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1. Reliable Spanners for Metric Spaces

   https://doi.org/10.1145/3563356  

   Har-Peled, Sariel; Mendel, Manor; Oláh, Dániel (January 2023, ACM Transactions on Algorithms)

   A spanner is reliable if it can withstand large, catastrophic failures in the network. More precisely, any failure of some nodes can only cause a small damage in the remaining graph in terms of the dilation. In other words, the spanner property is maintained for almost all nodes in the residual graph. Constructions of reliable spanners of near linear size are known in the low-dimensional Euclidean settings. Here, we present new constructions of reliable spanners for planar graphs, trees, and (general) metric spaces. 

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2. Secure and Reliable Network Updates

   https://doi.org/10.1145/3556542  

   Lembke, James; Ravi, Srivatsan; Roman, Pierre-Louis; Eugster, Patrick (February 2023, ACM Transactions on Privacy and Security)

   Software-defined wide area networking (SD-WAN) enables dynamic network policy control over a large distributed network via network updates . To be practical, network updates must be consistent (i.e., free of transient errors caused by updates to multiple switches), secure (i.e., only be executed when sent from valid controllers), and reliable (i.e., function despite the presence of faulty or malicious members in the control plane), while imposing only minimal overhead on controllers and switches. We present SERENE: a protocol for se cure and re liable ne twork updates for SD-WAN environments. In short: Consistency is provided through the combination of an update scheduler and a distributed transactional protocol. Security is preserved by authenticating network events and updates, the latter with an adaptive threshold cryptographic scheme. Reliability is provided by replicating the control plane and making it resilient to a dynamic adversary by using a distributed ledger as a controller failure detector. We ensure practicality by providing a mechanism for scalability through the definition of independent network domains and exploiting the parallelism of network updates both within and across domains. We formally define SERENE’s protocol and prove its safety with regards to event-linearizability. Extensive experiments show that SERENE imposes minimal switch burden and scales to large networks running multiple network applications all requiring concurrent network updates, imposing at worst a 16% overhead on short-lived flow completion and negligible overhead on anticipated normal workloads. 

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3. Reliable Timekeeping for Intermittent Computing

   https://doi.org/10.1145/3373376.3378464  

   de Winkel, Jasper; Delle Donne, Carlo; Yildirim, Kasim Sinan; Pawełczak, Przemysław; Hester, Josiah (March 2020, Proceedings of the Twenty-Fifth International Conference on Architectural Support for Programming Languages and Operating Systems)

   null (Ed.)

   Energy-harvesting devices have enabled Internet of Things applications that were impossible before. One core challenge of batteryless sensors that operate intermittently is reliable timekeeping. State-of-the-art low-power real-time clocks suffer from long start-up times (order of seconds) and have low timekeeping granularity (tens of milliseconds at best), often not matching timing requirements of devices that experience numerous power outages per second. Our key insight is that time can be inferred by measuring alternative physical phenomena, like the discharge of a simple RC circuit, and that timekeeping energy cost and accuracy can be modulated depending on the run-time requirements. We achieve these goals with a multi-tier timekeeping architecture, named Cascaded Hierarchical Remanence Timekeeper (CHRT), featuring an array of different RC circuits to be used for dynamic timekeeping requirements. The CHRT and its accompanying software interface are embedded into a fresh batteryless wireless sensing platform, called Botoks, capable of tracking time across power failures. Low start-up time (max 5 ms), high resolution (up to 1 ms) and run-time reconfigurability are the key features of our timekeeping platform. We developed two time-sensitive batteryless applications to demonstrate the approach: a bicycle analytics tool, where the CHRT is used to track time between revolutions of a bicycle wheel, and wireless communication, where the CHRT enables radio synchronization between two intermittently-powered sensors. 

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4. Toward reliable biodiversity dataset references

   https://doi.org/10.1016/j.ecoinf.2020.101132  

   Elliott, Michael J.; Poelen, Jorrit H.; Fortes, José A.B. (September 2020, Ecological Informatics)
5. Reliable learning in challenging environments

   Balcan, Maria-Florina; Hanneke, Steve; Pukdee, Rattana; Sharma, Dravyansh (September 2023, Thirty-seventh Conference on Neural Information Processing Systems)