Abstract Storage Devices

The purpose of this paper is to initiate the study of a combinatorial abstraction, called abstract storage device (ASD), which models deterministic storage devices with the property that only partial information about the state can be read, but that there is a degree of freedom as to which partial information should be retrieved. We study combinatorial problems related to ASD’s, including reducibility among ASD’s, which is proved to be NP-complete, and the factorization of ASD’s. In particular, we prove that the factorization into binary-output ASD’s (if it exists) is unique

Long-time Low-latency Quantum Memory by Dynamical Decoupling

Quantum memory is a central component for quantum information processing devices, and will be required to provide high-fidelity storage of arbitrary states, long storage times and small access latencies. Despite growing interest in applying physical-layer error-suppression strategies to boost fidelities, it has not previously been possible to meet such competing demands with a single approach. Here we use an experimentally validated theoretical framework to identify periodic repetition of a high-order dynamical decoupling sequence as a systematic strategy to meet these challenges. We provide analytic bounds-validated by numerical calculations-on the characteristics of the relevant control sequences and show that a "stroboscopic saturation" of coherence, or coherence plateau, can be engineered, even in the presence of experimental imperfection. This permits high-fidelity storage for times that can be exceptionally long, meaning that our device-independent results should prove instrumental in producing practically useful quantum technologies.Comment: abstract and authors list fixe

Supercapatteries as High-Performance Electrochemical Energy Storage Devices

Abstract: The development of novel electrochemical energy storage (EES) technologies to enhance the performance of EES devices in terms of energy capacity, power capability and cycling life is urgently needed. To address this need, supercapatteries are being developed as innovative hybrid EES devices that can combine the merits of rechargeable batteries with the merits of supercapacitors into one device. Based on these developments, this review will present various aspects of supercapatteries ranging from charge storage mechanisms to material selection including electrode and electrolyte materials. In addition, strategies to pair different types of electrode materials will be discussed and proposed, including the bipolar stacking of multiple supercapattery cells internally connected in series to enhance the energy density of stacks by reducing the number of bipolar plates. Furthermore, challenges for this stack design will also be discussed together with recent progress on bipolar plates. Graphic Abstract: Supercapattery is an innovated hybrid electrochemical energy storage (EES) device that combines the merit of rechargeable battery and supercapacitor characteristics into one device. This article reviews supercapatteries from the charge storage mechanisms to the selection of materials including the materials of electrodes and electrolytes. Strategies for pairing different kinds of electrode materials and device engineering are discussed.[Figure not available: see fulltext.

Last Developments in Polymers for Wearable Energy Storage Devices

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Our modern and technological society requests enhanced energy storage devices to tackle the current necessities. In addition, wearable electronic devices are being demanding because they offer many facilities to the person wearing it. In this manuscript, a historical review is made about the available energy storage devices focusing on super-capacitors and lithium-ion batteries, since they currently are the most present in the industry, and the possible polymeric materials suitable on wearable energy storage devices. Polymers are a suitable option because they not only possess remarkable mechanical resistance, flexibility, long life-times, easy manufacturing techniques and low cost in addition to they can be environmentally friendly, nontoxic, and even biodegradable too. Moreover, the electrical and electrochemical polymer properties can be tunning with suitable fillers giving to versatile conducting polymer composites with a good cost and properties' ratio. Although the advances are promising, there are still many drawbacks that need to be overcome. Future research should focus on improving both the performance of materials and their processability on an industrial scale, where additive manufacturing offers many possibilities. The sustainability of new energy storage devices should not be forgotten, encouraging the use of more environmentally friendly materials and manufacturing processes.The authors thank the financial support from Ministerio de Ciencia e Innovation/FEDER (project ref; PID2020-116976RB-I00) and Xunta de Galicia-FEDER (Program of Consolidation and structuring competitive research units [ED431C 2019/17]). Funding for open access charge from Universidade da Coruña/CISUGXunta de Galicia; ED431C 2019/1

Amorphous Placement and Retrieval of Sensory Data in Sparse Mobile Ad-Hoc Networks

Abstract—Personal communication devices are increasingly being equipped with sensors that are able to passively collect information from their surroundings – information that could be stored in fairly small local caches. We envision a system in which users of such devices use their collective sensing, storage, and communication resources to query the state of (possibly remote) neighborhoods. The goal of such a system is to achieve the highest query success ratio using the least communication overhead (power). We show that the use of Data Centric Storage (DCS), or directed placement, is a viable approach for achieving this goal, but only when the underlying network is well connected. Alternatively, we propose, amorphous placement, in which sensory samples are cached locally and informed exchanges of cached samples is used to diffuse the sensory data throughout the whole network. In handling queries, the local cache is searched first for potential answers. If unsuccessful, the query is forwarded to one or more direct neighbors for answers. This technique leverages node mobility and caching capabilities to avoid the multi-hop communication overhead of directed placement. Using a simplified mobility model, we provide analytical lower and upper bounds on the ability of amorphous placement to achieve uniform field coverage in one and two dimensions. We show that combining informed shuffling of cached samples upon an encounter between two nodes, with the querying of direct neighbors could lead to significant performance improvements. For instance, under realistic mobility models, our simulation experiments show that amorphous placement achieves 10% to 40% better query answering ratio at a 25% to 35% savings in consumed power over directed placement.National Science Foundation (CNS Cybertrust 0524477, CNS NeTS 0520166, CNS ITR 0205294, EIA RI 0202067

Challenges in Modelling and Verification of Transmitter Circuits for Advanced Mobile Storage Physical layer

Abstract: Flash memory is a key component of today’s mobile phones providing embedded storage for text and media and removable storage for a variety of purposes e.g. Video. Many standard bodies support mobile storage e.g. sdcard.org, Universal flash storage org. Mobile storage today is evolving continuously with ever increasing bandwidth and capacity demands. IP Blocks and Technologies Groups specializes in providing Host controller and Physical Layer solution for variety of mobile devices including phones, tablets, laptops/ultra-books Current project is focusing on Physical layer design and verification – which consists of Digital Frontend (DFE) including Serial/De-serializer, encoding, decoding schemes, and an analog front-end (AFE) which consists of Transmitter/Receiver Circuits. The Phy also includes PLL, Clock Distribution and Compensation circuits to support DFE and AFE. The focus of the current project is to develop methodology and techniques to validate transmitter circuit for mobile storage comprehensively. DOI: 10.17762/ijritcc2321-8169.15066