Non-fungible tokens (NFTs), attracting interest from a variety of audiences including collectors and traders, saw transactions exceeding $50 billion in 2022. The inherent features of blockchain technology–distributed, immutable, and transparent–make it an ideal platform for verifying ownership of digital assets. Despite these advantages, the high computational and transaction costs of networks, which utilizes proof of work pose significant challenges. To overcome these, alternative public blockchains have been developed, each offering unique benefits for NFT marketplaces. Choosing the right blockchain platform is crucial but complex. In our study, we introduce a prototype NFT marketplace optimized for scalability and efficiency, capable of rapidly handling a large volume of NFT transactions. We also conducted a comparative analysis of various public blockchains to identify the most cost-effective and reliable options for NFT exchanges. Further, we developed two predictive models to enhance decision-making around transaction fees and error management, thus improving cost-efficiency and reliability. We also propose a self-adaptive mechanism that allows for dynamic switching between blockchain platforms, enhancing the flexibility, and overall performance of the marketplace. Our contributions are integrated into IntelliChain, a self-adaptive framework designed to predict optimal transaction fees, reduce errors, and adapt to changing conditions like network stability and fee structures, bolstering efficiency, and reliability.

As microservice and cloud computing operations increasingly adopt automation, the importance of models for fostering resilient and efficient adaptive architectures becomes paramount. This paper presents InstantOps, a novel approach to system failure prediction and root cause analysis leveraging a three-fold modality of IT observability data: logs, metrics, and traces. The proposed methodology integrates Graph Neural Networks (GNN) to capture spatial information and Gated Recurrent Units (GRU) to encapsulate the temporal aspects within the data. A key emphasis lies in utilizing a stitched representation derived from logs, microservices events(e.g. Image Pull Back Off, PVC Pending), and resource metrics to predict system failures proactively. The traces are aggregated to construct a comprehensive service call flow graph and represented as a dynamic graph. Furthermore, permutation testing is applied to harness node scores, aiding in the identification of root causes behind these failures. To evaluate the efficiency of InstantOps, we utilized in-house data from the open-source application Quote of the Day (QoTD) as well as two publicly available datasets, MicroSS and Train Ticket. The F1 scores obtained in predicting the system failures from these data sets were 0.96, 0.98, and 0.97, respectively, beating the stateof-the-art. Additionally, we further evaluated the efficiency of root cause analysis using MAR and MFR. These results also outperform the state of the art.

Blockchain technology has gained momentum due to its immutability and transparency. Several blockchain platforms, each with different consensus protocols, have been proposed. However, choosing and configuring such a platform is a non-trivial task. Numerous benchmarking tools have been introduced to test the performance of blockchain solutions. Yet, these tools are often limited to specific blockchain platforms or require complex configurations. Moreover, they tend to focus on one-off batch evaluation models, which may not be ideal for longer-running instances under continuous workloads. In this work, we presentBlockCompass, an all-inclusive blockchain benchmarking tool that can be easily configured and extended. We demonstrate howBlockCompasscan evaluate the performance of various blockchain platforms and configurations, including Ethereum Proof-of-Authority, Ethereum Proof-of-Work, Hyperledger Fabric Raft, Hyperledger Sawtooth with Proof-of-Elapsed-Time, Practical Byzantine Fault Tolerance, and Raft consensus algorithms, against workloads that continuously fluctuate over time. We show how continuous transactional workloads may be more appropriate than batch workloads in capturing certain stressful events for the system. Finally, we present the results of a usability study about the convenience and effectiveness offered byBlockCompassin blockchain benchmarking.