This thesis examines the design of a QPSK demodulator frontend for GPON transceiver at end user's side. Since lowering the cost of the terminal transceivers in an access network like GPON is a key requirement, CMOS technology is used and several area-saving design techniques are applied. The designed frontend circuit saved more than 80% area of the key components like the mixers and the QVCO than some published designs which can also fit the application. A measurement in frequency domain and a simulation in time domain verified that this frontend is able to demodulate a QPSK signal with a data rate as high as 5 Gbit/s. Two structures of quadrature oscillators are firstly presented and compared. One is an LC QVCO centered at 5 GHz, which has a tuning range of 3 GHz, a phase noise of -100.8 dBc/Hz at 1 MHz offset, and an area of 0.15 mm2 excluding pads. The other is a ring QVCO which only takes an area of 0.019 mm2. But it has a higher phase noise of -81 dBc/Hz at 1 MHz offset. Then two broadband mixers are described separately. The first one provides a high conversion gain, but its input linearity is insufficient to meet the input power requirement. The second mixer obtains required input linearity but with a trade-off of conversion gain. Both mixers have a broadband input impedance match from 2 GHz to 8 GHz. The first mixer has a conversion gain of 8.5 dB and an input 1 dB compresion point at -17 dBm. The second mixer has a conversion gain of -7 dB with an on-chip buffer or -2.1 dB without buffer, but an input 1 dB compresion point at -5 dBm. A frontend circuit is lastly presented. It integrates the compact ring QVCO, two broadband mixers with high input linearity, and two second-order LC ladder low pass filters. A Frequency domain measurement shows the expected spectrum down conversion of a 2.5 Gsym/s QPSK signal centered at 5 GHz. The whole frontend circuit including pads takes 1 mm2 area, and consumed 157 mW power. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-06-29 10:59:45.312

The goal of this thesis is to design and implement a SQL frontend for Bobox framework which is being developed by Department of software engineering MFF UK. The development of the Bobox framework is motivated by the effort to simplify writing parallel software. The Bobox framework is one of many system implementations for processing stream data and provides runtime environment for evaluating execution plans in the parallel environment. This thesis deals with implementation of a frontend for this framework. The input is a query in SQL language and information about database structure. Frontend will perform syn- tactic and semantic analysis and then translate the input query into intermediate code. The output of this frontend is the intermediate code in the form of relatio- nal algebra written as XML and is used as the input for the following optimizing backend.

I Januari 2019 så verkställdes lagen för Webbtillgänglighetsdirektivet. Detta innebär att samtliga webbplatser som inkluderas inom den offentliga sektorn ska anpassas efter särskilda riktlinjer. Webbtillgänglighetsdirektivet är en effekt av en lagstiftning från Europeiska Unionen som vill skapa en harmoniserad tillgänglighetsstandard bland dess medlemsstater. Många företag som arbetar med webbutveckling omfattas av detta direktiv men brister i deras arbetssätt på hur de ska täcka de punkter som direktivet vill att deras webbplatser ska uppnå. Därför är högst lägligt att undersöka hur företag kan få in de krav direktivet ställer i sin arbetsprocess. Att göra detta skulle gynna företag ekonomiskt men även öka tillgängligheten för alla olika typer av användare. Målet med detta arbete är att se över hur företag som är omfattade av direktivet arbetar med tillgänglighet i dagsläget samt hur direktivet kommer förändra hur de arbetar i framtiden. Utöver detta så ska arbetet undersöka hur anställda på företagen ser på tillgänglighet och om det finns en medvetenhet kring direktivet hos de personer som arbetar med webbutveckling. Arbetet ska även se över ifall det finns något verktyg som kan hjälpa företag uppfylla de krav som direktivet ställer innan en webbplats publiceras. För att besvara dessa frågeställningar genomfördes en litteraturstudie på Webbtillgänglighetsdirektivet. Efter att ha identifierat kärnan i direktivet och de riktlinjer så lades en grund att genomföra intervjuer med anställda på företag som arbetar inom webbutveckling och tillgänglighet på webb för att kunna få ta del av deras syn på tillgänglighet samt medvetenhet kring direktivet. För att sedan identifiera hur direktivet kommer påverka framtida arbeten genomfördes analyser av två webbplatser som är utvecklade efter en tidigare upplaga av de riktlinjer som ska följas enligt direktivet. Verktyget som företag ska använda resulterade i en checklista där samtliga krav som direktivet ställer finns listade. Utifrån denna checklista kan företag undvika missar av de krav direktivet ställer och därmed dra en ekonomisk vinst men även tidigare se till att alla användare kan använda webbplatsen på samma villkor.

The permeation of CMOS technology to radio frequencies and beyond has fuelled an urgent need for a diverse array of passive and active circuits that address the challenges of rapidly emerging wireless applications. While traditional analog based design approaches satisfy some applications, the stringent requirements of newly emerging applications cannot necessarily be addressed by existing design ideas and compel designers to pursue alternatives. One such alternative, an amalgamation of microwave and analog design techniques, is pursued in this work. A number of passive and active circuits have been designed using a combination of microwave and analog design techniques. For passives, the most crucial challenge to their CMOS implementation is identified as their large dimensions that are not compatible with CMOS technology. To address this issue, several design techniques – including multi-layered design and slow wave structures – are proposed and demonstrated through experimental results after being suitably tailored for CMOS technology. A number of novel passive structures - including a compact 10 GHz hairpin resonator, a broadband, low loss 25-35 GHz Lange coupler, a 25-35 GHz thin film microstrip (TFMS) ring hybrid, an array of 0.8 nH and 0.4 nH multi-layered high self resonant frequency (SRF) inductors are proposed, designed and experimentally verified. A number of active circuits are also designed and notable experimental results are presented. These include 3-10 GHz and DC-20 GHz distributed low noise amplifiers (LNA), a dual wideband Low noise amplifier and 15 GHz distributed voltage controlled oscillators (DVCO). Distributed amplifiers are identified as particularly effective in the development of wideband receiver front end sub-systems due to their gain flatness, excellent matching and high linearity. The most important challenge to the implementation of distributed amplifiers in CMOS RFICs is identified as the issue of their miniaturization. This problem is solved by using integrated multi-layered inductors instead of transmission lines to achieve over 90% size compression compared to earlier CMOS implementations. Finally, a dual wideband receiver front end sub-system is designed employing the miniaturized distributed amplifier with resonant loads and integrated with a double balanced Gilbert cell mixer to perform dual band operation. The receiver front end measured results show 15 dB conversion gain, and a 1-dB compression point of -4.1 dBm in the centre of band 1 (from 3.1 to 5.0 GHz) and -5.2 dBm in the centre of band 2 (from 5.8 to 8 GHz) with input return loss less than 10 dB throughout the two bands of operation.

The primary reason for the wireless technology evolution is towards building capacity and obtaining higher data rates. Enclosed locations, densely populated campus, indoor offices, and device-to-device communication will require radios that need to operate at data rates up to 10 Gbps. In the next few years, a new generation of communication systems would emerge to better handle the ever-increasing demand for much wider bandwidth requirements. Simultaneously, key factors such as size, cost, and energy consumption play a distinctive role towards shaping the success of future wireless technologies. In the perspective of 3GPP 5G next generation wireless communication systems, the X band was explicitly targeted with a vast range of applications in point to point radio, point to multi point radio, test equipment, sensors and future wireless communication. An X-band RF front-end circuit for next generation wireless network applications is presented in this work. It details the design of a low noise amplifier and a power amplifier for X band operation. The designed amplifiers were integrated with a wideband single-pole-double-throw switch to achieve an overall front-end structure for 10 GHz. The design was carried out and sent for fabrication using a GaN 0.15µm process provided by NRC, a novel design kit. Due to higher breakdown voltage, high power density, high efficiency, high linearity and better noise performance, GaN HEMTs are a suitable choice for future wireless communication. Thus, the assumption is to further explore capabilities of this process in front-end design for future wireless communications.

Micro Frontends är en ny mjukvarusystemarkitektur som påstås lösa många av problemen som drabbar monolitiska frontends med stora kodbaser. Den begränsade andelen forskning som undersökt konceptet har nått motsägelsefulla slutsatser kring arkitekturens effekt i praktiken. Detta är problematiskt då många företag överväger att migrera till arkitekturen men är tveksamma, vilket motiveras av den bristande kunskapen om konceptet. Denna kvantitativa studie ämnar undersöka om utvecklare som jobbar med Micro Frontends upplever dess fördelar och nackdelar genom att jämföra deras upplevelse med utvecklare som jobbar med en monolitisk frontend. Datan samlades in genom en surveyundersökning och analyserades med statistiska metoder. Resultaten av den kvantitativa analysen visade att kodduplicering samt att hålla ett UX konsekvent är problematiska aspekter vid användandet av Micro Frontends. Studiens låga svarsfrekvens gör att dessa resultat inte anses som generaliserbara. / Micro Frontends is a new software system architecture that is said to solve many of the problems that exist in monolithic frontends with large codebases. The limited amount of research that has examined the concept have reached contradictory conclusions about the effect of the architecture in practice. This is problematic as many companies are considering migrating to the Micro Frontend architecture but are hesitant, which is motivated by the lack of knowledge about the concept. This quantitative study aims to investigate whether developers working with Micro Frontends experience its theorized advantages and disadvantages by comparing their experience with developers working with a monolithic frontend. The data were collected through a survey and analyzed using statistical methods. The results of the quantitative analysis showed that code duplication and keeping a consistent UX is problematic when using Micro Frontends. The study's low response rate however means that these results are not considered generalizable.

This thesis contains present trends in frontend web development. On the basis of this, there is made web application which is responsive a it is usable on mobile devices. In the theoretical part, there are described news and present trends of frontend web development and in the practical part, there is described whole process, which contains design, development, testing and deployment. This thesis could be very useful for beginners in the subject.

The objective of this study has been to investigate and compare frontend javascript frameworks and cloud services in order to find which ones are most suitable to implement a web based product development application. The application will be based on the "House of Quality" methodology, which is commonly used in product development. It is basically a way to organize customer requirements, identify relevant quantifiable technical parameters and rank them in order to find out which ones are most important for the finished product. By using this very methodology on the application itself, the most important parameters were found to be data update delays and the need for additional services. The selected cloud services were benchmarked according to these parameters. For framework comparison, the methodology was based on existing research regarding what developers actually base their selection of frontend javascript frameworks on, which resulted in the metrics maturity, community size and documentation. SQL queries and benchmarking scripts were constructed in order to gather statistics from online services and run performance benchmarks. The results reveal substantial differences between frameworks as well as in performance among cloud services. A combination of the frontend framework Angular, the backend service Firebase and the authentication service Auth0 were found to be well suited for fulfilling the requirements of the product development application. Finally, potential problems, ethical considerations and areas where more research is required are discussed.

Webbens centrala position i det moderna informationssamhället kan svårligen ifrågasättas. Men övergången till ett digitalt informationssamhälle kan också innebära problem för en grupp människor i samhället. I takt med webbens tilltagande inflytande i samhället ökar den demokratiska betydelsen av att innehållet är tillgängligt för alla som vill ta del av det, oavsett fysiska och kognitiva förutsättningar. För att underlätta för personer med funktionsnedsättningar att använda internet växte begreppet webbtillgänglighet fram. Trots ämnets ökade relevans har studier konstaterat att webben av idag är behäftad med stora tillgänglighetsbarriärer. Webbutvecklare är dem yrkeskategori som har störst inflytande över webbplatsers tekniska utformning och således ett starkt inflytande över webbens tillgänglighet. Den här studien undersöker varför professionella webbutvecklare inte efterlever standarder och inte skapar tillgängliga webbplatser – trots att en rad uppsättning riktlinjer och verktyg finns tillhands för att åstadkomma detta. Studien följer en interpretativ forskningsansats och bygger på semi-strukturerade intervjuer med fem professionella webbutvecklare. Ett av studiens grundläggande slutsatser är att webbtillgänglighet idag ofta är nedprioriterad aspekt som endast beaktas explicit om beställaren efterfrågar detta. Ett hinder utvecklare möter i arbetet med att skapa tillgängliga webbplatser är således brist på efterfrågan från beställare vilket i sin tur ger begränsade tids- och budgetresurser och affärsmässiga incitament. I de fall där tillgänglighet efterfrågas görs det nästan uteslutande av företrädare från offentliga organisationer vars regelmässiga kontext kräver det. I dessa sammanhang kan otydliga riktlinjer samt otillräckliga kunskaper vara en faktorer som försvårar arbetet med tillgänglighet. WCAG-riktlinjer upplevs av webbutvecklare som alltför omfattande och omoderna vilket medför att riktlinjerna inte fungerar som den stödjande resurs som är avsikten. Dessutom verkar det råda förvirring kring vad som definierar god tillgänglighet och hur en webbplats tillgänglighet ska utvärderas. Avsaknaden av moderna och lättillgängliga riktlinjer tillsammans med tydligt definierade mätpunkter och tillhörande utvärderingsverktyg är ett hinder för utvecklare i arbetet med webbtillgänglighet.

Radio-frequency (RF) switches are widely used in electrical systems, telecommunications, and wireless applications. In RF systems, it is often desirable to change the signal path effectively, by us-ing couplers, duplexers, and RF switches for signal division and combining. Typically, in modern RF systems, the RF switch is mostly capitalized in order to reduce the RF footprint but with efficient switch characteristics. A simple method to reduce transceiver space requirement is to integrate RF switches with the frontend module on a single chip. Recent advances in Gallium Nitride (GaN) technology allows RF designers to design faster, smaller, and efficient components using this technology. With high data rates in demand for wireless communication systems, wideband characteristics are needed in modern systems [1]. Therefore, it is desirable to design wideband circuits; such as, mixers, amplifiers, and switches. In this work, a comprehensive study of NRC GaN150 HEMT is conducted to design broadband RF switches. Single pole and double pole switch topologies operating at 1-12 GHz are designed to evaluate GaN 0.15μm RF switches. The main objectives were to design compact sized switches, while having high power handling, low insertion loss, high isolation and high return loss. Additionally, a transmit-receive switch is designed for integration into a frontend module and further fabricated to operate at 10 GHz. There are many applications of RF switches in an RF transceiver, one of which is an impedance tuner. Impedance tuner are attractive for many applications where mobile devices are used for wireless communications. As mobile technology continues to evolve, they are designed to be com-pact, leaving minimal space for the antenna. Consequently, the radiating element is often electrically small and sensitive to near-field coupling requiring tuning. Matching networks aim to tune matching conditions; for example, loading effects due to human hand [2]. For such situations, specialized matching networks can be designed to account for specific loading environmental effects. However, for mobile systems, the environment is unknown; thereby, yielding unpredictable antenna loading, especially for electrically small antennas that have rapidly changing real and imaginary impedance. As a result, it is necessary to design a reconfigurable impedance-matching network to account for possible load impedances. In this work, a 16-bit reconfigurable impedance tuner design comprising of passive microwave components and NRC GaN 0.15μm FET operating at X-band is presented to evaluate its performance for integration with the frontend module on a single chip to reduce cost and increase efficiency of the system.