Busyairah Syd Ali

An approach for crosscutting concern identification at requirements level using NLP

Poor requirements analysis process results in incomplete software applications. Some requirements appear as scattered and tangled concerns within requirements document. Hence it is difficult to identify such requirements. A number of research approaches such as Theme/Doc, early aspects identification, information retrieval and aspects identification using UML have been developed to identify crosscutting concern at the requirements level. Nevertheless, these approaches are only supported by semi-automated tools whereby human intervention is required to achieve the desired results. This research focuses on developing a tool to automatically identify crosscutting concern at the requirements level. A model based on Theme/Doc and early aspects identification approaches is formulated as the basis of this tool, 3CI. 3CI adopts natural language processing (NLP) techniques such as verb frequency analysis, part-of-speech tagging and dominant verb analysis. The tool usability, efficiency and scalability are evaluated by comparing the performance of a requirements engineer conducting similar task manually. Our evaluation on 3CI demonstrates 75% of accuracy.

Developing tool for crosscutting concern identification using NLP

Aspect-oriented requirements engineering shows encouraging results in improving, identification, modularization and composition of crosscutting concerns. For instance, many techniques have been developed for crosscutting concern identification activity. This crucial activity is useful at the requirements level; it avoids coupling between requirements, improves traceability among requirements, eases function modularization, reduces software complexity, enhances the correctness of the software design, and most importantly it saves the cost. However, existing studies do not provide us with a clear definition of the term crosscutting concern and aspect. In terms of tools, most of these techniques in the existing studies are only supported by semi-automated tool. It means human intervention is required to achieve the desired results. In this paper, we describe a tool that provides automated support for identifying crosscutting concern at the requirements level. The tool utilises natural language processing technique to reason about properties of the concerns and model their structure and relationship.

3CI: A Tool for Crosscutting Concern Identification

Certain requirements in requirements document are scattered and tangled. Often software developers neglect these requirements during implementation or repeat the same functionality throughout the codes. These requirements are called crosscutting concerns. Identifying and analyzing these concerns manually is a hassle due to its ambiguous characteristics and massive volume of requirement sources. Aspect-oriented requirements engineering (AORE) supports crosscutting concern identification at various software development phases. However it is crucial at the requirements level; to avoid coupling between requirements, improve traceability among requirements, eases function modularization, reduce software complexity, enhance correctness of the software design, and most importantly it saves the cost. Many techniques have been developed for crosscutting concern identification at the requirements level such as Theme/Doc and Early Aspects. However all of these techniques in the existing studies are only supported by semi-automated tool whereby human intervention is required to achieve the desired results. In this paper, we describe a tool, 3CI that automatically identifies crosscutting concern as well as their crosscutting relationships at the requirement level. The tool utilizes NLP techniques to extract linguistic properties in each unique requirement and exploits these properties to identify crosscutting concerns and its influences in a requirements document. NLP techniques such as part-of-speech analysis, word frequency analysis and dominant verb analysis contribute in the processing of requirements phrases to assist aspects mining.

ADS-B: Probabilistic Safety Assessment

In the effort to quantify Automatic Dependent Surveillance Broadcast (ADS-B) system safety, the authors have identified potential ADS-B failure modes in Syd Ali et al. (2014). Based on the findings, six potential hazards of ADS-B are identified in this paper. The authors then applied the Probabilistic Safety Assessment approach which includes Fault Tree Analysis (FTA) and Importance Analysis methods to quantify the system safety. FTA is applied to measure ADS-B system availability for each identified hazard while Importance Analysis is conducted to identify the most significant failure modes that may lead to the occurrence of the hazards. In addition, risk significance and safety significance of each failure mode are also identified. The result shows that the availability for the ADS-B system as a sole surveillance means is low at 0·898 in comparison to the availability of ADS-B system as supplemental or as primary means of surveillance at 0·95 and 0·999 respectively. The latter availability values are obtained from Minimum Aviation System Performance Standards (MASPS) for Automatic Dependent Surveillance-Broadcast (DO-242A).

Evaluation of the Capability of Automatic Dependent Surveillance Broadcast to Meet the Requirements of Future Airborne Surveillance Applications

Automatic Dependent Surveillance Broadcast (ADS-B) Out supports various ground applications including Air Traffic Control (ATC) surveillance in radar airspace, non-radar airspace and on the airport surface. In addition, the capability of aircraft to receive ADS-B Out messages from other aircraft within their coverage (ADS-B In) enables enhanced airborne surveillance applications. The requirements of the application vary depending on its safety-criticality. More stringent applications will require higher levels of performance. It is therefore critical that the ADS-B system performance is measured against the most stringent application it is designed for. This paper reviews the various enhanced airborne surveillance applications and the required ADS-B information to support them. It identifies the ADS-B based applications required for Air Traffic Management (ATM) modernisation under the SESAR/NextGen programs. It discusses existing ADS-B Out versions and their capabilities. A mapping exercise is undertaken to assess the credibility of the ADS-B system performance to support the functionalities and requirements of the various enhanced airborne surveillance applications and establish those that require further research and development, highlighting some of the key challenges.

System specifications for developing an Automatic Dependent Surveillance-Broadcast (ADS-B) monitoring system

Automatic Dependent Surveillance-Broadcast (ADS-B) is a surveillance system placed in aircraft that periodically transmits state vector estimates and other information to air traffic control centers and other nearby aircraft (and may also receive traffic and weather information from various entities). The state vector estimates are derived from navigation avionics and are transmitted via a common communications channel, which means that ADS-B is highly dependent on aircraft navigation and communication systems. ADS-B also requires ground stations to receive information from aircraft. As a result of this complex architecture, the ADS-B system is prone to various failure modes. A systematic and comprehensive performance monitoring system is required to ensure the safe use of ADS-B data for air traffic control operations. It is vital that such monitoring systems are in place before a global ADS-B implementation date is mandated by the International Civil Aviation Organization. A number of air navigation service providers and regulators have developed ADS-B performance monitoring methods without a standardized guideline for system specifications. These include Airservices Australia, the U.S. Federal Aviation Administration, EUROCONTROL, the Civil Aviation Authority of Singapore and the Civil Aviation Department of Hong Kong. This paper presents a holistic set of system specifications for ADS-B monitoring systems. In particular, the paper analyzes the ADS-B infrastructure, conducts a systematic review of existing ADS-B monitoring systems, classifies the system characteristics to identify gaps, and derives a set of specifications for developing ADS-B monitoring systems. The paper also assesses the compliance of existing ADS-B monitoring systems against the proposed specifications using a mapping exercise. The system specifications serve as a foundation or minimum requirements for air navigation service providers and original equipment manufacturers to develop systematic and comprehensive ADS-B monitoring systems.

A Review on Approaches for Identifying Crosscutting Concerns

Brito argued that there are certain properties that the existing software development approaches are not able to modularize. Brito claimed, these properties cut across a large number of artefacts that compose the system. Therefore it is difficult to modularise them in separate modules. These properties are known as cross cutting concerns, which is encapsulated into aspect. Rosenhainer defined aspects as modular artefacts that encapsulate crosscutting concerns. Aspect-oriented requirements engineering shows encouraging results in improving, identification, modularization and composition of crosscutting concerns. For instance, many techniques have been developed for crosscutting concern identification activity. This crucial activity is useful at the requirements level. It avoids coupling between requirements, improves traceability among requirements, eases function modularization, reduces software complexity, enhances the correctness of the software design, and most importantly it saves the cost. Although the research area is still in its infancy, several techniques for crosscutting concern identification have already been developed. However, all of the techniques reviewed are based on semi-automated way. Human intervention is required to achieve the desired results using these techniques. Therefore this paper reviews the existing approaches on its effectiveness to solve this issue.