Towards software process patterns: An empirical analysis of the behavior of student teams

Traditional software engineering processes are composed of practices defined by roles, activities and artifacts. Software developers have their own understanding of practices and their own ways of implementing them, which could result in variations in software development practices. This paper presents an empirical study based on six teams of five students each, involving three different projects. Their process practices are monitored by time slips based on the effort expended on various process-related activities. This study introduces a new 3-pole graphical representation to represent the process patterns of effort expended on the various discipline activities. The purpose of this study is to quantify activity patterns in the actual process, which in turn demonstrates the variability of process performance. This empirical study provides three examples of patterns based on three empirical axes (engineering, coding and V&V). The idea behind this research is to make developers aware that there is wide variability in the actual process, and that process assessments might be weakly related to actual process activities. This study suggests that in-process monitoring is required to control the process activities. In-process monitoring is likely to provide causal information between the actual process activities and the quality of the implemented components.     

供应商一级密封报价博弈模型研究

在一个复杂的供应链系统中,由于供应商之间信息保密,那么供应商之间将会出现不完全信息竞争博弈。基于一级密封拍卖方式与供应链中供应商的投标报价的相似性,利用一级密封拍卖模型对供应商的竞争报价进行了研究,建立了供应商报价博弈模型,得到供应商的最优报价策略,定量地解决了报价中的信息不完全的问题,为供应商的报价决策提供参考。     

Analysis of the efficiency of electronic reverse auction settings: big data evidence

Electronic Commerce Research - Despite the existence of research in the field of electronic reverse auctions (eRAs), there is still a limited understanding of the determinants of auction savings...     

Purchase behavior in virtual worlds: An empirical investigation in Second Life

Virtual worlds are an emerging online transaction context in which millions of players around the world participate and trade virtual items with one another. However, little research has been conducted into purchase behavior in this new context. To address this gap, we developed and tested a conceptual model of purchase behavior in virtual worlds using a combination of existing and new constructs. An online survey was conducted within Second Life (n = 250) and tested using structural equation modeling. We conclude with implications for practice and research limitations.     

Common motifs in scientific workflows: An empirical analysis

Workflow technology continues to play an important role as a means for specifying and enacting computational experiments in modern science. Reusing and re-purposing workflows allow scientists to do new experiments faster, since the workflows capture useful expertise from others. As workflow libraries grow, scientists face the challenge of finding workflows appropriate for their task, understanding what each workflow does, and reusing relevant portions of a given workflow. We believe that workflows would be easier to understand and reuse if high-level views (abstractions) of their activities were available in workflow libraries. As a first step towards obtaining these abstractions, we report in this paper on the results of a manual analysis performed over a set of real-world scientific workflows from Taverna, Wings, Galaxy and Vistrails. Our analysis has resulted in a set of scientific workflow motifs that outline (i) the kinds of data-intensive activities that are observed in workflows (Data-Operation motifs), and (ii) the different manners in which activities are implemented within workflows (Workflow-Oriented motifs). These motifs are helpful to identify the functionality of the steps in a given workflow, to develop best practices for workflow design, and to develop approaches for automated generation of workflow abstractions.     

Comparing coverage criteria for dynamic web application: An empirical evaluation

Web applications have become popular and a preferred mean for users to do various crucial tasks such as selling and buying goods, doing short tasks, controlling smart houses and bank account management. The correctness of all such applications is important and requires thorough testing. Structural testing is widely used to achieve correctness in traditional software's, however, for web applications, it is challenging because of its dynamic and heterogeneous nature. To achieve desired structural coverage of web applications different dynamic coverage criteria are used as a quality assessment indicator. However, there is a lack of empirical evidence regarding the effectiveness of the proposed coverage criteria. In this paper, we conduct an empirical evaluation by evaluating and comparing the fault detection effectiveness and efficiency of various dynamic coverage criteria by performing mutation analysis. We conduct a series of experiments to assess and compare four widely used coverage criteria on seven open-source case studies including small to large scale applications. We performed mutation analysis by first generating different faulty versions (mutants) for the case studies and then by executing test suites to record mutation score for each criterion. The results from most of the subject applications show that DOM coverage is the most effective and efficient criterion followed by Virtual DOM, HTML Element and Statement coverage criteria.     

Herding behavior in online P2P lending: An empirical investigation

We study lender behavior in the peer-to-peer (P2P) lending market, where individuals bid on unsecured microloans requested by other individual borrowers. Online P2P exchanges are growing, but lenders in this market are not professional investors. In addition, lenders have to take big risks because loans in P2P lending are granted without collateral. While the P2P lending market shares some characteristics of online markets with respect to herding behavior, it also has characteristics that may discourage it. This study empirically investigates herding behavior in the P2P lending market where seemingly conflicting conditions and features of herding are present. Using a large sample of daily data from one of the largest P2P lending platforms in Korea, we find strong evidence of herding and its diminishing marginal effect as bidding advances. We employ a multinomial logit market-share model in which relevant variables from prior studies on P2P lending are assessed.     

Bidding strategies in dynamic electricity markets

In this paper the problem of developing bidding strategies for the participants of dynamic oligopolistic electricity markets is studied. Attention is given to strategic bidding of load serving entities (LSE) in these markets. We model oligopolistic electricity markets as non-linear dynamical systems and use discrete-time Nash bidding strategies. We assume a Cournot model for our game, where the LSEs decide on demand quantities and the market price is the marginal cost of producing electricity.Attention is given to a problem, where the objective functions are quadratic in the deviations of trajectories from desired trajectories and quadratic in the control deviations from the nominal controls. It is assumed that each power marketer can estimate his/her competitors' benefit function coefficients.The optimal bidding strategies are developed mathematically using dynamic game theory. We deal with games that are non-linear in the state equations. We linearize these equations for complex non-linear oligopolistic electricity multi-markets and use discrete-time Nash strategies. We show that the actual dynamic excursions from the operating point where we linearize are small so that the linearization is valid. The developed algorithm is applied to an IEEE 14-bus power system. We show that the LSEs' expected profits are higher for our method than those for other methods in the literature (F. Wen, A.K. David, Optimal bidding strategies and modeling of imperfect information among competitive generators. IEEE Transactions on Power Systems, Vol. 16, No. 1, pp.15–21, Feb. 2001.     

An empirical analysis of spreadsheet calculation

Spreadsheet calculation is a powerful tool in simple administrative data processing. Formulae in spreadsheets have similar forms to expressions in traditional programming languages, but the implementation of control structures is totally different. This paper contains an analysis of 101 spreadsheets made and used in business and government. The analysis concerns general properties, such as cell contents and referencing, the role of input, output and computation, and the different ways iteration is implemented. Finally some effects of expertise are studied. The results show that less than half of the available functions are really used, only one cell in 25 contains computation, and iteration is implemented in at least four different ways. Formulae are found to differ in their contents from expressions of programming languages, as control structures are implemented differently in these systems. Summation with a constant skip is suggested to be included in the set of functions of spreadsheet calculation.     

An empirical analysis of COBOL programs

This paper describes results obtained from a static analysis of 340 COBOL programs collected from commercial and industrial installations. The analysis was performed by a syntax analyser designed specifically to analyse source program statements, gather detailed information and produce a report on the definition and use of data and language in the programs analysed.     

Fuzzy application in service quality analysis: An empirical study

Service activities have become the fundamental and dominant factors of the economic system over the past three decades and the significance and influence of service quality have been recognized through the great effect on customer satisfaction and customer loyalty. It should be noted that the assessment results obtained from multiple attributes decision-making problems of diverse intensity, such as service quality evaluation, may be misleading if the fuzziness of subjective human judgment is not taken into account. This paper develops an analysis architecture, which consists of fuzzy measurement of P–I gap, modified P–I analysis for attributes and ranking order determination for subjects, to deal with service quality measurement more effectively. The fuzzy measurement of P–I gap takes advantage of including the vagueness of evaluators’ judgment. By using the results of modified P–I analysis, effective ways for improving service quality perceptions can be focused on the attributes of high importance yet poor quality; meanwhile, resources or efforts attached to the attributes of low importance and good quality can be shifted to those of high importance yet poor quality. According to the ranking order of subjects, managers could devote more efforts to assist the subjects with inferior rankings to improve the service activities. The proposed analysis architecture can be used to investigate service quality effectively and track the trends periodically. An empirical study is conducted by using the proposed approach.     

Expert systems and economic policy analysis: An application to OCS auction leasing

In this paper we argue that expert systems can be powerful tools for modelling microeconomic systems, including both individual decision making and the coordination of individual agents in a resource allocation mechanism. Using the fact that expert systems are essentially computerized versions of decision processes, we illustrate how they can be viewed as generalized process models of decision-making. We argue that the expert system approach is beneficial because it allows a policy analyst to explore the implication of policy alternatives without having to incur the generally prohibitive cost of field implementation studies. Further, enables the incorporation and updating of decision strategies and qualitative information, which human experts typically use but which is not amenable to pure mathematical modelling.One particular microeconomic system we suggest could be modelled as an expert system is the OCS offshore oil lease auction process. Moreover, we argue that constructing such an expert system model would require the development of two integrated expert systems: one for the auction process and subsequent resource allocation and the other to model the individual bidding behavior of the auction participants. We set out the structure of the auction expert system in some detail and discuss rules of thumb used by bidders inferred from our empirical research on past OCS auctions.Such an expert system of an auction leasing process could provide benefits to both bidders (e.g., oil companies) and the auctioneer (e.g., the Department of the Interior) as well. Bidders, by trying different strategies against different hypothesized strategies by their opponents could use such an integrated expert system to improve their bidding performances. The auctioneer, on the other hand, could test the efficiency of various proposed auction institutions under different assumptions about bidding behavior. In some circumstances, it might be desirable to even automate the auction process with a network coordinating the expert systems used by the individual firms and a computerized auctioneer.     

Leadership behavior and business process reengineering (BPR) outcomes: An empirical analysis of 30 BPR projects

Lack of leadership is frequently a cause for the high failure rate of business process reengineering (BPR) projects. According to many experts, BPR implementation requires a top-down, directive leadership style. Yet, it also requires the management of motivated, skilled, independent-thinking people doing non-programmable tasks for which a non-directive leadership style is most suited. This creates an inherent conflict for BPR leaders on choosing the appropriate style. Applying the leadership effectiveness framework, this study conducted an in-depth empirical analyses of the relationship between IS leadership behavior and BPR outcomes for 30 BPR projects. We found that successful BPR leaders use leadership styles that fit the type of task that needs to be done and the needs of the people that will perform the tasks. Also, successful BPR leaders balance their efforts between meeting the needs of the people doing the work and the needs of the work. The results provide guidelines for both leadership practice and empirical research.     

Ethical reciprocity in digitalized transactions: An empirical study of pre- and post-contractual behavior

Are unethical e-service providers more tolerant of disloyal users? Only a few studies have been done on the attitude of the e-service providers who behave unethically. This research intends to fill this gap in current literature. We identify two different perspectives, behavior consistency and ethical reciprocity, in explaining the attitude of e-service providers towards their users who have breached the service contracts. We further investigate such attitude in respect of the perceived mutual commitment between these providers and their users. We test our propositions by a survey on financial e-service providers and our findings support the perspective of ethical reciprocity.     

Internet positioning and performance of e-tailers: An empirical analysis

This paper presents an empirical study of e-tailers’ Internet positioning. Using a sample of 138 US web-based businesses and 20 positioning variables, the paper analyzes the visibility of e-tailers’ web pages, their relevance in search engines, their reputation in shopping portals and their popularity in blogs and news portals. Principal component analysis is used to conduct an exploratory examination. The relationship between Internet positioning and e-tailers’ performance is also examined in two ways: web metrics in terms of the number of visitors to the website, and financial results based on sales, profits, productivity, and sales growth. The results identify two kinds of Internet positioning: people-based and search engine-based. The study finds two basic kinds of competitive advantage for e-tailers: cost leadership and differentiation. No positive relationship is found between positioning and sales growth.     

Mobile app adoption in different life stages: An empirical analysis

The analysis of individuals’ current life stages is a powerful approach for identifying und understanding patterns of human behavior. Different stages imply different preferences and consumer demands. Thus, life stages play an important role in marketing, economics, and sociology. However, such information is difficult to be obtained especially in the digital world. This work thus contributed to both theory and practice from two aspects. First, we conducted a large-scale empirical study with 1435 participants and showed that a person’s mobile app adoption pattern is strongly influenced by her current life stage. Second, we presented a data-driven, highly-scalable, and real-time approach of predicting an individual’s current life stage based on the apps she has installed on smartphone. Result showed that our predictive models were able to predict life stages with 241.0% higher precision and 148.2% higher recall than a random guess on average.     

Comparing model-based and dynamic event-extraction based GUI testing techniques: An empirical study

Graphical user interfaces are pervasive in modern software systems, and to ensure their quality it is important to test them. Two primary classes of automated GUI testing approaches, those based on static models and those based on dynamic event-extraction, present tradeoffs in cost and effectiveness. For example, static model-based GUI testing techniques can create test cases that contain nonexecutable events, whereas dynamic event-extraction based GUI testing techniques can create larger numbers of duplicate test cases. To better understand the effects of these tradeoffs, we created a GUI testing framework that facilitates fair comparison of different GUI testing techniques, and we conducted a controlled experiment comparing representative versions of static-model based and dynamic event-extraction based testing techniques on several GUI-based Java applications. Our study reveals several cost and effectiveness tradeoffs between the techniques, with implications for research and practice.     

An empirical analysis of c preprocessor use

This is the first empirical study of the use of the C macro preprocessor, Cpp. To determine how the preprocessor is used in practice, this paper analyzes 26 packages comprising 1.4 million lines of publicly available C code. We determine the incidence of C preprocessor usage-whether in macro definitions, macro uses, or dependences upon macros-that is complex, potentially problematic, or inexpressible in terms of other C or C++ language features. We taxonomize these various aspects of preprocessor use and particularly note data that are material to the development of tools for C or C++, including translating from C to C++ to reduce preprocessor usage. Our results show that, while most Cpp usage follows fairly simple patterns, an effective program analysis tool must address the preprocessor. The intimate connection between the C programming language and Cpp, and Cpp's unstructured transformations of token streams often hinder both programmer understanding of C programs and tools built to engineer C programs, such as compilers, debuggers, call graph extractors, and translators. Most tools make no attempt to analyze macro usage, but simply preprocess their input, which results in a number of negative consequences; an analysis that takes Cpp into account is preferable, but building such tools requires an understanding of actual usage. Differences between the semantics of Cpp and those of C can lead to subtle bugs stemming from the use of the preprocessor, but there are no previous reports of the prevalence of such errors. Use of C++ can reduce some preprocessor usage, but such usage has not been previously measured. Our data and analyses shed light on these issues and others related to practical understanding or manipulation of real C programs. The results are of interest to language designers, tool writers, programmers, and software engineers.     

Quantitative analysis of fault density in design patterns: An empirical study

ContextThere are many claimed advantages for the use of design patterns and their impact on software quality. However, there is no enough empirical evidence that supports these claimed benefits and some studies have found contrary results.ObjectiveThis empirical study aims to quantitatively measure and compare the fault density of motifs of design patterns in object-oriented systems at different levels: design level, category level, motif level, and role level.MethodAn empirical study was conducted that involved five open-source software systems. Data were analyzed using appropriate statistical test of significance differences.ResultsThere is no consistent difference in fault density between classes that participate in design motifs and non-participant classes. However, classes that participate in structural design motifs tend to be less fault-dense. For creational design motifs, it was found that there is no clear tendency for the difference in fault density. For behavioral design motifs, it was found that there is no significant difference between participant classes and non-participant classes. We observed associations between five design motifs (Builder, Factory Method, Adapter, Composite and Decorator) and fault density. At the role level, we found that only one pair of roles (Adapter vs. Client) shows a significant difference in fault density.ConclusionThere is no clear tendency for the difference in fault density between participant and non-participant classes in design motifs. However, structural design motifs have a negative association with fault density. The Builder design motif has a positive association with fault density whilst the Factory Method, Adapter, Composite, and Decorator design motifs have negative associations with fault density. Classes that participate in the Adapter role are less dense in faults than classes that participate in the Client role.