Textual Notation Research Articles

Graphical versus textual software measurement modelling: an empirical study

Model-driven Engineering (MDE) has attained great importance in both the Software Engineering industry and the research community, where it is now widely used to provide a suitable approach with which to improve productivity when developing software artefacts. In this scenario, measurement models (software artefacts) have become a fundamental point in improvement of productivity, where MDE and Software Measurement can reap mutual benefits. MDE principles and techniques can be used in software measurement to build more automatic and generic solutions, and to achieve this, it is fundamental to be able to develop software measurement models. To facilitate this task, a domain-specific language named "Software Measurement Modelling Language" (SMML) has been developed. This paper tackles the question of whether the use of SMML can assist in the definition of software measurement models. An empirical study was conducted, with the aim of verifying whether SMML makes it easier to construct measurement models which are more usable and maintainable as regards textual notation. The results show that models which do not use the language are more difficult--in terms of effort, correctness and efficiency--to understand and modify than those represented with SMML. Additional feedback was also obtained, to verify the suitability of the graphical representation of each symbol (element or relationship) of SMML.

VisualLISA: A visual environment to develop attribute grammars

The focus of this paper is on crafting a new visual language for attribute grammars (AGs), and on the development of the associated programming environment. We present a solution for rapid development of VisualLISA editor using DEViL. DEViL uses traditional attribute grammars, to specify the language's syntax and semantics, extended by visual representations to be associated with grammar symbols. From these specifications a visual programming environment is automatically generated. In our case, the environment allows us to edit a visual description of an AG that is automatically translated into textual notations, including an XML-based representation for attribute grammars (XAGra), and is intended to be helpful for beginners and rapid development of small AGs. XAGra allows us to use VisualLISA with other compiler-compiler tools.

The Role of Visual Modeling and Model Transformations in Business-driven Development

This paper explores the emerging paradigm of business-driven development, which presupposes a methodology for developing IT solutions that directly satisfy business requirements and needs. At the core of business-driven development are business processes, which are usually modeled by combining graphical and textual notations. During the business-driven development process, business-process models are taken down to the IT level, where they describe the so-called choreography of services in a Service-Oriented Architecture. The derivation of a service choreography based on a business-process model is simple and straightforward for toy examples only—for realistic applications, many challenges at the methodological and technical level have to be solved. This paper explores these challenges and describes selected solutions that have been developed by the research team of the IBM Zurich Research Laboratory.

FENECIA: failure endurable nested-transaction based execution of composite Web services with incorporated state analysis

Interest in the Web services (WS) composition (WSC) paradigm is increasing tremendously. A real shift in distributed computing history is expected to occur when the dream of implementing Service-Oriented Architecture (SOA) is realized. However, there is a long way to go to achieve such an ambitious goal. In this paper, we support the idea that, when challenging the WSC issue, the earlier that the inevitability of failures is recognized and proper failure-handling mechanisms are defined, from the very early stage of the composite WS (CWS) specification, the greater are the chances of achieving a significant gain in dependability. To formalize this vision, we present the FENECIA (Failure Endurable Nested-transaction based Execution of Composite Web services with Incorporated state Analysis) framework. Our framework approaches the WSC issue from different points of view to guarantee a high level of dependability. In particular, it aims at being simultaneously a failure-handling-devoted CWS specification, execution, and quality of service (QoS) assessment approach. In the first section of our framework, we focus on answering the need for a specification model tailored for the WS architecture. To this end, we introduce WS-SAGAS, a new transaction model. WS-SAGAS introduces key concepts that are not part of the WS architecture pillars, namely, arbitrary nesting, state, vitality degree, and compensation, to specify failure-endurable CWS as a hierarchy of recursively nested transactions. In addition, to define the CWS execution semantics, without suffering from the hindrance of an XML-based notation, we describe a textual notation that describes a WSC in terms of definition rules, composability rules, and ordering rules, and we introduce graphical and formal notations. These rules provide the solid foundation needed to formulate the execution semantics of a CWS in terms of execution correctness verification dependencies. To ensure dependable execution of the CWS, we present in the second section of FENECIA our architecture THROWS, in which the execution control of the resulting CWS is distributed among engines, discovered dynamically, that communicate in a peer-to-peer fashion. A dependable execution is guaranteed in THROWS by keeping track of the execution progress of a CWS and by enforcing forward and backward recovery. We concentrate in the third section of our approach on showing how the failure consideration is trivial in acquiring more accurate CWS QoS estimations. We propose a model that assesses several QoS properties of CWS, which are specified as WS-SAGAS transactions and executed in THROWS. We validate our proposal and show its feasibility and broad applicability by describing an implemented prototype and a case study.

A Metamodel-based Language and a Simulation Engine for Abstract State Machines

In this paper, we present a concrete textual notation, called AsmetaL, and a general-purpose simulation engine, called AsmetaS, for Abstract State Machine (ASM) specifications. They have been developed as part of the ASMETA (ASMs mETAmodelling) toolset, which is a set of tools for ASMs based on the metamod- elling approach of the Model-driven Engineering. We briefly present the ASMETA framework, and we discuss how the language and the simulator have been developed exploiting the advantages offered by the metamodelling approach. We introduce the language AsmetaL used to write ASM specifications, and we provide the AsmetaL encoding of ASM specifications of increasing complexity. We explain the AsmetaS ar- chitecture, its kernel engine, and how the simulator works within the ASMETA tool set. We discuss the features currently supported by the simulator and how it has been validated.

Defining syntax and providing tool support for Agent UML using a textual notation

An important role in software engineering is played by design notations. The Agent UML (AUML) notation for sequence diagrams has been widely used to capture the design of interactions between agents. However, AUML is not precisely defined, and there is very little in the way of tool support available. We argue that using a textual notation allows the notation to be precisely defined, and facilitates the development of tool support. We present a textual notation that we have developed, and describe a number of tools that support this notation. One of these tools is a 'renderer' which takes a textual AUML protocol and generates the standard graphical view. The layout of graphical elements in the generated graphical view is done automatically, using a layout algorithm which we present.

IOM/T: interaction-oriented model by textual notation

A Multiagent System (MAS) is a useful approach for complex systems. However, it is difficult to develop a MAS because the current techniques have trouble dealing with interactions, which is one of the most important concepts. Although there are many researches about MAS developments, we believe the concepts are too logical and not easy to use. We analyse the language functionalities for implementing and testing interactions and design a new language for implementing interactions. In this paper, we propose our language, named IOM/T, and show how it works. IOM/T helps us to implement interactions from the design model. Furthermore, it helps us test the implementation with Design by Contract (DbC).

West2East: exploiting WEb Service Technologies to Engineer Agent-based SofTware

This paper describes West2East, a computer-aided Agent-Oriented Software Engineering (AOSE) toolkit aimed at supporting the implementation of Multiagent Systems (MASs). West2East exploits languages for Web Services (WSs) for sharing Agent Interaction Protocols (AIPs), modelled using AUML, across the web, and Computational Logic to reason about them. In particular, West2East offers libraries for the translation of AIPs represented in AUML into 1) a textual notation proposed by Winikoff; 2) an XML notation proposed by ourselves; 3) a couple of WS-BPEL and WSDL documents; and 4) a Prolog term. It also offers 5) a mechanism for allowing agents that read a published AIP to reason about it before engaging in a dialogue with its publisher, and 6) libraries for the automatic generation of an executable program compliant with the original interaction protocol.

Classification hierarchies for product data modelling

ion is an essential element in data modelling that appears mainly in one of the following forms: generalisation, classification or aggregation. In the design of complex products classification hierarchies can be found product families that are viewed as classes of product types, while product types are seen as classes of product instances. So far data models, if they support levels of classification, do not support the inheritance of product properties the way product family hierarchies are supposed to. This paper proposes an interpretation of the member of construct that enables one to define inheritance in classification hierarchies. Unified modelling language (UML) static structures are used as data modelling language. A textual notation is added that enables the introduction of data structures and corresponding data contents in the course of an analysis.

Subtext

Representing programs as text strings makes programming harder then it has to be. The source text of a program is far removed from its behavior. Bridging this conceptual gulf is what makes programming so inhumanly difficult -- we are not compilers. Subtext is a new medium in which the representation of a program is the same thing as its execution. Like a spreadsheet, a program is visible and alive, constantly executing even as it is edited. Program edits are coherent semantic transformations.The essence of this new medium is copying. Programs are constructed by copying and executed by copy flow : the projection of changes through copies. The simple idea of copying develops into a rich theory of higher-order continual copying of trees . Notably absent are symbolic names, the workhorse of textual notation, replaced by immediately-bound explicit relationships. Subtext unifies traditionally distinct programming tools and concepts, and enables some novel ones. Ancestral structures are a new primitive data type that combines the features of lists and records, along with unproblematic multiple inheritance. Adaptive conditionals use first-class program edits to dynamically adapt behavior.A prototype implementation shows promise, but calls for much further research. Subtext suggests that we can make programming radically easier, if we are willing to be radical.

Specifying Component Behavior with Port State Machines

Protocol State Machines (PSM) in UML 2.0 [13] describe valid sequences of operation calls. To support modeling components, UML 2.0 introduces a Port associated with a set of provided and required interfaces. Unfortunately, a PSM is applicable only to a single interface, either a provided or required one; moreover, nested calls cannot be modeled with a PSM. Furthermore, the definition of protocol conformance is rather fuzzy and reasoning on this relation is not possible in general; thus reasoning on consistency in component composition is not possible with PSMs. Behavior Protocols [17] capture the behavior of a component via a set of traces. A textual notation similar to regular expressions is provided to approximate the behavior with a regular language. In [1,17], the compliance relation and consent operator are defined to reason on consistency of component composition; a verifier tool [18] is available for the compliance relation. In this paper, we propose the Port State Machine (PoSM) to model the communication on a Port. Building on our experience with behavior protocols, we model an operation call as two atomic events request and response, permitting PoSM to capture the interleaving and nesting of operation calls on provided and required interfaces of the Port. The trace semantics of PoSM yields a regular language. We apply the compliance relation of behavior protocols to PoSMs, allowing us to reason on behavior compliance of components in software architectures; the existing verifier tool can be applied to PoSMs.

On the declarative specification of models

Computer power and automatic graph-drawing algorithms have sufficiently advanced so as to allow the automatic placement of graph nodes on the canvas and the near optimal routing of the respective edges. So, we can design models using a declarative textual representation and subsequently view, publish, and share them in graphical form. Creating models in a declarative, textual notation offers several advantages. The model composition mechanism matches well both the programmer's high-level skills and low-level skills.

See What You Need: Helping End-users to Build Abstractions

It has been argued that most end-users would not want to write programs, no matter what kind of tools they had to help them. This paper analyzes the reasons for that situation, and addresses them with a new approach to programming. There is a large class of users who are very reluctant to create any kind of abstraction within a computer (they will not create a new directory, let alone a Word macro). But these people do create abstractions in their everyday lives outside the computer. The reason for their computer habits can be explained in terms of a simple investment and risk model. See What You Need (SWYN) is a system intended to deliver the capabilities—not just of Word macros, but of Perl—to end-users. The techniques it adopts are those of programming by example, visual program representation and direct manipulation. SWYN is not intended to be a complete system, and is unlikely to develop into a complete Perl replacement. It is a research vehicle, supporting the evaluation of specific features aimed at reducing the perceived risk of abstraction in programming. This paper describes two elements of the SWYN project, both of them related to the regular expressions that are central to pattern matching in Perl. The first is a prototype system that acquires regular expressions from the type of examples required in direct manipulation of data for programming. The second is an experimental evaluation of alternative notations for visualizing regular expressions. This experiment demonstrated a clear advantage for graphical notations in typical end-user tasks, both over conventional regular expressions, and over a tutorial-style textual notation. The overall effect is a reduction both in programming investment and in perceived risk.

Bidirectional reaction steps in metabolic networks: IV. Optimal design of isotopomer labeling experiments.

This article generalizes the statistical tools for the evaluation of carbon-labeling experiments that have been developed for the case of positional enrichment systems in part II of this series to the general case of isotopomer systems. For this purpose, a new generalized measurement equation is introduced that can describe all kinds of measured data, like positional enrichments, relative (13)C nuclear magnetic resonance ((13)C NMR) multiplet intensities, or mass isotopomer fractions produced with mass spectroscopy (MS) instruments. Then, to facilitate the specification of the various measurement procedures available, a new flexible textual notation is introduced from which the complicated generalized measurement equations are generated automatically. Based on these measurement equations, a statistically optimal flux estimator is established and parameter covariance matrices for the flux estimation are computed. Having implemented these tools, different kinds of labeling experiments can be compared by using statistical quality measures. A general framework for the optimal design of carbon-labeling experiments is established on the basis of this method. As an example it is applied to the Corynebacterium network from part II extended by various NMR and MS measurements. In particular, the positional enrichment, multiplet, or mass isotopomer measurements with the greatest information content for flux estimation are computed (measurement design) and various differently labeled input substrates are compared with respect to flux estimation (input design). It is examined in detail how the measurement procedure influences the estimation quality of specific fluxes like the pentose phosphate pathway influx.

Exemplary and complete object interaction descriptions

Due to their graphical and intuitive syntax Message Sequence Charts (MSC) [(IT94) ITU-T. Z.120—Message Sequence Chart (MSC). ITU-T, Geneva, 1994; (IT96) ITU-T. Z.120—Message Sequence Chart (MSC). ITU-T, Geneva, 1996] are an excellent description technique to capture interaction sequences among components. MSCs are used in a variety of modeling techniques and development phases. Examples of their wide-spread applicability are communication patterns in software architectures, as well as message flow protocols between business corporations. In this paper, we present a variant of message sequence charts called Extended Event Traces (EETs). We provide the graphical and the textual notation, discuss the methodological use of EETs to describe behavior of object-oriented business information systems, and sketch their semantics. Special emphasis is put on the different implications of using EETs for exemplary and complete interaction descriptions. The possibility to describe interactions between single objects as well as composite objects with EETs makes them particularly suitable to describe the behavior of large systems.

Constraint-oriented style for object-oriented formal specification

The authors propose a specification style which combines the features and advantages of object-oriented and constraint-oriented system decomposition. A system description is decomposed into data-handling objects, which usually reflect objects and individual operations in the real system, and temporal-ordering constraints, which capture aspects of functionality as behavioural sequences, with a possibility to also introduce entities which blur the distinction between these two extreme cases. Composition is achieved via synchronisation on shared operations: different objects/constraints insisting on an operation express different views on the enabling conditions and effects of that operation. Objects, constraints, and their composition can be formally specified in Object-Z, an object-oriented extension of the Z notation, with pure temporal ordering constraints equivalently expressed as transition graphs. However, expressing object/constraint compositions in Object-Z is cumbersome. This problem is solved by proposing a natural textual notation, called co-expression, which is a most direct description of an object/constraint interconnection graph, and we define a mapping from co-expressions to Object-Z. Thus, specifications in an object/constraint-oriented style can be conveniently written using transition graphs and interconnection diagrams mixed with Object-Z text, and then translated into this language.

Visual Depiction of Decision Statements: What is Best forProgrammers and Non-Programmers?

This paper reports the results of two experiments investigating differences in comprehensibility of textual and graphical notations for representing decision statements. The first experiment was a replication of a prior experiment that found textual notations to be better than particular graphical notations. After replicating this study, two other hypotheses were investigated in a second experiment. Our first claim is that graphics may be better for technical, non-programmers than they are for programmers because of the great amount of experience that programmers have with textual notations in programming languages. The second is that modifications to graphical forms may improve their usefulness. The results support both of these hypotheses.

Declarative specifications

AbstractDeriving formal specifications from informal requirements is extremely difficult since one has to overcome the conceptual gap between an application domain and the domain of formal specification methods. To reduce this gap we introduce application-specific specification languages, i.e., graphical and textual notations that can be unambiguously mapped to formal specifications in a logic language. We describe a number of realised approaches based on this idea, and evaluate them with respect to their domain specificity vs. generality.

Methodology for the development of distributed telecommunications services

This article proposes a new object-oriented methodology for the specification and design of open distributed telecommunications services. The proposed methodology combines the ODP (Open Distributed Processing) concepts and structuring rules with the systematic development process advocated by a second generation object-oriented software engineering method called fusion. We first examine the motivations for such a combination as well as how it can be achieved. Based on these observations, we propose a seamless thread from problem definition to the realization of the distributed telecommunications system, based on hierarchically related abstraction levels. We then define the models that are to be established to produce the enterprise, information, and computational specifications of the ODP system under study. Mapping rules and guidelines are provided on how and when each model should be built, in particular, based on models performed at a higher abstraction level. Finally, both graphical and textual notations are provided for most models.

Visual representation and manipulation of matrices

Visual programming is best suited to manipulating objects which are naturally represented visually. Two-dimensional matrices are an example of such objects. Expressing computations involving such matrices can be accomplished relatively easily by pointing at individual components, columns, rows or submatrices, whereas developing corresponding textual descriptions may be rather complex and require considerable notation. In this paper we explore visual programming using direct maniupulation of matrices. Our exploration is within the context of Forms/3, a form-based visual programming language. An approach is presented which minimizes the complexity of expressing matrix operations, eliminates most of the associated textual notation and avoids expressing inessential evaluation ordering constraints. This approach, when compared with other language approaches, exploits the potential of visual languages to increase understandability and reduce the required expertise of users.