Larry Wen

Using Composition Trees to Model and Compare Software Process

Software processes described by natural languages are frequently ambiguous and it is usually difficult to compare the similarity and difference between one process defined in one standard and its counterpart defined in another standard. This paper proposes Composition Tree (CT) as a graphic language to model software process based on its purpose and expected outcomes. CT is a formal graphic notation originally designed for modeling component based software system. This paper demonstrates that CT can be a powerful notation to give a clear and unambiguous description of a software process as well. This paper also investigates an algorithm which can compare two CT-modeled processes and provide an intuitive view called a Comparison Composition Tree (CCT) to highlight the differences and similarities between the two processes.

Using Composition Trees to Validate an Entry Profile of Software Engineering Lifecycle Profiles for Very Small Entities (VSEs)

ISO/IEC TR 29110-5-1 provides a Software Engineering life cycle reference model for Very Small Entities on small software projects (less than 6 people month). This paper uses Composition Trees (CT) as a formal notation to model part of this process, and compares it with its counterpart process (which is also modeled in a CT) from ISO/IEC 12207. The outcome of the comparison is a Comparison Composition Tree (CCT). This CCT shows clearly the similarity and difference between the VSE Entry Profile and ISC12207. This information may help people to validate and understand the VSE Profile. This paper also proposes this approach can be used as a general approach for people to develop, study, and implement software processes.

Enterprise Architecture Cybernetics for Collaborative Networks: Reducing the Structural Complexity and Transaction Cost via Virtual Brokerage

This paper demonstrates that the efficiency of Virtual Organisation (VO) creation by Collaborative Networks (CNs) can be limited by the complexity of the network itself. The authors previously proposed the use of distributed Enterprise Engineering methods based on Extended Axiomatic Design Theory to limit the complexity of VOs, and of the CN itself. This paper formulates methods to calculate and reduce the structural complexity of CNs and the cost of VO creation transactions through virtual brokerages. The method is demonstrated through an example and also yields a heuristic rule regarding the optimal size of such brokerages.

Approaches to measuring inconsistency for stratified knowledge bases

A number of proposals have been proposed for measuring inconsistency for knowledge bases. However, it is rarely investigated how to incorporate preference information into inconsistency measures. This paper presents two approaches to measuring inconsistency for stratified knowledge bases. The first approach, termed the multi-section inconsistency measure (MSIM for short), provides a framework for characterizing the inconsistency at each stratum of a stratified knowledge base. Two instances of MSIM are defined: the naive MSIM and the stratum-centric MSIM. The second approach, termed the preference-based approach, aims to articulate the inconsistency in a stratified knowledge base from a global perspective. This approach allows us to define measures by taking into account the number of formulas involved in inconsistencies as well as the preference levels of these formulas. A set of desirable properties are introduced for inconsistency measures of stratified knowledge bases and studied with respect to the inconsistency measures introduced in the paper. Computational complexity results for these measures are presented. In addition, a simple but explanatory example is given to illustrate the application of the proposed approaches to requirements engineering.

Exploring the Impact of IT Service Management Process Improvement Initiatives: A Case Study Approach

IT companies worldwide have started to improve their service management processes based on best practice frameworks, such as IT Infrastructure Library (ITIL). However, many of these companies face difficulties in demonstrating the positive outcomes of IT service management (ITSM) process improvement. This has led us to investigate the research problem: What positive impacts have resulted from IT service management process improvement? The main contributions of this paper are 1) to identify the ITSM process improvement outcomes in two IT service provider organizations and 2) provide advice as lessons learnt.

Detecting Requirements Defects Utilizing A Mathematical Framework for Behavior Engineering

Behavior Engineering (BE) provides a rigorous way to derive a formal specification of a software system from the requirements written in natural language. Its graphical specification language, Behavior Tree (BT), has been used with success in industry to systematically translate large, complex, and often erroneous requirements into an integrated model of the software system. BEs process, the Behavior Modeling Process (BMP), allows requirements to be translated into individual requirement BTs one at a time, which are then integrated to form a holistic view of the system. The integrated BT then goes through a series of modifications to construct a specification BT, which is used for validation and verification. The BMP also addresses different types of defects in the requirements throughout its process. However, BT itself is a graphical modeling notation, and the types of integration relations, how they correspond to particular issues, how they should be integrated and how to get formal specification have not been clearly defined. As a result, the BMP is informal, and provides guidelines to perform all these tasks on an ad-hoc basis. In this paper, we first introduce a mathematical framework which defines the graphical form of BTs which we use to define the integration relationships of BTs and to formalize the integration strategy of the BMP. We then formulate semi- automated requirements defects detection techniques by utilizing this underlying mathematical framework, which may be extended to formalize the BMP, develop change management framework for it, build techniques for round-trip engineering and so on.

Formalizing Manufacturing Process Modeling Using Composition Trees

Optimizing manufacturing process modeling is critical to improving the efficiency and quality of manufacturing. However, manufacturing processes in general can be very complicated. A manufacturing process may involve (a) transforming a material into a new form, (b) combining different materials to form a new object, and (c) retrieving a certain part from a material as a new entity. All those activities could be confusing because many intermediate objects that exist only for a short period during the manufacturing process may have no formal names. To solve this problem, this paper proposes that composition trees (CT) can be successfully used to model manufacturing processes. Composition trees are parts of the formal notation in behavior engineering (BE), which is an innovative approach to the development of large software systems. For a composition tree, its characteristics of being intuitive, expressive and formal give it many advantages over other formal and informal modeling languages in software engineering. This paper uses a cooking case study to demonstrate how to use a composition tree model manufacturing processes. It is argued that the method could be applied to process engineering to good effect.

An axiom based metamodel for software process formalisation: An ontology approach

Software development usually follows well known process models and standards for development processes. However, these are usually diverse and described in natural language which complicates their automation, adaptivity and verification. The need for process formalisation has long been highlighted, and we have provided a formalisation and translation algorithm to that effect in earlier work. However, to systematically and faithfully formalise heterogeneous processes from different standards and process models, there is a need to utilise uniform concepts to underpin the formalisation process. Metamodels and ontologies have been explored recently to lay a foundation for structuring and expressing additional rigour to process formalisation. In this study, we develop an axiom based metamodel utilising powertype patterns as a conceptual framework to underpin homogeneous process formalisation. The advantage of an axiomatic and powertype based metamodel approach lies in its potential to determine the metamodel basic constituents and formalism as well as its extensibility and adaptability. We formalise the metamodel using ontologies while adopting use cases from ISO/IEC 29110 and ISO/IEC 24744 standards for metamodel illustrations. Ontology based process descriptions enable process automated verification and adaptivity capability through the use of ontology reasoning support engines.

Local Search for Maximum Vertex Weight Clique on Large Sparse Graphs with Efficient Data Structures

The Maximum Vertex Weight Clique (MVWC) problem is a generalization of the Maximum Clique problem, which exists in many real-world applications. However, it is NP-hard and also very difficult to approximate. In this paper we developed a local search MVWC solver to deal with large sparse instances. We first introduce random walk into the multi-neighborhood greedy search, and then implement the algorithm with efficient data structures. Experimental results showed that our solver significantly outperformed state-of-the-art local search MVWC solvers. It attained all the best-known solutions, and found new best-known solutions on some instances.

Reducing the structural complexity and transaction cost of collaborative networks using extended axiomatic design theory and virtual brokerage

The paradigm of forming and sustaining collaborative networks as environments that create virtual organisations assumes that effective (and efficient) enterprise engineering capabilities and processes are available. However, these processes are only effective if they produce virtual organisations that have sufficiently limited complexity, because as complexity grows, the virtual organisation’s behaviour becomes increasingly harder to predict under all circumstances. This article demonstrates that the efficiency of virtual organisation creation by collaborative networks can be limited by the complexity of the network itself. This article proposes the use of enterprise engineering methods based on extended axiomatic design theory to limit the complexity of virtual organisations – and of the collaborative network itself. This article also formulates methods to calculate and reduce the structural complexity of collaborative networks and the cost of virtual organisation creation transactions through virtual brokerages. The method is demonstrated through an example and also yields a heuristic rule regarding the optimal size of such brokerages. Also, process and people capability maturity levels were introduced for the use of enterprise engineering methods based on extended axiomatic design theory, whereupon higher maturity implies higher probability of success of collaborative networks in creating and maintaining virtual organisations, and success of the virtual organisations themselves (i.e. higher capability to limit the complexity of virtual organisations and of collaborative network itself). This article also formulates strategies for capability improvement, intended to achieve higher levels of enterprise engineering maturity.