Abstract-Crowdsourcing is evolving as a distributed problemsolving and business production model in recent years. In crowdsourcing paradigm, tasks are distributed to networked people to complete such that a company's production cost can be greatly reduced. In 2003, Luis von Ahn and his colleagues pioneered the concept of "human computation", which utilizes human abilities to perform computation tasks that are difficult for computers to process. Later, the term "crowdsourcing" was coined by Jeff Howe in 2006. Since then, a lot of work in crowdsourcing has focused on different aspects of crowdsourcing, such as computational techniques and performance analysis. In this paper, we give a survey on the literature on crowdsourcing which are categorized according to their applications, algorithms, performances and datasets. This paper provides a structured view of the research on crowdsourcing to date.

SUMMARY BackgroundSafety of traditional Chinese medicine in patients with chronic hepatitis B is unknown.

Background: Few studies have evaluated the health-related quality of life (HRQOL) of Southern Chinese with chronic hepatitis B (CHB) infection.

Summary Background:  Peptic ulcer disease is mainly caused by Helicobacter pylori infection and the use of non‐steroidal anti‐inflammatory drugs. Aim:  To investigate the trends in the prevalence of peptic ulcer disease, H. pylori infection and non‐steroidal anti‐inflammatory drug use in uninvestigated dyspeptic patients over recent years in Hong Kong. Methods:  Data from consecutive patients with uninvestigated dyspeptic symptoms referred by family physicians for open access upper endoscopy during 1997 and 2003 were analysed in relation to peptic ulcer disease, H. pylori infection and non‐steroidal anti‐inflammatory drug use. Results:  Among 2700 patients included, 405 (15%) had peptic ulcer disease and 14 (0.5%) had gastric cancer. There was a reduced trend from 1997 to 2003 in the prevalence of peptic ulcer disease (17, 20, 14, 16, 13, 14 and 14%, respectively, χ2 = 5.80, P = 0.016) (mainly because of decrease in duodenal ulcers), H. pylori infection (44, 50, 49, 44, 40, 40, 36 and 43%, respectively, χ2 = 13.55, P < 0.001) and non‐steroidal anti‐inflammatory drug use (13, 5, 5, 6, 3, 4, 4 and 5% respectively, χ2 = 13.61, P < 0.001). The prevalence of peptic ulcer disease, H. pylori infection and non‐steroidal anti‐inflammatory drug use between 2001 and 2003 were significantly lower than that between 1997 and 2000 (17% vs. 13%, OR = 0.78, 95% CI: 0.63–0.96, P = 0.020 for peptic ulcer disease; 47% vs. 39%, OR =0.72, 95% CI: 0.60–0.86, P < 0.001 for H. pylori infection; and 6% vs. 4%, OR = 0.56, 95% CI: 0.39–0.82, P = 0.002 for non‐steroidal anti‐inflammatory drug use). H. pylori infection was associated with both duodenal ulcer (OR = 15.87, 95% CI: 10.60–23.76, P < 0.001) and gastric ulcer (OR = 3.12, 95% CI: 2.15–4.53, P < 0.001) whereas non‐steroidal anti‐inflammatory drug use was only associated with gastric ulcer (OR = 2.97, 95% CI: 1.70–5.20, P < 0.001). Conclusions:  The prevalence of peptic ulcer disease, mainly duodenal ulcers, was reduced in association with a decreasing trend in the prevalence of H. pylori infection and non‐steroidal anti‐inflammatory drug use from 1997 to 2003.