171,630 research outputs found
On quantum vertex algebras and their modules
We give a survey on the developments in a certain theory of quantum vertex
algebras, including a conceptual construction of quantum vertex algebras and
their modules and a connection of double Yangians and Zamolodchikov-Faddeev
algebras with quantum vertex algebras.Comment: 18 pages; contribution to the proceedings of the conference in honor
of Professor Geoffrey Maso
Impact of Channel Estimation Errors on Multiuser Detection via the Replica Method
For practical wireless DS-CDMA systems, channel estimation is imperfect due
to noise and interference. In this paper, the impact of channel estimation
errors on multiuser detection (MUD) is analyzed under the framework of the
replica method. System performance is obtained in the large system limit for
optimal MUD, linear MUD and turbo MUD, and is validated by numerical results
for finite systems.Comment: To appear in the EURASIP Journal on Wireless Communication and
Networking - Special Issue on Advanced Signal Processing Algorithms for
Wireless Communication
Consistent Energy-based Atomistic/Continuum Coupling for Two-body Potentials in Three Dimensions
Very few works exist to date on development of a consistent energy-based
coupling of atomistic and continuum models of materials in more than one
dimension. The difficulty in constructing such a coupling consists in defining
a coupled energy whose minimizers are free from uncontrollable errors on the
atomistic/continuum interface. In this paper a consistent coupling in three
dimensions is proposed. The main achievement of this work is to identify and
efficiently treat a modified Cauchy-Born continuum model which can be coupled
to the exact atomistic model. The convergence and stability of the method is
confirmed with numerical tests.Comment: 29 pages, 1 Matlab code. Typos corrected, exposition improve
Bridging the Semantic Gap with SQL Query Logs in Natural Language Interfaces to Databases
A critical challenge in constructing a natural language interface to database
(NLIDB) is bridging the semantic gap between a natural language query (NLQ) and
the underlying data. Two specific ways this challenge exhibits itself is
through keyword mapping and join path inference. Keyword mapping is the task of
mapping individual keywords in the original NLQ to database elements (such as
relations, attributes or values). It is challenging due to the ambiguity in
mapping the user's mental model and diction to the schema definition and
contents of the underlying database. Join path inference is the process of
selecting the relations and join conditions in the FROM clause of the final SQL
query, and is difficult because NLIDB users lack the knowledge of the database
schema or SQL and therefore cannot explicitly specify the intermediate tables
and joins needed to construct a final SQL query. In this paper, we propose
leveraging information from the SQL query log of a database to enhance the
performance of existing NLIDBs with respect to these challenges. We present a
system Templar that can be used to augment existing NLIDBs. Our extensive
experimental evaluation demonstrates the effectiveness of our approach, leading
up to 138% improvement in top-1 accuracy in existing NLIDBs by leveraging SQL
query log information.Comment: Accepted to IEEE International Conference on Data Engineering (ICDE)
201
Disaggregating non-volatile memory for throughput-oriented genomics workloads
Massive exploitation of next-generation sequencing technologies requires dealing with both: huge amounts of data and complex bioinformatics pipelines. Computing architectures have evolved to deal with these problems, enabling approaches that were unfeasible years ago: accelerators and Non-Volatile Memories (NVM) are becoming widely used to enhance the most demanding workloads. However, bioinformatics workloads are usually part of bigger pipelines with different and dynamic needs in terms of resources. The introduction of Software Defined Infrastructures (SDI) for data centers provides roots to dramatically increase the efficiency in the management of infrastructures. SDI enables new ways to structure hardware resources through disaggregation, and provides new hardware composability and sharing mechanisms to deploy workloads in more flexible ways. In this paper we study a state-of-the-art genomics application, SMUFIN, aiming to address the challenges of future HPC facilities.This work is partially supported by the European Research Council (ERC) under the EU Horizon 2020 programme (GA 639595), the Spanish Ministry of Economy, Industry and Competitivity (TIN2015-65316-P) and the Generalitat de Catalunya (2014-SGR-1051).Peer ReviewedPostprint (author's final draft
Non-Fermi-Liquid Behavior from the Fermi-Liquid Approach
Non-Fermi liquid behavior of strongly correlated Fermi systems is derived
within the Landau approach. We attribute this behavior to a phase transition
associated with a rearrangement of the Landau state that leads to flattening of
a portion of the single-particle spectrum in the vicinity
of the Fermi surface. We demonstrate that the quasiparticle subsystem
responsible for the flat spectrum possesses the same thermodynamic properties
as a gas of localized spins. Theoretical results compare favorably with
available experimental data. While departing radically from prevalent views on
the origin of non-Fermi-liquid behavior, the theory advanced here is
nevertheless a conservative one of in continuing to operate within the general
framework of Landau theory.Comment: 8 pages, 4 figures, corrected list of author
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