350,268 research outputs found
Symbol as Points: Panoptic Symbol Spotting via Point-based Representation
This work studies the problem of panoptic symbol spotting, which is to spot
and parse both countable object instances (windows, doors, tables, etc.) and
uncountable stuff (wall, railing, etc.) from computer-aided design (CAD)
drawings. Existing methods typically involve either rasterizing the vector
graphics into images and using image-based methods for symbol spotting, or
directly building graphs and using graph neural networks for symbol
recognition. In this paper, we take a different approach, which treats graphic
primitives as a set of 2D points that are locally connected and use point cloud
segmentation methods to tackle it. Specifically, we utilize a point transformer
to extract the primitive features and append a mask2former-like spotting head
to predict the final output. To better use the local connection information of
primitives and enhance their discriminability, we further propose the attention
with connection module (ACM) and contrastive connection learning scheme (CCL).
Finally, we propose a KNN interpolation mechanism for the mask attention module
of the spotting head to better handle primitive mask downsampling, which is
primitive-level in contrast to pixel-level for the image. Our approach, named
SymPoint, is simple yet effective, outperforming recent state-of-the-art method
GAT-CADNet by an absolute increase of 9.6% PQ and 10.4% RQ on the FloorPlanCAD
dataset. The source code and models will be available at
https://github.com/nicehuster/SymPoint.Comment: ICLR 202
Minimality for puncturing convolutional codes
This paper investigates encoders optimization for the Hamming weight after periodic puncturing, and discusses minimality issues that may affect the performance of the punctured encoders. Periodically puncturing a minimal encoder produces a higher rate encoder that may or may not be minimal. If it is not minimal, it may have a zero-output loop and it may be catastrophic. A code search can use a fast algorithm to determine whether an encoder's state diagram has a zero-output loop under periodic symbol puncturing, and a proposed method to assess the performance of codes with a zero-output loop that are not catastrophic. As an example, the paper optimizes rate-1/4 unpunctured codes for Hamming weight under both bit-wise and symbol-wise periodic puncturing. Code tables and simulation results are included
A Machine-Independent Debugger--Revisited
Most debuggers are notoriously machine-dependent, but some recent research
prototypes achieve varying degrees of machine-independence with novel designs.
Cdb, a simple source-level debugger for C, is completely independent of its
target architecture. This independence is achieved by embedding symbol tables
and debugging code in the target program, which costs both time and space. This
paper describes a revised design and implementation of cdb that reduces the
space cost by nearly one-half and the time cost by 13% by storing symbol tables
in external files. A symbol table is defined by a 31-line grammar in the
Abstract Syntax Description Language (ASDL). ASDL is a domain-specific language
for specifying tree data structures. The ASDL tools accept an ASDL grammar and
generate code to construct, read, and write these data structures. Using ASDL
automates implementing parts of the debugger, and the grammar documents the
symbol table concisely. Using ASDL also suggested simplifications to the
interface between the debugger and the target program. Perhaps most important,
ASDL emphasizes that symbol tables are data structures, not file formats. Many
of the pitfalls of working with low-level file formats can be avoided by
focusing instead on high-level data structures and automating the
implementation details.Comment: 12 pages; 6 figures; 3 table
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