6 results
Search Results
2. Demand and level of service inflation in Floating Catchment Area (FCA) methods.
- Author
-
Paez, Antonio, Higgins, Christopher D., and Vivona, Salvatore F.
- Subjects
WATERSHEDS ,IMPEDANCE matrices ,MEDICAL care ,SUPPLY & demand ,METROPOLITAN areas - Abstract
Floating Catchment Area (FCA) methods are a popular tool to investigate accessibility to public facilities, in particular health care services. FCA approaches are attractive because, unlike other accessibility measures, they take into account the potential for congestion of facilities. This is done by 1) considering the population within the catchment area of a facility to calculate a variable that measures level of service, and then 2) aggregating the level of service by population centers subject to catchment area constraints. In this paper we discuss an effect of FCA approaches, an artifact that we term demand and level of service inflation. These artifacts are present in previous implementations of FCA methods. We argue that inflation makes interpretation of estimates of accessibility difficult, which has possible deleterious consequences for decision making. Next, we propose a simple and intuitive approach to proportionally allocate demandand and level of service in FCA calculations. The approach is based on a standardization of the impedance matrix, similar to approaches popular in the spatial statistics and econometrics literature. The result is a more intiuitive measure of accessibility that 1) provides a local version of the provider-to-population ratio; and 2) preserves the level of demand and the level of supply in a system. We illustrate the relevant issues with some examples, and then empirically by means of a case study of accessibility to family physicians in the Hamilton Census Metropolitan Area (CMA), in Ontario, Canada. Results indicate that demand and supply inflation/deflation affect the interpretation of accessibility analysis using existing FCA methods, and that the proposed adjustment can lead to more intuitive results. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
3. Best Match: New relevance search for PubMed.
- Author
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Fiorini, Nicolas, Canese, Kathi, Starchenko, Grisha, Kireev, Evgeny, Kim, Won, Miller, Vadim, Osipov, Maxim, Kholodov, Michael, Ismagilov, Rafis, Mohan, Sunil, Ostell, James, and Lu, Zhiyong
- Subjects
SEARCH engines ,SEARCH algorithms ,INTERNET searching ,DATA mining ,MEDICAL literature - Abstract
PubMed is a free search engine for biomedical literature accessed by millions of users from around the world each day. With the rapid growth of biomedical literature—about two articles are added every minute on average—finding and retrieving the most relevant papers for a given query is increasingly challenging. We present Best Match, a new relevance search algorithm for PubMed that leverages the intelligence of our users and cutting-edge machine-learning technology as an alternative to the traditional date sort order. The Best Match algorithm is trained with past user searches with dozens of relevance-ranking signals (factors), the most important being the past usage of an article, publication date, relevance score, and type of article. This new algorithm demonstrates state-of-the-art retrieval performance in benchmarking experiments as well as an improved user experience in real-world testing (over 20% increase in user click-through rate). Since its deployment in June 2017, we have observed a significant increase (60%) in PubMed searches with relevance sort order: it now assists millions of PubMed searches each week. In this work, we hope to increase the awareness and transparency of this new relevance sort option for PubMed users, enabling them to retrieve information more effectively. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
4. A personalized channel recommendation and scheduling system considering both section video clips and full video clips
- Author
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SeungGwan Lee and Daeho Lee
- Subjects
Computer science ,Section (typography) ,Video Recording ,Social Sciences ,lcsh:Medicine ,02 engineering and technology ,computer.software_genre ,Geographical locations ,Machine Learning ,Database and Informatics Methods ,Learning and Memory ,0202 electrical engineering, electronic engineering, information engineering ,Data Mining ,Psychology ,Computer Networks ,CLIPS ,lcsh:Science ,Statistical Data ,computer.programming_language ,Multidisciplinary ,Multimedia ,Applied Mathematics ,Simulation and Modeling ,IPTV ,Scheduling system ,Physical Sciences ,Information Retrieval ,020201 artificial intelligence & image processing ,Information Technology ,Algorithms ,Statistics (Mathematics) ,Research Article ,Communication channel ,Computer and Information Sciences ,Schedule ,Minnesota ,Broadcasting ,Research and Analysis Methods ,Computer Communication Networks ,Artificial Intelligence ,Learning ,Humans ,Internet ,business.industry ,Communications Media ,lcsh:R ,Cognitive Psychology ,Biology and Life Sciences ,020207 software engineering ,Models, Theoretical ,United States ,North America ,Cognitive Science ,lcsh:Q ,People and places ,business ,computer ,Mathematics ,Neuroscience - Abstract
With the convergence of various broadcasting systems, the amount of content available in mobile terminals including IPTV has significantly increased. In this paper, we propose a system that enables users to schedule programs considering both section video clips and full video clips based on the user detection method with similar preference. And, since the system constituting the contents can be classified according to the program, the proposed method can store a program desired by the user, and thus create and schedule a kind of individual channel. Experimental results show that the proposed method has a higher prediction accuracy; this is accomplished by comparing existing channel recommendation methods with the program recommendation methods proposed in this paper.
- Published
- 2018
5. Assessing the role of transmission chains in the spread of HIV-1 among men who have sex with men in Quebec, Canada.
- Author
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Villandré, Luc, Labbe, Aurélie, Brenner, Bluma, Ibanescu, Ruxandra-Ilinca, Roger, Michel, and Stephens, David A.
- Subjects
HIV infection transmission ,MEN who have sex with men ,PHYLOGENY ,MAXIMUM likelihood statistics - Abstract
Background: Phylogenetics has been used to investigate HIV transmission among men who have sex with men. This study compares several methodologies to elucidate the role of transmission chains in the dynamics of HIV spread in Quebec, Canada. Methods: The Quebec Human Immunodeficiency Virus (HIV) genotyping program database now includes viral sequences from close to 4,000 HIV-positive individuals classified as Men who have Sex with Men (MSMs), collected between 1996 and early 2016. Assessment of chain expansion may depend on the partitioning scheme used, and so, we produce estimates from several methods: the conventional Bayesian and maximum likelihood-bootstrap methods, in combination with a variety of schemes for applying a maximum distance criterion, and two other algorithms, DM-PhyClus, a Bayesian algorithm that produces a measure of uncertainty for proposed partitions, and the Gap Procedure, a fast non-phylogenetic approach. Sequences obtained from individuals in the Primary HIV Infection (PHI) stage serve to identify incident cases. We focus on the period ranging from January 1st 2012 to February 1st 2016. Results and conclusion: The analyses reveal considerable overlap between chain estimates obtained from conventional methods, thus leading to similar estimates of recent temporal expansion. The Gap Procedure and DM-PhyClus suggest however moderately different chains. Nevertheless, all estimates stress that longer older chains are responsible for a sizeable proportion of the sampled incident cases among MSMs. Curbing the HIV epidemic will require strategies aimed specifically at preventing such growth. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
6. Demand and level of service inflation in Floating Catchment Area (FCA) methods
- Author
-
Antonio Páez, Christopher Higgins, and Salvatore F. Vivona
- Subjects
Inflation ,Medical Doctors ,Operations research ,Health Care Providers ,Health Services Accessibility ,Geographical locations ,Database and Informatics Methods ,0302 clinical medicine ,Catchment Area, Health ,Medicine and Health Sciences ,Medical Personnel ,030212 general & internal medicine ,Database Searching ,Geographic Areas ,media_common ,Ontario ,education.field_of_study ,Multidisciplinary ,Geography ,Applied Mathematics ,Simulation and Modeling ,05 social sciences ,Physicians, Family ,Deflation ,Professions ,Variable (computer science) ,Physical Sciences ,Medicine ,050703 geography ,Algorithms ,Research Article ,Urban Areas ,Canada ,Science ,media_common.quotation_subject ,Decision Making ,Population ,0507 social and economic geography ,Research and Analysis Methods ,Supply and demand ,03 medical and health sciences ,Physicians ,Humans ,Computer Simulation ,education ,Models, Statistical ,Health Care Policy ,Level of service ,Health Care ,People and Places ,North America ,Earth Sciences ,Population Groupings ,Catchment area ,Mathematics - Abstract
Floating Catchment Area (FCA) methods are a popular tool to investigate accessibility to public facilities, in particular health care services. FCA approaches are attractive because, unlike other accessibility measures, they take into account the potential for congestion of facilities. This is done by 1) considering the population within the catchment area of a facility to calculate a variable that measures level of service, and then 2) aggregating the level of service by population centers subject to catchment area constraints. In this paper we discuss an effect of FCA approaches, an artifact that we term demand and level of service inflation. These artifacts are present in previous implementations of FCA methods. We argue that inflation makes interpretation of estimates of accessibility difficult, which has possible deleterious consequences for decision making. Next, we propose a simple and intuitive approach to proportionally allocate demandand and level of service in FCA calculations. The approach is based on a standardization of the impedance matrix, similar to approaches popular in the spatial statistics and econometrics literature. The result is a more intiuitive measure of accessibility that 1) provides a local version of the provider-to-population ratio; and 2) preserves the level of demand and the level of supply in a system. We illustrate the relevant issues with some examples, and then empirically by means of a case study of accessibility to family physicians in the Hamilton Census Metropolitan Area (CMA), in Ontario, Canada. Results indicate that demand and supply inflation/deflation affect the interpretation of accessibility analysis using existing FCA methods, and that the proposed adjustment can lead to more intuitive results.
- Published
- 2019
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