Quantization Watermarking for Joint Compression and Data Hiding Schemes

International audienceEnrichment and protection of JPEG2000 images is an important issue. Data hiding techniques are a good solution to solve these problems. In this context, we can consider the joint approach to introduce data hiding technique into JPEG2000 coding pipeline. Data hiding consists of imperceptibly altering multimedia content, to convey some information. This process is done in such a way that the hidden data is not perceptible to an observer. Digital watermarking is one type of data hiding. In addition to the imperceptibility and payload constraints, the watermark should be robust against a variety of manipulations or attacks. We focus on trellis coded quantization (TCQ) data hiding techniques and propose two JPEG2000 compression and data hiding schemes. The properties of TCQ quantization, defined in JPEG2000 part 2, are used to perform quantization and information embedding during the same time. The first scheme is designed for content description and management applications with the objective of achieving high payloads. The compression rate/imperceptibility/payload trade off is our main concern. The second joint scheme has been developed for robust watermarking and can have consequently many applications. We achieve the better imperceptibility/robustness trade off in the context of JPEG2000 compression. We provide some experimental results on the implementation of these two schemes

Isolated Giant Primary Splenic Hydatid Cyst: A Case Report

INTRODUCTION: Cystic lesions of the spleen are infrequent and usually diagnosed, incidentally. These lesions are rare and their differential diagnosis is very wide. Splenic hydatid cyst (HC) is uncommon and its isolated involvement is very rare ((<2%). in frequency order, it is the third affected organ after liver and lung. caused by infection with Echinococcus granulosus larvae leading to the development of cysts. MATERIAL AND METHODS: We are presenting a case of isolated hydatid cyst of spleen in a thirty eight year old female patient with complaints of pain in the left hypochondrium, dyspepsia and features of gastritis for the last 1 year. The diagnosis was confirmed by Contrast enhanced CT scan (CECT) objectifying a giant cyst of spleen with wall thickening and hypo-dense content, the hydatid serology came back negative. The first diagnosis that was mentioned is isolated splenic hydatid cyst (endemic area). RESULTS: Open splenectomy was performed; the operative consequences were simple. Macroscopic and microscopic appearance confirms the diagnosis of hydatid disease. CONCLUSION The aim of this case report is to emphasize that the most important factor in diagnosing splenic hydatid cyst is the awareness of its possibility and the intraoperative precautions which will decrease morbidity and mortality in the postoperative periodINTRODUCTION: Cystic lesions of the spleen are infrequent and usually diagnosed, incidentally. These lesions are rare and their differential diagnosis is very wide. Splenic hydatid cyst (HC) is uncommon and its isolated involvement is very rare ((<2%). in frequency order, it is the third affected organ after liver and lung. caused by infection with Echinococcus granulosus larvae leading to the development of cysts. MATERIAL AND METHODS: We are presenting a case of isolated hydatid cyst of spleen in a thirty eight year old female patient with complaints of pain in the left hypochondrium, dyspepsia and features of gastritis for the last 1 year. The diagnosis was confirmed by Contrast enhanced CT scan (CECT) objectifying a giant cyst of spleen with wall thickening and hypo-dense content, the hydatid serology came back negative. The first diagnosis that was mentioned is isolated splenic hydatid cyst (endemic area). RESULTS: Open splenectomy was performed; the operative consequences were simple. Macroscopic and microscopic appearance confirms the diagnosis of hydatid disease. CONCLUSION The aim of this case report is to emphasize that the most important factor in diagnosing splenic hydatid cyst is the awareness of its possibility and the intraoperative precautions which will decrease morbidity and mortality in the postoperative perio

Perceived risk of infection and death from COVID-19 among community members of low- and middle-income countries: A cross-sectional study [version 1; peer review: awaiting peer review]

Background: Risk perceptions of coronavirus disease 2019 (COVID-19) are considered important as they impact community health behaviors. The aim of this study was to determine the perceived risk of infection and death due to COVID-19 and to assess the factors associated with such risk perceptions among community members in low- and middle-income countries (LMICs) in Africa, Asia, and South America. Methods: An online cross-sectional study was conducted in 10 LMICs in Africa, Asia, and South America from February to May 2021. A questionnaire was utilized to assess the perceived risk of infection and death from COVID-19 and its plausible determinants. A logistic regression model was used to identify the factors associated with such risk perceptions. Results: A total of 1,646 responses were included in the analysis of the perceived risk of becoming infected and dying from COVID-19. Our data suggested that 36.4% of participants had a high perceived risk of COVID-19 infection, while only 22.4% had a perceived risk of dying from COVID-19. Being a woman, working in healthcare-related sectors, contracting pulmonary disease, knowing people in the immediate social environment who are or have been infected with COVID-19, as well as seeing or reading about individuals infected with COVID-19 on social media or TV were all associated with a higher perceived risk of becoming infected with COVID-19. In addition, being a woman, elderly, having heart disease and pulmonary disease, knowing people in the immediate social environment who are or have been infected with COVID-19, and seeing or reading about individuals infected with COVID-19 on social media or TV had a higher perceived risk of dying from COVID-19. Conclusions: The perceived risk of infection and death due to COVID-19 are relatively low among respondents; this suggests the need to conduct health campaigns to disseminate knowledge and information on the ongoing pandemic

Cryptography and its main reference systems

When the companies and the universities had one computer center, the problem of security did not happen. It was enough to place a guard at the entrance. Maintaining with the arrival of the networks possibilities, the use of connecting satellites and Internet has made the situation radically different, in case of a similar message transiting by several machines before reaching its destination. The message may be at each step, copied, lost or distorted. Encoding is thus necessary in order that the data will not be understandable except within the desired audience. Before (appearance of the computers), cryptography treated crypto systems based upon the letters or characters, the various cryptographic algorithms replaced characters by others or transposed them. The best systems used so far the two operations several times. Cryptography nowadays (the era of computers) is more complex, but the principle remained the same. The major difference is that the current algorithms handle the bits instead of the characters. It is only a change of size of alphabet that passes from 36 alphanumeric elements to 2 binary bits (0 and the 1) and nothing more. The objective of this communication is to introduce the cryptology and the principal systems of encoding to secret key (DES), public key (RSA); the algorithm of the electronic signature (DSA) and the algorithm with combination wrench (PGP). Key words: Cryptography/ Public Key/ RSA/ Secret Key/ DES/Electronic Signature/ DSS/ Combination Wrench/ PGP/ Cryptanalyse. Resume Lorsque les entreprises et les universités n'avaient qu'un seul centre d'ordinateur, le problème de sécurité ne se pose pas. Il suffit de placer un garde à l'entrée de la salle. Maintenant avec la venue des réseaux, l'emploi des liaison satellites et l'utilisation de l'Internet la situation a radicalement changé, dans la mesure où un même message transite par plusieurs machines avant d'atteindre son destinataire. A chaque étape, il peut être copié, perdu ou altéré. Le cryptage est donc nécessaire pour que les données soit non-intelligibles sauf à l'auditoire voulu. Avant (l'apparition des ordinateurs), la cryptographie trait des crypto systèmes basés sur les lettres ou caractères. Les différents algorithmes cryptographiques remplaçaient des caractères par d'autres ou transposaient les caractères. Les meilleurs systèmes faisaient les deux opérations plusieurs fois. La cryptographie de nos jours (l'ère des ordinateurs) est plus complexe, mais la philosophie est restée la même. La différence majeure est que les algorithmes actuels manipulent les bits au lieu des caractères. Ce n'est finalement qu'un changement de taille d'alphabet on passe de 36 éléments alphanumériques à 2 éléments binaires (0 et le 1) et rien de plus. L'objectif de cette communication est d'introduire la cryptologie et les principaux systèmes de cryptage à clé secrète (DES) à clé publique (RSA); l'algorithme de la signature électronique (DSA) et l'algorithme à clé mixte (PGP). Mots clés: Cryptographie/ Clé Publique/ Clé Secrète/ Signature électronique/ Clé Mixte/PGP/ Cryptanalyse. (Revue d'Information Scientifique et Technique: 2002 12(1): 173-194

Using Fuzzy Arithmetic for Power Flow Analysis with Uncertainty

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Stéganographie: Sécurité par Dissimulation

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Valuation of dynamic reactive power support in multitransaction power systems

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