Cost and Response Time Simulation for Web-based Applications on Mobile Channels

When considering the addition of a mobile presentation channel to an existing web-based application, a key question that has to be answered even before development begins is how the mobile channel’s characteristics will impact the user experience and the cost of using the application. If either of these factors is outside acceptable limits, economical considerations may forbid adding the channels, even if it would be feasible from a purely technical perspective. Both of these factors depend considerably on two metrics: The time required to transmit data over the mobile network, and the volume transmitted. The PETTICOAT method presented in this paper uses the dialog flow model and web server log files of an existing application to identify typical interaction sequences and to compile volume statistics, which are then run through a tool that simulates the volume and time that would be incurred by executing the interaction sequences on a mobile channel. From the simulated volume and time data, we can then calculate the cost of accessing the application on a mobile channel

Performance tuning and cost discovery of mobile web-based applications

When considering the addition of a mobile presentation channel to an existing web-based application, project managers should know how the mobile channel|s characteristics will impact the user experience and the cost of using the application, even before development begins. The PETTICOAT (Performance Tuning and cost discovery of mobile web-based Applications) approach presented here provides decision-makers with indicators on the economical feasibility of mobile channel development. In a nutshell, it involves analysing interaction patterns on the existing stationary channel, identifying key business processes among them, measuring the time and data volume incurred in their execution, and then simulating how the same interaction patterns would run when subjected to the frame conditions of a mobile channel. As a result of the simulation, we then gain time and volume projections for those interaction patterns that allow us to estimate the costs incurred by executing certain business processes on different mobile channels

Cost Simulation and Performance Optimization of Web-based Applications on Mobile Channels

When considering the addition of a mobile presentation channel to an existing web-based application, a key question that has to be answered even before development begins is how the mobile channel's characteristics will impact the user experience and the cost of using the application. If either of these factors is outside acceptable limits, economical considerations may forbid adding the channels, even if it would be feasible from a purely technical perspective. Both of these factors depend considerably on two metrics: The time required to transmit data over the mobile network, and the volume transmitted. The PETTICOAT method presented in this paper uses the dialog flow model and web server log files of an existing application to identify typical interaction sequences and to compile volume statistics, which are then run through a tool that simulates the volume and time that would be incurred by executing the interaction sequences on a mobile channel. From the simulated volume and time data, we can then calculate the cost of accessing the application on a mobile channel, and derive suitable approaches for optimizing cost and response times

A Methodology for Deriving the Architectural Implications of Different Degrees of Mobility in Information Systems

When building information systems that can be accessed through desktop and mobile devices, developers often face the same basic design decisions that depend on a number of still unstructured criteria. Going through the whole decision-making process for every project is inefficient and error-prone, however, a comprehensive set of best practices has not yet been established. We therefore present the foundations of a classification scheme for mobile commerce systems that helps developers to categorize applications according to high-level requirements. After a discussion of the criteria, we suggest implications that can be drawn from it and present examples for their application

Der Einfluss verschiedener Mobilitätsgrade auf die Architektur von Informationssystemen

Bei der Entwicklung von mobilen Informationssystemen stehen die Entwickler oft vor immer wiederkehrenden Entwurfsentscheidungen, die von einer Anzahl noch unstrukturierter Kriterien abhängen. Den kompletten Entscheidungsprozess für jedes einzelne Projekt von vorne bis hinten zu durchlaufen ist ineffizient und fehleranfällig, trotzdem gibt es noch keine umfassende Sammlung von „Best Practices“, die diesen Prozess verkürzen könnte. Wir präsentieren daher die Grundlagen eines Klassifikationsschemas für mobile Informationssysteme, das Entwicklern hilft, Anwendungen anhand von Anforderungen auf höherer Ebene zu klassifizieren und entsprechende Architekturentscheidungen zu treffen. Im Anschluss an die Diskussion der vorgestellten Kriterien schlagen wir Erweiterungen des Klassifikationsschemas und Folgerungen, die daraus gezogen werden können, vor

ASA Status, NPPA/NPPB Haplotype and Coronary Artery Disease Have an Impact on BNP/NT-proBNP Plasma Levels.

Plasma concentrations of natriuretic peptides (NP) contribute to risk stratification and management of patients undergoing non-cardiac surgery. However, genetically determined variability in the levels of these biomarkers has been described previously. In the perioperative setting, genetic contribution to NP plasma level variability has not yet been determined. A cohort of 427 patients presenting for non-cardiac surgery was genotyped for single-nucleotide polymorphisms (SNPs) from the NPPA/NPPB locus. Haplotype population frequencies were estimated and adjusted haplotype trait associations for brain natriuretic peptide (BNP) and amino-terminal pro natriuretic peptide (NT-proBNP) were calculated. Five SNPs were included in the analysis. Compared to the reference haplotype TATAT (rs198358, rs5068, rs632793, rs198389, rs6676300), haplotype CACGC, with an estimated frequency of 4%, showed elevated BNP and NT-proBNP plasma concentrations by 44% and 94%, respectively. Haplotype CGCGC, with an estimated frequency of 9%, lowered NT-proBNP concentrations by 28%. ASA classification status III and IV, as well as coronary artery disease, were the strongest predictors of increased NP plasma levels. Inclusion of genetic information might improve perioperative risk stratification of patients based on adjusted thresholds of NP plasma levels

Induction of Bim and Bid gene expression during accelerated apoptosis in severe sepsis

ABSTRACT: INTRODUCTION: In transgenic animal models of sepsis, members of the Bcl-2-family of proteins regulate lymphocyte apoptosis and survival of sepsis. This study investigates the gene regulation of pro- and anti-apoptotic members of the Bcl-2-family of proteins in patients with early stage severe sepsis. METHODS: In this prospective case-control study patients were recruited from three intensive care units in a university hospital. Sixteen patients were enrolled as soon as they fulfilled the criteria of severe sepsis. Ten critically ill but non-septic patients and eleven healthy volunteers served as controls. Blood samples were immediately obtained at inclusion. To confirm the presence of accelerated apoptosis in the patient groups, caspase-3 activation and phosphatidylserine (PS) externalization in CD4+, CD8+ and CD19+ lymphocyte subsets were assessed by flow cytometry. Specific mRNA's of Bcl-2 family members were quantified from whole blood by real-time polymerase chain reaction. To test for statistical significance, Kruskal-Wallis testing with Dunn's multiple comparison test for post hoc testing was performed. RESULTS: In all lymphocyte populations caspase-3 (p<0.05) was activated, which was reflected in an increased PS externalization (p<0.05). Accordingly, lymphocyte counts were decreased in early severe sepsis. In CD4+ T-cells (p<005) and in B-cells (p<0.001) the Bcl-2 protein was decreased in severe sepsis. Gene expression of the BH3-only Bim was massively upregulated as compared to critically ill patients (p<0.001) and 51.6 fold as compared to healthy controls (p<0.05). Bid was increased 12.9 fold compared to critically ill (p<0.001). In the group of the mitochondrial apoptosis-inducers, Bak was upregulated 5.6 fold, while the expression of Bax showed no significant variations. By contrast, the pro-survival members Bcl-2 and Bcl-xl were both downregulated in severe sepsis (p<0.001, p<0.05). CONCLUSIONS: In early severe sepsis a gene expression pattern with induction of the pro-apoptotic Bcl-2 family members Bim, Bid and Bak and a downregulation of the anti-apoptotic Bcl-2 and Bcl-xl was observed in peripheral blood. This constellation may affect cellular susceptibility to apoptosis and complex immune dysfunction in sepsis

A MIF haplotype is associated with the outcome of patients with severe sepsis: a case control study

<p>Abstract</p> <p>Background</p> <p>Macrophage migration inhibitory factor (MIF) plays an important regulatory role in sepsis. In the promoter region a C/G single nucleotide polymorphism (SNP) at position -173 (rs755622) and a CATT_5-8microsatellite at position -794 are related to modified promoter activity. The purpose of the study was to analyze their association with the incidence and outcome of severe sepsis.</p> <p>Methods</p> <p>Genotype distributions and allele frequencies in 169 patients with severe sepsis, 94 healthy blood donors and 183 postoperative patients without signs of infection or inflammation were analyzed by real time PCR and Sequence analysis. All included individuals were Caucasians.</p> <p>Results</p> <p>Genotype distribution and allele frequencies of severe sepsis patients were comparable to both control groups. However, the genotype and allele frequencies of both polymorphisms were associated significantly with the outcome of severe sepsis. The highest risk of dying from severe sepsis was detectable in patients carrying a haplotype with the alleles -173 C and CATT₇(p = 0.0005, fisher exact test, RR = 1,806, CI: 1.337 to 2.439).</p> <p>Conclusion</p> <p>The haplotype with the combination of the -173 C allele and the -794 CATT₇allele may not serve as a marker for susceptibility to sepsis, but may help identify septic patients at risk of dying.</p

Improved detection of blood stream pathogens by real-time PCR in severe sepsis

Objective: Evaluation of the technical and diagnostic feasibility of commercial multiplex real-time polymerase chain reaction (PCR) for detection of blood stream infections in a cohort of intensive care unit (ICU) patients with severe sepsis, performed in addition to conventional blood cultures. Design: Dual-center cohort study. Setting: Surgical ICU of two university hospitals. Patients and participants: One hundred eight critically ill patients fulfilling the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) severe sepsis criteria were included. Interventions: None. Measurements and results: PCR results obtained in 453 blood samples from 108 patients were compared with corresponding blood culture results. PCR resulted in a twofold higher positivity rate when compared with conventional blood culture (BC) testing (114 versus 58 positive samples). In 40 out of 58 PCR positive assays the results of the corresponding blood cultures were identical to microorganisms detected by PCR. In 18 samples PCR and BC yielded discrepant results. Compared with conventional blood culture the sensitivity and specificity of PCR was 0.69 and 0.81, respectively. Further evaluation of PCR results against a constructed gold standard including conventional microbiological test results from other significant patient specimen (such as bronchio-alveolar lavage fluid, urine, swabs) and additionally generated clinical and laboratory information yielded sensitivity of 0.83 and specificity of 0.93. Conclusions: Our cohort study demonstrates improved pathogen detection using PCR findings in addition to conventional blood culture testing. PCR testing provides increased sensitivity of blood stream infection. Studies addressing utility including therapeutic decision-making, outcome, and cost-benefit following diagnostic application of PCR tests are needed to further assess its value in the clinical settin