Supply sensitive services in Swiss ambulatory care: an analysis of basic health insurance records for 2003-2007

Swiss ambulatory care is characterized by independent, and primarily practice-based, physicians, receiving fee for service reimbursement. This study analyses supply sensitive services using ambulatory care claims data from mandatory health insurance. A first research question was aimed at the hypothesis that physicians with large patient lists decrease their intensity of services and bill less per patient to health insurance, and vice versa: physicians with smaller patient lists compensate for the lack of patients with additional visits and services. A second research question relates to the fact that several cantons are allowing physicians to directly dispense drugs to patients ('self-dispensation') whereas other cantons restrict such direct sales to emergencies only. This second question was based on the assumption that patterns of rescheduling patients for consultations may differ across channels of dispensing prescription drugs and therefore the hypothesis of different consultation costs in this context was investigated.

The Small Project Observatory: Visualizing Software Ecosystems

Software evolution research has focused mostly on analyzing the evolution of single software systems. However, it is rarely the case that a project exists as standalone, independent of others. Rather, projects exist in parallel within larger contexts in companies, research groups or even the open-source communities. We call these contexts software ecosystems, and on this paper we present The Small Project Observatory, a prototype tool which aims to support the analysis of project ecosystems through interactive visualization and exploration. We present a case-study of exploring an ecosystem using our tool, we describe about the architecture of the tool, and we distill the lessons learned during the tool-building experience.

ABCtoolbox: a versatile toolkit for approximate Bayesian computations

Background The estimation of demographic parameters from genetic data often requires the computation of likelihoods. However, the likelihood function is computationally intractable for many realistic evolutionary models, and the use of Bayesian inference has therefore been limited to very simple models. The situation changed recently with the advent of Approximate Bayesian Computation (ABC) algorithms allowing one to obtain parameter posterior distributions based on simulations not requiring likelihood computations. Results Here we present ABCtoolbox, a series of open source programs to perform Approximate Bayesian Computations (ABC). It implements various ABC algorithms including rejection sampling, MCMC without likelihood, a Particle-based sampler and ABC-GLM. ABCtoolbox is bundled with, but not limited to, a program that allows parameter inference in a population genetics context and the simultaneous use of different types of markers with different ploidy levels. In addition, ABCtoolbox can also interact with most simulation and summary statistics computation programs. The usability of the ABCtoolbox is demonstrated by inferring the evolutionary history of two evolutionary lineages of Microtus arvalis. Using nuclear microsatellites and mitochondrial sequence data in the same estimation procedure enabled us to infer sex-specific population sizes and migration rates and to find that males show smaller population sizes but much higher levels of migration than females. Conclusion ABCtoolbox allows a user to perform all the necessary steps of a full ABC analysis, from parameter sampling from prior distributions, data simulations, computation of summary statistics, estimation of posterior distributions, model choice, validation of the estimation procedure, and visualization of the results.

Package Patterns for Visual Architecture Recovery

Recovering the architecture is the first step towards reengineering a software system. Many reverse engineering tools use top-down exploration as a way of providing a visual and interactive process for architecture recovery. During the exploration process, the user navigates through various views on the system by choosing from several exploration operations. Although some sequences of these operations lead to views which, from the architectural point of view, are mode relevant than others, current tools do not provide a way of predicting which exploration paths are worth taking and which are not. In this article we propose a set of package patterns which are used for augmenting the exploration process with in formation about the worthiness of the various exploration paths. The patterns are defined based on the internal package structure and on the relationships between the package and the other packages in the system. To validate our approach, we verify the relevance of the proposed patterns for real-world systems by analyzing their frequency of occurrence in six open-source software projects.

Monte Carlo source model for photon beam radiotherapy: photon source characteristics

A major barrier to widespread clinical implementation of Monte Carlo dose calculation is the difficulty in characterizing the radiation source within a generalized source model. This work aims to develop a generalized three-component source model (target, primary collimator, flattening filter) for 6- and 18-MV photon beams that match full phase-space data (PSD). Subsource by subsource comparison of dose distributions, using either source PSD or the source model as input, allows accurate source characterization and has the potential to ease the commissioning procedure, since it is possible to obtain information about which subsource needs to be tuned. This source model is unique in that, compared to previous source models, it retains additional correlations among PS variables, which improves accuracy at nonstandard source-to-surface distances (SSDs). In our study, three-dimensional (3D) dose calculations were performed for SSDs ranging from 50 to 200 cm and for field sizes from 1 x 1 to 30 x 30 cm2 as well as a 10 x 10 cm2 field 5 cm off axis in each direction. The 3D dose distributions, using either full PSD or the source model as input, were compared in terms of dose-difference and distance-to-agreement. With this model, over 99% of the voxels agreed within +/-1% or 1 mm for the target, within 2% or 2 mm for the primary collimator, and within +/-2.5% or 2 mm for the flattening filter in all cases studied. For the dose distributions, 99% of the dose voxels agreed within 1% or 1 mm when the combined source model-including a charged particle source and the full PSD as input-was used. The accurate and general characterization of each photon source and knowledge of the subsource dose distributions should facilitate source model commissioning procedures by allowing scaling the histogram distributions representing the subsources to be tuned.

Simulation of four stroke engine cycle for a 4 - valve pentroof engine in KIVA 3VR2

The main purpose of this project is to understand the process of engine simulation using the open source CFD code called KIVA. This report mainly discusses the simulation of the 4-valve Pentroof engine through KIVA 3VR2. KIVA is an open source FORTRAN code which is used to solve the fluid flow field in the engines with the transient 2D and 3D chemically reactive flow with spray. It also focuses on the complete procedure to simulate an engine cycle starting from pre- processing until the final results. This report will serve a handbook for the using the KIVA code.

PROBABILISTIC MODELING OF RAINFALL INDUCED LANDSLIDE HAZARD ASSESSMENT IN SAN JUAN LA LAGUNA, SOLOLÁ, GUATEMALA

The municipality of San Juan La Laguna, Guatemala is home to approximately 5,200 people and located on the western side of the Lake Atitlán caldera. Steep slopes surround all but the eastern side of San Juan. The Lake Atitlán watershed is susceptible to many natural hazards, but most predictable are the landslides that can occur annually with each rainy season, especially during high-intensity events. Hurricane Stan hit Guatemala in October 2005; the resulting flooding and landslides devastated the Atitlán region. Locations of landslide and non-landslide points were obtained from field observations and orthophotos taken following Hurricane Stan. This study used data from multiple attributes, at every landslide and non-landslide point, and applied different multivariate analyses to optimize a model for landslides prediction during high-intensity precipitation events like Hurricane Stan. The attributes considered in this study are: geology, geomorphology, distance to faults and streams, land use, slope, aspect, curvature, plan curvature, profile curvature and topographic wetness index. The attributes were pre-evaluated for their ability to predict landslides using four different attribute evaluators, all available in the open source data mining software Weka: filtered subset, information gain, gain ratio and chi-squared. Three multivariate algorithms (decision tree J48, logistic regression and BayesNet) were optimized for landslide prediction using different attributes. The following statistical parameters were used to evaluate model accuracy: precision, recall, F measure and area under the receiver operating characteristic (ROC) curve. The algorithm BayesNet yielded the most accurate model and was used to build a probability map of landslide initiation points. The probability map developed in this study was also compared to the results of a bivariate landslide susceptibility analysis conducted for the watershed, encompassing Lake Atitlán and San Juan. Landslides from Tropical Storm Agatha 2010 were used to independently validate this study’s multivariate model and the bivariate model. The ultimate aim of this study is to share the methodology and results with municipal contacts from the author's time as a U.S. Peace Corps volunteer, to facilitate more effective future landslide hazard planning and mitigation.

THE USE OF LIFE-CYCLE ANALYSIS TO REDUCE THE ENVIRONMENTAL IMPACT OF MATERIALS IN MANUFACTURING

This thesis is composed of three life-cycle analysis (LCA) studies of manufacturing to determine cumulative energy demand (CED) and greenhouse gas emissions (GHG). The methods proposed could reduce the environmental impact by reducing the CED in three manufacturing processes. First, industrial symbiosis is proposed and a LCA is performed on both conventional 1 GW-scaled hydrogenated amorphous silicon (a-Si:H)-based single junction and a-Si:H/microcrystalline-Si:H tandem cell solar PV manufacturing plants and such plants coupled to silane recycling plants. Using a recycling process that results in a silane loss of only 17 versus 85 percent, this results in a CED savings of 81,700 GJ and 290,000 GJ per year for single and tandem junction plants, respectively. This recycling process reduces the cost of raw silane by 68 percent, or approximately $22.6 and $79 million per year for a single and tandem 1 GW PV production facility, respectively. The results show environmental benefits of silane recycling centered around a-Si:H-based PV manufacturing plants. Second, an open-source self-replicating rapid prototype or 3-D printer, the RepRap, has the potential to reduce the environmental impact of manufacturing of polymer-based products, using distributed manufacturing paradigm, which is further minimized by the use of PV and improvements in PV manufacturing. Using 3-D printers for manufacturing provides the ability to ultra-customize products and to change fill composition, which increases material efficiency. An LCA was performed on three polymer-based products to determine the CED and GHG from conventional large-scale production and are compared to experimental measurements on a RepRap producing identical products with ABS and PLA. The results of this LCA study indicate that the CED of manufacturing polymer products can possibly be reduced using distributed manufacturing with existing 3-D printers under 89% fill and reduced even further with a solar photovoltaic system. The results indicate that the ability of RepRaps to vary fill has the potential to diminish environmental impact on many products. Third, one additional way to improve the environmental performance of this distributed manufacturing system is to create the polymer filament feedstock for 3-D printers using post-consumer plastic bottles. An LCA was performed on the recycling of high density polyethylene (HDPE) using the RecycleBot. The results of the LCA showed that distributed recycling has a lower CED than the best-case scenario used for centralized recycling. If this process is applied to the HDPE currently recycled in the U.S., more than 100 million MJ of energy could be conserved per annum along with significant reductions in GHG. This presents a novel path to a future of distributed manufacturing suited for both the developed and developing world with reduced environmental impact. From improving manufacturing in the photovoltaic industry with the use of recycling to recycling and manufacturing plastic products within our own homes, each step reduces the impact on the environment. The three coupled projects presented here show a clear potential to reduce the environmental impact of manufacturing and other processes by implementing complimenting systems, which have environmental benefits of their own in order to achieve a compounding effect of reduced CED and GHG.

TANK SIZING AND OPTIMIZING LOOP PLACEMENT IN A BRANCHED WATER DISTRIBUTION SYSTEM

More than eighteen percent of the world’s population lives without reliable access to clean water, forced to walk long distances to get small amounts of contaminated surface water. Carrying heavy loads of water long distances and ingesting contaminated water can lead to long-term health problems and even death. These problems affect the most vulnerable populations, women, children, and the elderly, more than anyone else. Water access is one of the most pressing issues in development today. Boajibu, a small village in Sierra Leone, where the author served in Peace Corps for two years, lacks access to clean water. Construction of a water distribution system was halted when a civil war broke out in 1992 and has not been continued since. The community currently relies on hand-dug and borehole wells that can become dirty during the dry season, which forces people to drink contaminated water or to travel a far distance to collect clean water. This report is intended to provide a design the system as it was meant to be built. The water system design was completed based on the taps present, interviews with local community leaders, local surveying, and points taken with a GPS. The design is a gravity-fed branched water system, supplied by a natural spring on a hill adjacent to Boajibu. The system’s source is a natural spring on a hill above Boajibu, but the flow rate of the spring is unknown. There has to be enough flow from the spring over a 24-hour period to meet the demands of the users on a daily basis, or what is called providing continuous flow. If the spring has less than this amount of flow, the system must provide intermittent flow, flow that is restricted to a few hours a day. A minimum flow rate of 2.1 liters per second was found to be necessary to provide continuous flow to the users of Boajibu. If this flow is not met, intermittent flow can be provided to the users. In order to aid the construction of a distribution system in the absence of someone with formal engineering training, a table was created detailing water storage tank sizing based on possible source flow rates. A builder can interpolate using the source flow rate found to get the tank size from the table. However, any flow rate below 2.1 liters per second cannot be used in the table. In this case, the builder should size the tank such that it can take in the water that will be supplied overnight, as all the water will be drained during the day because the users will demand more than the spring can supply through the night. In the developing world, there is often a problem collecting enough money to fund large infrastructure projects, such as a water distribution system. Often there is only enough money to add only one or two loops to a water distribution system. It is helpful to know where these one or two loops can be most effectively placed in the system. Various possible loops were designated for the Boajibu water distribution system and the Adaptive Greedy Heuristic Loop Addition Selection Algorithm (AGHLASA) was used to rank the effectiveness of the possible loops to construct. Loop 1 which was furthest upstream was selected because it benefitted the most people for the least cost. While loops which were further downstream were found to be less effective because they would benefit fewer people. Further studies should be conducted on the water use habits of the people of Boajibu to more accurately predict the demands that will be placed on the system. Further population surveying should also be conducted to predict population change over time so that the appropriate capacity can be built into the system to accommodate future growth. The flow at the spring should be measured using a V-notch weir and the system adjusted accordingly. Future studies can be completed adjusting the loop ranking method so that two users who may be using the water system for different lengths of time are not counted the same and vulnerable users are weighted more heavily than more robust users.

Kostenorientiertes Controlling von E-Learning-Plattformen mit dem TCO-Konzept

Zur administrativen Unterstützung von Lehr- und Lernprozessen werden E-Learning-Plattformen eingesetzt, die auf der Grundlage des Internet Funktionen zur Distribution von Lehr- und Lernmaterialien und zur Kommunikation zwischen Lehrenden und Lernenden anbieten. Zahlreiche wissenschaftliche Beiträge und Marktstudien beschäftigen sich mit der multikriteriellen Evaluation dieser Softwareprodukte zur informatorischen Fundierung strategischer Investitionsentscheidungen. Demgegenüber werden Instrumente zum kostenorientierten Controlling von E-Learning-Plattformen allenfalls marginal thematisiert. Dieser Beitrag greift daher das Konzept der Total Cost of Ownership (TCO) auf, das einen methodischen Ansatzpunkt zur Schaffung von Kostentransparenz von E-Learning-Plattformen bildet. Aufbauend auf den konzeptionellen Grundlagen werden Problembereiche und Anwendungspotenziale für das kostenorientierte Controlling von LMS identifiziert. Zur softwaregestützten Konstruktion und Analyse von TCO-Modellen wird das Open Source-Werkzeug TCO-Tool eingeführt und seine Anwendung anhand eines synthetischen Fallbeispiels erörtert. Abschließend erfolgt die Identifikation weiterführender Entwicklungsperspektiven des TCO-Konzepts im Kontext des E-Learning. Die dargestellte Thematik ist nicht nur von theoretischem Interesse, sondern adressiert auch den steigenden Bedarf von Akteuren aus der Bildungspraxis nach Instrumenten zur informatorischen Fundierung von Investitions- und Desinvestitionsentscheidungen im Umfeld des E-Learning.

Exploring Urban Environments Using Virtual and Augmented Reality

In this paper, we propose the use of specific system architecture, based on mobile device, for navigation in urban environments. The aim of this work is to assess how virtual and augmented reality interface paradigms can provide enhanced location based services using real-time techniques in the context of these two different technologies. The virtual reality interface is based on faithful graphical representation of the localities of interest, coupled with sensory information on the location and orientation of the user, while the augmented reality interface uses computer vision techniques to capture patterns from the real environment and overlay additional way-finding information, aligned with real imagery, in real-time. The knowledge obtained from the evaluation of the virtual reality navigational experience has been used to inform the design of the augmented reality interface. Initial results of the user testing of the experimental augmented reality system for navigation are presented.

Stud.IP

Dieser Beitrag beschreibt die Konzeption, den Funktionsumfang und Erfahrungswerte der Open-Source-eLearning-Plattform Stud.IP. Der Funktionsumfang umfasst für jede einzelne Veranstaltung Ablaufpläne, das Hochladen von Hausarbeiten, Diskussionsforen, persönliche Homepages, Chaträume u.v.a. Ziel ist es hierbei, eine Infrastruktur des Lehrens und Lernens anzubieten, die dem Stand der Technik entspricht. Wissenschaftliche Einrichtungen finden zudem eine leistungsstarke Umgebung zur Verwaltung ihres Personals, Pflege ihrer Webseiten und der automatischer Erstellung von Veranstaltungs- oder Personallisten vor. Betreiber können auf ein verlässliches Supportsystem zugreifen, dass sie an der Weiterentwicklung durch die Entwickler- und Betreiber-Community teilhaben lässt.

Simulation von Förderprozessen bei Vibrationsförderanlagen

Die erzielbare Fördergeschwindigkeit bei Vibrationsförderern hängt maßgeblich von der Bewegungsfunktion des Förderorganes ab. Für die gezielte Simulation dieser Anlagen mittels der diskreten Elemente Methode (DEM) ist es notwendig die geometrisch vernetzen Förderorgannachbildungen mit praxisrelevanten Bewegungsfunktionen zu beaufschlagen. Der Artikel beschreibt die Einbindung dieser Bewegungsfunktionen in die quellenoffene DEM-Software LIGGGHTS. Während des Simulationsprozesses wird eine Bewegung vernetzter CAD-Modelle durch trigonometrische Reihen ermöglicht.

“Advertising Psychology – The Blog Seminar”.

The aim of the web-based course “Advertising Psychology – The Blog Seminar” was to offer a contemporary teaching design using typical Web 2.0 characteristics such as comments, discussions and social media integration which covers facebook and Twitter support, as nowadays, this is a common part of students’ everyday life. This weblog (blog)-based seminar for Advertising Psychology was set up in order to make the course accessible to students from different campuses in the Ruhr metropolitan area. The technical aspect of the open-source content management system Drupal 6.0 and the didactical course structure, based on Merrill’s five first principles of instruction, are introduced. To date, this blog seminar has been conducted three times with a total of 84 participants, who were asked to rate the course according to the benefits of different didactical elements and with regard to Kirkpatrick’s levels of evaluation model. This model covers a) reactions such as reported enjoyment, perceived usefulness and perceived difficulty, and b) effects on learning through the subjectively reported increase in knowledge and attitude towards the seminar. Overall, the blog seminar was evaluated very positively and can be considered as providing support for achieving the learning objectives. However, a successful blended learning approach should always be tailored to the learning contents and the environment.

Vergleich von Softwarelösungen für die Ökobilanzierung – eine softwareergonomische Analyse

Ökobilanzierung von Produktsystemen dient der Abschätzung ihrer Wirkung auf die Umwelt. Eine vollständige Lebenswegbetrachtung erfordert auch die Einbeziehung intralogistischer Transportprozesse bzw. -mittel. Für die Erstellung von Ökobilanzen wird i. d. R. ein Computerprogramm verwendet. Die Demoversionen dreier kommerzieller Softwarelösungen (SimaPro, GaBi und Umberto NXT LCA) und die Vollversion einer Open Source Software (openLCA) wurden aus softwareergonomischer Sicht analysiert. Hierzu erfolgte u. a. der Nachbau der bereitgestellten Tutorials bzw. die Modellierung eigener Produktsysteme. Im Rahmen der Analyse wurden die Punkte • Entstehung, Verbreitung, Zielgruppe, • Eignung der Tutorials, Erlernbarkeit, • Grafische Benutzeroberfläche, Individualisierbarkeit der Software, • Umsetzung der Anforderungen aus den Ökobilanzierungsnormen, • Notwendige Arbeitsschritte zur Erstellung einer Ökobilanz einer vergleichenden Betrachtung unterzogen. Der Beitrag beinhaltet eine Einführung in die wesentlichen Prinzipien der Ökobilanzierung und die Grundsätze der Softwareergonomie. Diese werden zu softwareergonomischen Eigenschaften für Ökobilanzsoftwarelösungen subsumiert. Anschließend werden die Ergebnisse des Softwarevergleiches dargestellt. Abschließend erfolgt eine Zusammenfassung der Erkenntnisse.