Professional networking at in-person events plays a crucial role in career growth. However, many professionals struggle to maintain and transition these connections to online platforms like LinkedIn. Missed opportunities often arise due to challenges in tracking interactions, forgetting to add contacts, and the absence of tools that facilitate seamless networking. This paper examines how professionals network at events and the factors influencing their connection decisions. Through a comprehensive survey, we analyze networking behaviors, the use of social platforms, and the challenges faced in transitioning from offline to online transitions. Based on that analysis, we propose a mobile application that leverages Bluetooth and activity sensors to record social proximity, detect meaningful interactions, and provide intelligent recommendations for adding relevant connections. By bridging the gap between offline encounters and online professional networks, our approach enhances networking efficiency, ensuring that valuable connections made at events are sustained beyond the physical space.

Professional networking at in-person events plays a crucial role in career growth. However, many professionals struggle to maintain and transition these connections to online platforms like LinkedIn. Missed opportunities often arise due to challenges in tracking interactions, forgetting to add contacts, and the absence of tools that facilitate seamless networking. This paper examines how we can track those missed opportunities to connect with people from events by developing a protocol to find and record proximity interactions using Bluetooth while maintaining security and privacy of individual and device data, and then implementing that protocol in a proximity networking application developed for mobile phones. By bridging the gap between offline encounters and online professional networks, we believe that our approach enhances networking efficiency, ensuring that valuable connections made at events are sustained beyond the physical space.

Researchers have investigated the bug bounty ecosystem from the lens of platforms, programs, and bug hunters. Understanding the perspectives of bug bounty report reviewers, especially those who historically lack a security background and little to no funding for bug hunters, is currently under-studied. In this paper, we primarily investigate the perspective of open-source software (OSS) maintainers who have used huntr, a bug bounty platform that pays bounties to bug hunters who find security bugs in GitHub projects and have had valid vulnerabilities patched as a result. We address this area by conducting three studies: identifying characteristics through a listing survey$(n_{1}=51)$, their ranked importance with Likert-scale survey data$(n_{2}=90)$, and conducting semi-structured interviews to dive deeper into real-world experiences$(n_{3} =17)$. As a result, we categorize 40 identified characteristics into benefits, challenges, helpful features, and wanted features. We find that private disclosure and project visibility are the most important benefits, while hunters focused on money or CVEs and pressure to review are the most challenging to overcome. Surprisingly, lack of communication with bug hunters is the least challenging, and CVE creation support is the second-least helpful feature for OSS maintainers when reviewing bug bounty reports. We present recommendations to make the bug bounty review process more accommodating to open-source maintainers and identify areas for future work.

Scholars have investigated numerous barriers to accessible software development tools and processes for Blind and Low Vision (BLV) developers. However, the research community has yet to study the accessibility of software development meetings, which are known to play a crucial role in software development practice. We conducted semi-structured interviews with 26 BLV software professionals about software development meeting accessibility. We found four key themes related to in-person and remote software development meetings: (1) participants observed that certain meeting activities and software tools used in meetings were inaccessible, (2) participants performed additional labor in order to make meetings accessible, (3) participants avoided disclosing their disability during meetings due to fear of career repercussions, (4) participants suggested technical, social and organizational solutions for accessible meetings, including developing their own solutions. We suggest recommendations and design implications for future accessible software development meetings including technical and policy-driven solutions.

Many mainstream programming languages lack extensive support for architectural constructs, such as software components, which limits software developers in employing many benefits of architecture-based development. To address this issue, Java, one of the most popular and widely-used programming languages, has introduced the Java Platform Module System (JPMS) in its 9th and subsequent versions. JPMS provides the notion of architectural constructs, i.e., software components, as an encapsulation of modules that helps developers construct and maintain large applications efficiently—as well as improving the encapsulation, security, and maintainability of Java applications in general and the JDK itself. However, ensuring that module declarations reflect the actual usage of modules in an application remains a challenge that results in developers mistakenly introducing inconsistent module dependencies at both compile- and run-time. In this paper, we studied JPMS properties and architectural notions in-depth and defined a defect model consisting of eight inconsistent modular dependencies that may arise in Java applications. Based on this defect model, we also present DARCY, a framework that leverages the defect model and static analysis techniques to automatically detect and repair the specified inconsistent dependencies within Java applications at both compile- and run-time. The results of our experiments, conducted over 52 open-source Java 9+ applications, indicate that architectural inconsistencies are widespread and demonstrate DARCY’s effectiveness for automated resolution of these inconsistencies.

Application-specific hardware acceleration of computation-intensive kernels can often provide significant performance and power efficiency improvements over general-purpose software, but it is difficult and costly to incorporate them into existing software systems. Designing hardware accelerators and modifying legacy software to incorporate them are already complex tasks. Furthermore, identifying a suitable kernel for acceleration is complicated by the PCIe-attached architecture of commodity FPGA cards, meaning bandwidth and latency overhead must be considered for kernel selection. For example, small blocking kernels may not benefit from acceleration due to PCIe latency. As a remedy, we present FarSlayer, a high-level source-to-source compiler for end-to-end acceleration of legacy software. FarSlayer analyzes existing software code and emits an accelerated version of it, where the kernel is automatically selected considering data movement over PCIe. Specifically, FarSlayer identifies kernels which can be called asynchronously to hide the PCIe latency, while also having a high operational intensity for low bandwidth requirements. The entire process is automatic, meaning the programmer does not necessarily need to understand the existing code, or reason about hardware development. We demonstrate FarSlayer on multiple existing scientific computing software systems, and demonstrate it can automatically achieve significant performance improvements.

Vehicles controlled by autonomous driving software (ADS) are expected to bring many social and economic benefits, but at the current stage not being broadly used due to concerns with regard to their safety. Virtual tests, where autonomous vehicles are tested in software simulation, are common practices because they are more efficient and safer compared to field operational tests. Specifically, search-based approaches are used to find particularly critical situations. These approaches provide an opportunity to automatically generate tests; however, system-atically producing bug-revealing tests for ADS remains a major challenge. To address this challenge, we introduce DoppelTest, a test generation approach for ADSes that utilizes a genetic algorithm to discover bug-revealing violations by generating scenarios with multiple autonomous vehicles that account for traffic control (e.g., traffic signals and stop signs). Our extensive evaluation shows that DoppelTest can efficiently discover 123 bug-revealing violations for a production-grade ADS (Baidu Apollo) which we then classify into 8 unique bug categories.

Android is a highly fragmented platform with a diverse set of devices and users. To support the deployment of apps in such a heterogeneous setting, Android has introduced dynamic delivery —a new model of software deployment in which optional, device- or user-specific functionalities of an app, called Dynamic Feature Modules (DFMs) , can be installed, as needed, after the app’s initial installation. This model of app deployment, however, has exacerbated the challenges of properly testing Android apps. In this article, we first describe the results of an extensive study in which we formalized a defect model representing the various conditions under which DFM installations may fail. We then present DeltaDroid —a tool aimed at assisting the developers with validating dynamic delivery behavior in their apps by augmenting their existing test suite. Our experimental evaluation using real-world apps corroborates DeltaDroid ’s ability to detect many crashes and unexpected behaviors that the existing automated testing tools cannot reveal.

Autonomous Vehicles (AVs) leverage advanced sensing and networking technologies (e.g., camera, LiDAR, RADAR, GPS, DSRC, 5G, etc.) to enable safe and efficient driving without human drivers. Although still in its infancy, AV technology is becoming increasingly common and could radically transform our transportation system and by extension, our economy and society. As a result, there is tremendous global enthusiasm for research, development, and deployment of AVs, e.g., self-driving taxis and trucks from Waymo and Baidu. The current practice for testing AVs uses virtual tests—where AVs are tested in software simulations—since they offer a more efficient and safer alternative compared to field operational tests. Specifically, search-based approaches are used to find particularly critical situations. These approaches provide an opportunity to automatically generate tests; however, systematically creatingvalidandeffectivetests for AV software remains a major challenge. To address this challenge, we introducescenoRITA, a test generation approach for AVs that uses an evolutionary algorithm with (1) a novel gene representation that allows obstacles to befully mutable, hence, resulting in more reported violations and more diverse scenarios, (2) 5 test oracles to determine both safety and motion sickness-inducing violations and (3) a novel technique to identify and eliminate duplicate tests. Our extensive evaluation shows thatscenoRITAcan produce test scenarios that are more effective in revealing ADS bugs and more diverse in covering different parts of the map compared to other state-of-the-art test generation approaches.

As a software system evolves, its architecture tends to decay, leading to the occurrence of architectural elements that become resistant to maintenance or prone to defects. To address this problem, engineers can significantly benefit from determining which architectural elements will decay before that decay actually occurs. Forecasting decay allows engineers to take steps to prevent decay, such as focusing maintenance resources on the architectural elements most likely to decay. To that end, we construct novel models that predict the quality of an architectural element by utilizing multiple architectural views (both structural and semantic) and architectural metrics as features for prediction. We conduct an empirical study using our prediction models on 38 versions of five systems. Our findings show that we can predict low architectural quality, i.e., architectural decay, with high performance—even for cases of decay that suddenly occur in an architectural module. We further report the factors that best predict architectural quality.

Over the past three decades software engineering researchers have produced a wide range of techniques and tools for understanding the architectures of large, complex systems. However, these have tended to be one-off research projects, and their idiosyncratic natures have hampered research collaboration, extension and combination of the tools, and technology transfer. The area of software architecture is rich with disjoint research and development infrastructures, and datasets that are either proprietary or captured in proprietary formats. This paper describes a concerted effort to reverse these trends. We have designed and implemented a flexible and extensible infrastructure (SAIN) with the goal of sharing, replicating, and advancing software architecture research. We have demonstrated that SAIN is capable of incorporating the constituent tools extracted from three independently developed, large, long-lived software architecture research environments. We discuss SAIN's ambitious goals, the challenges we have faced in achieving those goals, the key decisions made in SAIN's design and implementation, the lessons learned from our experience to date, and our ongoing and future work.

Android apps include third-party native libraries to increase performance and to reuse functionality. Native code is directly executed from apps through the Java Native Interface or the Android Native Development Kit. Android developers add precompiled native libraries to their projects, enabling their use. Unfortunately, developers often struggle or simply neglect to update these libraries in a timely manner. This results in the continuous use of outdated native libraries with unpatched security vulnerabilities years after patches became available. To further understand such phenomena, we study the security updates in native libraries in the most popular 200 free apps on Google Play from Sept. 2013 to May 2020. A core difficulty we face in this study is the identification of libraries and their versions. Developers often rename or modify libraries, making their identification challenging. We create an approach called LibRARIAN (LibRAry veRsion IdentificAtioN) that accurately identifies native libraries and their versions as found in Android apps based on our novel similarity metric bin2sim. LibRARIAN leverages different features extracted from libraries based on their metadata and identifying strings in read-only sections. We discovered 53/200 popular apps (26.5%) with vulnerable versions with known CVEs between Sept. 2013 and May 2020, with 14 of those apps remaining vulnerable. We find that app developers took, on average, 528.71±40.20 days to apply security patches, while library developers release a security patch after 54.59 ± 8.12 days-a 10 times slower rate of update.

This paper identifies a model of software evolution that is prevalent in large, long-lived academic research tool suites (3L-ARTS). This model results in an "archipelago" of related but haphazardly organized architectural "islands", and inherently induces technical debt. We illustrate the archipelago model with examples from two 3L-ARTS archipelagos identified in literature.

Self-driving cars, or Autonomous Vehicles (AVs), are increasingly becoming an integral part of our daily life. About 50 corporations are actively working on AVs, including large companies such as Google, Ford, and Intel. Some AVs are already operating on public roads, with at least one unfortunate fatality recently on record. As a result, understanding bugs in AVs is critical for ensuring their security, safety, robustness, and correctness. While previous studies have focused on a variety of domains (e.g., numerical software; machine learning; and error-handling, concurrency, and performance bugs) to investigate bug characteristics, AVs have not been studied in a similar manner. Recently, two software systems for AVs, Baidu Apollo and Autoware, have emerged as frontrunners in the open-source community and have been used by large companies and governments (e.g., Lincoln, Volvo, Ford, Intel, Hitachi, LG, and the US Department of Transportation). From these two leading AV software systems, this paper describes our investigation of 16,851 commits and 499 AV bugs and introduces our classification of those bugs into 13 root causes, 20 bug symptoms, and 18 categories of software components those bugs often affect. We identify 16 major findings from our study and draw broader lessons from them to guide the research community towards future directions in software bug detection, localization, and repair.

This paper presents the design, implementation, and usage details of ARCADE, an extensible workbench for supporting the recovery of software systems' architectures, and for evaluating architectural change and decay. ARCADE has been developed and maintained over the past decade, and has been deployed in a number of research labs as well as within three large companies. ARCADE's implementation is available at https://bitbucket.org/joshuaga/arcade and the video depicting its use at https://tinyurl.com/arcade-tool-demo.

Java is one of the most widely used programming languages. However, the absence of explicit support for architectural constructs, such as software components, in the programming language itself has prevented software developers from achieving the many benefits that come with architecture-based development. To address this issue, Java 9 has introduced the Java Platform Module System (JPMS), resulting in the first instance of encapsulation of modules with rich software architectural interfaces added to a mainstream programming language. The primary goal of JPMS is to construct and maintain large applications efficiently-as well as improve the encapsulation, security, and maintainability of Java applications in general and the JDK itself. A challenge, however, is that module declarations do not necessarily reflect actual usage of modules in an application, allowing developers to mistakenly specify inconsistent dependencies among the modules. In this paper, we formally define 8 inconsistent modular dependencies that may arise in Java-9 applications. We also present DARCY, an approach that leverages these definitions and static program analyses to automatically (1) detect the specified inconsistent dependencies within Java applications and (2) repair those identified inconsistencies. The results of our experiments, conducted over 38 open-source Java-9 applications, indicate that architectural inconsistencies are widespread and demonstrate the benefits of DARCY in automated detection and repair of these inconsistencies.

The number of malicious Android apps has been and continues to increase rapidly. These malware can damage or alter other files or settings, install additional applications, obfuscate their behaviors, propagate quickly, and so on. To identify and handle such malware, a security analyst can significantly benefit from identifying the family to which a malicious app belongs rather than only detecting if an app is malicious. To address these challenges, we present a novel machine learning-based Android malware detection and family-identification approach, RevealDroid, that operates without the need to perform complex program analyses or extract large sets of features. RevealDroid's selected features leverage categorized Android API usage, reflection-based features, and features from native binaries of apps. We assess RevealDroid for accuracy, efficiency, and obfuscation resilience using a large dataset consisting of more than 54,000 malicious and benign apps. Our experiments show that RevealDroid achieves an accuracy of 98% in detection of malware and an accuracy of 95% in determination of their families. We further demonstrate RevealDroid's superiority against state-of-the-art approaches. [URL of original paper: https://dl.acm.org/citation.cfm?id=3162625]

The Android platform has been the dominant mobile platform in recent years resulting in millions of apps and security threats against those apps. Anti-malware products aim to protect smartphone users from these threats, especially from malicious apps. However, malware authors use code obfuscation on their apps to evade detection by anti-malware products. To assess the effects of code obfuscation on Android apps and anti-malware products, we have conducted a large-scale empirical study that evaluates the effectiveness of the top anti-malware products against various obfuscation tools and strategies. To that end, we have obfuscated 3,000 benign apps and 3,000 malicious apps and generated 73,362 obfuscated apps using 29 obfuscation strategies from 7 open-source, academic, and commercial obfuscation tools. The findings of our study indicate that (1) code obfuscation significantly impacts Android anti-malware products; (2) the majority of anti-malware products are severely impacted by even trivial obfuscations; (3) in general, combined obfuscation strategies do not successfully evade anti-malware products more than individual strategies; (4) the detection of anti-malware products depend not only on the applied obfuscation strategy but also on the leveraged obfuscation tool; (5) anti-malware products are slow to adopt signatures of malicious apps; and (6) code obfuscation often results in changes to an app's semantic behaviors.

Multi-criteria test-suite minimization aims to remove redundant test cases from a test suite based on some criteria such as code coverage, while trying to optimally maintain the capability of the reduced suite based on other criteria such as fault-detection effectiveness. Existing techniques addressing this problem with integer linear programming claim to produce optimal solutions. However, the multi-criteria test-suite minimization problem is inherently nonlinear, due to the fact that test cases are often dependent on each other in terms of test-case criteria. In this paper, we propose a framework that formulates the multi-criteria test-suite minimization problem as an integer nonlinear programming problem. To solve this problem optimally, we programmatically transform this nonlinear problem into a linear one and then solve the problem using modern linear solvers. We have implemented our framework as a tool, called Nemo, that supports a number of modern linear and nonlinear solvers. We have evaluated Nemo with a publicly available dataset and minimization problems involving multiple criteria including statement coverage, fault-revealing capability, and test execution time. The experimental results show that Nemo can be used to efficiently find an optimal solution for multi-criteria test-suite minimization problems with modern solvers, and the optimal solutions outperform the suboptimal ones by up to 164.29% in terms of the criteria considered in the problem.

The current security mechanisms for Android apps, both static and dynamic analysis approaches, are insufficient for detection and prevention of the increasingly dynamic and sophisticated security attacks. Static analysis approaches suffer from false positives whereas dynamic analysis approaches suffer from false negatives. Moreover, they all lack the ability to efficiently analyze systems with incremental changes—such as adding/removing apps, granting/revoking permissions, and dynamic components’ communications. Each time the system changes, the entire analysis needs to be repeated, making the existing approaches inefficient for practical use. To mitigate their shortcomings, we have developed SALMA, a novel self-protecting Android software system that monitors itself and adapts its behavior at runtime to prevent a wide-range of security risks. SALMA maintains a precise architectural model, represented as a Multiple-Domain-Matrix, and incrementally and efficiently analyzes an Android system in response to incremental system changes. The maintained architecture is used to reason about the running Android system. Every time the system changes, SALMA determines (1) the impacted part of the system, and (2) the subset of the security analyses that need to be performed, thereby greatly improving the performance of the approach. Our experimental results on hundreds of real-world apps corroborate SALMA’s scalability and efficiency as well as its ability to detect and prevent security attacks at runtime with minimal disruption.

The number of malicious Android apps is increasing rapidly. Android malware can damage or alter other files or settings, install additional applications, and so on. To determine such behaviors, a security analyst can significantly benefit from identifying the family to which an Android malware belongs rather than only detecting if an app is malicious. Techniques for detecting Android malware, and determining their families, lack the ability to handle certain obfuscations that aim to thwart detection. Moreover, some prior techniques face scalability issues, preventing them from detecting malware in a timely manner. To address these challenges, we present a novel machine-learning-based Android malware detection and family identification approach, RevealDroid, that operates without the need to perform complex program analyses or to extract large sets of features. Specifically, our selected features leverage categorized Android API usage, reflection-based features, and features from native binaries of apps. We assess RevealDroid for accuracy, efficiency, and obfuscation resilience using a large dataset consisting of more than 54,000 malicious and benign apps. Our experiments show that RevealDroid achieves an accuracy of 98% in detection of malware and an accuracy of 95% in determination of their families. We further demonstrate RevealDroid’s superiority against state-of-the-art approaches.

Many techniques have been proposed to automatically recover software architectures from software implementations. A thorough comparison among the recovery techniques is needed to understand their effectiveness and applicability. This study improves on previous studies in two ways. First, we study the impact of leveraging accurate symbol dependencies on the accuracy of architecture recovery techniques. In addition, we evaluate other factors of the input dependencies such as the level of granularity and the dynamic-bindings graph construction. Second, we recovered the architecture of a large system, Chromium, that was not available previously. Obtaining the ground-truth architecture of Chromium involved two years of collaboration with its developers. As part of this work, we developed a new submodule-based technique to recover preliminary versions of ground-truth architectures. The results of our evaluation of nine architecture recovery techniques and their variants suggest that (1) using accurate symbol dependencies has a major influence on recovery quality, and (2) more accurate recovery techniques are needed. Our results show that some of the studied architecture recovery techniques scale to very large systems, whereas others do not.

Although a wide variety of approaches identify vulnerabilities in Android apps, none attempt to determine exploitability of those vulnerabilities. Exploitability can aid in reducing false positives of vulnerability analysis, and can help engineers triage bugs. Specifically, one of the main attack vectors of Android apps is their inter-component communication interface, where apps may receive messages called Intents. In this paper, we provide the first approach for automatically generating exploits for Android apps, called LetterBomb, relying on a combined path-sensitive symbolic execution-based static analysis, and the use of software instrumentation and test oracles. We run LetterBomb on 10,000 Android apps from Google Play, where we identify 181 exploits from 835 vulnerable apps. Compared to a state-of-the-art detection approach for three ICC-based vulnerabilities, LetterBomb obtains 33%-60% more vulnerabilities at a 6.66 to 7 times faster speed.

In parallel with the meteoric rise of mobile software, we are witnessing an alarming escalation in the number and sophistication of the security threats targeted at mobile platforms, particularly Android, as the dominant platform. While existing research has made significant progress towards detection and mitigation of Android security, gaps and challenges remain. This paper contributes a comprehensive taxonomy to classify and characterize the state-of-the-art research in this area. We have carefully followed the systematic literature review process, and analyzed the results of more than 300 research papers, resulting in the most comprehensive and elaborate investigation of the literature in this area of research. The systematic analysis of the research literature has revealed patterns, trends, and gaps in the existing literature, and underlined key challenges and opportunities that will shape the focus of future research efforts.

The rising popularity of Android and the GUI-driven nature of its apps have motivated the need for applicable automated GUI testing techniques. Although exhaustive testing of all possible combinations is the ideal upper bound in combinatorial testing, it is often infeasible, due to the combinatorial explosion of test cases. This paper presents TrimDroid, a framework for GUI testing of Android apps that uses a novel strategy to generate tests in a combinatorial, yet scalable, fashion. It is backed with automated program analysis and formally rigorous test generation engines. TrimDroid relies on program analysis to extract formal specifications. These specifications express the app's behavior (i.e., control flow between the various app screens) as well as the GUI elements and their dependencies. The dependencies among the GUI elements comprising the app are used to reduce the number of combinations with the help of a solver. Our experiments have corroborated TrimDroid's ability to achieve a comparable coverage as that possible under exhaustive GUI testing using significantly fewer test cases.

Many techniques have been proposed to automatically recover software architectures from software implementations. A thorough comparison among the recovery techniques is needed to understand their effectiveness and applicability. This study improves on previous studies in two ways. First, we study the impact of leveraging more accurate symbol dependencies on the accuracy of architecture recovery techniques. Previous studies have not seriously considered how the quality of the input might affect the quality of the output for architecture recovery techniques. Second, we study a system (Chromium) that is substantially larger (9.7 million lines of code) than those included in previous studies. Obtaining the ground-truth architecture of Chromium involved two years of collaboration with its developers. As part of this work we developed a new sub module-based technique to recover preliminary versions of ground-truth architectures. The other systems that we study have been examined previously. In some cases, we have updated the ground-truth architectures to newer versions, and in other cases we have corrected newly discovered inconsistencies. Our evaluation of nine variants of six state-of-the-art architecture recovery techniques shows that symbol dependencies generally produce architectures with higher accuracies than include dependencies. Despite this improvement, the overall accuracy is low for all recovery techniques. The results suggest that (1) in addition to architecture recovery techniques, the accuracy of dependencies used as their inputs is another factor to consider for high recovery accuracy, and (2) more accurate recovery techniques are needed. Our results show that some of the studied architecture recovery techniques scale to the 10M lines-of-code range (the size of Chromium), whereas others do not.

From its very inception, the study of software architecture has recognized architectural decay as a regularly occurring phenomenon in long-lived systems. Architectural decay is caused by repeated changes to a system during its lifespan. Despite decay's prevalence, there is a relative dearth of empirical data regarding the nature of architectural changes that may lead to decay, and of developers' understanding of those changes. In this paper, we take a step toward addressing that scarcity by conducting an empirical study of changes found in software architectures spanning several hundred versions of 14 open-source systems. Our study reveals several new findings regarding the frequency of architectural changes in software systems, the common points of departure in a system's architecture during maintenance and evolution, the difference between system-level and component-level architectural change, and the suitability of a system's implementation-level structure as a proxy for its architecture.

A domain-specific software architecture (DSSA) represents an effective, generalized, reusable solution to constructing software systems within a given application domain. In this paper, we revisit the widely cited DSSA for the domain of grid computing. We have studied systems in this domain over the last ten years. During this time, we have repeatedly observed that, while individual grid systems are widely used and deemed successful, the grid DSSA is actually underspecified to the point where providing a precise answer regarding what makes a software system a grid system is nearly impossible. Moreover, every one of the existing purported grid technologies actually violates the published grid DSSA. In response to this, based on an analysis of the source code, documentation, and usage of eighteen of the most pervasive grid technologies, we have significantly refined the original grid DSSA. We demonstrate that this DSSA much more closely matches the grid technologies studied. Our refinements allow us to more definitively identify a software system as a grid technology, and distinguish it from software libraries, middleware, and frameworks.

Android is the most popular platform for mobile devices. It facilitates sharing of data and services among applications using a rich inter-app communication system. While access to resources can be controlled by the Android permission system, enforcing permissions is not sufficient to prevent security violations, as permissions may be mismanaged, intentionally or unintentionally. Android’s enforcement of the permissions is at the level of individual apps, allowing multiple malicious apps to collude and combine their permissions or to trick vulnerable apps to perform actions on their behalf that are beyond their individual privileges. In this paper, we presentCOVERT, a tool for compositional analysis of Android inter-app vulnerabilities. COVERT’s analysis is modular to enable incremental analysis of applications as they are installed, updated, and removed. It statically analyzes the reverse engineered source code of each individual app, and extracts relevant security specifications in a format suitable for formal verification. Given a collection of specifications extracted in this way, a formal analysis engine (e.g., model checker) is then used to verify whether it is safe for a combination of applications—holding certain permissions and potentially interacting with each other—to be installed together. Our experience with using COVERT to examine over 500 real-world apps corroborates its ability to find inter-app vulnerabilities in bundles of some of the most popular apps on the market.

Undocumented evolution of a software system and its underlying architecture drives the need for the architecture's recovery from the system's implementation-level artifacts. While a number of recovery techniques have been proposed, they suffer from known inaccuracies. Furthermore, these techniques are difficult to evaluate due to a lack of “ground-truth” architectures that are known to be accurate. To address this problem, we argue for establishing a suite of ground-truth architectures, using a recovery framework proposed in our recent work. This framework considers domain-, application-, and context-specific information about a system, and addresses an inherent obstacle in establishing a ground-truth architecture - the limited availability of engineers who are closely familiar with the system in question. In this paper, we present our experience in recovering the ground-truth architectures of four open-source systems. We discuss the primary insights gained in the process, analyze the characteristics of the obtained ground-truth architectures, and reflect on the involvement of the systems' engineers in a limited but critical fashion. Our findings suggest the practical feasibility of obtaining ground-truth architectures for large systems and encourage future efforts directed at establishing a large scale repository of such architectures.

Many automated techniques of varying accuracy have been developed to help recover the architecture of a software system from its implementation. However, rigorously assessing these techniques has been hampered by the lack of architectural “ground truths”. Over the past several years, we have collected a set of eight architectures that have been recovered from open-source systems and independently, carefully verified. In this paper, we use these architectures as ground truths in performing a comparative analysis of six state-of-the-art software architecture recovery techniques. We use a number of metrics to assess each technique for its ability to identify a system's architectural components and overall architectural structure. Our results suggest that two of the techniques routinely outperform the rest, but even the best of the lot has surprisingly low accuracy. Based on the empirical data, we identify several avenues of future research in software architecture recovery.

Distributed event-based (DEB) systems contain highly-decoupled components that interact by exchanging messages. This enables flexible system composition and adaptation, but also makes DEB systems difficult to maintain. Most existing program analysis techniques to support maintenance are not well suited to DEB systems, while those that are tend to suffer from inaccuracy or make assumptions that limit their applicability. This paper presents Eos, a static analysis technique that identifies message information useful for maintaining a DEB system, namely, message types and message flow within a system. Eos has been evaluated on six off-the-shelf DEB systems spanning five different middleware platforms, and has exhibited excellent accuracy and efficiency. Furthermore, a case study involving a range of maintenance activities undertaken on three existing DEB systems shows that, on average, Eos enables an engineer to identify the scope and impact of required changes more accurately than existing alternatives.

Architectures of implemented software systems tend to drift and erode as they are maintained and evolved. To properly understand such systems, their architectures must be recovered from implementation-level artifacts. Many techniques for architectural recovery have been proposed, but their degrees of automation and accuracy remain unsatisfactory. To alleviate these shortcomings, we present a machine learning-based technique for recovering an architectural view containing a system's components and connectors. Our approach differs from other architectural recovery work in that we rely on recovered software concerns to help identify components and connectors. A concern is a software system's role, responsibility, concept, or purpose. We posit that, by recovering concerns, we can improve the correctness of recovered components, increase the automation of connector recovery, and provide more comprehensible representations of architectures.

Software behavioral models have proven useful for design, validation, verification, and maintenance. However, existing approaches for deriving such models sometimes overgeneralize what behavior is legal. We outline a novel approach that utilizes inferred likely program invariants and method invocation sequences to obtain an object-level model that describes legal execution sequences. The key insight is using program invariants to identify similar states in the sequences. We exemplify how our approach improves upon certain aspects of the state-of-the-art FSA-inference techniques.

Modern software-intensive systems are expected to adapt, often while the system is executing, to changing requirements, failures, and new operational contexts. This paper describes an approach to dynamic system adaptation that utilizes plan-based and architecture-based mechanisms. Our approach utilizes an architecture description language (ADL) and a planning-as-model-checking technology to enable dynamic replanning. The ability to automatically generate adaptation plans based solely on ADL models and an application problem description simplifies the specification and use of adaptation mechanisms for system architects. The approach uses a three-layer architecture that, while similar to previous work, provides several significant improvements. We apply our approach within the context of a mobile robotics case study.

Maintenance engineers need to understand component dependencies in a system to successfully modify component implementations. Interaction dependencies are especially hard to understand in event-based systems, since transfer of control between components typically happens implicitly and asynchronously. We present a framework for event-based systems that guarantees that unspecified event-based dependencies do not occur. Consequently, the framework enables automated computation of architectural dependencies that are more precise than those possible in other event-based frameworks.