Richard Schumi

Singapore Management University | smu · School of Information Systems

Neural networks can be regarded as a new programming paradigm, i.e., instead of building ever-more complex programs through (often informal) logical reasoning in the programmers' mind, complex 'AI' systems are built by optimising generic neural network models with big data. In this new paradigm, AI frameworks such as TensorFlow and PyTorch play a k...

Compilers are error-prone due to their high complexity. They are relevant for not only general purpose programming languages, but also for many domain specific languages. Bugs in compilers can potentially render all programs at risk. It is thus crucial that compilers are systematically tested, if not verified. Recently, a number of efforts have bee...

Blockchains are distributed systems, in which security is a critical factor for their success. However, despite their increasing popularity and adoption, there is a lack of standardized models that study blockchain-related security threats. To fill this gap, the main focus of our work is to systematize and extend the knowledge about the security an...

It is crucial that smart contracts are tested thoroughly due to their immutable nature. Even small bugs in smart contracts can lead to huge monetary losses. However, testing is not enough; it is also important to ensure the quality and completeness of the tests. There are already several approaches that tackle this challenge with mutation testing,...

Due to their specific features, such as decentralization and immutability, blockchains have become popular in recent years. Blockchains are full-stack distributed systems in terms of realization, where security is a critical factor for their success. However, despite increasing popularity and adoption, there is a lack of standardized models to stud...

The blockchain is a key technology that has been adopted in many application areas to increase security and reliability and to avoid the need for a central trusted authority. One of its essential underlying foundations are smart contracts, which are executable programs for managing data or assets on the blockchain. It is crucial that smart contract...

The Internet of things (IoT) is spreading into the everyday life of millions of people. However, the quality of the underlying communication technologies is still questionable. In this work, we are analysing the performance of an implementation of MQTT, which is a major communication protocol of the IoT. We perform model-based test-case generation...

Since computers have become increasingly more powerful, users are less willing to accept slow responses of systems. Hence, performance testing is important for interactive systems. However, it is still challenging to test if a system provides acceptable performance or can satisfy certain response-time limits, especially for different usage scenario...

Property-based testing is well suited for web-service applications, which was already shown in various case studies. For example, it has been demonstrated that JSON schemas can be used to automatically derive test case generators for web forms. In this work, we present a test case generation approach for a rule engine-driven web-service application...

Performance testing is becoming increasingly important for interactive systems. Evaluating their performance with respect to user expectations is complex, especially for different system deployments. Various load-testing approaches and performance-simulation methods aim at such analyses. However, these techniques have certain disadvantages, like a...

Performance evaluation of critical software is important but also computationally expensive. It usually involves sophisticated load-testing tools and demands a large amount of computing resources. Analysing different user populations requires even more effort, becoming infeasible in most realistic cases. Therefore, we propose a model-based approach...

While many approaches for automatic test case generation have been proposed over the years, it is often difficult to predict which of them may work well on concrete problems. In this paper, we therefore present a case study in automatic, model-based test case generation: We implemented several graph-based methods that compute test cases with a mode...