WebSpec: a visual language for specifying interaction and navigation requirements in web applications

Web application development is a complex and time-consuming process that involves different stakeholders (ranging from customers to developers); these applications have some unique characteristics like navigational access to information, sophisticated interaction features, etc. However, there have been few proposals to represent those requirements that are specific to Web applications. Consequently, validation of requirements (e.g., in acceptance tests) is usually informal and as a result troublesome. To overcome these problems, we present WebSpec, a domain-specific language for specifying the most relevant and characteristic requirements of Web applications: those involving interaction and navigation. We describe WebSpec diagrams, discussing their abstraction and expressive power. With a simple though realistic example, we show how we have used WebSpec in the context of an agile Web development approach discussing several issues such as automatic test generation, management of changes in requirements, and improving the understanding of the diagrams through application simulation.     

Vibes: A visual language for specifying behavioral requirements of algorithms

Manually verifying the behavior of software systems with respect to a set of requirements is a time-consuming and error-prone task. If the verification is automatically performed by a model checker however, time can be saved, and errors can be prevented. To be able to use a model checker, requirements need to be specified using a formal language. Although temporal logic languages are frequently used for this purpose, they are neither commonly considered to have sufficient usability, nor always naturally suited for specifying behavioral requirements of algorithms. Such requirements can be naturally specified as regular language recognizers such as deterministic finite accepters, which however suffer from poor evolvability: the necessity to re-compute the recognizer whenever the alphabet of the underlying model changes. In this paper, we present the visual language Vibes that both is naturally suited for specifying behavioral requirements of algorithms, and enables the creation of highly evolvable specifications. Based on our observations from controlled experiments with 23 professional software engineers and 21 M.Sc. computer science students, we evaluate the usability of Vibes in terms of its understandability, learnability, and operability. This evaluation suggests that Vibes is an easy-to-use language.     

Evaluating a data abstraction testing system based on formal specifications

A compiler-based specification and testing system for defining data types has been developed. The system, DAISTS (data abstraction implementation, specification, and testing system) includes formal algebraic specifications and statement and expression test coverage monitors. This paper describes our initial attempt to evaluate the effectiveness of the system in helping users produce software. In an exploratory study, subjects without prior experience with DAISTS were encouraged by the system to develop effective sets of test cases for their implementations. Furthermore, an analysis of the errors remaining in the implementations provided valuable hints about additional useful testing metrics.     

Requirements for tools for ambiguity identification and measurement in natural language requirements specifications

This paper proposes a two-step approach to identifying ambiguities in natural language (NL) requirements specifications (RSs). In the first step, a tool would apply a set of ambiguity measures to a RS in order to identify potentially ambiguous sentences in the RS. In the second step, another tool would show what specifically is potentially ambiguous about each potentially ambiguous sentence. The final decision of ambiguity remains with the human users of the tools. The paper describes several requirements-identification experiments with several small NL RSs using four prototypes of the first tool based on linguistic instruments and resources of different complexity and a manual mock-up of the second tool.

Toward a language for specifying summarizing statistics

We introduce the ordered weighted averaging (OWA) operator and discuss how it can provide a basis for generating summarizing statistics over large data sets. We further note how different forms of OWA operators can be induced using weight generating functions. We show how these weight generating functions can provide a vehicle with which a data analyst can express desired summarizing statistics. Our goal is to develop an understanding of the relationship between weight generating functions and resulting summarizing statistics.     

Integrating domain knowledge,requirements, and specifications

This paper describes efforts to develop a transformation-based software environment that supports the acquisition and validation of software requirements specifications. These requirements may be stated informally at first, and then gradually formalized and elaborated. Support is provided for groups of requirements analysts working together, focusing on different analysis tasks and areas of concern. The environment assists in the validation of formalized requirements by translating them into natural language and graphical diagrams and testing them against a running simulation of the system to be built. Requirements defined in terms of domain concepts are transformed into constraints on system components. The advantages of this approach are that specifications can be traced back to requirements and domain concepts, which in turn have been precisely defined.     

A reference model for requirements and specifications

The authors define a reference model for applying formal methods to the development of user requirements and their reduction to a behavioral system specification. The approach focuses on the shared phenomena that define the interface between the system and the environment     

On a new formal proof model for RFID location privacy

We discuss a recently proposed formal proof model for RFID location privacy. We show that protocols which intuitively and in several other models are considered not to be location private, are provably location private in this model. Conversely, we also show that protocols which obviously are location private, are not considered location private in this model.Specifically, we prove a protocol in which every tag transmits the same constant message to not be location private in the proposed model. Then we prove a protocol in which a tag's identity is transmitted in clear text to be weakly location private in the model.     

On the use of a formal requirements engineering language: The Generalized Railroad Crossing Problem

In this paper, we report on the use of theAlbert II requirements specification language through the handling of the Generalized Railroad Crossing case study. This formal language is based on an ontology of concepts used for capturing requirements inherent in real-time, distributed systems. Because of itsnaturalness, the language supports a direct mapping of customers’ informal needs onto formal statements, without having to introduce artificial elements. The language is founded on a formal framework (real-time temporal logic) which supports the reasoning process of the analyst during the elaboration of the specification. Such support for the reasoning is illustrated in the context of a goal-oriented approach adopted for the elaboration of the case study.     

RAPS: a rule-based language for specifying resource allocation andtime-tabling problems

A general language for specifying resource allocation and time-tabling problems is presented. The language is based on an expert system paradigm that was developed previously by the authors and that enables the solution of resource allocation problems by using experts' knowledge and heuristics. The language enables the specification of a problem in terms of resources, activities, allocation rules, and constraints, and thus provides a convenient knowledge acquisition tool. The language syntax is powerful and allows the specification of rules and constraints that are very difficult to formulate with traditional approaches, and it also supports the specification of various control and backtracking strategies. We constructed a generalized inference engine that runs compiled resource allocation problem specification language (RAPS) programs and provides all necessary control structures. This engine acts as an expert system shell and is called expert system for resource allocation (ESRA). The performance of RAPS combined with ESRA is demonstrated by analyzing its solution of a typical resource allocation problem     

Tools for producing formal specifications: a view of current architectures and future directions

During the last decade, one important contribution towards requirements engineering has been the advent of formal specification languages. They offer a well‐defined notation that can improve consistency and avoid ambiguity in specifications. However, the process of obtaining formal specifications that are consistent with the requirements is itself a difficult activity. Hence, various researchers are developing systems that aid the transition from informal to formal specifications. The kind of problems tackled and the contributions made by these proposed systems are very diverse. This paper brings these studies together to provide a vision for future architectures that aim to aid the transition from informal to formal specifications. The new architecture, which is based on the strengths of existing studies, tackles a number of key issues in requirements engineering such as identifying ambiguities, incompleteness, and reusability. The paper concludes with a discussion of the research problems that need to be addressed in order to realise the proposed architecture.     

数据流特征感知的交换机流表智能更新方法

针对软件定义网络（SDN）中交换机流表匹配率低的问题,提出了数据流特征感知的交换机流表智能更新方法。首先,论述流表项的生存超时时间timeout对数据包匹配的影响,并且分析比较基于先进先出（FIFO）、近期最少使用（LRU）等一般方法存在的不足;其次,根据流表项的生存时间和数据流的特征密切相关的思想,利用基于隐马尔可夫模型（HMM）的深度流检测（DFI）技术对数据流进行分类;最后,根据流表资源和控制器计算资源状况,实现对不同类型数据流流表项的智能更新。采用校园数据中心网络行为数据的模拟实验表明,与流表更新的一般方法相比,智能方法能使流表匹配率提高5%以上,对SDN交换机的管理有实际意义。     

RMoCap: an R language package for processing and kinematic analyzing motion capture data

Multimedia Systems - Package RMoCap is an advanced open-source tool for scientists, engineers and computer graphics familiar with R language who work with motion capture (MoCap) technology. Package...     

Debugging formal specifications: a practical approach using model-based diagnosis and counterstrategies

Creating a formal specification for a design is an error-prone process. At the same time, debugging incorrect specifications is difficult and time consuming. In this work, we propose a debugging method for formal specifications that does not require an implementation. We handle conflicts between a formal specification and the informal design intent using a simulation-based refinement loop, where we reduce the problem of debugging overconstrained specifications to that of debugging unrealizability. We show how model-based diagnosis can be applied to locate an error in an unrealizable specification. The diagnosis algorithm computes properties and signals that can be modified in such a way that the specification becomes realizable, thus pointing out potential error locations. In order to fix the specification, the user must understand the problem. We use counterstrategies to explain conflicts in the specification. Since counterstrategies may be large, we propose several ways to simplify them. First, we compute the counterstrategy not for the original specification but only for an unrealizable core. Second, we use a heuristic to search for a countertrace, i.e., a single input trace which necessarily leads to a specification violation. Finally, we present the countertrace or the counterstrategy as an interactive game against the user, and as a graph summarizing possible plays of this game. We introduce a user-friendly implementation of our debugging method and present experimental results for GR(1) specifications.