This text is documentation for multi-access system, which supports recoverable materials. It deals with structure possibilities according to functional system specification and its implementation through the PHP together with using MySQL database system. It analyses a progress of system creation from ER diagram through use-case diagram to programming itself. This work shows how to design web advertisement system which enables an user to define personal multi-level views on data. This project might have been as basis for commerce project, which can check up usability designed structure of individual parts.

This work is focused on building a content management system for municipal websites. It compares some proprietary and open source systems. Moreover, it aims to create a new content management sys­tem for little-municipal websites. The system is created with a use of PHP script language and MySQL database system. The final application runs on Apache and MySQL servers. This project allows the municipal units to create their own websites easily and quickly. They can define both the structure and the content of the pages. The project is designed to be multi-user. It puts great emphasis on the easiness of use and the blind-friendliness.

Dataflow systems have become the norm for developing data-intensive computing applications. These systems provide transparent scalability and fault tolerance. For fault tolerance, many dataflow-system adopt a snapshotting approach which persists the state of an operator once it has received a snapshot marker on all its input channels. This approach requires channels to be blocked for potentially prolonged durations until all other input channels have received their markers to guarantee that no events from the future make it into the operator’s present state snapshot. Alignment can for this reason have a severe performance impact. In particular, for black-box user-defined operators, the system has no knowledge about how events from different channels affect the operator’s state. Thus, the system must conservatively assume that all events affect the same state and align all channels. In this thesis, we argue that alignment between two channels is unnecessary if messages from those channels are not written to the same output channel. We propose a snapshotting approach for the fault tolerance and call it partial approach. The partial approach does not require alignment when an operator’s input channels are independent. Two input channels are independent if their events do not affect the same state and are never written to the same output channel. We propose the use of static code analysis to identify such dependencies. To enable this analysis, we translate operators into finite state machines that make the operator’s state explicit. As a proof of concept, we extend the implementation of Arc-Lang, an existing dataflow language, so that applications written in it transparently execute with fault tolerance. We evaluate our approach by comparing it to a baseline eager approach that always requires alignment between the input channels. The conducted experiments’ results show that the partial approach performs about 47 % better than the eager approach when the streaming sources are producing data at different velocities. / Dataflödessystem har blivit normen för utveckling av dataintensiva datorapplikationer. Dessa system erbjuder transparent skalbarhet och felhantering. För felhantering adopterar många dataflödessystem en snapshot-approach som sparar en operatörs tillstånd när den har fått en snapshot-markör på alla sina ingångskanaler. Denna metod kräver att kanalerna blockeras under möjligen förlängda tidsperioder tills alla andra ingångskanaler har fått sina markörer, vilket görs för att garantera att inga händelser från framtiden når operatörens nuvarande tillstånd. Synkronisering mellan kanaler kan därför ha en allvarlig prestandapåverkan. Särskilt för black-box användardefinierade operatörer där systemet inte har kunskap om hur händelser från olika kanaler påverkar operatörens tillstånd. Systemet måste därför konservativt anta att alla händelser påverkar samma tillstånd och synkronisera alla kanaler. I denna avhandling argumenterar vi för att synkroniseringen mellan två kanaler inte är nödvändig om meddelanden från de kanalerna inte skrivs till samma utgångskanal. Vi föreslår en snapshot-approach för felhantering och kallar den för partial-approach. Partial-approach kräver inte justering när en operatörs ingångskanaler är oberoende. Två ingångskanaler är oberoende om deras händelser inte påverkar samma tillstånd och aldrig skrivs till samma utgångskanal. Vi föreslår användning av statisk kodanalys för att identifiera sådana beroenden. För att möjliggöra denna analys översätter vi operatörer till finite state machines som gör operatörens tillstånd explicit. För att bevisa konceptet utökar vi implementeringen av Arc-Lang, vilket är en existerande dataflödesspråk, så att program skrivna i den transparent körs med felhantering. Vi utvärderar vår approach genom att jämföra den med en baseline eager-approach som alltid kräver justering mellan ingångskanalerna. Resultaten från de genomförda experimenten visar att partial-approach presterar cirka 47 % bättre än eager-approach när sourcestreams producerar data i otakt.

Interactive visualization is an essential tool for data analysis. Cloud-based data analysis software must handle growing data sets without relying on powerful end-user hardware. This thesis explores and tests various methods to speed up primarily time series plots of large data sets on the web for the biotechnology research company Sartorius. To increase rendering speed, I focused on two main approaches: downsampling and hardware acceleration. To find which sampling algorithms suit Sartorius's needs, I implemented multiple alternatives and compared them quantitatively and qualitatively. The results show that downsampling increases or eliminates data set size limits and that test users favored algorithms maintaining local outliers. With hardware acceleration that substantially increased the amount of simultaneously rendered points for more detailed representations, these methods pave the way for efficient visualization of large data sets on the web.

Artifact-based research provides a mechanism whereby researchers may study the creation of software yet avoid many of the difficulties of direct observation and experimentation. Open source software forges are of great value to the software researcher, because they expose many of the artifacts of software development. However, many challenges affect the quality of artifact-based studies, especially those studies examining software evolution. This thesis addresses one of these threats: the presence of very large commits, which we refer to as "Cliff Walls." Cliff walls are a threat to studies of software evolution because they do not appear to represent incremental development. In this thesis we demonstrate the existence of cliff walls in open source software projects and discuss the threats they present. We also seek to identify key causes of these monolithic commits, and begin to explore ways that researchers can mitigate the threats of cliff walls.

Serverless computing and Function-as-a-Service are rising in popularity due to their ease of use, provided scalability and cost-efficient billing model. One such platform is Apache Flink Stateful Functions. It allows application developers to run serverless functions with state that is persisted using the underlying stream processing engine Apache Flink. Stateful Functions use an embedded RocksDB state backend, where state is stored locally at each worker. One downside of this architecture is that state is lost if a worker fails. To recover, a recent snapshot of the state is fetched from a persistent file system. This can be a costly operation if the size of the state is large. In this thesis, we designed and developed a new decoupled state backend for Apache Flink Stateful Functions, with the goal of increasing availability while measuring potential performance trade-offs. It extends an existing decoupled state backend for Flink, FlinkNDB, to support the operations of Stateful Functions. FlinkNDB stores state in a separate highly available database, RonDB, instead of locally at the worker nodes. This allows for fast recovery as large state does not have to be transferred between nodes. Two new recovery methods were developed, eager and lazy recovery. The results show that lazy recovery can decrease recovery time by up to 60% compared to RocksDB when the state is large. Eager recovery did not provide any recovery time improvements. The measured performance was similar between RocksDB and FlinkNDB. Checkpointing times in FlinkNDB were however longer, which cause short periodic performance degradation. The evaluation of FlinkNDB suggests that decoupled state can be used to improve availability, but that there might be performance deficits included. The proposed solution could thus be a viable option for applications with high requirements of availability and lower performance requirements. / Serverlös datorberäkning och Function-as-a-Service (FaaS) ökar i popularitet på grund av dess enkelhet att använda, skalbarhet och kostnadseffektiva fakturerings-model. En sådan platform är Apache Flink Stateful Functions. Den tillåter applikationsutvecklare att köra serverlösa funktioner med varaktigt tillstånd genom den underliggande strömprocesseringsmotorn Apache Flink. Stateful Functions använder en inbyggd RocksDB tillståndslagring, där tillstånd lagras lokalt på arbetarnoderna. Ett problem med denna arkitektur är att tillstånd förloras om en arbetarnod krashar. För att återhämta sig behöver systemet hämta en tidigare sparad tillståndskopia från ett varaktivt filsystem, vilket kan bli kostsamt om tillståndet är stort. I denna uppsatts har vi designat och utvecklat en ny prototyp för att separat hantera tillstånd i Apache Flink Stateful Functions, med målet att öka tillgängligheten utan att förlora prestanda. Prototypen är en vidareutveckling av en existerande separat tillståndshantering för Flink, FlinkNDB, som utökades för att kunna hantera Stateful Functions. FlinkNDB sparar tillstånd i en separat högtillgänglig database, RonDB, istället för att spara tillstånd lokalt på arbetarnoderna. Detta möjliggör snabb återhämtning då inte stora mängder tillstånd behöver skickas mellan noder. Två återhämtningsmetoder utvecklades, ivrig och lat återhämtning. Resultaten visar att lat återhämtning kan sänka återhämtningstiden med upp till 60% jämfört med RocksDB då tillståndet är stort. Ivrig återhämtning visade inte några förbättringar i återhämtningstid. Prestandan var liknande mellan RocksDB och FlinkNDB. Tiden för checkpoints var däremot längre för FlinkNDB vilket orsakade korta periodiska prestandadegraderingar jämfört med RocksDB. Evalueringen av FlinkNDB föreslår att separat tillståndshantering kan öka tillgängligheten av Stateful Functions, men att detta kan innebära vissa prestanda degraderingar. Den föreslagna lösningen kan således vara ett bra alternativ när det finns höga krav på tillgänglighet, men lågra krav på prestanda.

Fatigue-crack growth data for the lower arm of the Apache helicopter’s scissor assembly is presented from an Army alternate source qualification test. The lower arm model is imported to finite element analysis software to obtain the stress state at a crack location. The stress state and geometry are used in seven fatigue-crack growth cases in NASGRO and AFGROW, with an additional four cases discussed briefly. The results from the fatigue-crack growth routines are compared to the fatigue-crack growth data from the Army’s test. One case reproduces the crack growth data prior to breakthrough. Some cases are shown to be more applicable to this configuration than others are. The process of performing fatigue life estimates is discussed. Suggestions are made on the viability of this approach and possible future avenues for development.

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El presente trabajo tiene como objetivo explicar cómo funciona la tecnología Server-Side Scripting en la generación de páginas web dinámicas, desarrollando dos versiones de un intérprete basado en las reglas del lenguaje Pascal. La primera de estas versiones corre como un módulo DSO (Dynamic Shared Object) integrada al servidor Apache, mientras que la segunda es un intérprete independiente que genera las páginas dinámicamente interactuando con el servidor Apache vía CGI.