structured codes
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2021 ◽  
Author(s):  
Touheed Anwar Atif ◽  
Arun Padakandla ◽  
S. Sandeep Pradhan
Keyword(s):  

Author(s):  
Maleah Rakestraw ◽  
Pat Crawford ◽  
Eunsil Lee

Regulation has long since guided urban growth, and it is essential for municipalities to construct regulation that is conducive to creating visually stimulating public spaces. Minimal scientific research has been conducted on the impacts of commercial signage and the varying arrangements created by different sign regulations in regard to perception (Jourdan, Hurd, & Hawkins, 2013; Portella, 2014). With the rise of public involvement in planning (Lane, 2005; Sanoff, 2000), it is essential that designers and non-designers coordinate to develop sign controls that contribute to urban growth. This research studies the differences and similarities in perceptions of planning and design professionals and non-designers to aid in the development of future, more positively perceived, signage regulation. By using visual models presented in the form of a survey, findings show both similarities and differences between these groups in their assessment of signscapes regarding communication, perceptions of characteristics like beauty, interest, and order, an overall preference toward highly structured codes, and a difference in harshness of evaluation. 


2021 ◽  
Vol 16 (1) ◽  
pp. 20-48
Author(s):  
Paolo Santini ◽  
Edoardo Persichetti ◽  
Marco Baldi

Abstract Structured linear block codes such as cyclic, quasi-cyclic and quasi-dyadic codes have gained an increasing role in recent years both in the context of error control and in that of code-based cryptography. Some well known families of structured linear block codes have been separately and intensively studied, without searching for possible bridges between them. In this article, we start from well known examples of this type and generalize them into a wider class of codes that we call ℱ-reproducible codes. Some families of ℱ-reproducible codes have the property that they can be entirely generated from a small number of signature vectors, and consequently admit matrices that can be described in a very compact way. We denote these codes as compactly reproducible codes and show that they encompass known families of compactly describable codes such as quasi-cyclic and quasi-dyadic codes. We then consider some cryptographic applications of codes of this type and show that their use can be advantageous for hindering some current attacks against cryptosystems relying on structured codes. This suggests that the general framework we introduce may enable future developments of code-based cryptography.


2019 ◽  
Vol 65 (10) ◽  
pp. 6263-6289
Author(s):  
Mohsen Heidari ◽  
Farhad Shirani ◽  
S. Sandeep Pradhan
Keyword(s):  

Author(s):  
Alain Nathan Sahin ◽  
Andrew Goldstein ◽  
Chunhua Weng

Abstract This study reports the first assessment of published comments in the family medicine literature using structured codes, which produced commentary annotations that will be the foundation of a knowledge base of appraisals of family medicine trials. Evidence appraisal occurs in a variety of formats and serves to shed light on the quality of research. However, scientific discourse generally and evidence appraisal in particular has not itself been analyzed for insights. A search strategy was devised to identify all journal comments indexed in PubMed linked to controlled intervention studies published in a recent 15-year period in major family medicine journals. A previously developed structured representation in the form of a list of appraisal concepts was used to formally annotate and categorize the journal comments through an iterative process. Trends in family medicine evidence appraisal were then analyzed. A total of 93 comments on studies from five journals over 15 years were included in the analysis. Two thirds of extracted appraisals were negative criticisms. All appraisals of measurement instruments were negative (100%). The participants baseline characteristics, the author discussions, and the design of the interventions were also criticized (respectively 91.7%, 84.6% and 83.3% negative). In contrast, appraisals of the scientific basis of the studies were positive (81.8%). The categories with the most appraisals were, most generally, those focused on the study design, and most specifically, those focused on the scientific basis. This study provides a new data-driven approach to review scientific discourse regarding the strengths and limitations of research within academic family medicine. This methodology can potentially generalize to other medical domains. Structured appraisal data generated here will enable future clinical, scientific, and policy decision-making and broader meta-research in family medicine.


2017 ◽  
Vol 2 (3) ◽  
pp. 191 ◽  
Author(s):  
Gianluigi Liva ◽  
Shumei Song ◽  
Lan Lan ◽  
Yifei Zhang ◽  
Shu Lin ◽  
...  

This survey paper provides fundamentals in the design of LDPC codes. To provide a target for the code designer, we first summarize the EXIT chart technique for determining(near-)optimal degree distributions for LDPC code ensembles. We also demonstrate the simplicity of representing codes by protographs and how this naturally leads to quasi-cyclic LDPC codes. The EXIT chart technique is then extended to the special case of protograph-based LDPC codes. Next, we present several design approaches for LDPC codes which incorporate one or more accumulators, including quasi-cyclic accumulatorbased codes. The second half the paper then surveys severalalgebraic LDPC code design techniques. First, codes based on finite geometries are discussed and then codes whose designs are based on Reed-Solomon codes are covered. The algebraic designs lead to cyclic, quasi-cyclic, and structured codes. The masking technique for converting regular quasi-cyclic LDPC codes to irregular codes is also presented. Some of these results and codes have not been presented elsewhere. The paper focuses on the binary-input AWGN channel (BI-AWGNC). However, as discussed in the paper, good BI-AWGNC codes tend to be universally good across many channels. Alternatively, the reader may treat this paper as a starting point for extensions to more advanced channels. The paper concludes with a brief discussion of open problems.


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