New decoding scheme for LDPC codes based on simple product code structure

In this paper, a new decoding scheme for low-density parity-check (LDPC) codes using the concept of simple product code structure is proposed based on combining two independently received soft-decision data for the same codeword. LDPC codes act as horizontal codes of the product codes and simple algebraic codes are used as vertical codes to help decoding of the LDPC codes. The decoding capability of the proposed decoding scheme is defined and analyzed using the paritycheck matrices of vertical codes and especially the combined-decodability is derived for the case of single parity-check (SPC) and Hamming codes being used as vertical codes. It is also shown that the proposed decoding scheme achieves much better error-correcting capability in high signal to noise ratio (SNR) region with low additional decoding complexity, compared with a conventional decoding scheme.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

A Study on the Causal Relationship between Spot Price and Futures Price of Crude Oil and Agricultural Products

This paper studies the relationship between the agricultural, energy, and derivatives markets. This study empirically analyzes how the results of previous studies on the Granger causality between oil price and the spot price of agricultural products appear in the futures market by using the Toda and Yamamoto (1995)’ causality test. There are two main findings. First, 7 bidirectional causalities and 27 causalities between oil and 6 agricultural products are found, providing strong evidence of a causal relationship. Second, causality is found between oil prices and grain and oilseed type agricultural products, and the spot price of oil has relatively more causalities on agricultural product prices than the futures price of oil. Lastly, testing each period shows that a financial crisis can strengthen the relationship between the agriculture markets and the energy market