Abstract
Mobile devices have become indispensable in our daily life and reducing the energy consumed by them has become essential. However, developing energy-efficient mobile applications is not a trivial task. To address this problem, we present EcoAndroid, an Android Studio plugin that automatically applies energy patterns to Java source code. It currently supports ten different cases of energy-related refactorings, divided over five energy patterns taken from the literature. We used EcoAndroid to analyze 100 Java mobile applications (approximate to 1.5M LOC) and we found that 35 of the projects had a total of 95 energy code smells. EcoAndroid was able to automatically refactor all the code smells identified.

Abstract

Abstract
As quantum computing approaches its first commercial implementations, quantum simulation emerges as a potentially ground-breaking technology for several domains, including biology and chemistry. However, taking advantage of quantum algorithms in quantum chemistry raises a number of theoretical and practical challenges at different levels, from the conception to its actual execution. We go through such challenges in a case study of a quantum simulation for the hydrogen (H-2) and lithium hydride (LiH) molecules, at an actual commercially available quantum computer, the IBM Q. The former molecule has always been a playground for testing approximate calculation methods in quantum chemistry, while the latter is just a little bit more complex, lacking the mirror symmetry of the former. Using the variational quantum eigensolver method, we study the molecule's ground state energy versus interatomic distance, under the action of stationary electric fields (Stark effect). Additionally, we review the necessary calculations of the matrix elements of the second quantization Hamiltonian encompassing the extra terms concerning the action of electric fields, using STO-LG-type atomic orbitals to build the minimal basis sets.

Abstract
Traditional post-hoc high-fidelity scientific visualization (HSV) of numerical simulations requires multiple I/O check-pointing to inspect the simulation progress. The costs of these I/O operations are high and can grow exponentially with increasing problem sizes. In situ HSV dispenses with costly check-pointing I/O operations, but requires additional computing resources to generate the visualization, increasing power and energy consumption. In this paper we present LOOM, a new interweaving approach supported by a task scheduling framework to allow tightly coupled in situ visualization without significantly adding to the overall simulation runtime. The approach exploits the idle times of the numerical simulation threads, due to workload imbalances, to perform the visualization steps. Overall execution time (simulation plus visualization) is minimized. Power requirements are also minimized by sharing the same computational resources among numerical simulation and visualization tasks. We demonstrate that LOOM reduces time to visualization by 3 × compared to a traditional non-interwoven pipeline. Our results here demonstrate good potential for additional gains for large distributed-memory use cases with larger interleaving opportunities. © 2021 ACM.

Abstract

Abstract
Conflict-free Replicated Data Types (CRDTs) are abstract data types that support developers when designing and reasoning about distributed systems with eventual consistency guarantees. In their core they solve the problem of how to deal with concurrent operations, in a way that is transparent for developers. However in the real world, distributed systems also suffer from other relevant problems, including security and privacy issues and especially when participants can be untrusted. In this paper we present new privacy-preserving CRDT protocols that can be used to help secure distributed cloud-backed applications, including NoSQL geo-replicated databases. Our proposals are based on standard CRDTs, such as sets and counters, augmented with cryptographic mechanisms that allow their operations to be performed on encrypted data. We accompany our proposals with formal security proofs and implement and integrate them in An-tidoteDB, a geo-replicated NoSQL database that leverages CRDTs for its operations. Experimental evaluations based on the Danish Shared Medication Record dataset (FMK) exhibit the tradeoffs that our different proposals make and show that they are ready to be used in practical applications.