Beiträge zur Automatisierung der frühen Entwurfsphasen verteilter Systeme

With the rapid increasing speed of electronic devices systems with highercomplexity, interconnectedness and heterogeneity can be developed. The developmentof such systems can only be done by teams of specialists. Atthe same time the development needs to happen in parallel to ensure anearly time to market. Therefore in the traditional design process the designis described in form of a written specification of the common system andpartitioned to several teams. This takes place in early design stages at highproduct uncertainty. Sub system development assumptions and decisions aremade without being able to evaluate the effect on the common system. Thusmany critical errors, especially those, caused by coupling effects, are discoveredduring system integration at the end of the design process. Furthermorean optimization of the common system is not possible, because of the lack ofa common system model. Hence the traditional design process is a high riskdevelopment process. In the Mission Level Design approach, an executable specification of thecommon system instead of a written specification is developed after conceptdevelopment. These is validated and optimized against the requirements ofthe common system. The such validated specification of the coupled systemis then passed on to specialist teams for sub system development. The subsystems are then integrated. In this manner integration problems can besolved in the early design stages. Development time and risk can be reducedsignificantly. To increase the specification quality and speed while developing common systemmodels, in the present work, standardized methods for specification andperformance evaluation of distributed systems and methods for automatedmapping of function into architecture are developed. This allows architectureoptimization of the common system in the early design stages. In addition,methods for transformation of the abstract design into implementations aredeveloped.Mit der rapide steigenden Geschwindigkeit elektronischer Bauelemente könnenSysteme mit erhöhter Komplexität, Vernetzung und Heterogenität entwickeltwerden. Dies hat zur Folge, dass eine Entwicklung nur durch Teamsvon Spezialisten durchführbar ist. Gleichzeitig muss die Entwicklung parallelerfolgen, um eine möglichst frühzeitige Produkteinführung zu ermöglichen.Im traditionellen Entwurfsprozess wird daher der Entwurf in Form einer geschriebenenSpezifikation des Gesamtsystems erfasst und anschließend aufmehrere Teams aufgeteilt. Dies erfolgt in den frühen Entwurfsphasen, welchedurch eine hohe Unsicherheit über das Produkt gekennzeichnet sind. Dabeimüssen bei der Entwicklung der Subsysteme Annahmen und Entscheidungengetroffen werden, ohne den Einfluss auf das Gesamtsystem abschätzenzu können. Kopplungseffekte werden weitestgehend ignoriert. Viele kritische,insbesondere durch Kopplungseffekte hervorgerufene Fehler, können folglicherst bei der Integration am Ende der Entwicklung entdeckt werden. Zudem isteine Optimierung des Gesamtsystems nicht möglich, da kein Gesamtsystemmodellvorliegt. Der traditionelle Entwurfsprozess besitzt daher ein hohesEntwicklungsrisiko. Beim Entwurfsansatz Mission Level Design wird nach dem Konzeptentwurfanstatt einer geschriebenen eine ausführbare Spezifikation des Gesamtsystemsentwickelt. Diese wird gegen die Gesamtsystemanforderungen validiertund optimiert. Daraufhin wird die Spezifikation des gekoppelten Gesamtsystemsan mehrere Teams zur Entwicklung der Subsysteme weitergegeben,welche dann wieder zu einem Gesamtsystem integriert werden. Integrationsproblemewerden so schon in den frühen Entwurfsphasen gelöst, was einewesentliche Verringerung von Entwicklungszeit und -risiko bewirkt. Um die Spezifikationsqualität und -geschwindigkeit bei der Entwicklung vonGesamtsystemmodellen zu erhöhen, werden im Rahmen der Arbeit standardisierteMethoden zur Beschreibung und Leistungsbewertung verteilterSysteme, sowie zum automatisierten Mapping von Funktion in Architekturentwickelt. Dies ermöglicht bereits in den frühen Entwurfsphasen eine Architekturoptimierungdes Gesamtsystems. Zusätzlich werden Methoden zurÜberführung des abstrakten Entwurfs in Implementationen entwickelt

Pellicle Modification with Casein and Mucin Does Not Affect Surface Loss from Erosion and Abrasion.

AIM A combination of the proteins casein and mucin is known to modify the salivary pellicle and improve its protection of the underlying enamel from erosion. It is so far not known if this protection is confined solely to erosion, or if it also extends to abrasion, and this in vitro study aimed at investigating this question. METHODS A total of 72 human enamel specimens were prepared and randomly assigned to four groups: pellicle (P), casein/mucin (CM), pellicle + casein/mucin (PCM), and control (Ctrl). Each specimen underwent five cycles, each cycle consisting of a pellicle/treatment part, an erosion part (3 min in 1% citric acid, pH 3.6, 25°C, 70 rpm), and an abrasion part (50 toothbrush strokes within 25 s in toothpaste slurry with a 200-g load). The pellicle/treatment part consisted of 2 h of incubation in whole human saliva for group P, 2 h of incubation (25°C, 70 rpm) in a protein mixture of 1% casein and 0.27% mucin for group CM, and 2 h of incubation in saliva followed by 2 h of incubation in the protein mixture for group PCM. The fourth group (Ctrl) served as the control and was kept in a humid chamber without saliva or protein treatment. The enamel surfaces were scanned with an optical profilometer initially and after the final cycle, and surface loss was analyzed. Furthermore, the surface microhardness (SMH) was measured initially, after each pellicle/treatment part and each erosion cycle, and after the final abrasion cycle. The results were analyzed with Kruskal-Wallis and Wilcoxon tests with Bonferroni corrections. RESULTS The different treatments did not show differences in surface loss and therefore did not protect enamel from surface loss by abrasion. Nonetheless, we observed differences in the SMH values, namely the Ctrl group being significantly softer than the experimental groups. CONCLUSION The observed differences in SMH suggest that a different abrasion protocol could lead to differences in surface loss, and further investigation of whether and under which conditions pellicle modification leads to increased resistance to abrasion remains worthwhile

On the Necessity for High-availability Data Center Backends in a Distributed Wireless System

When business processes depend on the processing capabilities within a data center, the typical system architecture use a high-availability setup to maintain a high level of service. Faced with a specific machine-to-machine system consisting of many endpoints that collect and forward data to the data center we argue that the dependability of the overall system does not necessitate a high level of service for the data center components. Taking an existing discrete event simulation model of a distributed technical system we investigate and discuss the effects of prolonged outages of the data center on the major business processes of the system

Expression of defensins in non-infected araneomorph spiders

Defensins are a major family of antimicrobial peptides found throughout the phylogenetic tree. From the spider species: Cupiennius salei, Phoneutria reidyi, Polybetes pythagoricus, Tegenaria atrica, and Meta menardi, defensins belonging to the ‘ancestral' class of invertebrate defensins were cloned and sequenced. The deduced amino acid sequences contain the characteristic six cysteines of this class of defensins and reveal precursors of 60 or 61 amino acid residues. The mature peptides consist of 37 amino acid residues, showing up to 70% identities with tick and scorpion defensins. In C. salei, defensin mRNA was found to be constitutively expressed in hemocytes, ovaries, subesophageal nerve mass, hepatopancreas, and muscle tissue. This is the first report presenting and comparing antimicrobial peptides belonging to the family of defensins from spider

Differences in susceptibility of deciduous and permanent teeth to erosion exist, albeit depending on protocol design and method of assessment.

Controversial results showing that deciduous teeth are more susceptible to erosion than permanent teeth might be related to study designs. We investigated how different conditions (pH: 3.0, 4.0, 5.0; acid agitation: gentle or vigorous; acid exposure times: 1-5 min) affect the susceptibility of both teeth to erosion. Enamel specimens (90 deciduous, 90 permanent) were distributed into groups (n = 15 permanent, n = 15 deciduous) according to acid pH (pH 5, 4 or 3) and agitation (gentle or vigorous) during erosive challenge. Both milder (less incubation time, gentle agitation, and higher pH) and more severe (longer incubation times, vigorous shaking, and lower pH) conditions were used. Demineralization was measured by relative surface microhardness (rSMH) and calcium released to the acid. Demineralization increased gradually for both teeth with increasing incubation time, agitation (gentle or vigorous), and with decreasing acid pH. The differences between deciduous and permanent teeth depended on the protocol design and assessment method. Under milder conditions, demineralization was better detectable with rSMH. Under more severe conditions, differences were more perceptible with calcium analyses. Differences exist in the susceptibility to erosion between deciduous and permanent teeth, but they are only distinguishable when the appropriate assessment method is used for the specific erosive condition

Network-wide Measurement of TCP RTT in 2G Networks

We analyze existing server-side log data of a large scale automatic toll system to measure the TCP round-trip-time (RTT) as experienced by the communication between the central system and the on-board units (OBUs) deployed for tolling heavy-goods vehicles. The RTT is estimated from passive monitoring by parsing server-side log files and aggregating fleet-wide statistics over time. Using this data we compare the characteristics of the four different types of OBU and the three GPRS (2G) networks used. We find the RTT data to be consistent with existing, smaller samples and extend the observed RTT range by an order of magnitude. The OBU types exhibit a markedly different behavior, most notably for long RTTs, and we find one of the 2G networks to -˜hum’ at 50 Hz and harmonics

Modeling the GPRS Network Latency with a Double Pareto-lognormal or a Generalized Beta Distribution

Taking a newly collected large data set on the TCP connection termination latency in GPRS networks we try to identify the underlying statistical distribution. The data extends the observed latencies to large time scales necessitating a heavy-tail distribution. Many distributions work well for the main body of the data. However, the heavy tail of the distribution benefits from mixing different statistical distributions. We compare several distributions and find that the double Pareto-lognormal distribution and the generalized Beta distribution of the second kind fit the data equally well

Erosive effect of different dietary substances on deciduous and permanent teeth.

OBJECTIVES We investigated the effect of different dietary substances on deciduous and permanent enamel. MATERIALS AND METHODS Enamel specimens were prepared from human teeth (n = 108 deciduous molars and n = 108 permanent premolars). We measured the chemical parameters (pH, titratable acidity, viscosity, calcium, phosphate, fluoride concentration and degree of saturation) of nine dietary substances. The teeth were immersed in the respective substance (2 × 2 min; 30 °C; shaking), and we measured the baseline surface hardness (SH) in Vickers hardness numbers (VHN), and the changes in SH after 2 min (ΔSH2-0) and the 4 min (ΔSH4-0) immersion. We analysed the differences between deciduous and permanent teeth using the Wilcoxon test and correlated ΔSH to the different chemical parameters. RESULTS Deciduous teeth were significantly softer (549.53 ± 59.41 VHN) than permanent teeth (590.15 ± 55.31 VHN; p < 0.001) at baseline, but they were not more vulnerable to erosive demineralization. Only orange juice, which presented milder erosive potential, caused significantly more demineralisation in deciduous teeth at ΔSH4-0. Practically all chemical parameters significantly correlated with ΔSH (p < 0.05). Substances with lower pH, higher titratable acidity, lower Ca, higher Pi and lower F concentrations, higher viscosity and more undersaturated solutions presented more erosive demineralisation. CONCLUSION Different parameters in dietary substances affect erosive demineralisation in deciduous and permanent teeth, but we generally observed no differences in susceptibility to erosion between both types of teeth; only orange juice (less severe acid conditions) caused perceptible differences. CLINICAL RELEVANCE We observe that permanent teeth are harder than deciduous teeth, but most substances cause no perceptible difference in erosive demineralisation in both types of teeth

Synergistic effect between plant extracts and fluoride to protect against enamel erosion: An in vitro study.

Polyphenol-rich solutions, such as plant extracts and teas, can modify the salivary pellicle and improve the protection against dental erosion. In this study, we further explored how these polyphenol-rich plant extracts solutions behave in the presence of fluoride. We distributed enamel specimens into 9 groups (n = 15): Control_No_F- (Deionized water); Control_F- (500 ppm F-), Grape_Seed_No_F- (Grape seed extract), Grape_Seed_F- (Grape seed extract + 500 ppm F-), Grapefruit_Seed_No_F- (Grapefruit seed extract), Grapefruit_Seed_F- (Grapefruit seed extract + 500 ppm F-), Blueberry_No_F- (Blueberry extract), Blueberry_F- (Blueberry extract + 500 ppm F-), and Sn2+/F-_Rinse (commercial solution containing 800 ppm Sn2+ and 500 ppm F-). The specimens were submitted to 5 cycles (1 cycle per day), and each cycle consisted of: salivary pellicle formation (human saliva, 30 min, 37°C), modification of the pellicle (2 min, 25°C), pellicle formation (60 min, 37°C), and an erosive challenge (1 min, citric acid). Between cycles, the specimens were kept in a humid chamber. Relative surface hardness (rSH), relative surface reflection intensity (rSRI) and calcium released to the acid were analysed, using general linear models, and Kruskal-Wallis with post-hoc Dunn's tests. We observed that the presence of fluoride in synergy with the extract solutions provided better protection than the groups containing extract or fluoride only. For rSH, we observed a significant main effect of extracts (F(4,117) = 9.20; p<0.001) and fluoride (F(1,117) = 511.55; p<0.001), with a significant interaction (F(3,117) = 6.71; p<0.001). Grape_Seed_F- showed the best protection, better than fluoride, and Sn2+/F-_Rinse. Calcium results also showed greater protection for the groups containing fluoride, whereas for rSRI, despite a significant interaction between extract and fluoride (F(3,117) = 226.05; p<0.001), the differences between the groups were not as clearly observed. We conclude that polyphenols from plant extracts, when combined with fluoride, improve the protective effect of salivary pellicles against enamel erosion

Rinsing solutions containing natural extracts and fluoride prevent enamel erosion in vitro

Polyphenols interact with salivary proteins and thus can improve the pellicle’s erosion protective properties. This effect could be exploited to create rinsing solutions with polyphenols as active ingredients for erosion prevention. Different from the current gold standard for erosion protective rinsing solutions, these rinses would not rely on stannous ions. This would offer alternatives for patients with concerns regarding the composition of rinsing solutions and preferring bio-products. Objective: To develop an erosion-preventive rinsing solution containing natural polyphenol-rich extracts. Methodology: Solutions were prepared with polyphenols from either grapeseed extract or cranberry extract, 500 ppm fluoride added, and additionally flavors and sweeteners. Controls were deionized water, 500 ppm fluoride solution, and the gold standard rinse in the field (Sn2+/F-). In total, 135 enamel specimens (n=15/group) were subjected to five cycles of salivary pellicle formation (30 min, 37°C), modification with the solutions (2 min, 25°C), further salivary pellicle formation (60 min, 37°C), and erosive challenge (1 min, 1% citric acid, pH 3.6). Relative surface microhardness (rSMH), surface reflection intensity (rSRI), and amount of calcium release (CaR) were investigated. Data were analyzed with Kruskal-Wallis and Wilcoxon rank sum tests (α=0.05). Results: The polyphenol solutions containing fluoride, as well as additional flavors, protected enamel better than fluoride alone, and similar to the Sn2+/F- solution, when investigating both rSMH and CaR. When measuring rSRI, Sn2+/F- showed the best protection, while the polyphenol solutions were similar to fluoride. Conclusion: For two of the three assessed parameters (rSMH and CaR), both developed polyphenol-rich rinsing solutions were able to protect enamel from erosion, improving/potentializing the effect of fluoride and matching the protection offered by the current gold standard rinsing solution