Multiversion Software Research Articles

Software for "A Study on Optimal Release Schedule for Multiversion Software"

Research on software reliability growth models (SRGMs) has been extensively conducted for decades, and the models were often developed based on two assumptions: (1) once the errors are detected, they can be completely removed instantly, and (2) errors can be removed eternally, and the debugging tasks will not produce any new errors. How-ever, both assumptions are unrealistic. This study proposes an SRGM that ignores these restricted assumptions by introducing a detection process that may remove an error after a period of time once it has been detected and by considering imperfect debugging, which indicates that new errors may emerge through corresponding debugging tasks. In addi-tion, because software can be upgraded to respond on a timely basis to constantly changing consumer expectations and thus extend product life in the market, the proposed SRGM also considers software upgrades for the multiversion software, and a dynamic program-ming approach is used to effectively obtain the optimal release schedule with consideration of the constraint of budget. Real data sets are used to examine the effectiveness of the pro-posed model, and the fitting results show that the proposed model outperforms other existing models. The results of numerical validation indicate that the proposed dynamic programming method with information updating outperforms the sequential solution method in determining the optimal release time for each version. Moreover, decision makers should carefully evaluate the parameters because overestimating the parameters of the mean value functions will cause serious software risk due to excessively shortening the testing time.

A Study on Optimal Release Schedule for Multiversion Software

Research on software reliability growth models (SRGMs) has been extensively conducted for decades, and the models were often developed based on two assumptions: (1) once the errors are detected, they can be completely removed instantly, and (2) errors can be removed eternally, and the debugging tasks will not produce any new errors. However, both assumptions are unrealistic. This study proposes an SRGM that ignores these restricted assumptions by introducing a detection process that may remove an error after a period of time once it has been detected and by considering imperfect debugging, which indicates that new errors may emerge through corresponding debugging tasks. In addition, because software can be upgraded to respond on a timely basis to constantly changing consumer expectations and thus extend product life in the market, the proposed SRGM also considers software upgrades for the multiversion software, and a dynamic programming approach is used to effectively obtain the optimal release schedule with consideration of the constraint of budget. Real data sets are used to examine the effectiveness of the proposed model, and the fitting results show that the proposed model outperforms other existing models. The results of numerical validation indicate that the proposed dynamic programming method with information updating outperforms the sequential solution method in determining the optimal release time for each version. Moreover, decision makers should carefully evaluate the parameters because overestimating the parameters of the mean value functions will cause serious software risk due to excessively shortening the testing time. History: Accepted by Pascal Van Hentenryck, Area Editor for Computational Modeling: Methods & Analysis. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information ( https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2021.0141 ) as well as from the IJOC GitHub software repository ( https://github.com/INFORMSJoC/2021.0141 ). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/ .

Модель надежности многопроцессорных аппаратно-программных комплексов систем управления реального времени с мультиверсионным программным обеспечением

Reliability is a critical parameter of real-time control systems. In practice, the reliability of hardware and software complexes included in such systems, is ensured by creating redundancy of hardware components and a multi-version approach to software development. But the redundant reservation of hardware devices and too many versions of software can lead to unjustified growth in the cost of creating and operating the projected control system. A rational approach to the design requires the creation of a model, which allows evaluating the reliability of different hardware and software complex configurations at the design stage. We proposed a mathematical reliability model of hardware and software complexes of real-time control systems, built with the use of mathematical apparatus of the queueing theory, which is a system of differential equations for the probability of finding states in the system, in which one or another component of the hardware and software complex is faulty. From the system of differential equations, the system of linear algebraic equations for probabilities of states in a steady-state mode was obtained. An analytical solution of this system is given, which allows us to evaluate the reliability of multiprocessor hardware-software complexes with multi-version software without significant expenditure of computational resources. Possibilities of using the results obtained to optimize the reliability of multiprocessor hardware-software complexes with multi-version software are presented and directions for further research are proposed

Modification of the ant colony algorithm for multiversion software application development

The article discusses a modification of the ant colony algorithm, which is used to solve the problem of forming the composition of multiversion software with a dynamic architecture. The algorithm was tested for a specific composition of multiversion modules. The graphical dependencies that characterize the changes in the parameters of the cost and reliability of the multiversion software complex with the specified resource constraints are presented.

Algorithms for implementing optimization models for developing multi-version software for spacecraft control systems

In this paper, the author discusses conventional algorithms for implementing optimization models for developing multi-version software for spacecraft control systems. The proposed algorithms are represented by implicit search procedures, including an implicit search algorithm with the search area being intersected by neighboring points, and a set of algorithms based on the general scheme of the branch and boundary method.

Software package for the implementation of bioinspired algorithms for the design of fault-tolerant control systems

The article considers a software package that allows you to form the composition of multiversion software for fault-tolerant control systems. The software implementation is based on a modified ant colony algorithm, which belongs to the class of bioinspired algorithms. The algorithm implements the search direction in order to minimize the cost of a program consisting of a set of modules. For each module, there are several versions of its implementation, developed within the framework of the multiversion programming methodology. The search direction is also implemented in order to maximize the reliability of the modular program in multiversion execution. The software implementation of the algorithm allows a number of experiments to be performed to obtain data that can be used to compare the performance of the standard and modified ant colony algorithms.

Development and implementation of X-ray fluorescence technique for gold determination in jewelry alloys at the analytical center of the JSC «Krastsvetmet»

A technique of the X-ray fluorescence analysis (XRF) based on a linear regression providing correlation between the gold content in the sample and radiation intensities of the elements of the analyzed alloy is developed at the analytical center of the JSC «Krastsvetmet» (laboratory of X-ray spectral analysis) to increase the rapidity of gold determination in gold-based alloys. The regression equation chosen by the methods including the influencing factor (contributor) and estimating correlation between the disparities and influencing factor takes into account the effect of such elements as Ag, Cu, Zn, Ni, and Pd on the gold line intensity. Virtual calibration samples (VCS) — the results of the analysis of real samples (X-ray line intensities of elements and gold values obtained by the assay method) taken from electronic database (DB) are used to form a system of linear algebraic equations (SLAE) which is to be solved for determination the desired linear regression coefficients. VCS for which the line intensities of the elements are close to those measured for the analyzed sample are selected from the database using a specific filter: the filter value is determined for each of the elements (metals) in the sample. The developed and integrated into the laboratory information system (LIMS) multi-version software (MVS) for solving SLAE includes several algorithms implemented in various programming languages. The use of the presented methodology significantly reduces the time of analysis. The error of gold determination does not exceed 0.13% which is comparable with that in the assay method.

Reliability modeling of multi-version software system incorporating the impact of infected patching

PurposeThe purpose of the present work is to mathematically model the reliability growth of a multi-version software system that is affected by infected patches.Design/methodology/approachThe work presents a mathematical model that studies the reliability change due to the insertion of an infected patch in multi-version software. Various distribution functions have been considered to highlight the varied aspects of the model. Furthermore, weighted criteria approach has been discussed to facilitate the choice of the model.FindingsThe model presented here is able to quantify the effect of an infected patch on multi-version software. The model captures the hike in bug content due to an infected patch.Originality/valueMulti-version systems have been studied widely, but the role of an infected patch has not been yet explored. The effect of an infected patch has been quantified by modeling the extra bugs generated in the system. This bug count would prove helpful in further studies for optimal resource allocation and testing effort allocation.

The development and reliability analysis environment of fault-tolerance multiversion software

The article considers the software toolkit «SA-Analysis» which is intended for designing and the analysis of fault tolerant software reliability. Fault tolerance is reached due to application multiversion software architecture. The description of software system toolkit is given. Application of similar system allows to raise efficiency of software engineering process and to create highly reliable software products.

Implementation of multiversion software based on an object-oriented approach

The article discusses the concept of redundant programming and its implementation based on an object-oriented approach. Three components of multiversion programming, which are basic in the synthesis of fault-tolerant software, are identified. In comparison with the standard software life cycle, the basic procedures of the multiversion programming methodology are considered. The concept of abstract state of the multiversion software components version is based on the object-oriented approach.

On the problem of version selection to create a graph for the ant colony optimization algorithm

The article considers various graph creation methods for presenting the structure of a multiversion software package in solving its optimization problem by the ant colony optimization algorithm. The paper presents a method for calculating the weights of arcs for a static version of the graph and the reliability characteristics of the software package, taking into account its architecture. The version of creating a dynamic version of the graph is considered. A comparative analysis of these versions is conducted. The conclusions about the preferred application of the static version of the graph are made.

Choice of optimal multiversion software for a small satellite ground-based control and command complex

This paper discusses the criteria and restrictions, which arise during the solution of problems relevant to the synthesis of software for a ground-based control and command complex for small satellites. The authors suggest a number of models for forming multiversion software for this complex.

Formation of optimal composition of the modules of single-function multiversion software for automated control system of the satellite communication system

When creating the automated control systems (ACS) for satellite systems, the main task is to ensure high quality and reliability of all hardware and software complex components. It conserns not only spacecrafts but also the ground segments of system.In this direction there is an active work. In this article we want to focus on the development of software for satellite communication systems that can be implemented in both space and ground segments. One of the promising directions in this area is the introduction of multiversion technology. The proposed model significantly develops the approach of development of highly reliable software, as it deals with multiversion software for ACS of satellite communication systems, consisting of one or more programs, and each program consists of a number of modules, the serial execution of which corresponds to the successful implementation of the function. Below is a model that is applicable to various structures of multiversion software for ACS of satellite communication systems (from a very simple structure to a more complex) and gives the designer the flexibility in choosing the appropriate modules for the designed software of the system.

Development of methods for equivalent transformation of GERT networks for application in multi-version software

The usage of information and control systems in various fields of production and research requires a certain level of reliability in the functioning of these systems. One of the most promising and already positively proven methodologies to ensure high reliability and fault tolerance of software is multi-version designing. The greatest value this factor have in the areas where control system failure can result in significant financial and material losses, as well as harm to human health and life.

OPTIMAL SCHEDULING OF MULTIVERSION SOFTWARE TASKS

This article reviews the problem of the optimal scheduling of multiversion software tasks. Multiversion approach to software development ensures a high level of its reliability. This approach is based on software redundancy. It leads to the use of additional resources during both the design and development of software and its execution phase. The requirements to minimize the execution time of multiversion software vary from desired to obligatory. Building the optimal multiversion software tasks schedule is intended to solve this problem. In the paper the use of the well-known and well-proven Hu’s scheduling algorithm is proposed. The article provides an example of solving the problem of the optimal scheduling of multiversion software tasks.

The minimization of inter-module interface for the achievement of reliability of multi-version software

This article shows that the use of the modular principle for the stage of technical designing of multi-version software is connected to the optimization process of the structure and interaction of its components. The new problem definition of the designing of the multi-version, modular structure of software, which provides the minimization of inter-module interface, is presented. This problem definition allows us to create the multi-version set of components which are used in software in the predefined sequences as well as in the random sequences. Simultaneously, the set of versions matches the predefined conditions, providing the maximum reliability for personal computers and the minimal values of the attributes of the inter-module interface.

A Dependent Model for Fault Tolerant Software Systems During Debugging

This paper proposes a special redundant model for describing the s-dependency of multi-version programming software during testing and debugging. N-version programming (NVP) is one of the most important software fault tolerance techniques. Many papers have studied the issue of fault correlation among versions. However, only a few of them consider this issue during the testing and debugging part of the software development life cycle. During testing and debugging, faults may not be successfully removed. Imperfect debugging may result in unsuccessful removal, and the introduction of new faults. Different from existing NVP models, the model proposed in this paper allows an assessment of s-dependency when correlated failures may not necessarily occur at the same execution time point. The model focuses on 2 VP systems. It is developed to be a bivariate counting process by assuming positive s-dependency among versions. Considering imperfect debugging, this bivariate process characterizes dynamic changes of fault contents for each version during testing and debugging. The system reliability, expected number of faults, probability of perfect debugging, and parameter estimation of model parameters are presented. An application example is given to illustrate the proposed model. The paper provides an alternative approach for evaluating the reliability of 2 VP software systems when there is positive s -dependency between versions.

Multi-granularity evolution analysis of software using complex network theory

Software systems are a typical kind of man-made complex systems. Understanding their evolutions can lead to better software engineering practices. In this paper, the authors use complex network theory as a tool to analyze the evolution of object-oriented (OO) software from a multigranularity perspective. First, a multi-granularity software networks model is proposed to represent the topological structures of a multi-version software system from three levels of granularity. Then, some parameters widely used in complex network theory are applied to characterize the software networks. By tracing the parameters’ values in consecutive software systems, we have a better understanding about software evolution. A case study is conducted on an open source OO project, Azureus, as an example to illustrate our approach, and some underlying evolution characteristics are uncovered. These results provide a different dimension to our understanding of software evolutions and also are very useful for the design and development of OO software systems.

Lock-free and scalable multi-version software transactional memory

Software Transactional Memory (STM) was initially proposed as a lock-free mechanism for concurrency control. Early implementations had efficiency limitations, and soon obstruction-free proposals appeared, to tackle this problem, often simplifying STM implementation. Today, most of the modern and top-performing STMs use blocking designs, relying on locks to ensure an atomic commit operation. This approach has revealed better in practice, in part due to its simplicity. Yet, it may have scalability problems when we move into many-core computers, requiring fine-tuning and careful programming to avoid contention. In this paper we present and discuss the modifications we made to a lock-based multi-version STM in Java, to turn it into a lock-free implementation that we have tested to scale at least up to 192 cores, and which provides results that compete with, and sometimes exceed, some of today's top-performing lock-based implementations. The new lock-free commit algorithm allows write transactions to proceed in parallel, by allowing them to run their validation phase independently of each other, and by resorting to helping from threads that would otherwise be waiting to commit, during the write-back phase. We also present a new garbage collection algorithm to dispose of old unused object versions that allows for asynchronous identification of unnecessary versions, which minimizes its interference with the rest of the transactional system.

The Use of Multilegged Arguments to Increase Confidence in Safety Claims for Software-Based Systems: A Study Based on a BBN Analysis of an Idealized Example

The work described here concerns the use of so-called multilegged arguments to support dependability claims about software-based systems. The informal justification for the use of multilegged arguments is similar to that used to support the use of multiversion software in pursuit of high reliability or safety. Just as a diverse 1-out-of-2 system might be expected to be more reliable than each of its two component versions, so might a two-legged argument be expected to give greater confidence in the correctness of a dependability claim (for example, a safety claim) than would either of the argument legs alone. Our intention here is to treat these argument structures formally, in particular, by presenting a formal probabilistic treatment of "confidence,? which will be used as a measure of efficacy. This will enable claims for the efficacy of the multilegged approach to be made quantitatively, answering questions such as, "How much extra confidence about a system's safety will I have if I add a verification argument leg to an argument leg based upon statistical testing?? For this initial study, we concentrate on a simplified and idealized example of a safety system in which interest centers upon a claim about the probability of failure on demand. Our approach is to build a "Bayesian Belief Network? (BBN) model of a two-legged argument and manipulate this analytically via parameters that define its node probability tables. The aim here is to obtain greater insight than what is afforded by the more usual BBN treatment, which involves merely numerical manipulation. We show that the addition of a diverse second argument leg can indeed increase confidence in a dependability claim; in a reasonably plausible example, the doubt in the claim is reduced to one-third of the doubt present in the original single leg. However, we also show that there can be some unexpected and counterintuitive subtleties here; for example, an entirely supportive second leg can sometimes undermine an original argument, resulting, overall, in less confidence than what came from this original argument. Our results are neutral on the issue of whether such difficulties will arise in real life?that is, when real experts judge real systems.