No abstract

No abstract

No abstract

Digital watermarking can be used to protect the intellectual property for multimedia data. In this paper, we introduce an image watermarking scheme based on the SVD (Singular Value Decomposition) compression. In particular, we divide the cover image into blocks and apply the SVD to each block; the watermark is embedded in all the non-zero singular values according to the local features of the cover image so as to balance embedding capacity with distortion. The watermarking system we propose is robust against typical attacks, including low-pass and high-pass filtering, as evaluated by the Checkmark benchmarking tool

OBJECTIVE: To explore the 1‐year point prevalences (July–September 1996) of symptomatic gastroesophageal reflux (GER), gastroesophageal reflux disease (GERD) and reflux esophagitis (RE) in the adult population of two Chinese city‐regions (Beijing and Shanghai) and to identify the conditions that predispose patients to GERD. METHODS: Phase I: 5000 residents of the two regions aged between 18 and 70 years were studied via a questionnaire. The study was carried out by cluster sampling from city, suburban and rural areas by using simple random sampling. Symptom scores (Sc) of the intensity and frequency of heartburn, acid reflux and regurgitation within 1 year of the time of study were taken as indices of acid reflux (highest score, Sc = 18) and Sc ≥ 6 indicated the presence of symptomatic GER. Phase II: a small number of patients who were identified as having symptomatic GER in the survey were enrolled in a case– control study using gastroscopy and 24‐h pH monitoring to obtain correct diagnostic rates of GERD and RE. Estimates of the prevalence of GERD and RE were then adjusted according to the rates of correct diagnosis. RESULTS: A total of 4992 subjects completed the survey, 2.5% had heartburn once daily, 8.97% had symptomatic GER (Sc ≥ 6) and the male to female ratio was 1:1.11. Point prevalences for the year for GERD and RE were 5.77 and 1.92%, respectively. Stratified analysis indicated that the prevalence of symptomatic GER in Beijing (10.19%) was higher than that in Shanghai (7.76%) and there was also a higher prevalence of GER in males, manual laborers, people from rural areas and people older than 40 years of age in Beijing as compared with Shanghai. Stepwise logistic analysis indicated that GER had a close relationship with dental, pharyngolaryngeal disorders and respiratory diseases. The conditions that predispose patients to GERD are (OR, odds ratio): age > 40 (OR = 1.01), eating greasy/oily food (OR = 6.56), overeating (OR = 1.99), tiredness (OR = 2.35), emotional stress (OR = 2.22), pregnancy (OR = 6.80) and constipation (OR = 1.65). CONCLUSIONS: Gastroesophageal reflux disease is a common disease in the adult Chinese population and it is more common in Beijing than in Shanghai.