Modeling population dynamics in the city: From a regional to a multi-agent approach

The paper reviews different approaches to urban population from the point of view of the theory of complex systems. Regional models deal with large numbers of urban regions involved in exchanging population and resources among themselves. In contrast, ecological models deal with several qualitatively different types of relationships between a small number of components, aimed at understanding the most general laws of urban dynamic. Two relatively new approaches, namely Cellular Automata and multi-agent ones describe the macro-processes resulting from uniform collective processes at the micro-level of land parcels and migrating city individuals. Recent results of the multi-agent simulations regarding abstract and real-world systems are presented in more details

Estimating the potential demand for Demand-Responsive Transport based on smartcard transactions

The future of Demand-Responsive Transport (DRT) is investigated in respect to the potential travelers' demand. The potential demand for the DRT service is studied based on a database of 63 million records of the public transportation (PT) trips made in Israel using a smartcard in June, 2019. Our major assumption is that travelers may prefer a DRT service over conventional PT for making a non-routine trip that occurs only once a month. The behavioral patterns of PT users were revealed by clustering their boarding records based on the location of the boarding stops and the boarding time of day using an extended DBSCAN algorithm. We make three major discoveries: at least 30 percent of the PT trips do not belong to any cluster of monthly user activity; conventional home-work-home commuters are a minority and constitute less than 15 percent of the drivers; the vast majority of the users make, during the month, both recurrent and occasional trips. The share of occasional trips is 25 percent for frequent users who make over 40 trips a month, and as high as 60 percent for those who board PT up to 10 times a month. We uncover the dependencies of trip regularity on population group, time of day and land use composition around the location of trip origin. We conclude that in high-density urban areas, conventional PT may lose substantial ridership to DRT. The spillover to DRT may be prevented by improving the level of service and incentivizing conventional PT users. We discuss using our approach to identify city areas and PT lines where occasional ridership is common, and user groups that are more likely to switch from conventional PT to DRT

The evolution of the land developers' industry in a planned city: An agent based simulation model

The paper presents agent-based model and simulations of the evolution of land developers' industry in a city regulated by a land use plan. We start with developers who are homogeneous in terms of wealth and simulate their economic growth as they make investments in lands and accumulate profits from construction. Over time some developers accumulate wealth enabling them to make investments and to take risks. We demonstrate that the introduction of advantage to size in purchasing parcels of land for future development and obtaining construction permits create a positive feed-back effects that increases the divergence between big and small developers. The interaction between developers' decisions regarding the location of land purchases and planner's approvals of piecemeal construction permits and comprehensive updates of zoning result in bifurcations of city structure that occur at times of plan modification and leads to a polycentric city

The impact of antibiotic use on transmission of resistant bacteria in hospitals: Insights from an agent-based model

Extensive antibiotic use over the years has led to the emergence and spread of antibiotic resistant bacteria (ARB). Antibiotic resistance poses a major threat to public health since for many infections antibiotic treatment is no longer effective. Hospitals are focal points for ARB spread. Antibiotic use in hospitals exerts selective pressure, accelerating the spread of ARB. We used an agent-based model to explore the impact of antibiotics on the transmission dynamics and to examine the potential of stewardship interventions in limiting ARB spread in a hospital. Agents in the model consist of patients and health care workers (HCW). The transmission of ARB occurs through contacts between patients and HCW and between adjacent patients. In the model, antibiotic use affects the risk of transmission by increasing the vulnerability of susceptible patients and the contagiousness of colonized patients who are treated with antibiotics. The model shows that increasing the proportion of patients receiving antibiotics increases the rate of acquisition non-linearly. The effect of antibiotics on the spread of resistance depends on characteristics of the antibiotic agent and the density of antibiotic use. Antibiotic's impact on the spread increases when the bacterial strain is more transmissible, and decreases as resistance prevalence rises. The individual risk for acquiring ARB increases in parallel with antibiotic density both for patients treated and not treated with antibiotics. Antibiotic treatment in the hospital setting plays an important role in determining the spread of resistance. Interventions to limit antibiotic use have the potential to reduce the spread of resistance, mainly by choosing an agent with a favorable profile in terms of its impact on patient's vulnerability and contagiousness. Methods to measure these impacts of antibiotics should be developed, standardized, and incorporated into drug development programs and approval packages

Defining localities of inadequate treatment for childhood asthma: A GIS approach

BACKGROUND: The use of Geographic Information Systems (GIS) has great potential for the management of chronic disease and the analysis of clinical and administrative health care data. Asthma is a chronic disease associated with substantial morbidity, mortality, and health care use. Epidemiologic data from all over the world show an increasing prevalence of asthma morbidity and mortality despite the availability of effective treatment. These facts led to the emergence of strategies developed to improve the quality of asthma care. THE OBJECTIVE: To develop an efficient tool for quality assurance and chronic disease management using a Geographic Information System (GIS). GEOGRAPHIC LOCATION: The southern region of Israel. January 1998 – October 2000. DATABASES: Administrative claims data of the largest HMO in Israel: drug dispensing registry, demographic data, Emergency Room visits, and hospitalization data bases. METHODS: We created a list of six markers for inadequate pharmaceutical treatment of childhood asthma from the Israeli clinical guidelines. We used this list to search the drug dispensing registry to identify asthmatic children who received inadequate treatment and to assess their health care utilization and bad outcomes: emergency room visits and hospitalizations. Using GIS we created thematic maps on which we located the clinics with a high percentage of children for whom the treatment provided was not in adherence with the clinical guidelines. RESULTS: 81% of the children were found to have at least one marker for inadequate treatment; 17.5% were found to have more than one marker. Children with markers were found to have statistically significant higher rates of Emergency Room visits, hospitalizations and longer length of stay in hospital compared with children without markers. The maps show in a robust way which clinics provided treatment not in accord with the clinical guidelines. Those clinics have high rates of Emergency Room visits, hospitalizations and length of stay. CONCLUSION: Integration of clinical guidelines, administrative data and GIS can create an efficient interface between administrative and clinical information. This tool can be used for allocating sites for quality assurance interventions

An Ancient Relation between Units of Length and Volume Based on a Sphere

The modern metric system defines units of volume based on the cube. We propose that the ancient Egyptian system of measuring capacity employed a similar concept, but used the sphere instead. When considered in ancient Egyptian units, the volume of a sphere, whose circumference is one royal cubit, equals half a hekat. Using the measurements of large sets of ancient containers as a database, the article demonstrates that this formula was characteristic of Egyptian and Egyptian-related pottery vessels but not of the ceramics of Mesopotamia, which had a different system of measuring length and volume units