Human agents and intelligent agents: an experiment on the Internet

To understand the strengths and limitations of software agents is very important. Many issues and limitations have been discussed in the literature, for example, software agents have limited learning capability. However, if we could see such limitations in a controlled environment and measure how such limitations affect the agents' performance, such research can be extremely helpful to design better software agents. We developed an artificial market with networked computers to simulate the environment of the Internet. This artificial market allows players, such as, humans or software agents, to compete in a simulated dynamic market. We conducted two sets of experiments to study the limitations of software agents. The first set of five experiments were used to identify the knowledge or strategies that human subjects applied in competition. We classified the knowledge or strategies into four levels: perception, uses of simple model and heuristics, application of long-term strategies and psychological tactics, and prediction or forecasting. The second set of five experiments studied how much humans can transfer their knowledge to the software agents. In all the experiments, subjects received monetay rewards From the statistical analysis of the decisions of humans and software agents, we have identified several limitations to the software agents. For example, some subjects used veiy complicated strategies and psychological tactics in earning high profits. However, they could not transfer such knowledge to the software agents. From interviews and questionnaires we confirmed such findings. Based on these Jindings, we conclude that software agents are suitable for wellstructured and repeating tasks and not suitable for critical and high-risk task, such as, investment.published_or_final_versio

Virtual Learning Environment (VLE): a Web-based collaborative learning system

Using the Internet and the World Wide Web (WWW) to support teaching or learning has become a trend in modern higher education. However, most distance-learning or virtual-learning sites are still limited to the dissemination of teaching materials. The strengths of the Internet and WWW have not been maximized nor have their functions (e.g. supporting autonomous, exploratory, interactive and collaborative learning) been fully utilized. Hong Kong University (HKU) has developed a virtual learning system, called the Virtual Learning Environment (VLE), to prove that such kind of learning is possible with Internet and WWW technologies.published_or_final_versio

A multi-agent approach to the deregulation and restructuring of power industry

In recent years, the electric utility industry throughout the world has been facing pressure to deregulate or restructure in order to increase its efficiency, to reduce operational costs or to give consumers more alternatives. The once centralized system planning and operation management must be remodelled to adapt to the new market environment. Subject to unavoidable constraints such as the capacity of generation stations, physical limitations of the transmission lines, and demand on days-ahead scheduling, the current trading mechanism needs to be revised so that any party can be involved in this free-market environment. The paper presents a multi-agent approach to resolve the multilateral trading problem. The authors have implemented a prototype based on bilateral Shapley value and Internet technologies. The prototype has been tested with a classical six-bus system.published_or_final_versio

Quality as a function of quantity in electronic brainstorming

The quality of ideas a team generates constitutes an upper limit on the quality of the problem solving process. Much research has been done about causes of idea quantity and causes of idea quality. It has been noted by some researchers that idea quality appears to correlate with idea quantity, and several have argued that it is not necessary to go to expense and effort required to evaluate idea quality since it correlates with quantity. This paper draws on Team Theory to develop a causal link between quantity and quality. It then presents a low-cognitive-load, high-reliability method for evaluating idea quality. It reports on a study that addresses the question, “Will an increase in idea quantity cause more good ideas to be generated?”. The results support the hypothesis that there is a modest causal connection between quantity and quality, but the data suggest other factors are far more important for determining the number of good ideas a team generates. It concludes that researchers must continue to measure the effects of their brainstorming treatments on idea quality; it is not sufficient to assume that quality will always track quantity. Other factors not accounted for by the quality-quantity model may well counter and outweigh this effect.published_or_final_versio

Intelligent spider for Internet searching

As World Wide Web (WWW) based Internet services become more popular, information overload also becomes a pressing research problem. Difficulties with searching on the Internet get worse as the amount of information that is available increases. A scalable approach to support Internet search is critical to the success of Internet services and other current or future national information infrastructure (NII) applications. A new approach to build an intelligent personal spider (agent), which is based on automatic textual analysis of Internet documents, is proposed. Best first search and genetic algorithm have been tested to develop the intelligent spider. These personal spiders are able to dynamically and intelligently analyze the contents of the users' selected homepages as the starting point to search for the most relevant homepages based on the links and indexing. An intelligent spider must have the capability to make adjustments according to progress of searching in order to be an intelligent agent. However, the current searching engines do not have communication between the users and the robots. The spider presented in the paper uses Java to develop the user interface such that the users can adjust the control parameters according to the progress and observe the intermediate results. The performances of the genetic algorithm based and best first search based spiders are also reported.published_or_final_versio

Contribution of ocean overturning circulation to tropical rainfall peak in the Northern Hemisphere

Rainfall in the tropics is largely focused in a narrow zonal band near the Equator, known as the intertropical convergence zone. On average, substantially more rain falls just north of the Equator. This hemispheric asymmetry in tropical rainfall has been attributed to hemispheric asymmetries in ocean temperature induced by tropical landmasses. However, the ocean meridional overturning circulation also redistributes energy, by carrying heat northwards across the Equator. Here, we use satellite observations of the Earth's energy budget, atmospheric reanalyses and global climate model simulations to study tropical rainfall using a global energetic framework. We show that the meridional overturning circulation contributes significantly to the hemispheric asymmetry in tropical rainfall by transporting heat from the Southern Hemisphere to the Northern Hemisphere, and thereby pushing the tropical rain band north. This northward shift in tropical precipitation is seen in global climate model simulations when ocean heat transport is included, regardless of whether continents are present or not. If the strength of the meridional overturning circulation is reduced in the future as a result of global warming, as has been suggested, precipitation patterns in the tropics could change, with potential societal consequences.close9

Appendicitis risk prediction models in children presenting with right iliac fossa pain (RIFT study): a prospective, multicentre validation study.

Background Acute appendicitis is the most common surgical emergency in children. Differentiation of acute appendicitis from conditions that do not require operative management can be challenging in children. This study aimed to identify the optimum risk prediction model to stratify acute appendicitis risk in children. Methods We did a rapid review to identify acute appendicitis risk prediction models. A prospective, multicentre cohort study was then done to evaluate performance of these models. Children (aged 5\u201315 years) presenting with acute right iliac fossa pain in the UK and Ireland were included. For each model, score cutoff thresholds were systematically varied to identify the best achievable specificity while maintaining a failure rate (ie, proportion of patients identified as low risk who had acute appendicitis) less than 5%. The normal appendicectomy rate was the proportion of resected appendixes found to be normal on histopathological examination. Findings 15 risk prediction models were identified that could be assessed. The cohort study enrolled 1827 children from 139 centres, of whom 630 (34\ub75%) underwent appendicectomy. The normal appendicectomy rate was 15\ub79% (100 of 630 patients). The Shera score was the best performing model, with an area under the curve of 0\ub784 (95% CI 0\ub782\u20130\ub786). Applying score cutoffs of 3 points or lower for children aged 5\u201310 years and girls aged 11\u201315 years, and 2 points or lower for boys aged 11\u201315 years, the failure rate was 3\ub73% (95% CI 2\ub70\u20135\ub72; 18 of 539 patients), specificity was 44\ub73% (95% CI 41\ub74\u201347\ub72; 521 of 1176), and positive predictive value was 41\ub74% (38\ub75\u201344\ub74; 463 of 1118). Positive predictive value for the Shera score with a cutoff of 6 points or lower (72\ub76%, 67\ub74\u201377\ub74) was similar to that of ultrasound scan (75\ub70%, 65\ub73\u201383\ub71). Interpretation The Shera score has the potential to identify a large group of children at low risk of acute appendicitis who could be considered for early discharge. Risk scoring does not identify children who should proceed directly to surgery. Medium-risk and high-risk children should undergo routine preoperative ultrasound imaging by operators trained to assess for acute appendicitis, and MRI or low-dose CT if uncertainty remains. Funding None