23 research outputs found
Spatial Pattern Simulation of Antenna Base Station Positions Using Point Process Techniques
Spatial statistics is a powerful tool for analyzing data that are illustrated as points or positions in a regular or non-regular state space. Techniques that are proposed to investigate the spatial association between neighboring positions are based on the point process analysis. One of the main goals is to simulate real data positions (such as antenna base stations) using the type of point process that most closely matches the data. Spatial patterns could be detailed describing the observed positions and appropriate models were proposed to simulate these patterns. A common model to simulate spatial patterns is the Poisson point process. In this work analyses of the Poisson point process—as well as modified types such as inhibition point process and determinantal Poisson point process—are presented with simulated data close to the true data (i.e., antenna base station positions). Investigation of the spatial variation of the data led us to the spatial association between positions by applying Ripley’s K-functions and L-Function
Management Information Services for Enhancing Interoperability in Radiology through Segmentation Techniques
An efficient information sharing environment can enhance interoperability within any organization. Healthcare organizations and hospitals, in particular, are no exception. Indeed, managing hospital processes, through the appropriate techniques, may provide the basis for designing information services that can support healthcare provision. Radiology information services aid in exploding imaging modalities, generate views from different anatomical structures contained in CT data sets and perform treatment plan techniques. Important issues for the design of such information services include a) the extraction of the corresponding data from the image and b) accurate definition of the target volumes as well as organs at risk for the treatment outcome. Implementation of this radiology information could be achieved by using simulators, which are medical devices used in the oncology clinics to perform the simulation for the external beam radiotherapy treatment. Virtual Simulators in particular offer a excellent cost benefit ratio for a clinic and further assist physician to detect the tumor site from different viewpoints to design orientation, to evaluate treatment, to calculate the dose distribution around tumor and finally to design an effective planning. The implemented high-end visualization techniques allow the users to simulate every function of the real simulator, including the mechanical component movements, radiation beam projection and fluoroscopy. In this work, a hospital process map is provided and a twofold study is conducted: A. Information management for supporting the interoperability of hospital processes; and B. Design radiology information services through image segmentation techniques. Thus, we present a process that can be used for the accurate semi-automatic segmentation of the important target in use organs (like skin, lungs, spinal canal, and bronchus) in three dimensions from CT images. Our clinical experience is described using patient example (breast cancer). The advantages of virtual simulation system over classical simulation would be presented, and the clinical effectiveness would be emphasized
Patterns Simulations Using Gibbs/MRF Auto-Poisson Models
Pattern analysis is the process where characteristics of big data can be recognized using specific methods. Recognition of the data, especially images, can be achieved by applying spatial models, explaining the neighborhood structure of the patterns. These models can be introduced by Markov random field (MRF) models where conditional distribution of the pixels may be defined by a specific distribution. Various spatial models could be introduced, explaining the real patterns of the data; one class of these models is based on the Poisson distribution, called auto-Poisson models. The main advantage of these models is the consideration of the local characteristics of the image. Based on the local analysis, various patterns can be introduced and models that better explain the real data can be estimated, using advanced statistical techniques like Monte Carlo Markov Chains methods. These methods are based on simulations where the proposed distribution must converge to the original (final) one. In this work, an analysis of a MRF model under Poisson distribution would be defined and simulations would be illustrated based on Monte Carlo Markov Chains (MCMC) process like Gibbs sampler. Results would be illustrated using simulated and real patterns data
S.: An accurate 3d segmentation method of the spinal canal applied to CT data. In: Bildverarbeitung fur die Medizin
Abstract. With the modern treatment planning techniques the accurate definition of the target volume as well as the organs at risk is a crucial step for the treatment outcome. One of the key organs that must be protected during the irradiation treatment is the spinal cord. Nowadays, high resolution computed tomography (CT) data are required to perform accurate treatment planning, and there is the demand for quick but accurate segmentation tools. In this work we present a very simple approach that can accurately extract the spinal canal in three dimensions (3D) from CT images. The user must define only the starting point for the algorithm and the rest of the process is performed automatically. The core of our method is a boundary-tracing algorithm combined with linear interpolation techniques in the longitudinal (z) direction.
Heatwave 1987: the Piraeus versus Athens case [version 2; peer review: 2 approved]
Background Heatwaves represent the main indices of climate change, while mortality is one of the established markers of their human effects. For unknown reasons populations adapt to temperature variations/challenges differently. Thus, to allow better precision and prediction, heatwave evaluations should be enriched by historical context and local data. Methods The mortality data for 1987 were collected from the Piraeus municipality registry, whereas data for Athens were obtained from literature retrieved from PUBMED. Ambient characteristics were extracted from the Geronikolou’s 1991 BSc thesis and the reports of national organizations. From the death events, the odds ratio and relative risk in Piraeus compared to the Athens were calculated. Finally, a simple neural network proposed the dominant ambient parameter of the heatwave effects in the city residents of each location. Results The 1987 heatwave was more lethal (seven-fold) in Athens than in Piraeus and dependent on atmospheric nitric oxide (NO) concentration (with probability 0.999). In the case of Piraeus in 1987, ozone characterized the phenomenon (with probability 0.993). Conclusions The odds of dying due to a heatwave are highly dependent on lifestyle, population sensitivity to preventive measures and public health policy, while the phenomenon was mainly moderated by ozone in Piraeus in 1987, and NO in Athens irrespective of year
The Use of Geographical Information System in Health Sector
The provision of health care has undergone radical changes during the
last years. Geography plays an important role in understanding the
dynamics of health, as well as the reasons why a disease is spreading.
In general, a Geographic Information System (GIS) is based on the same
principals with a traditional relational database. The main idea behind
this study is the methodological approach as far as the implementation
of a real-time electronic healthcare record is concerned, for the
descriptive statistical analysis that uses geographical information to
identify spatial data related to accidents. The purpose of developing
such a health care record is to record the patients who were injured in
accidents. The database that will be used for the development of the EHR
is based on Microsoft Office 2007, which is considered to be one of the
best tools for developing databases. The main table of the database
includes the fields with demographics, ie name, surname, age, sex,
address and place of birth. The primary key of the table Demographics is
Patient ID. The demographics from the table are connected to the table
Admission with a relationship type one-to-many. The combination of these
features in a graphic representation can be used to display the health
problems on the map, so that the proper health policies can be applied.
The results of the monitoring could be used as pilot instructions for
spatial epidemiological analysis
Diverse radiofrequency sensitivity and radiofrequency effects of mobile or cordless phone near fields exposure in Drosophila melanogaster.
INTRODUCTION:The impact of electromagnetic fields on health is of increasing scientific interest. The aim of this study was to examine how the Drosophila melanogaster animal model is affected when exposed to portable or mobile phone fields. METHODS/RESULTS:Two experiments have been designed and performed in the same laboratory conditions. Insect cultures were exposed to the near field of a 2G mobile phone (the GSM 2G networks support and complement in parallel the 3G wide band or in other words the transmission of information via voice signals is served by the 2G technology in both mobile phones generations) and a 1880 MHz cordless phone both digitally modulated by human voice. Comparison with advanced statistics of the egg laying of the second generation exposed and non-exposed cultures showed limited statistical significance for the cordless phone exposed culture and statistical significance for the 900 MHz exposed insects. We calculated by physics, simulated and illustrated in three dimensional figures the calculated near fields of radiation inside the experimenting vials and their difference. Comparison of the power of the two fields showed that the difference between them becomes null when the experimental cylinder radius and the height of the antenna increase. CONCLUSIONS/SIGNIFICANCE:Our results suggest a possible radiofrequency sensitivity difference in insects which may be due to the distance from the antenna or to unexplored intimate factors. Comparing the near fields of the two frequencies bands, we see similar not identical geometry in length and height from the antenna and that lower frequencies tend to drive to increased radiofrequency effects
Correction: Diverse radiofrequency sensitivity and radiofrequency effects of mobile or cordless phone near fields exposure in Drosophila melanogaster.
[This corrects the article DOI: 10.1371/journal.pone.0112139.]