4,993 research outputs found
Multicomputer communication system
A local area network is provided for a plurality of autonomous computers which operate at different rates and under different protocols coupled by network bus adapters to a global bus. A host computer (HC) divides a message file to be transmitted into blocks, each with a header that includes a data type identifier and a trailer. The associated network bus adapter (NBA) then divides the data into packets, each with a header to which a transport header and trailer is added with frame type code which specifies one of three modes of addressing in the transmission of data, namely a physical address mode for computer to computer transmission using two bytes for source and destination addresses, a logical address mode and a data type mode. In the logical address mode, one of the two addressing bytes contains a logical channel number (LCN) established between the transmitting and one or more receiving computers. In the data type mode, one of the addressing bytes contains a code identifying the type of data
Addressable time division multiplexer system /cable and connector study/ Final report
Reliability studies of single interrogation and single data cables used in prototype addressable time division multiplexer syste
Fast, Small and Exact: Infinite-order Language Modelling with Compressed Suffix Trees
Efficient methods for storing and querying are critical for scaling
high-order n-gram language models to large corpora. We propose a language model
based on compressed suffix trees, a representation that is highly compact and
can be easily held in memory, while supporting queries needed in computing
language model probabilities on-the-fly. We present several optimisations which
improve query runtimes up to 2500x, despite only incurring a modest increase in
construction time and memory usage. For large corpora and high Markov orders,
our method is highly competitive with the state-of-the-art KenLM package. It
imposes much lower memory requirements, often by orders of magnitude, and has
runtimes that are either similar (for training) or comparable (for querying).Comment: 14 pages in Transactions of the Association for Computational
Linguistics (TACL) 201
Select-based random access to variable-byte encodings
Enormous datasets are a common occurence today and compressing them is often beneficial.
Fast direct access to any element in the compressed data is a requirement in the field of compressed data structures, which is not easily supported with traditional compression methods.
Variable-byte encoding is a method for compressing integers of different byte lengths. It removes unused leading bytes and adds an additional continuation bit to each byte to denote whether the compressed integer continues to the next byte or not. An existing solution using a rank data structure performs well in this given task. This thesis introduces an alternative solution
using a select data structure and compares the two implementations. An experimentation is also done on retrieving a subarray from the compressed data structure.
The rank implementation performs better on data containing mostly small integers. The select implementation benefits on larger integers. The select implementation has significant advantages on subarray fetching due to how the data is compressed
Implementation of Fault-tolerant Quantum Logic Gates via Optimal Control
The implementation of fault-tolerant quantum gates on encoded logic qubits is
considered. It is shown that transversal implementation of logic gates based on
simple geometric control ideas is problematic for realistic physical systems
suffering from imperfections such as qubit inhomogeneity or uncontrollable
interactions between qubits. However, this problem can be overcome by
formulating the task as an optimal control problem and designing efficient
algorithms to solve it. In particular, we can find solutions that implement all
of the elementary logic gates in a fixed amount of time with limited control
resources for the five-qubit stabilizer code. Most importantly, logic gates
that are extremely difficult to implement using conventional techniques even
for ideal systems, such as the T-gate for the five-qubit stabilizer code, do
not appear to pose a problem for optimal control.Comment: 18 pages, ioptex, many figure
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