Lu Xiao

Stevens Institute of Technology · School of Systems and Enterprises

Software architecture is the foundation of a system's ability to achieve various quality attributes, including software performance. However, there lacks comprehensive and in-depth understanding of why and how software architecture and performance analysis are integrated to guide related future research. To fill this gap, this paper presents a syst...

The AAA pattern, i.e. arrange, act, and assert, provides a unified structure for unit test cases, which benefits comprehension and maintenance. However, there is little understanding regarding whether and how common real-life developers structure unit test cases following AAA in practice. In particular, are there recurring anti-patterns that deviat...

Software performance is critical for system efficiency, with performance issues potentially resulting in budget overruns, project delays, and market losses. Such problems are reported to developers through issue tracking systems, which are often under-tagged, as the manual tagging process is voluntary and time-consuming. Existing automated performa...

Modularity is recognized as a general and effective solution to tackle the complexity of system of systems in modern society. Despite the value and benefits of modularity, it has been a known challenge to measure and evaluate the modularity of complex systems in real life, especially early in the development life cycle such as in the requirement en...

Mocking frameworks provide convenient APIs, which create mock objects, manipulate their behavior, and verify their execution, for the purpose of isolating test dependencies in unit testing. This study contributes an in-depth empirical study of whether and how mocking frameworks are used in Apache projects. The key findings and insights of this stud...

Healthcare systems and applications are increasingly used to improve patient care. However, these applications face data security, privacy, and regulatory compliance challenges. The Health Insurance Portability and Accountability Act (HIPAA) regulates the use and disclosure of patient health information. Ensuring HIPAA compliance in the Software En...

The AAA pattern (i.e., Arrange-Act-Assert ) is a common and natural layout to create a test case. Following this pattern in test cases may benefit comprehension, debugging, and maintenance. The AAA structure of real-life test cases, however, may not be clear due to their high complexity. Manually labeling AAA statements in test cases is ted...

Software performance is a critical quality attribute that determines the success of a software system. However, practitioners lack comprehensive and holistic understanding of how real-life performance issues are caused and resolved in practice from the technical, engineering, and economic perspectives. This paper presents a large-scale empirical st...

Unit testing focuses on verifying the functions of individual units of a software system. It is challenging due to the high inter dependencies among software units. Developers address this by mocking—replacing the dependency by a “fake” object. Despite the existence of powerful, dedicated mocking frameworks, developers often turn to a “hand-rolled”...

Architectural Technical Debt ( ATD ) refers to sub-optimal architectural design in a software system that incurs high maintenance “interest” over time. Previous research revealed that ATD has significant negative impact on daily development. This paper contributes an approach to enable an architect to precisely locate ATDs , as well as capture...

In recent years, cyber‐physical systems (CPS) have been widely used in different problem domains. The hardware and software components in a CPS are deeply intertwined at various levels of abstraction under changing contexts to achieve the desired goals. One way to manage this complexity is through the use of modular architecture that enables portio...

In large-scale software systems, error-prone or change-prone files rarely stand alone. They are typically architecturally connected and their connections usually exhibit architecture problems causing the propagation of error-proneness or change-proneness. In this paper, we propose and empirically validate a suite of architecture anti-patterns that...

Performance problems widely exist in modern software systems. Existing performance optimization techniques, including profiling-based and pattern-based techniques, usually fail to consider the architectural impacts among methods that easily slow down the overall system performance. This paper contributes a new approach, named Speedoo, to identify g...

Socio-Technical Congruence (STC) indicates that social interactions among developers should be congruent with technical dependencies among their tasks. Prior research discovered that the lack of the "should-happen" communication will lead to integration errors and productivity decrease. However, the opposite scenario, excessive communication not ma...

In this paper, we propose an architecture model called Design Rule Space (DRSpace). We model the architecture of a software system as multiple overlapping DRSpaces, reflecting the fact that any complex software system must contain multiple aspects, features, patterns, etc. We show that this model provides new ways to analyze software quality. In pa...

Our prior work showed that the majority of error-prone source files in a software system are architecturally connected. Flawed architectural relations propagate defects among these files and accumulate high maintenance costs over time, just like debts accumulate interest. We model groups of architecturally connected files that accumulate high maint...

Despite decades of research on software metrics, we still cannot reliably measure if one design is more maintainable than another. Software managers and architects need to understand whether their software architecture is "good enough", whether it is decaying over time and, if so, by how much. In this paper, we contribute a new architecture maintai...

In this paper, we propose and empirically validate a suite of hotspot patterns: recurring architecture problems that occur in most complex systems and incur high maintenance costs. In particular, we introduce two novel hotspot patterns, Unstable Interface and Implicit Cross-module Dependency. These patterns are defined based on Baldwin and Clark's...

Modularity debt is the most difficult kind of technical debt to quantify and manage. Modularity decay, thus modularity debt, causes huge losses over time in terms of reduced ability to provide new functionality and fix bugs, operational failures, and even canceled projects. As modularity debt accumulates over time, software system managers are ofte...

Software development suffers from a lack of predictability with respect to cost, time, and quality. Predictability is one of the major concerns addressed by modern manufacturing execution systems (MES). A MES doesn't actually execute the manufacturing (e.g., controlling equipment and producing goods), but rather collects, analyzes, integrates, and...

In this tool demo, we will illustrate our tool---Titan---that supports a new architecture model: design rule spaces (DRSpaces). We will show how Titan can capture both architecture and evolutionary structure and help to bridge the gap between architecture and defect prediction. We will demo how to use our toolset to capture hundreds of buggy files...

Numerous techniques have been proposed to locate buggy files in a code base, but the problem of fixing one bug unexpectedly affecting other files is persistent and prevailing. Our recent study revealed that buggy files are usually architecturally connected by architecture issues such as unstable interfaces and modularity violations. We aim to detec...

Context: Long-term software management decisions are directly impacted by the quality of the software's architecture. Goal: Herein, we present a replication case study where structural information about a commercial software system is used in conjunction with bug-related change frequencies to measure and predict architecture quality. Method: Metric...

In this paper, we investigate software architecture as a set of overlapping design rule spaces, formed by one or more structural or evolutionary relationships and clustered using our design rule hierarchy algorithm. Considering evolutionary coupling as a special type of relationship, we investigated (1) whether design rule spaces can reveal structu...

This case study combines known software structure and revision history analysis techniques, in known and new ways, to predict bug-related change frequency, and uncover architecture-related risks in an agile industrial software development project. We applied a suite of structure and history measures and statistically analyzed the correlations betwe...