2,056 research outputs found
An On-line BIST RAM Architecture with Self Repair Capabilities
The emerging field of self-repair computing is expected to have a major impact on deployable systems for space missions and defense applications, where high reliability, availability, and serviceability are needed. In this context, RAM (random access memories) are among the most critical components. This paper proposes a built-in self-repair (BISR) approach for RAM cores. The proposed design, introducing minimal and technology-dependent overheads, can detect and repair a wide range of memory faults including: stuck-at, coupling, and address faults. The test and repair capabilities are used on-line, and are completely transparent to the external user, who can use the memory without any change in the memory-access protocol. Using a fault-injection environment that can emulate the occurrence of faults inside the module, the effectiveness of the proposed architecture in terms of both fault detection and repairing capability was verified. Memories of various sizes have been considered to evaluate the area-overhead introduced by this proposed architectur
Content addressable memory project
A parameterized version of the tree processor was designed and tested (by simulation). The leaf processor design is 90 percent complete. We expect to complete and test a combination of tree and leaf cell designs in the next period. Work is proceeding on algorithms for the computer aided manufacturing (CAM), and once the design is complete we will begin simulating algorithms for large problems. The following topics are covered: (1) the practical implementation of content addressable memory; (2) design of a LEAF cell for the Rutgers CAM architecture; (3) a circuit design tool user's manual; and (4) design and analysis of efficient hierarchical interconnection networks
LightChain: A DHT-based Blockchain for Resource Constrained Environments
As an append-only distributed database, blockchain is utilized in a vast
variety of applications including the cryptocurrency and Internet-of-Things
(IoT). The existing blockchain solutions have downsides in communication and
storage efficiency, convergence to centralization, and consistency problems. In
this paper, we propose LightChain, which is the first blockchain architecture
that operates over a Distributed Hash Table (DHT) of participating peers.
LightChain is a permissionless blockchain that provides addressable blocks and
transactions within the network, which makes them efficiently accessible by all
the peers. Each block and transaction is replicated within the DHT of peers and
is retrieved in an on-demand manner. Hence, peers in LightChain are not
required to retrieve or keep the entire blockchain. LightChain is fair as all
of the participating peers have a uniform chance of being involved in the
consensus regardless of their influence such as hashing power or stake.
LightChain provides a deterministic fork-resolving strategy as well as a
blacklisting mechanism, and it is secure against colluding adversarial peers
attacking the availability and integrity of the system. We provide mathematical
analysis and experimental results on scenarios involving 10K nodes to
demonstrate the security and fairness of LightChain. As we experimentally show
in this paper, compared to the mainstream blockchains like Bitcoin and
Ethereum, LightChain requires around 66 times less per node storage, and is
around 380 times faster on bootstrapping a new node to the system, while each
LightChain node is rewarded equally likely for participating in the protocol
Product assurance technology for custom LSI/VLSI electronics
The technology for obtaining custom integrated circuits from CMOS-bulk silicon foundries using a universal set of layout rules is presented. The technical efforts were guided by the requirement to develop a 3 micron CMOS test chip for the Combined Release and Radiation Effects Satellite (CRRES). This chip contains both analog and digital circuits. The development employed all the elements required to obtain custom circuits from silicon foundries, including circuit design, foundry interfacing, circuit test, and circuit qualification
Stochastic Analysis of a Churn-Tolerant Structured Peer-to-Peer Scheme
We present and analyze a simple and general scheme to build a churn
(fault)-tolerant structured Peer-to-Peer (P2P) network. Our scheme shows how to
"convert" a static network into a dynamic distributed hash table(DHT)-based P2P
network such that all the good properties of the static network are guaranteed
with high probability (w.h.p). Applying our scheme to a cube-connected cycles
network, for example, yields a degree connected network, in which
every search succeeds in hops w.h.p., using messages,
where is the expected stable network size. Our scheme has an constant
storage overhead (the number of nodes responsible for servicing a data item)
and an overhead (messages and time) per insertion and essentially
no overhead for deletions. All these bounds are essentially optimal. While DHT
schemes with similar guarantees are already known in the literature, this work
is new in the following aspects:
(1) It presents a rigorous mathematical analysis of the scheme under a
general stochastic model of churn and shows the above guarantees;
(2) The theoretical analysis is complemented by a simulation-based analysis
that validates the asymptotic bounds even in moderately sized networks and also
studies performance under changing stable network size;
(3) The presented scheme seems especially suitable for maintaining dynamic
structures under churn efficiently. In particular, we show that a spanning tree
of low diameter can be efficiently maintained in constant time and logarithmic
number of messages per insertion or deletion w.h.p.
Keywords: P2P Network, DHT Scheme, Churn, Dynamic Spanning Tree, Stochastic
Analysis
Adiabatic Quantum Optimization for Associative Memory Recall
Hopfield networks are a variant of associative memory that recall information
stored in the couplings of an Ising model. Stored memories are fixed points for
the network dynamics that correspond to energetic minima of the spin state. We
formulate the recall of memories stored in a Hopfield network using energy
minimization by adiabatic quantum optimization (AQO). Numerical simulations of
the quantum dynamics allow us to quantify the AQO recall accuracy with respect
to the number of stored memories and the noise in the input key. We also
investigate AQO performance with respect to how memories are stored in the
Ising model using different learning rules. Our results indicate that AQO
performance varies strongly with learning rule due to the changes in the energy
landscape. Consequently, learning rules offer indirect methods for
investigating change to the computational complexity of the recall task and the
computational efficiency of AQO.Comment: 22 pages, 11 figures. Updated for clarity and figures, to appear in
Frontiers of Physic
The Cost of Address Translation
Modern computers are not random access machines (RAMs). They have a memory
hierarchy, multiple cores, and virtual memory. In this paper, we address the
computational cost of address translation in virtual memory. Starting point for
our work is the observation that the analysis of some simple algorithms (random
scan of an array, binary search, heapsort) in either the RAM model or the EM
model (external memory model) does not correctly predict growth rates of actual
running times. We propose the VAT model (virtual address translation) to
account for the cost of address translations and analyze the algorithms
mentioned above and others in the model. The predictions agree with the
measurements. We also analyze the VAT-cost of cache-oblivious algorithms.Comment: A extended abstract of this paper was published in the proceedings of
ALENEX13, New Orleans, US
Quantum-dot Cellular Automata: Review Paper
Quantum-dot Cellular Automata (QCA) is one of the most important discoveries that will be the successful alternative for CMOS technology in the near future. An important feature of this technique, which has attracted the attention of many researchers, is that it is characterized by its low energy consumption, high speed and small size compared with CMOS. Inverter and majority gate are the basic building blocks for QCA circuits where it can design the most logical circuit using these gates with help of QCA wire. Due to the lack of availability of review papers, this paper will be a destination for many people who are interested in the QCA field and to know how it works and why it had taken lots of attention recentl
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