Mexican Institute of Petroleum

About: Mexican Institute of Petroleum is a government organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Catalysis & Asphaltene. The organization has 3273 authors who have published 4170 publications receiving 87269 citations.

An effective fragile watermarking scheme for color image tampering detection and self-recovery

Abstract: In this paper, a fragile watermarking scheme for color-image authentication and self-recovery is proposed. Original image is divided into non-overlapping blocks, and for each i -th block, the watermarks used for recovery and authentication are generated, which are embedded into a different block according to an embedding sequence given by a permutation process. The designed scheme embeds the watermarks generated by each block within the 2-LSB, where a bit-adjustment phase is subsequently applied to increase the quality of the watermarked image. In order to increase the quality of the recovered image, we use in the post-processing stage the bilateral filter that efficiently suppresses noise preserving image edges. Additionally, in the tamper detection process high accuracy is achieved employing a hierarchical tamper detection algorithm. Finally, to solve tampering coincidence problem, three recovery watermarks are embedded in different positions to reconstruct a specific block, and a proposed inpainting algorithm is implemented to regenerate those regions affected by this problem. Simulation results demonstrate that the watermarked images appear to demonstrate higher quality, and the proposed novel scheme can reconstruct the alteration of extremely high rates (up to 80%), obtaining good quality for altered regions that are self-recovered with higher visual performance compared with a similar scheme from state of the-art methods.

Symmetry/anti-symmetry phase transitions in crude oil markets

Abstract: Daily records of international crude oil prices are studied by means of a Zipf-type analysis. By using simple up-down information on price fluctuations, we have observed phase transitions between symmetric states, where occurrence of up and down fluctuations are almost equal, to anti-symmetric states, where there is a significant imbalance between up and down occurrences. Symmetric phase provides a time-scale domain for risk-neutral transactions. On the other hand, anti-symmetric phase can be exploited by speculators and consumers to accommodate contracts that take advantage of the spread between up and down occurrences.

Origin of Oil in the Sureste Basin, Mexico

Abstract: Geochemical and biological marker analyses of oils and rock samples from the Sureste basin of Mexico were effective in identifying and geographically limiting four major oil families related by age and source rock depositional environment: Oxfordian, Tithonian, Early Cretaceous, and Tertiary. The source rocks giving rise to the Jurassic and Cretaceous oils are associated with marine carbonate environments. In contrast, the source rocks giving rise to the Tertiary oils are associated with a marine deltaic siliciclastic depositional setting. Biomarker and isotope differences observed in the oils derived from marine carbonate environments can be interpreted in terms of salinity, clay content, and oxygen depletion variations. These differences provide diagnostic criteria for recognizing and differentiating five distinct organic-rich depositional regimes as the sources for these oil types: an anoxic hypersaline marine-carbonate environment associated with a narrow and shallow semirestricted sea (Oxfordian age, family 1 oil); an anoxic marine-carbonate environment associated with a silled basin geometry (Tithonian age, family 2 oils, subtype 2a); an anoxic marine-carbonate environment associated with a shallow, gentle, broad marine-carbonate ramp in a distal position (Tithonian age, family 2 oils, subtype 2b); a clay-rich suboxic/anoxic marine-carbonate environment associated with a carbonate platform in a proximal position (Tithonian age, family 2 oils, subtype 2c); and an anoxic marine-evaporitic environment (Early Cretaceous age, family 3 oils). The Tertiary oils (family 4) are derived from bacterially reworked terrigenous and marine organic source materials deposited in a marine-deltaic environment. The Tithonian-related oils in the Mexican southern side of the Gulf of Mexico accumulated both offshore and onshore and throughout the stratigraphic column from Kimmeridgian to Pleistocene reservoirs, suggesting vertical pathways as the principal secondary migration mechanism. The lateral variations of these oils can be interpreted to reflect the Tithonian paleogeography in the area and could be useful in predicting differences in the oil compositions.