9,819 research outputs found
An Algorithm for Clustered Data Generalized Additive Modelling with S-PLUS
We present a set of functions in S-PLUS to implement the clustered data generalized additive marginal modelling (CDGAM) strategy proposed by Berhane and Tibshirani (1998). A variety of working correlation structures are supported, and the regression basis may include components from the family of smoothing splines.
Asymptotic Dynamical Difference between the Nonlocal and Local Swift-Hohenberg Models
In this paper the difference in the asymptotic dynamics between the nonlocal
and local two-dimensional Swift-Hohenberg models is investigated. It is shown
that the bounds for the dimensions of the global attractors for the nonlocal
and local Swift-Hohenberg models differ by an absolute constant, which depends
only on the Rayleigh number, and upper and lower bounds of the kernel of the
nonlocal nonlinearity. Even when this kernel of the nonlocal operator is a
constant function, the dimension bounds of the global attractors still differ
by an absolute constant depending on the Rayleigh number.Comment: 13 pages, LaTex fil
Ownership Restriction and Housing Value: Evidence from American Housing survey
Amendments to the Fair Lending Act have exempted an age restriction on ownership from fair housing prohibitions. This paper studies the economic impact of such ownership restriction on housing values. Using American Housing Survey data, we find that there is a significant premium attached to the restrictive covenant when other factors are controlled. In particular, we find that imposing age restriction on ownership increases the housing values by anywhere from 10.5% to 12.7%. At the average house value, this is equivalent to a dollar amount between 17,399. The estimates are robust to different specifications in hedonic equations.
Mosaic number and Tile number of Corner Connection Tiles
Lomonaco and Kauffman introduced knot mosaics in 2008 to model physical
quantum states. These mosaics use a set of tiles to represent knots on
grids. In 2023 Heap introduced a new set of tiles that can represent knots on a
smaller board for small knots. Completing an exhaustive search of all knots or
links, , on different board sizes and types is the most common way to
determine invariants for knots, such as the smallest board size needed to
represent a knot, , and the least number of tiles needed to represent a
knot, . In this paper, we propose a solution to an open question by
providing a proof that all knots or links can be represented on corner
connection mosaics using fewer tiles than traditional mosaics ,
where is the smallest number of corner connection tiles needed to
represent knot \textit{K}. We also define bounds for corner connection mosaic
size, , in terms of crossing number, , and simultaneously create
a tool called the \textit{Corner Mosaic Complement} that we use to discover a
relationship between traditional tiles and corner connection tiles. Finally, we
construct an infinite family of links where the corner connection mosaic
number is known and provide a tool to analyze the efficiency of corner
connection mosaic tiles.Comment: 24 pages, 14 figure
Multi-user lattice coding for the multiple-access relay channel
This paper considers the multi-antenna multiple access relay channel (MARC),
in which multiple users transmit messages to a common destination with the
assistance of a relay. In a variety of MARC settings, the dynamic decode and
forward (DDF) protocol is very useful due to its outstanding rate performance.
However, the lack of good structured codebooks so far hinders practical
applications of DDF for MARC. In this work, two classes of structured MARC
codes are proposed: 1) one-to-one relay-mapper aided multiuser lattice coding
(O-MLC), and 2) modulo-sum relay-mapper aided multiuser lattice coding
(MS-MLC). The former enjoys better rate performance, while the latter provides
more flexibility to tradeoff between the complexity of the relay mapper and the
rate performance. It is shown that, in order to approach the rate performance
achievable by an unstructured codebook with maximum-likelihood decoding, it is
crucial to use a new K-stage coset decoder for structured O-MLC, instead of the
one-stage decoder proposed in previous works. However, if O-MLC is decoded with
the one-stage decoder only, it can still achieve the optimal DDF
diversity-multiplexing gain tradeoff in the high signal-to-noise ratio regime.
As for MS-MLC, its rate performance can approach that of the O-MLC by
increasing the complexity of the modulo-sum relay-mapper. Finally, for
practical implementations of both O-MLC and MS-MLC, practical short length
lattice codes with linear mappers are designed, which facilitate efficient
lattice decoding. Simulation results show that the proposed coding schemes
outperform existing schemes in terms of outage probabilities in a variety of
channel settings.Comment: 32 pages, 5 figure
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