With the growing complexity of modern internet networks, we introduce a distributed, asynchronous, and scalable algorithm tailored for determining the centrality and importance of various levels of the global internet network topology at a massive scale. By utilizing triangle formations and neighborhood densities in these complex networks, our algorithm provides valuable insights into the structural importance of individual nodes and the intricate relationships among interconnected entities. Focusing on the global internet's prime components — routers, IP addresses, and Autonomous Systems — the algorithm provides a scalable solution extending to the global internet infrastructure, datacenters, cloud networks, and private networks. By taking advantage of the parallelism, distributed processing, efficient communication, and fine-grained asynchronous execution through an Actor-based programming system, our algorithm is capable of efficiently processing and performing rapid computations on large-scale internet networks. We perform scalability studies on the NERSC Perlmutter supercomputer and the Georgia Tech HPC PACE cluster using three large-scale real-world network datasets and one large-scale synthetic network dataset, achieving up to 91.7% parallel efficiency scaling out to 2K cores and reducing execution time from 5.7 hours to 18.3 seconds, while performing 105.4× better on average compared to related approaches. Our research contributes significantly to facilitating enhanced network management, fault tolerance and resilience, and security, but as well to improving overall network stability, reducing latency, and optimizing energy consumption across the vast internet network devices environment.

Blockchain provides the unique and accountable channel for financial forensics by mining its open and immutable transaction data. A recent surge has been witnessed by training machine learning models with cryptocurrency transaction data for anomaly detection, such as money laundering and other fraudulent activities. This paper presents a holistic applied data science approach to fraud detection in the Bitcoin network with two original contributions. First, we contribute the Elliptic++dataset, which extends the Elliptic transaction dataset to include over 822k Bitcoin wallet addresses (nodes), each with 56 features, and 1.27M temporal interactions. This enables both the detection of fraudulent transactions and the detection of illicit addresses (actors) in the Bitcoin network by leveraging four types of graph data: (i) the transaction-to-transaction graph, representing the money flow in the Bitcoin network, (ii) the address-to-address interaction graph, capturing the types of transaction flows between Bitcoin addresses, (iii) the address-transaction graph, representing the bi-directional money flow between addresses and transactions (BTC flow from input address to one or more transactions and BTC flow from a transaction to one or more output addresses), and (iv) the user entity graph, capturing clusters of Bitcoin addresses representing unique Bitcoin users. Second, we perform fraud detection tasks on all four graphs by using diverse machine learning algorithms. We show that adding enhanced features from the address-to-address and the address-transaction graphs not only assists in effectively detecting both illicit transactions and illicit addresses, but also assists in gaining in-depth understanding of the root cause of money laundering vulnerabilities in cryptocurrency transactions and the strategies for fraud detection and prevention. The Elliptic++ dataset is released at https://www.github.com/git-disl/EllipticPlusPlus.

The GPU-accelerated cloud, enabled by maturing GPU virtualization techniques, has become the most attractive platform for high-performance computing and machine learning workloads. However, it is notoriously challenging to build the multi-tenant GPU cloud where resources, like CPUs and GPUs, can be shared. One well-known and heavily studied reason is that workloads suffer from poor performance isolation and low GPU utilization when GPUs are shared. But little attention has been paid to another fundamental yet under studied problem: how sharing CPUs among GPU instances could affect the workload performance?Targeting this problem, the paper conducts experiments to measure the performance slowdown and vGPU utilization decrease under interference from CPU sharing. The results show that GPU workloads suffer from poor and unpredictable performance and heavy vGPU under-utilization because of CPU sharing. We find that such interference is the result of the complex interplay between the characteristics of CPU-GPU interactions and the special behavior of shared vCPUs: vCPU discontinuity. To diagnose how vCPU discontinuity causes the interference, the paper leverages NVIDIA Nsight Systems for fine-grained profiling and has the following findings: 1) vCPU discontinuity causes inefficient CPU-GPU synchronizations; 2) vCPU discontinuity delays task offloading to the vGPU; 3) Polling-based CPU-GPU synchronization suffers from interference more than blocking-based CPU-GPU synchronization; 4) GPU workloads with frequent task offloads and synchronizations are more vulnerable. Based on the findings, the paper proposes a novel polling-then-blocking CPU-GPU synchronization primitive. Evaluation shows that it can improve the performance by 4.2x.