Sedan smarta mobiltelefoner introducerades har användningen och likaså behovet av mobilapplikationer ökat exponentiellt. När utvecklingsprocessen för en mobilapplikation påbörjas måste en utvecklare utvärdera ett antal faktorer som kan påverka mobilapplikationens användning eller prestanda, till exempel utvecklingsplattform som denna studie fokuserar på. Syftet med denna studie är att fastställa prestandaskillnaderna för native Android och Xamarin cross-compile med hjälp av en experimentell studie. Tesen för denna studie är baserad på tidigare forskning som tyder på att cross-platform och Xamarin cross-compile har sämre prestanda än native Android, resultatet av denna studie kan bidra till valet av utvecklingsplattform för utvecklare. Avgränsningar har valts i form av Android som plattform, exekveringstid, CPU-användning samt RAM-användning för prestandamätning. Beräkningar som utförs är iterativ bubble sort i form av best case, worst case och random case med varierande antal nummer och en rekursiv Fibonaccisekvens med olika utgångspunkter. Resultatet av denna studie stämmer överens med tesen, Xamarin har i dagsläget sämre prestanda än native Android. / Throughout the last decade the mobile phone market has grown rapidly and with it, the need for mobile applications has grown as well. When the development process for a mobile application starts, a developer must review various factors that can affect the mobile applications usage or performance, for example the development platform to use which is the focus of this study. The purpose of this study is to determine the difference in performance between native Android and Xamarin cross-compile with the use of an experimental study. The hypothesis of this study is based on previous research which shows that cross-platform and Xamarin cross-compile have worse performance than native Android, the result of this study can contribute can help a developer make the decision on what development platform to choose. The delimitations have been chosen as Android as platform, execution time, CPU-usage and RAM-usage for performance testing. The algorithms that were chosen were an iterative bubble sort, in form of best case, worst case and random case with varying numbers, and a recursive Fibonacci sequence with different starting points. The result of this study is consistent with the hypothesis, Xamarin shows worse performance than native Android.

Web applications are often described as being cross-platform. They are accessible from a multitude of different web browsers, which in turn are running on a multitude of different operating systems. For a time now, developers have used many different tools to create cross-platform applications for mobile devices with web technologies. However, these applications fail to deliver when taken out of their native environment, and often do not feel native at all. Enter Progressive Web Applications, PWA. PWA’s are applications written for the web with web technologies, running in a browser,  but seasoned with some techniques that can make them behave like a native application when running on a mobile device. They are just ordinary web applications with native behaviour such as offline support, installability, and push notifications. The question that arises is - can this new type of web applications match Native Android Applications in performance, especially the response time when accessing the device's hardware? This report will try to answer that question

This master's thesis deals with face detection on mobile phones with Android OS. The introduction describes some algorithms used for pattern detection from image, as well as various techniques of features extracting. After that Android platform development specifics, including basic description of development tools, are described. Architecture of SIMD is introduced in next part of this work. After acquiring basic knowleage analysis and implementation of final app are descrited. Performance tests are conducted whose results are summarized in the conclusion.