State-independent decodable DC-free codes with complex-valued signalling alphabets
Bibliographic record
Abstract
Traditionally, constrained sequence coding has been employed exclusively in codes using binary or multilevel signalling. This thesis extends the procedure for constructing DC-free constrained sequence codes to alphabets that use signalling constellations with complex-valued symbols. In particular, the codes are separated into two types: i) constraints with independent logical signalling dimensions and ii) constraints using dependent logical signalling dimensions. In both cases, constraint modelling for the purpose of the evaluation of capacity is explored. Within the case of dependent signalling dimensions, the state machines can contain a finite or an infinite number of states, depending on the signalling constellation that is used. Evaluation of capacity of these types of constrained systems is considered in detail. Building upon the capacity analysis and constraint modelling techniques, DC-free codes using complex-valued signalling constellations are constructed. The three constellations that are considered in detail in this thesis are quadrature phase shift keying (QPSK), 8 phase shift keying (PSK), and 16 quadrature amplitude modulation (QAM). A number of codes have been constructed for each of the three types for various RDS spans. Further, it is shown that Justesen's relationship for codes using binary-valued symbols, which relates the value of the sum variance to the width of the spectral notch around DC, also holds for codes using complex-valued symbols. To complete the code construction procedure for DC-free codes using complex-valued signalling alphabets, which involves state-based encoding and decoding, an algorithm was developed to construct codes that can be decoded at the receiver without requiring state information. This algorithm was designed to execute in polynomial time with respect to the size of the input and to be both general and flexible, so that it can operate on any family of constrained sequence codes. In addition to codes with complex-valued symbols, a number of binary DC-free RLL block codes are constructed using this algorithm, achieving the maximum possible code rates with codeword lengths less than 20. This algorithm is also extended to include the principles of weakly constrained coding.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".