results showed business role-related differences in some specific areas and agreement in many others. The results suggest that a strong shared culture may be able to bridge the gulf created between holders of IT and business stakeholder roles.     

基于FPGA的图像中值滤波器设计

介绍了基于FPGA的图像采集及处理系统的总体结构和模块设计。在图像处理模块中,根据FPGA并行计算的特点,提出了改进的中值滤波算法。通过与原算法进行比较,论证了该算法在提高系统效率方面具有优势。     

基于FPGA的实时中值滤波器硬件实现

针对高清图像在中值滤波预处理过程中排序量多、速度慢的特点,提出适合邻域图像并行处理机的分块存储方法。在流水线结构下,1个时钟周期可以并行处理32个3×3邻域的中值滤波运算,实现了高速、实时的1 920×1 080灰度图像中值滤波器。     

Integrating the analysis of multiple non-functional properties in model-driven engineering

Software and Systems Modeling - This paper discusses the progress made so far and future challenges in integrating the analysis of multiple Non-Functional Properties (NFP) (such as performance,...     

基于四分法噪声检测的开关中值滤波算法

为了精确的检测出图像中的脉冲噪声并滤除,提出一种差分四分法的开关中值滤波算法.该算法对噪声检测窗口内像素按灰度值大小排序,通过差分方法划分出高、低阶信号块和高,低阶噪声块4部分.当待测像素属于高,低阶信号块时视其为信号点,否则,根据噪声块与信号块内像素比例关系确定其为噪声点或可能噪声点,若为可能噪声点,则扩展检测窗口重新检测.对于噪声点,基于其邻域噪声密度自适应的确定滤波窗口,取滤窗内信号点的中值作为滤波输出.实验证明该算法对脉冲噪声有很强的抑制作用.     

Verifying distributed real-time properties of embedded systems via graph transformations and model checking

Component middleware provides dependable and efficient platforms that support key functional, and quality of service (QoS) needs of distributed real-time embedded (DRE) systems. Component middleware, however, also introduces challenges for DRE system developers, such as evaluating the predictability of DRE system behavior, and choosing the right design alternatives before committing to a specific platform or platform configuration. Model-based technologies help address these issues by enabling design-time analysis, and providing the means to automate the development, deployment, configuration, and integration of component-based DRE systems. To this end, this paper applies model checking techniques to DRE design models using model transformations to verify key QoS properties of component-based DRE systems developed using Real-time CORBA. We introduce a formal semantic domain for a general class of DRE systems that enables the verification of distributed non-preemptive real-time scheduling. Our results show that model-based techniques enable design-time analysis of timed properties and can be applied to effectively predict, simulate, and verify the event-driven behavior of component-based DRE systems. This research was supported by the NSF Grants CCR-0225610 and ACI-0204028 Gabor Madl is a Ph.D. student and a graduate student researcher at the Center for Embedded Computer Systems at the University of California, Irvine. His advisor is Nikil Dutt. His research interests include the formal verification, optimization, component-based composition, and QoS management of distributed real-time embedded systems. He received his M.S. in computer science from Vanderbilt University and in computer engineering from the Budapest University of Technology and Economics. Dr. Sherif Abdelwahed received his Ph.D. degree in Electrical and Computer Engineering from the University of Toronto, Canada, in 2001. During 2000–2001, he was a research scientist with the system diagnosis group at the Rockwell Scientific Company. Since 2001 he has been with the Department of Electrical Engineering and Computer Science at Vanderbilt University as a Research Assistant Professor. His research interests include verification and control of distributed real-time systems, and model-based diagnosis of discrete-event and hybrid systems. Dr. Douglas C. Schmidt is a Professor of Computer Science, Associate Chair of the Computer Science and Engineering program, and a Senior Researcher in the Institute for Software Integrated Systems (ISIS) all at Vanderbilt University. He has published over 300 technical papers and 6 books that cover a range of research topics, including patterns, optimization techniques, and empirical analyses of software frameworks and domain-specific modeling environments that facilitate the development of distributed real-time and embedded (DRE) middleware and applications. Dr. Schmidt has served as a Deputy Office Director and a Program Manager at DARPA, where he lead the national R&D effort on middleware for DRE systems. In addition to his academic research and government service, Dr. Schmidt has over fifteen years of experience leading the development of ACE, TAO, CIAO, and CoSMIC, which are widely used, open-source DRE middleware frameworks and model-driven tools that contain a rich set of components and domain-specific languages that implement patterns and product-line architectures for high-performance DRE systems.     

Memory protection in embedded systems

With reference to an embedded system featuring no support for memory management, we present a model of a protection system based on passwords. At the hardware level, our model takes advantage of a memory protection unit (MPU) interposed between the processor and the complex of the main memory and the input-output devices. The MPU supports both concepts of a protection context and a protection domain. A protection context is a set of access rights for the memory pages; a protection domain is a set of one or more protection contexts. Passwords are associated with protection domains. A process that holds a given password can take advantage of this password to activate the corresponding domain. A small set of protection primitives makes it possible to modify the composition of the domains in a strictly controlled fashion.The proposed protection model is evaluated from a number of important viewpoints, which include password distribution, review and revocation, the memory requirements for storage of the information concerning protection, and the time necessary for password validation.     

A systematic review of search-based testing for non-functional system properties

Search-based software testing is the application of metaheuristic search techniques to generate software tests. The test adequacy criterion is transformed into a fitness function and a set of solutions in the search space are evaluated with respect to the fitness function using a metaheuristic search technique. The application of metaheuristic search techniques for testing is promising due to the fact that exhaustive testing is infeasible considering the size and complexity of software under test. Search-based software testing has been applied across the spectrum of test case design methods; this includes white-box (structural), black-box (functional) and grey-box (combination of structural and functional) testing. In addition, metaheuristic search techniques have also been applied to test non-functional properties. The overall objective of undertaking this systematic review is to examine existing work into non-functional search-based software testing (NFSBST). We are interested in types of non-functional testing targeted using metaheuristic search techniques, different fitness functions used in different types of search-based non-functional testing and challenges in the application of these techniques. The systematic review is based on a comprehensive set of 35 articles obtained after a multi-stage selection process and have been published in the time span 1996–2007. The results of the review show that metaheuristic search techniques have been applied for non-functional testing of execution time, quality of service, security, usability and safety. A variety of metaheuristic search techniques are found to be applicable for non-functional testing including simulated annealing, tabu search, genetic algorithms, ant colony methods, grammatical evolution, genetic programming (and its variants including linear genetic programming) and swarm intelligence methods. The review reports on different fitness functions used to guide the search for each of the categories of execution time, safety, usability, quality of service and security; along with a discussion of possible challenges in the application of metaheuristic search techniques.     

CONTREX: Design of embedded mixed-criticality CONTRol systems under consideration of EXtra-functional properties

The increasing processing power of today’s HW/SW platforms leads to the integration of more and more functions in a single device. Additional design challenges arise when these functions share computing resources and belong to different criticality levels. CONTREX complements current activities in the area of predictable computing platforms and segregation mechanisms with techniques to consider the extra-functional properties, i.e., timing constraints, power, and temperature. CONTREX enables energy efficient and cost aware design through analysis and optimization of these properties with regard to application demands at different criticality levels. This article presents an overview of the CONTREX European project, its main innovative technology (extension of a model based design approach, functional and extra-functional analysis with executable models and run-time management) and the final results of three industrial use-cases from different domain (avionics, automotive and telecommunication).     

A framework for utilizing qualitative spatial relations between networked embedded systems

With more and more everyday artifacts being equipped with networked embedded systems technology, their spatial situation or context–such as where they are located or whether two of them are near or far apart from each other–is becoming increasingly relevant. The emerging availability of sensor technologies for measuring properties of the physical space enables them to become aware of their spatial context and adapt to changes accordingly, which in turn contributes to the implementation of systems that operate autonomously in the background and interact with humans in a more unobtrusive way. In this article, we specifically address the use of spatial relations between technology-rich artifacts as well as their changes over time. A key aspect is the abstraction of spatial contexts in order to separate details which are not relevant for a certain application, and thereby save computational resources or provide spatial information in a way that is closer to human concepts of space. In this regard, our focus is on qualitatively represented spatial relations, which are used as the basic building blocks for the development of spatially aware applications. A novel software framework is presented for this purpose and evaluated with respect to its performance as well as its adequacy for building real-world applications.     

SPL Conqueror: Toward optimization of non-functional properties in software product lines

A software product line (SPL) is a family of related programs of a domain. The programs of an SPL are distinguished in terms of features, which are end-user visible characteristics of programs. Based on a selection of features, stakeholders can derive tailor-made programs that satisfy functional requirements. Besides functional requirements, different application scenarios raise the need for optimizing non-functional properties of a variant. The diversity of application scenarios leads to heterogeneous optimization goals with respect to non-functional properties (e.g., performance vs. footprint vs. energy optimized variants). Hence, an SPL has to satisfy different and sometimes contradicting requirements regarding non-functional properties. Usually, the actually required non-functional properties are not known before product derivation and can vary for each application scenario and customer. Allowing stakeholders to derive optimized variants requires us to measure non-functional properties after the SPL is developed. Unfortunately, the high variability provided by SPLs complicates measurement and optimization of non-functional properties due to a large variant space. With SPL Conqueror, we provide a holistic approach to optimize non-functional properties in SPL engineering. We show how non-functional properties can be qualitatively specified and quantitatively measured in the context of SPLs. Furthermore, we discuss the variant-derivation process in SPL Conqueror that reduces the effort of computing an optimal variant. We demonstrate the applicability of our approach by means of nine case studies of a broad range of application domains (e.g., database management and operating systems). Moreover, we show that SPL Conqueror is implementation and language independent by using SPLs that are implemented with different mechanisms, such as conditional compilation and feature-oriented programming.     

Hardware-software codesign of embedded systems

Designers generally implement embedded controllers for reactive real-time applications as mixed software-hardware systems. In our formal methodology for specifying, modeling, automatically synthesizing, and verifying such systems, design takes place within a unified framework that prejudices neither hardware nor software implementation. After interactive partitioning, this approach automatically synthesizes the entire design, including hardware-software interfaces. Maintaining a finite-state machine model throughout, it preserves the formal properties of the design. It also allows verification of both specification and implementation, as well as the use of specification refinement through formal verification     

Reuse factors in embedded systems design

At first glance, embedded systems appear to be poor candidates for incorporating reuse. Many embedded systems actively or passively prevent loss of life, so they usually meet stringent specifications for safety, reliability, and real-time operation. To meet these requirements, the obvious solution is to redesign hardware and software components for each application. At Siemens they have found that embedded system requirements are not compatible with reusing hardware and software components. Engineers, however, must consider certain factors from the beginning of the design     

一种低资源消耗的中值滤波硬件架构设计

针对传统的中值滤波算法在硬件实现时,在窗口较大的情况下会消耗较多资源的问题,根据位级运算的中值滤波比较算法,设计了一种低硬件资源消耗的基于5×5窗口大小的位级中值滤波硬件架构,并在Xilinx Vivado 2017. 1硬件平台上进行了仿真验证。相比较传统的中值滤波算法的硬件设计,本次硬件架构设计大大减少了硬件资源,且运算速度较快,满足实时性的要求。     

基于模糊推理的方向中值椒盐滤波算法

针对灰度图像中的椒盐噪声,提出了一种基于模糊逻辑推理的方向中值滤波算法.该算法先利用椒盐噪声的特点,将图像像素点分为信号像素点和噪声像素点,然后利用模糊推理在4个方向上推理出最接近理想值的非噪声点代替当前噪声点.同时算法中采用一种简便的方法检测出噪声点所处的滑动窗口中的边和线.仿真结果表明,该算法能在有效抑制噪声的同时较好地保存图像的细节信息.     

基于曲率和中值滤波的快速推移图像修复方法

提出了一种结合中值滤波和基于曲率扩散的图像修复方法.中值滤波修复方法对于灰度值变化比较平缓的图像,修复效果从时间性能和视觉效果上均比较好,但对于灰度值变化比较剧烈的图像,效果不能令人满意.在结合了基于曲率扩散的修复方法之后,中值滤波的不足之处得到了改善.基于曲率扩散的修复方法考虑了图像本身的几何信息,在修复图像的几何特征上有较高的准确度.图像修复顺序由已知区域向未知区域扩散时经过各破损点的时间决定,用快速推移方法计算该时间.实验表明,该算法能高效、稳定地处理破损区域的图像信息.     

HT高速总线及其在嵌入式系统中的应用

介绍了HT总线的特点,并比较了其与传统PCI总线及竞争者PCIe总线的异同点,阐述了HT总线的优势,HT总线在嵌入式系统中的设计、应用和调试经验。     

Specification and design of embedded hardware-software systems

Embedded-system specification and design consists of describing a system's desired functionality and mapping that functionality for implementation by a set of system components such as processors, ASICs, memories, and buses. This paper discusses the key problems of system specification and design, including specification capture, design exploration, hierarchical modeling, software and hardware synthesis, and cosimulation. The authors highlight existing tools and methods for solving those problems and describe a “specify-explore-refine” methodology for meeting today's embedded-system product development requirements