Telecommunications Software Research Articles

DATA MINING FOR PREDICTORS OF SOFTWARE QUALITY

"Knowledge discovery in data bases" (KDD) for software engineering is a process for finding useful information in the large volumes of data that are a byproduct of software development, such as data bases for configuration management and for problem reporting. This paper presents guidelines for extracting innovative process metrics from these commonly available data bases. This paper also adapts the Classification And Regression Trees algorithm, CART, to the KDD process for software engineering data. To our knowledge, this algorithm has not been used previously for empirical software quality modeling. In particular, we present an innovative way to control the balance between misclassification rates. A KDD case study of a very large legacy telecommunications software system found that variables derived from source code, configuration management transactions, and problem reporting transactions can be useful predictors of software quality. The KDD process discovered that for this software development environment, out of forty software attributes, only a few of the predictor variables were significant. This resulted in a model that predicts whether modules are likely to have faults discovered by customers. Software developers need such predictions early in development to target software enhancement techniques to the modules that need improvement the most.

Object model in Java: elements and application

The Java programming language is a new object-oriented programming language that is gaining widespread popularity in the computer software industry because of its ease of learning, simplicity, generality, portability and networking capabilities. In this article, we discuss the semantic implementation in Java of each of the elements of the object model, identified by Booch [G. Booch, Object-Oriented Analysis and Design with Applications, 2nd Edition, Addison-Wesley, 1994], in addition to the mobility element. We show that Java, unlike other object-oriented languages, covers and simplifies all elements of the object model. An example illustrating those elements in Java will be drawn from a telecom software application.

Hybrid approach to software interworking problems: managing interactions between legacy and evolving telecommunications software

Interworking problems between software services arise for a number of reasons; they may occur because the services, or their component parts, have evolved to fulfil different roles from the originally intended ones, resulting in conflicting requirements. Alternatively, the services themselves may be undocumented, poorly understood, or required to interwork with services from third party legacy systems. Interworking problems are difficult to predict and detect, as well as to resolve in an acceptable manner. The problems are particularly acute in the telecommunications domain with its supplementary concerns of real−time, distributed control and data, high reliability, rapid evolution, and a deregulated market that is encouraging multiple service providers. Approaches to interworking problems may be characterised as being either online or offline, formally or pragmatically/experimentally based. While numerous approaches have been developed, there have been very few attempts to combine formally based and online approaches to produce a technique. The research goal is to develop such a technique because experience with other combinations has led to the belief that they are not sufficient to deal with the interworking problems of complex, evolving software systems, as common in telecommunications. This is particularly the case for systems which also have to interwork with third party and legacy code: a hybrid approach which combines both online and formally based approaches promises to address problems which have proven very difficult to resolve with other techniques. The paper outlines a hybrid approach based on a transactional technique with rollback capability. While the approach described is applied specifically to telecommunications services software, many aspects of the approach are applicable to other software domains which exhibit similar characteristics of real-time, event driven operation, such as control systems.

Quality evaluation of software development process based on spiral modeling

Various activities associated with software development are now being standardized in the software life cycle process (SLCP) which is under review at ISO. In developing telecommunications software by taking a conventional approach to software development, the structured design technique based on the waterfall model has so far been used in a software development process which is one of the elements composing SLCP. It is pointed out, however, that this conventional design technique has limitations with respect to the transference of technology and quality evaluation. On the other hand, new techniques of software development, such as object-oriented programming, prototyping, and spiral modeling are being introduced into computer software development. These new development techniques are expected to provide a solution to the transference of technology and other problems related to software development. In practice, however, introduction of these techniques to the development of telecommunications software is delayed because the scale of development is relatively large, a high level of real-time performance is sought, memory capacity is limited, and other reasons. With the emergence of a general-purpose telecommunications operating system (OS), upgrading of development environments, and decreasing cost of memory in recent years, it is now becoming possible to introduce these new techniques into the field of computer software development. Against this background, we applied a new development approach based on spiral modeling to the development of telecommunications software and compared it with the conventional development approach with respect to the productivity of software development, the qualify of software programs, and other factors. Although the man-hour control and some other technical problems were left unsolved in experimenting with this new development approach based on spiral modeling, we were able to obtain overall good results regarding productivity and the quality of software. © 1998 Scripta Technica, Electron Comm Jpn Pt 1, 81(12): 55–64, 1998

Managing Feature Interactions Telecommunications Software Systems - Guest Editorial

Managing Feature Interactions Telecommunications Software Systems - Guest Editorial

Semantic verification and satisfiability verification of MSC specifications by means of Petri nets in telecommunication software testing

Semantic verification and satisfiability verification of MSC specifications by means of Petri nets in telecommunication software testing

A component-based approach to telecommunication software

This article discusses a domain-specific component-based architecture called distributed feature composition. Based on the well-known pipe-and-filter architecture, DFC has been refined for use in the telecommunication domain. The authors also point to ways this approach might work in other domains, including data networks.

Spec-based tests make sure telecom software works

Designers of contemporary telecommunications equipment face a daunting task, bringing quickly to market in an intensely competitive environment products that rely on ever more complex software. The author discusses a relatively new approach to creating software tests which is based on a graphical specification of the system's behaviour combined with an automatic test script generator. The approach is applied in Teradyne's TestMaster.

Application of neural networks to software quality modeling of a very large telecommunications system

Society relies on telecommunications to such an extent that telecommunications software must have high reliability. Enhanced measurement for early risk assessment of latent defects (EMERALD) is a joint project of Nortel and Bell Canada for improving the reliability of telecommunications software products. This paper reports a case study of neural-network modeling techniques developed for the EMERALD system. The resulting neural network is currently in the prototype testing phase at Nortel. Neural-network models can be used to identify fault-prone modules for extra attention early in development, and thus reduce the risk of operational problems with those modules. We modeled a subset of modules representing over seven million lines of code from a very large telecommunications software system. The set consisted of those modules reused with changes from the previous release. The dependent variable was membership in the class of fault-prone modules. The independent variables were principal components of nine measures of software design attributes. We compared the neural-network model with a nonparametric discriminant model and found the neural-network model had better predictive accuracy.

From Estelle to Erlang

Formal Description Techniques, like Estelle, are being used for the specifications of telecommunication protocols. While many telecommunication software manufacturers are still using programming languages that were developed in the late 1960s or 1970s, Ericson's Computer Science Laboratory in Sweden has developed a new declarative programming language, called Erlang, which supports concurrency, distribution, error handling and code updating. This article first describes how Estelle specifications can be translated into Erlang codes, then presents its application to the Alternating Bit protocol, and finally draws a comparison between this and the compilation method for automatic communication protocol implementation. The motivation behind this work comes from the need of having a better understanding between Erlang, being a very young declarative language and suited to implementing communication protocols due to the features that were built into it, and the FDT, Estelle, in order to obtain more benefits from these languages when implementing communication protocols.

Progressive retry for software failure recovery in message-passing applications

A method of execution retry for bypassing software faults in message-passing applications is described in this paper. Based on the techniques of checkpointing and message logging, we demonstrate the use of message replaying and message reordering as two mechanisms for achieving localized and fast recovery. The approach gradually increases the rollback distance and the number of affected processes when a previous retry fails, and is therefore named progressive retry. Examples from telecommunications software systems and performance measurements from an application-level implementation are described to illustrate the benefits of the scheme.

A Risk Index for Software Producers

Software risk management has been receiving increasing attention lately. A key activity of software risk management is the quantification of the risk of using a software product. Previous attempts to define the risk index have taken the users' viewpoint. The loss due to a product failure is computed based on its impact on the users. Yet, the impact of a failure on the software producer is different from that of the users. A high risk module according to the users may not be treated the same by the producer. This paper presents a method to determine the producer risk index for quantifying the probability and impact of failure on the producer at the product release time. The producer can use the results to determine whether it is more economical to improve the software quality or to release the product with the achieved quality level. The index can also be used to estimate the maintenance effort. The approach makes use of two recent developments in software complexity metrics, principal component analysis and reliability growth modelling. A new classification scheme for failure impact is introduced. Results from applying the producer risk index to a telecommunication software system are presented.

Feature interaction-how it works in telecommunication software

The results from feature interaction can be seen as a problem from different perspectives. The two primary perspectives are from the end user's view and the application developer's view. This article pursues solutions that originate from the applications designer's view. Even within this view, there are different ways to approach the feature interaction problem. These solutions, in turn, have the potential to introduce new problems. Each of these views lead to different solutions to our problem. The solution to the feature interaction has three parts. First, avoid undesirable interactions whenever possible. Second, detect interactions when they occur. Finally, resolve the interactions as quickly as possible. Preferably, this final step should be automated. Feature interactions will occur in real-time, and must be handled on-the-fly for our communication networks to perform as expected by the end user.

Emerald: software metrics and models on the desktop

As software becomes more and more sophisticated, industry has begun to place a premium on software reliability. The telecommunications industry is no exception. Consequently software reliability is a strategic business weapon in an increasingly competitive marketplace. In response to these concerns, BNR, Nortel, and Bell Canada developed the Enhanced Measurement for Early Risk Assessment of Latent Defects (Emerald), a decision support system designed to improve telecommunications software reliability. Emerald efficiently integrates software measurements, quality models, and delivery of results to the desktop of software developers. We have found that Emerald not only improves software reliability, but also facilitates the accurate correction of field problems. Our experiences developing Emerald have also taught us some valuable lessons about the implementation and adoption of this type of software tool.

Use of data in a radiology information system for labeling computed radiographs: an interface to connect the two systems.

Computers have greatly facilitated the processing and storage of radiologic information. Manufacturers of radiology information systems (RISs) are gradually incorporating options for interfacing their products with other computers (e.g., hospital information systems). However, a growing need exists to also interface RISs with digital radiologic equipment so that images (e.g., computed radiographs of the chest and skeleton) are automatically labeled with identification data. Such connectivity would eliminate redundant work by technologists, decrease errors in the labeling of images, and increase the consistency of patients' data within a radiology department. Unfortunately, the rapid advances in digital technology, combined with the lack of a well-defined standard for the transfer of demographic information between dissimilar systems, have delayed development of these interfaces. We have developed a widely applicable method to automatically transfer patients' demographic data from an RIS to a commercially available computed radiography system. A personal computer is configured with inexpensive programmable telecommunications software to create an interactive gateway, which eliminates the need for redundant data entry (compared with entering data once on the RIS and again on the stand-alone computed radiography system), and thus also decreases errors in the labeling of images.

Software benchmarking

In software, "benchmarking" usually compares two companies' practices and results, but, occasionally, it involves sets of companies. For example, there are benchmark comparisons of industry software, such as insurance software, military software, telecommunication software, commercial software, and the like. In other domains, "benchmark" usually means the collection of a substantial body of quantitative data. Benchmark comparisons of various computers, for example, rate their relative performance in at least half a dozen categories. Historically, software benchmarks have been qualitative rather than quantitative. Even the Software Engineering Institute's Capability Maturity Model (SEI CMM) is essentially a qualitative benchmark that ranks company performance on a five-point scale that lacks quantification for specific quality and productivity levels.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The automatic generation of load test suites and the assessment of the resulting software

Three automatic test case generation algorithms intended to test the resource allocation mechanisms of telecommunications software systems are introduced. Although these techniques were specifically designed for testing telecommunications software, they can be used to generate test cases for any software system that is modelable by a Markov chain provided operational profile data can either be collected or estimated. These algorithms have been used successfully to perform load testing for several real industrial software systems. Experience generating test suites for five such systems is presented. Early experience with the algorithms indicate that they are highly effective at detecting subtle faults that would have been likely to be missed if load testing had been done in the more traditional way, using hand-crafted test cases. A domain-based reliability measure is applied to systems after the load testing algorithms have been used to generate test data. Data are presented for the same five industrial telecommunications systems in order to track the reliability as a function of the degree of system degradation experienced. >

PLATyPus: experimenting with TINA

Presents some of the basic Telecommunications Information Networking Architecture (TINA) concepts and discusses the platform for TINA Prototyping (PLATyPus), an experimental implementation of TINA. TINA will provide a framework for telecommunications software in the future and is currently being specified by the TINA Consortium (TINA-C). This article covers the basic concepts underlying TINA, the tools and infrastructure under development (as part of the PLATyPus project) to implement a TINA-like application environment, and a description of a service design and implementation within that environment. >

A comparative study of pattern recognition techniques for quality evaluation of telecommunications software

The extreme risks of software faults in the telecommunications environment justify the costs of data collection and modeling of software quality. Software quality models based on data drawn from past projects can identify key risk or problem areas in current similar development efforts. Once these problem areas are identified, the project management team can take actions to reduce the risks. Studies of several telecommunications systems have found that only 4-6% of the system modules were complex /spl lsqb/LeGall et al. 1990/spl rsqb/. Since complex modules are likely to contain a large proportion of a system's faults, the approach of focusing resources on high-risk modules seems especially relevant to telecommunications software development efforts. A number of researchers have recognized this, and have applied modeling techniques to isolate fault-prone or high-risk program modules. A classification model based upon discriminant analytic techniques has shown promise in performing this task. The authors introduce a neural network classification model for identifying high-risk program modules, and compare the quality of this model with that of a discriminant classification model fitted with the same data. They find that the neural network techniques provide a better management tool in software engineering environments. These techniques are simpler, produce more accurate models, and are easier to use. >

Software reliability estimations for telecommunications products

Reliability of software used in telecommunications networks is a crucial determinant of network performance. Software reliability (SR) estimation is an important element of a network product's reliability management. In particular, SR estimation can guide the product's system testing process and releasability decisions. SR estimation is performed using an appropriate SR estimation model. However, the art of SR estimation is still evolving. There are many available SR estimation models to select from, with different models being appropriate for different applications. Although there is no "ultimate" and "universal" SR model on the horizon (and there may not be one in the foreseeable future), methods have been developed for selecting a trustworthy SR model for each application. The present authors have been analyzing and adapting these methods for applicability to network software. Their results indicate that there already exist methods for SR model selection which are practical to use for telecommunications software. If utilized, these methods can promote significant improvements in SR management. The paper presents the results to date.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>