Efficiency of mutation operators and selective mutation strategies: an empirical study

This paper investigates the mutation scores achieved by individual operators of the Mothra mutation system and their associated costs in order to determine the most efficient operators. The cost of mutation analysis includes both test set generation and equivalent mutant detection. The score and cost information is then used as a heuristic for choosing a subset of the operators for use in efficient selective mutation testing. Experiments were performed using a sample of 11 programs and a number of test sets for each program. The results show that the use of efficient operators can provide significant efficiency gains for selective mutation if the acceptable mutation score is not very close to one. When mutation scores very close to one are required, a randomly selected proportion of the mutants provides a more efficient strategy than a subset of efficient operators. Copyright © 1999 John Wiley & Sons, Ltd.     

An empirical study of control logic specifications for programmable logic controllers

This paper presents an empirical study of control logic specifications used to document industrial control logic code in manufacturing applications. More than one hundred input/output related property specifications from ten different reusable function blocks were investigated. The main purpose of the study was to provide understanding of how the specifications are expressed by industrial practitioners, in order to develop new tools and methods for specifying control logic software, as well as for evaluating existing ones. In this paper, the studied specifications are used to evaluate linear temporal logic in general and the specification language ST-LTL, tailored for functions blocks, in particular. The study shows that most specifications are expressed as implications, that should always be fulfilled, between input and output conditions. Many of these implications are complex since the input and output conditions may be mixed and involve sequences, timer issues and non-boolean variables. Using ST-LTL it was possible to represent all implications of this study. The few non-implication specifications could be specified in ST-LTL as well after being altered to suit the specification language. The paper demonstrates some advantages of ST-LTL compared to standard linear temporal logic and discusses possible improvements such as support for automatic rewrite of complex specifications.     

Organizational software piracy: an empirical assessment

Application of Information Technology (IT) has had a significant impact on all aspects of business. Due to technology, the ease with which software can be pirated is increasing and is leading to increased concern for copyright protection. This paper reviews and discusses software piracy issues from a global perspective and reports the findings of a survey concerning the impact of sectors like government, private and academic in Turkey. Although software piracy has long been attracting the interest of academics, no quantitative research has ever been realized in this field in the country. Elsewhere also, most of the software piracy-related studies are from individuals' perspectives and are limited to students, academics, cost, and attitudes. Very few have reported findings related to IT professionals and organizations. The survey was conducted among IT managers of large-scale organizations from different sectors such as the government, private and academic community. Based on the survey of 162 IT managers, the results indicated that sectors have significant impact on software piracy to some extent.     

Organizational software piracy: an empirical assessment

Application of Information Technology (IT) has had a significant impact on all aspects of business. Due to technology, the ease with which software can be pirated is increasing and is leading to increased concern for copyright protection. This paper reviews and discusses software piracy issues from a global perspective and reports the findings of a survey concerning the impact of sectors like government, private and academic in Turkey. Although software piracy has long been attracting the interest of academics, no quantitative research has ever been realized in this field in the country. Elsewhere also, most of the software piracy-related studies are from individuals' perspectives and are limited to students, academics, cost, and attitudes. Very few have reported findings related to IT professionals and organizations. The survey was conducted among IT managers of large-scale organizations from different sectors such as the government, private and academic community. Based on the survey of 162 IT managers, the results indicated that sectors have significant impact on software piracy to some extent.     

Multi-criteria assessment of user trust in Social Reviewing Systems with subjective logic fusion

By now people’s opinions and actions are more and more strongly influenced by what is posted and shared on the various social networks. Thus, malicious users can purposely manipulate other users posting fake news/reviews. In order to face this challenge, modern online social networks are beginning to adopt tool for user trustworthiness assessment. Current assessment solutions mainly adopt multi-criteria frameworks for user trustworthiness assessment but fail at properly dealing with uncertainty and vagueness in computed/collected scores and aggregating them in a robust manner. In this paper, we propose a larger set of criteria than existing related works, and the use of subjective logic to represent and combine subjective and objective scores. Specifically, several of assessment criteria are introduced for verifying user trust from different point of views (usefulness and quality of user reviews, users’ influence/importance in terms of activities and centrality within the social network, time dependent crown consensus investigating aspect-based sentiments and opinions of reviews w.r.t. the majority), aiming at improving accuracy and precision in trust estimation. The available fusion operators in the literature of subjective logic have been compared so as to find the best one fitting the needs of trust estimation. The proposed solution has been implemented and evaluated against public Yelp data-sets so as to prove its effectiveness and efficiency w.r.t. existing related works within the literature.     

An empirical study on trust in mobile banking: A developing country perspective

Trust is essential for Mobile Banking (MB) adoption and usage. MB technology has the potential to improve people's quality of life and to bring efficiency to banks. In this paper, MB trust was addressed in Brazil, a developing country that has an enormous potential for expansion of banking services. We used Confirmatory Factor Analysis and Structural Equation Modeling to analyze the database, which was composed of 1077 questionnaires. In this study sample, determinants of trust had similar behavior when compared to determinants of trust previously pointed out in the literature. Our discussion indicated a kind of information asymmetry that could be mitigated in order to build trust in MB and promote its adoption. However, we observed a negative relationship between trust in MB and undergraduate course area (dummy variable for undergraduate courses in technology). The inclusion and analysis of this new variable, especially in developing countries, may contribute with the literature on MB adoption.     

Implication operators in fuzzy logic

The choice of fuzzy implication as well as other connectives is an important problem in the theoretical development of fuzzy logic, and at the same time, it is significant for the performance of the systems in which fuzzy logic technique is employed. There are mainly two ways in fuzzy logic to define implication operators: (1) an implication operator is considered as the residuation of conjunction operator; and (2) it is directly defined in terms of negation, conjunction, and disjunction operators. The purpose of this paper is to determine the number of implication operators defined in the second way for some usual negation, conjunction and disjunction operators in fuzzy logic     

Sequential operators in computability logic

Computability logic (CL) is a semantical platform and research program for redeveloping logic as a formal theory of computability, as opposed to the formal theory of truth which it has more traditionally been. Formulas in CL stand for (interactive) computational problems, understood as games between a machine and its environment; logical operators represent operations on such entities; and “truth” is understood as existence of an effective solution, i.e., of an algorithmic winning strategy.The formalism of CL is open-ended, and may undergo series of extensions as the study of the subject advances. The main groups of operators on which CL has been focused so far are the parallel, choice, branching, and blind operators, with the logical behaviors of the first three groups resembling those of the multiplicatives, additives and exponentials of linear logic, respectively. The present paper introduces a new important group of operators, called sequential. The latter come in the form of sequential conjunction and disjunction, sequential quantifiers, and sequential recurrences (“exponentials”). As the name may suggest, the algorithmic intuitions associated with this group are those of sequential computations, as opposed to the intuitions of parallel computations associated with the parallel group of operations. Specifically, while playing a parallel combination of games means playing all components of the combination simultaneously, playing a sequential combination means playing the components in a sequential fashion, one after one.The main technical result of the present paper is a sound and complete axiomatization of the propositional fragment of computability logic whose vocabulary, together with negation, includes all three — parallel, choice and sequential — sorts of conjunction and disjunction. An extension of this result to the first-order level is also outlined.     

Toggling operators in computability logic

Computability logic (CoL) is a recently introduced semantical platform and research program for redeveloping logic as a formal theory of computability, as opposed to the formal theory of truth that logic has more traditionally been. Formulas in CoL stand for interactive computational problems, seen as games between a machine and its environment; logical operators represent operations on such entities; and “truth” is understood as existence of an effective solution, i.e., of an algorithmic winning strategy.The formalism of CoL is open-ended, and may undergo series of extensions as the studies of the subject advance. Propositional connectives and quantifiers in it come in a variety of indispensable versions. So far three sorts of conjunction and disjunction-parallel, sequential and choice-have been studied, with the first and the third sorts being reminiscent of the multiplicative and additive operators of linear logic, respectively. The present paper adds one more natural kind to this collection, termed toggling. The toggling operations can be characterized as lenient versions of choice operations where choices are retractable, being allowed to be reconsidered any finite number of times. This way, they model trial-and-error style decision steps in interactive computation. The main technical result of this paper is constructing a sound and complete axiomatization for the propositional fragment of computability logic whose vocabulary includes all four kinds of conjunction and disjunction: parallel, toggling, sequential and choice, together with negation. Along with toggling conjunction and disjunction, the paper also introduces the toggling versions of quantifiers and recurrence (“exponential”) operations.     

A credit assessment mechanism for wireless telecommunication debt collection: an empirical study

The wireless telecommunication market in Taiwan is now saturated. As the competition between wireless service carriers intensifies, retaining customers becomes more difficult. To prevent companies from increasing bad debt and experiencing customer churn, this study aims to apply data mining method to build a credit assessment mechanism that can effectively evaluate customer credit risks and help wireless service carriers to enhance the quality of debt collection processes by customizing collection strategies for various customer groups. The application of the proposed mechanism to related problems in a wireless telecommunication company in Taiwan has shown satisfactory effectiveness, accounting for a savings of $2 million of a total $500 million annual revenue. A mere 0.4 % savings is significant, given that wireless service carriers in Taiwan typically allocate 2–4 % of their revenue to uncollectible debts.     

Refactoring the aspectizable interfaces: an empirical assessment

Aspect oriented programming aims at addressing the problem of the crosscutting concerns, i.e., those functionalities that are scattered among several modules in a given system. Aspects can be defined to modularize such concerns. In this work, we focus on a specific kind of crosscutting concerns, the scattered implementation of methods declared by interfaces that do not belong to the principal decomposition. We call such interfaces aspectizable. All the aspectizable interfaces identified within a large number of classes from the Java Standard Library and from three Java applications have been automatically migrated to aspects. To assess the effects of the migration on the internal and external quality attributes of these systems, we collected a set of metrics and we conducted an empirical study, in which some maintenance tasks were executed on the two alternative versions (with and without aspects) of the same system. In this paper, we report the results of such a comparison.     

Subjective evaluation of software evolvability using code smells: An empirical study

This paper presents the results of an empirical study on the subjective evaluation of code smells that identify poorly evolvable structures in software. We propose use of the term software evolvability to describe the ease of further developing a piece of software and outline the research area based on four different viewpoints. Furthermore, we describe the differences between human evaluations and automatic program analysis based on software evolvability metrics. The empirical component is based on a case study in a Finnish software product company, in which we studied two topics. First, we looked at the effect of the evaluator when subjectively evaluating the existence of smells in code modules. We found that the use of smells for code evaluation purposes can be difficult due to conflicting perceptions of different evaluators. However, the demographics of the evaluators partly explain the variation. Second, we applied selected source code metrics for identifying four smells and compared these results to the subjective evaluations. The metrics based on automatic program analysis and the human-based smell evaluations did not fully correlate. Based upon our results, we suggest that organizations should make decisions regarding software evolvability improvement based on a combination of subjective evaluations and code metrics. Due to the limitations of the study we also recognize the need for conducting more refined studies and experiments in the area of software evolvability.

Scalable continual quality control of formative assessment items in an educational digital library: an empirical study

An essential component of any library of online learning objects is assessment items, for example, homework, quizzes, and self-study questions. As opposed to exams, these items are formative in nature, as they help the learner to assess his or her own progress through the material. When it comes to quality control of these items, their formative nature poses additional challenges. e.g., there is no particular time interval in which learners interact with these items, learners come to these items with very different levels of preparation and seriousness, guessing generates noise in the data, and the numbers of items and learners can be several orders of magnitude larger than in summative settings. This empirical study aims to find a highly scalable mechanism for continual quality control of this class of digital content with a minimalist amount of additional metadata and transactional data, while taking into account also characteristics of the learners. In a subsequent evaluation of the model on a limited set of transactions, we find that taking into account the learner characteristic of ability improves the quality of item metadata, and in a comparison to Item Response Theory (IRT), we find that the developed model in fact performs slightly better in terms of predicting the outcome of formative assessment transactions, while never matching the performance of IRT on predicting the outcome of summative assessment.     

Examining customers’ trust in online vendors and their dropout decisions: An empirical study

Customer dropouts represent a critical challenge to online vendors and have severely constrained the proliferation of electronic retailing, which greatly depends on the customer eventually clicking on the “confirm purchase” button. In this study, we investigate the relationship between customers’ trust in an online vendor and their dropouts in different stages of the purchase process. Using a well-established consumer decision-making process, we analyze salient online trust antecedents for each purchase stage, develop specific hypotheses, and test them empirically. Our results suggest that customers’ trust in an online vendor has significant effects on their decisions to exit from the vendor’s website, and that salient trust antecedents vary in different stages of the consumer decision process. According to our findings, customers by and large depend on general, subjective antecedents pertaining to personal traits or perceptions about the website’s ease of use to assess the trustworthiness of an online vendor in the early stages but focus on specific, objective, transaction-oriented antecedents directly related to their purchase decision making in the later stages. Our results have important implications for research and practice which are also discussed in the paper.     

Improving multiple-password recall: an empirical study

As one of the most common authentication methods, passwords help secure information by granting access only to authorized parties. To be effective, passwords should be strong, secret, and memorable. While password strength can be enforced by automated information technology policies, users frequently jeopardize secrecy to improve memorability. The password memorability problem is exacerbated by the number of different passwords a user is required to remember. While short-term memory theories have been applied to individual-password management problems, the relationship between memory and the multiple-password problem has not been examined. This paper treats the multiple-password management crisis as a search and retrieval problem involving human beings’ long-term memory. We propose that interference between different passwords is one of the major challenges to multiple-password recall and that interference alleviation methods can significantly improve multiple-password recall. A lab experiment was conducted to examine the effectiveness of two interference alleviation methods: the list reduction method and the unique identifier method. While both methods improve multiple-password recall performance, the list reduction method leads to statistically significant improvement. The results demonstrate the potential merit of practices targeting multiple-password interference. By introducing long-term memory theory to multiple-password memorability issues, this study presents implications benefiting users and serves as the potential starting point for future research.     

An empirical study on the synergy of multiple crossover operators

Typical evolutionary algorithms (EAs) exploit the different space-search properties of variation operators, such as crossover, mutation and local optimization. There are also various operators in each element. This paper provides an extensive empirical study on the synergy among multiple crossover operators. We choose a number of different crossover operators in an EA and investigate whether or not their combinations outperform the sole usage of the best crossover operator. The traveling salesman problem and the graph bisection problem were chosen for experimentation. Strong synergy effects were observed in both problems     

Software architectural patterns in practice: an empirical study

Software architecture involves a series of decisions based on many factors in a wide range of software development. Architects face recurring issues in different software architecture design, and to reduce huge cost and risks, software architecture decisions can rely on a set of idiomatic patterns commonly named architectural styles or patterns. Architectural pattern determines the vocabulary of components and connectors that are used in instances of the pattern together with a set of constraints to combine the two. Little contemporary data exists to document actual practices used by software professionals when selecting and incorporating architectural patterns for their projects in industry. Therefore, a comprehensive survey of software professionals was conducted to attempt to discover these practices. This exploratory survey and its quantitative results offer opportunities for further interpretation and comparison. Data from this survey are presented in this paper and include characteristics of projects, practices, organizations, and practitioners related to the usage of architectural patterns. Some of the notable findings include that architectural patterns are widely used in software projects with the Model–View–Controller being the most common. Despite reported difficulties in incorporating architectural patterns, the majority of the software professionals revealed that patterns were the most essential for completing the projects. The most difficult pattern to implement and the most expensive to adopt was the peer-to-peer, while the easiest was the client–server.

     

Perils of Internet fraud: an empirical investigation of deceptionand trust with experienced Internet consumers

This study examines consumer evaluations of a real commercial web site and a fraudulent site that imitates it. The forged site contains malicious manipulations designed to increase trust in the site, decrease perceived risk, and ultimately increase the likelihood that visitors would buy from it. Besides measuring the consumer's willingness to buy from the site, this study recorded the actual ordering of a laptop. Results show that most subjects failed to detect the fraud manipulations, albeit a few succeeded. The fraud has the effect of increasing the consumers' reliance in assurance mechanisms and trust mechanisms, which in turn decrease perceived risk and increase trust in the store. The study confirms hypothesized relationships between purchase behavior, willingness to buy, attitudes toward the store, risk, and trust that are consistent with other trust models found in the literature. Overall, the study sheds light on consumers' vulnerability to attack by hackers posing as a legitimate site     

Examining the role of initial trust in user adoption of mobile payment services: an empirical investigation

User adoption of mobile payment (m-payment) is low compared to the adoption of traditional forms of payments. Lack of user trust has been identified as the most significant long-term barrier for the success of mobile finances systems. Motivated by this fact, we proposed and tested an initial trust theoretical model for user adoption of m-payment systems. The model not only theorizes the role of initial trust in m-payment adoption, but also identifies the facilitators and inhibitors for a user’s initial trust formation in m-payment systems. The model is empirically validated via a sample of 851 potential m-payment adopters in Australia. Partial least squares structural equation modelling is used to assess the relationships of the research model. The results indicate that perceived information quality, perceived system quality, and perceived service quality as the initial trust facilitators are positively related to initial trust formation, while perceived uncertainty as the initial trust inhibitor exerts a significant negative effect on initial trust. Perceived asset specificity is found to have insignificant effect. In addition, the results show that initial trust positively affects perceived benefit and perceived convenience, and these three factors together predict usage intention. Perceived convenience of m-payment is also found to have a positive effect on perceived benefit. The findings of this study provide several important implications for m-payment adoption research and practice.