Reusing metamodels and notation with Diagram Definition

It is increasingly common for language specifications to describe visual forms (concrete syntax) separately from underlying concepts (abstract syntax). This is typically to enable interchange of visual information between graphical modeling tools, such as positions of nodes and routings of lines. Often overlooked is that separation of visual forms and abstract concepts enables languages to define multiple visual forms for the same underlying concepts and for the same visual form to be used for similar underlying concepts in different languages (many-to-many relationships between concrete and abstract syntax). Visual forms can be adapted to communities using different notations for the same concepts and can be used to integrate communities using the same notation for similar concepts. Models of concrete syntax have been available for some time, but are rarely used to capture these many-to-many relationships with abstract syntax. This paper shows how to model these relationships using concrete graphical syntax expressed in the Diagram Definition standard, examining cases drawn from the Unified Modeling Language and the Business Process Model and Notation. This gives definers of graphical languages a way to specify visual forms for multiple communities.     

Timed Behavior Trees for Failure Mode and Effects Analysis of time-critical systems

Behavior Trees are a graphical notation used for formalising functional requirements, and have been successfully applied to several industrial case studies. However, the standard notation does not support the concept of time, and consequently its application is limited to non-real-time systems. To overcome this limitation we extend the notation to timed Behavior Trees. We provide an operational semantics which is based on timed automata, and thus serves as a formal basis for the translation of timed Behavior Trees into the input notation of the timed model checker UPPAAL. System-level timing properties of a Behavior Tree model can then be automatically verified using UPPAAL. Based on the notational extensions with model checking support, we introduce timed Failure Mode and Effects Analysis, a process for identifying cause-consequence relationships between component failures and system hazards in real-time safety critical systems.     

A music notation construction engine for optical music recognition

Optical music recognition (OMR) systems are used to convert music scanned from paper into a format suitable for playing or editing on a computer. These systems generally have two phases: recognizing the graphical symbols (such as note‐heads and lines) and determining the musical meaning and relationships of the symbols (such as the pitch and rhythm of the notes). In this paper we explore the second phase and give a two‐step approach that admits an economical representation of the parsing rules for the system. The approach is flexible and allows the system to be extended to new notations with little effort—the current system can parse common music notation, Sacred Harp notation and plainsong. It is based on a string grammar and a customizable graph that specifies relationships between musical objects. We observe that this graph can be related to printing as well as recognizing music notation, bringing the opportunity for cross‐fertilization between the two areas of research. Copyright © 2003 John Wiley & Sons, Ltd.     

Avoiding Knotty Structures in Design: Schematic Functional Programming

Designers in general have used diagrams and sketches to help in the process of creation. This is particularly so for system designers whose output is a set of programs. It would seem reasonable that the conversion of diagrams directly into a program would be desirable and yet the work of Green and Petre [3–4, 13] and Citrin [2] has placed doubt on the viability of graphical programming notations. Some of this work is reviewed in this paper. The use of secondary notation and the matc–mismatch hypothesis is reconsidered in the light of functional programming. It is proposed that much of the criticism of graphical notation is due to the imperative (or process orientated) nature of programming. Many of the limitations observed in using graphical notation are lifted when functional programming is used. Eight engineering dimensions and four engineering relationships (coherences) are proposed to describe programming environments (including notation). The source of ‘knotty structures’ is identified as embedded ‘if then else’ or ‘if’ statements. On analysing both imperative and functional programs it was found that imperative programs used an order of magnitude larger number of ‘if’s than functional programs. The key to the success of a functional language as a general representation as well as its coherence with a graphical notation comes from its unique extensibility. Support for these arguments is drawn from examples of a schematic programming language used for industrial scale projects. It is concluded that the marriage between a functional language and its graphical representation overcomes most of the original criticisms of graphical programming. It is demonstrated that this combination makes a viable and expressive tool for industrial-sized applications.     

一种面向图形化建模语言表示法的元模型

对于图形化的建模语言,为定义其表示法一般需要解决3个问题:如何定义每个建模元素的图形符号,如何定义图形符号之间的位置关系以及如何将表示法映射到抽象语法.为了方便进行模型转换和代码生成,还需要使用模型化的方式描述建模语言的表示法.通过对UML及其语言家族中的表示法进行总结、分析和归纳,提出了一种表示法定义元模型(notation definition metamodel,简称NDM).针对定义表示法所面临的3个问题,NDM被分成基本图元及其布局、基本位置关系和抽象语法桥三部分.使用NDM定义好的表示法模型还可以通过代码生成技术生成可使用的源代码.将NDM与其他几种定义表示法的方法进行了比较,结果表明,NDM与其他方法相比具有优势.NDM已经在元建模工具PKU MetaModeler中实现.介绍了NDM在实际应用中的几个案例.     

Software design for finite difference schemes based on index notation

A formulation of finite difference schemes based on the index notation of tensor algebra is advocated. Finite difference operators on regular grids may be described as sparse, banded, “tensors”. Especially for higher space dimensions, it is claimed that a band tensor formulation better corresponds to the inherent problem structure than does conventional matrix notation.Tensor algebra is commonly expressed using index notation. The standard index notation is extended with the notion of index offsets, thereby allowing the common traversal of band tensor diagonals.The transition from mathematical index notation to implementation is presented. It is emphasized that efficient band tensor computations must exploit the particular problem structure, which calls for a combination of general index notation software with special-purpose band tensor routines.     

UML类图的形式化及分析

统一建模语言(UML)是一种通用的图形化建模语言,在面向对象系统的分析和设计中,它已成为事实上的工业标准。但是UML不是形式化的建模语言,缺乏精确的语义描述,因此会导致一些问题。Z是一种广泛使用的形式化规约语言,Z适合用来精确地表示模型的语法和语义。文章采用Z符号来表示UML类图的组成元素的语法和语义及其映射关系,最后对UML类图的一些性质进行分析和验证。     

Evaluating a graphical notation for modeling collaborative learning activities: A family of experiments

It is increasingly common to use languages and notations, mainly of a graphical nature, to assist in the design and specification of learning systems. There are several proposals, although few of them support the modeling of collaborative tasks. In this paper, we identify the main features to be considered for modeling this kind of activities and we propose the use of the CIAN notation for this purpose. In this work, we also try to empirically analyze the quality (in particular the understandability) of that notation. To this end, three empirical studies have been conducted. In these experiments we used several sources of information: subjective perception of the designers, their profiles and their performance on a set of understandability exercises, as well as the physical evidence provided by an eye tracker device. The results obtained denote positive perceptions about the use of the CIAN notation for modeling collaborative learning activities.     

Lean Cuisine+: an executable graphical notation for describing direct manipulation interfaces

The paper describes an executable semi-formal graphical notation, Lean Cuisine+, for describing the underlying behaviour of event-based direct manipulation interfaces, and outlines a methodology for constructing Lean Cuisine+ specifications. Lean Cuisine+ is a multilayered notation, and is a development of the meneme model of Lean Cuisine. A motivation of the research stems from the need for tools and techniques to facilitate high-level interface design. The research supports and brings together a number of views concerning the requirements of notations at this level. These are that a notation should be semi-formal, graphical, executable, and object-based, and that to be most effective it should be targeted at a specific category of interaction. The Lean Cuisine+ notation meets all these criteria, the underlying meneme model matching closely with the selection-based nature of direct manipulation interfaces.     

Correcting menu usability problems with sound

Future human-computer interfaces will use more than just graphical output to display information. In this paper we suggest that sound and graphics together can be used to improve interaction. We describe an experiment to improve the usability of standard graphical menus by the addition of sound. One common difficulty is slipping off a menu item by mistake when trying to select it. One of the causes of this is insufficient feedback. We designed and experimentally evaluated a new set of menus with much more salient audio feedback to solve this problem. The results from the experiment showed a significant reduction in the subjective effort required to use the new sonically-enhanced menus along with significantly reduced error recovery times. A significantly larger number of errors were also corrected with sound.     

A graphical model framework for decoding in the visual ERP-based BCI speller

We present a graphical model framework for decoding in the visual ERP-based speller system. The proposed framework allows researchers to build generative models from which the decoding rules are obtained in a straightforward manner. We suggest two models for generating brain signals conditioned on the stimulus events. Both models incorporate letter frequency information but assume different dependencies between brain signals and stimulus events. For both models, we derive decoding rules and perform a discriminative training. We show on real visual speller data how decoding performance improves by incorporating letter frequency information and using a more realistic graphical model for the dependencies between the brain signals and the stimulus events. Furthermore, we discuss how the standard approach to decoding can be seen as a special case of the graphical model framework. The letter also gives more insight into the discriminative approach for decoding in the visual speller system.     

Review of graphical notations for specifying direct manipulation interfaces

At the early stage of interface design, the designer requires models and notations that can assist with reasoning and the exploration of ideas, and which are unconstrained by implementation issues. The review focuses on graphical notations for specifying the underlying behaviour of direct manipulation interfaces. Parallels are drawn with the requirements of notations employed in the more general areas of system requirements specifications. A number of existing graphical notations are compared and contrasted through a common example drawn from the Macintosh interface, and the required scope of an ideal notation for describing the behaviour of direct manipulation interfaces is defined.     

The lime music editor: A diagram editor involving complex translations

Lime is a music editor, oriented to the production of printed music. A user manipulates the information content of the music notation, while viewing the physical appearance of the notation. To implement this, Lime must perform a complex translation from an abstract musical source representation to a graphical product. Techniques are discussed for providing automation without loss of customizability, for implementing WYSIWYG editing, for supporting multiple products (e.g. orchestral score and parts), and for providing good response time despite a slow translator. Similar design issues are encountered by editors for other types of diagrams, such as schematics, chemical formulas, and maps.     

Comparison of a textual versus a graphical notation for the maintainability of MDE domain models: an empirical pilot study

Models are a useful tool to increase the developer’s productivity and satisfaction when performing maintenance tasks. However, in order to maximise these advantages, the right selection of notations must be made. Unfortunately, the software engineering field lacks a body of empirical evidence that supports such selection. A suboptimal decision in this regard may have negative consequences over the maintenance process. The aim of the study was to compare a textual and a graphical notation with respect to the efficiency, effectiveness and satisfaction of junior software developers while performing analysability and modifiability tasks on two different applications. We have carried out a quasi-experiment with 86 third-year students of the Computer Engineering degree at the University of Alicante. Subjects were randomly classified into two groups, and each group performed 20 maintenance tasks with a textual and a graphical notation. We measured and compared the efficiency, effectiveness and satisfaction of subjects assigned to each treatment. The analysed data show that only the actual analysability coverage (AACov) and the actual modifiability efficiency (AMEffc) are affected by the type of notation used, regardless of the application. In both cases, subjects using the textual notation performed significantly better, although the effect size was low to moderate (AACov \(\eta ^2=0.106\), AMEffc \(\eta ^2=0.187\)). This is a pilot study, and it has been conducted to enhance the design of future studies in this area. Thus, it should be replicated to extend our conclusions to other subject profiles, different textual and graphical notations, and application types.     

Graphical reasoning in compact closed categories for quantum computation

Compact closed categories provide a foundational formalism for a variety of important domains, including quantum computation. These categories have a natural visualisation as a form of graphs. We present a formalism for equational reasoning about such graphs and develop this into a generic proof system with a fixed logical kernel for reasoning about compact closed categories. A salient feature of our system is that it provides a formal and declarative account of derived results that can include ‘ellipses’-style notation. We illustrate the framework by instantiating it for a graphical language of quantum computation and show how this can be used to perform symbolic computation.