Since the end of World War II the Importance of the teen-age market has steadily grown. An article by Grace and Fred Hechinqer (10) In the 1961 New York Times Magazine substantiates this statement: "the young slowly are capturing an ever-growing share of the nation's market, both through their own purchasing power, and through effective dictation to parents . "

abstract: Emerging from years of research and development, the Internet-of-Things (IoT) has finally paved its way into our daily lives. From smart home to Industry 4.0, IoT has been fundamentally transforming numerous domains with its unique superpower of interconnecting world-wide devices. However, the capability of IoT is largely constrained by the limited resources it can employ in various application scenarios, including computing power, network resource, dedicated hardware, etc. The situation is further exacerbated by the stringent quality-of-service (QoS) requirements of many IoT applications, such as delay, bandwidth, security, reliability, and more. This mismatch in resources and demands has greatly hindered the deployment and utilization of IoT services in many resource-intense and QoS-sensitive scenarios like autonomous driving and virtual reality. I believe that the resource issue in IoT will persist in the near future due to technological, economic and environmental factors. In this dissertation, I seek to address this issue by means of smart resource allocation. I propose mathematical models to formally describe various resource constraints and application scenarios in IoT. Based on these, I design smart resource allocation algorithms and protocols to maximize the system performance in face of resource restrictions. Different aspects are tackled, including networking, security, and economics of the entire IoT ecosystem. For different problems, different algorithmic solutions are devised, including optimal algorithms, provable approximation algorithms, and distributed protocols. The solutions are validated with rigorous theoretical analysis and/or extensive simulation experiments. / Dissertation/Thesis / Doctoral Dissertation Computer Science 2019

In order to achieve a cashless society, many countries have started to use electronic payment methods and tools to replace traditional payment methods. China and Sweden already have mature electronic payment tools, Swish, and Alipay. In this research, a phenomenological approach was used to interview users comparing two electronic payment tools, the Chinese Alipay and the Swedish Swish. The analysis of the respondents’ answers shows that convenience, security, and cost of electronic payment tools are the most important aspects to them, which is in line with previous research on acceptance, adoption and use of new technology, not only electronic payment tools. Convenience and security were more important. However, too much convenience will affect the interviewees' trust in electronic payment tools because it will make interviewees feel unsafe. Respondents' trust is affected by their own acquaintance; they trust electronic payment tools they know better.

The purpose of the presented dissertation thesis is to contribute to the development of the theory of electronic commerce in complex conditions of „network economy“ by the partial consolidation and integration of the highly fragmented existing knowledge and ideas, i.e. to offer more compact conceptual framework, based on research of the current state of knowledge and situation in the conditions of the Czech Republic. The thesis is focused on the contemporary theoretical knowledge analysis from the areas of interest concerning the electronic commerce security, used models of electronic shops and evaluation of its economic aspects, which this type of business bears. Next contribution is unification of this knowledge and creation of the conceptual base for the ongoing recognition and theory building related to electronic commerce. The work is also focused on the area of electronic cash, possible solution of some diversifications in payment transactions. On the practical level the author attempted to narrow the knowledge “gap” in the empirical cognition of the doctoral thesis issues concerning the effectiveness of electronic commerce and generally e-commerce applications. Proposed return on investment calculation methodology applied to e-commerce area may help managers making decisions in investing to these projects.

Mobile banking is a feature bringing customer transactions to the doorstep of mobile users by sitting at home. As the demand for mobile payment applications has increased, numerous payment applications are developed throughout the world. Every payment gateway must have certain customer acceptable conditions, usability is one such condition wherein every mobile payment application must fulfill the condition of user friendly with easily understandable features to the customer. Usability is guided by certain well-defined principles, for the optimum benefit of the user. Many researchers have worked on mobile payment applications but there are limited studies on usability comparison of payment gateways. Hence, an attempt is made in the present study to understand the two applications in two different socio-cultural contexts of Indian and Swedish societies, viz., Google Pay and PayPal respectively, on usability principles. The present study is designed with the objectives to analyze and compare satisfaction on Nielsen’s heuristic principles of PayPal and Google Pay payment users, and to the understanding association between satisfaction on Nielsen’s heuristic principles and various independent variables. A survey questionnaire, called “Personal Attitude Inventory for Measurement of satisfaction on Heuristic Principles” was developed to measure the satisfaction of users on heuristic principles of Nielsen of PayPal and Google Pay users. The validity and reliability of the questionnaire are established. The questionnaire is administered to 36 subjects, 18 subjects who are using Google Pay are drawn from India, and the other 18 subjects, using PayPal, are drawn from Sweden. Student t-tests and chi-squared tests are used to analyze the data. Significant differences are not found between PayPal and Google Pay users on the overall heuristic principles of Nielsen, and also on each of the 10 heuristic principles of Nielsen. It is inferred that both PayPal and Google Pay users are comparable on all heuristic principles. Majority of the users of these payment gateways have more satisfaction on all 10 heuristic principles. Results of the study further revealed no association between socio-demographic independent variables like age, gender, and different types of users of PayPal and Google Pay and satisfaction on heuristic principles. These two payment gateways have more or less equivalent features, facilitating similar perceptions and satisfaction levels on heuristic usability principles of Swedish and Indian samples. Several views are put forth for further research.

Payment Channel Networks (PCNs) provide a solution to the scalability problem in blockchain technology. They facilitate multiple-hop transactions via payment channels between peers, allowing for the execution of several transactions before updating each node’s balance on the blockchain. However, the performance of the network in effectively routing payments is affected by unbalanced channels. This imbalance reduces the network’s ability to route payments in both directions within a channel, resulting in decreased overall performance. Previous research has identified unidirectional payment flows in the network as the underlying cause of this issue. The payment flow is based on the demand for payments between peers and the paths these payments take. The aim of this study is to investigate the relationship between payment patterns and the average channel imbalance, where the payment pattern is a combination of demand patterns and what pathfinding algorithm is used. The study uses a model of PCNs that allows the relationship of the variables of interest to be measured, while other impacting variables are controlled. A deterministic value of the average channel imbalance for a PCN topology, demand pattern, and pathfinding strategy is achieved by computing the steady-state imbalance. The results show that the less homogeneous the demand pattern is, the more asymmetric the payment flow becomes, and the more imbalanced the network’s channels become. The results confirm what previous research mentions: unidirectional flow causes the payment channel to become imbalanced. The demand pattern that generates unidirectional flow imbalance significantly affects the entire network, regardless of the pathfinding strategy employed. Even with the possibility of a pathfinding strategy influencing payment flow to make it less unidirectional, the inherent unbalanced nature of the demand pattern remains a considerable challenge. The results also show that the pathfinding strategy has a less significant impact than the demand pattern on the balance of the network over time. / Payment Channel Networks (PCN) tillåter fler transaktioner utföras på kortare tid för en mindre kostnad, än att publicera varje enskild transaktion direkt på blockkedja och är en bra lösning på skalbarhetsroblem kopplat till blockedjor som baseras på proof-of-work. PCNs möjliggör för flerhoppstransaktioner via noder som kan vidarebefodra flera betalningar på varje enskild betalningskanal de håller öppna med andra noder. Inte förrän en kanal stängs publiceras den senaste uppdateringen av saldot för enskild betalningskanal på blockkedjan. Trots detta lider nätverkets prestanda av att kanaler blir obalanserade och ökar risken för att transaktioner misslyckas routas. Tidigare forskning nämner att orsaken till att kanaler blir obalanserade är enriktade betalningsflöden i nätverket, vilket beror av betalningsflödet som är en kombination av betalningsefterfråga (vem vill betala vem) mellan noderna och vilka vägar som dessa betalningar tar. Syftet med denna studie är att undersöka sambandet mellan betalmönster och genomsnittlig kanalobalans, där betalmönstret är en kombination av efterfrågansmönster och vägvalsstrategier. Studien använder en PCN-modell som möjliggör att undersöka sambandet mellan de variabler som är tänkt ska mätas, samtidigt som andra variabler kan kontrolleras. Genom att beräkna den stabila obalansen uppnås ett deterministiskt värde för genomsnittlig kanalobalans i varje nätverkstopologi. Resultaten visar att ju mindre homogent efterfrågemönstret är, desto mer asymmetriskt blir betalningsflödet och desto mer obalanserade blir nätverkets kanaler. Resultatet bekräftar det som tidigare forskning nämner: enriktade flöden orsakar obalans i betalningskanalen. Specifikt är det efterfrågansmönstern som skapar enriktade flöden som har de högsta stabila obalansen, oavsett vilken vägvalsstrategi som används. Resultaten visar också att vägvalsstrategin har mindre betydelse än efterfrågemönstret, åtminstone för vägvalsstrategier som leder till liknande valda vägar.

[pt] Ao menos desde 1916, a quitação é um instituto típico do Direito Privado brasileiro. Mas é certo que, muito antes disso, a quitação já era um instrumento socialmente típico e de absoluta relevância, com presença marcante no tráfico negocial. Apesar da sua importância prática, o instituto da quitação carece de trabalhos monográficos específicos a seu respeito. E custa caro aos tribunais brasileiros a inexistência de um estudo dedicado à sistematização do instituto e ao estabelecimento de parâmetros interpretativos para as situações em que o alcance da eficácia da quitação é objeto de controvérsia. Somente na Segunda Seção do Superior Tribunal de Justiça – órgão fracionário de elevada hierarquia dentro da Corte nacional que tem exatamente a função de uniformizar a jurisprudência – há entendimentos conflitantes sobre a interpretação da quitação que geram insegurança e incerteza ao jurisdicionado quanto aos critérios a serem analisados pelo intérprete para autorizar ou não a investida judicial para ver complementada uma obrigação já anteriormente quitada. Nesse cenário, com o objetivo de, em alguma medida, preencher tal lacuna doutrinária, este trabalho analisará o instituto da quitação de forma sistematizada à luz da legislação brasileira, abordará o seu perfil funcional, examinará precedentes do Superior Tribunal de Justiça que revelam séria divergência e buscará oferecer parâmetros interpretativos para os impasses a respeito do alcance da quitação. / [en] At least since 1916, the discharge is a typical institute of Brazilian Private Law. However, it is certain that, long before that, discharge was already a relevant and socially typical instrument, continuously present in business traffic. Despite its practical importance, the discharge institute lacks specific monographic works about it. And it is costly to the Brazilian courts that there is no study dedicated to systematizing the institute and establishing interpretative parameters for situations in which the scope of the effectiveness of the discharge is a controversial topic. For example, in the Second Section of the Brazilian Superior Court of Justice – a hierarchically high part within the national Court that has the exact function of standardizing the jurisprudence – there are conflicting understandings on the interpretation of the discharge that create insecurity and uncertainty for the person subject to its jurisdiction related to the criteria to be analyzed by the interpreter in order to authorize or not the judicial onslaught to see a previously settled obligation complemented. In this scenario, with the objective of, to some extent, filling this doctrinal gap, this work will analyze the institute of discharge in a systematized way in light of the Brazilian law system, address its functional profile, examine precedents of the Superior Court of Justice representing serious divergence and seek to offer interpretative parameters for certain impasses regarding the scope of the discharge.

Betalsystemet är en av de viktigaste delarna vi har i den finansiella infrastrukturen, störningar i systemet skulle snabbt kunna leda till allvarliga konsekvenser för både individen, företagen och samhället i stort. Syftet med studien är att ge inblick i hur beredskapen ser ut idag, att hantera dessa störningar. Vidare syftar studien till att reda i vilka åtgärder som behövs för att säkerställa betalsystemets funktion vid en allvarlig störning, där digitala betalmetoder inte är fungerande. För att utföra studien har en kvalitativ metod använts, underlaget för studien har varit intervjuer med sju sakkunniga personer från Finansinspektionen, Riksbanken, Swedbank, Bankomat AB, Regeringskansliet, MSB och Bankgirot. Detta i kombination med relevant teori. Av resultatet kan vi se att genom att skapa en starkare motståndskraft och bättre förmåga för systemen att återhämta sig, blir samhället mer förberett på hanteringen av en framtida kris. Vidare framgår det att samhället inte skulle klara av ett längre avbrott i betalsystemet i dagsläget. Det blir också tydligt att bristande rutiner och en oklar fördelning av ansvaret leder till ett instabilt betalsystem i ett krisläge. Det är oklart vem som står för kostnaderna, om aktörer och myndigheter behöver rusta upp sina system, men detta förväntas bli tydligare i samband med ny kommande lagstiftning. För att säkerställa ett fungerande betalsystem både i ett krisläge och i ett normalläge, behövs ett mer robust system, med tydligare rutiner och ansvarsfördelning. / The payment system is one of the most important functions in our society’s financial infrastructure. Disruptions in the system would rapidly lead to serious consequences for individuals, businesses, and society as a whole. The purpose of the thesis is to provide a better understanding of what the emergency preparedness process looks like in dealing with mentioned disruptions, what actions are needed, and how the different actors address the issue and what risks society faces in the event of prolonged interruptions in the payment system. The study was conducted using a qualitative method, with interviews with seven experts from Finansinspektionen, Riksbanken, Swedbank, Bankomat AB, Government Offices of Sweden, The Swedish Civil Contingencies Agency and Bankgirot as the primary foundation and combining this with the relevant theory. Conclusions that can be drawn are that by strengthening the resilience and preparing society we give our systems a better ability to recover from a future crisis in our payment systems. Furthermore, that the society would not manage to retain control of the payment system in case of extensive disruption. It also became clear that insufficient routines and an indistinct division of responsibilities, lead to an unstable payment system in the event of a crisis. At this time, it is not clear who would pay the costs, if actors and authorities need to enhance their payment systems, but this uncertainty is intended to diminish with forthcoming new legislation. To ensure a functioning payment system in both a crisis and a normal situation, a sturdier system is required, with adequate routines and a division of responsibilities.

When entering the age of information technology, cash payments were slowly been replaced by other methods including credit cards and online payment applications. On one hand, it brings convenience, on the other hand, people potentially spend more money than before. Previous researchers suggest multiple ways to reduce the overspending behavior on credit card payments, but rarely have these methods been tested in an online payment solution context. This study adopted these methods and categorized them into two groups, visual cues, and financial management mechanics. These two groups of the solution then been translated and develop into three practical prototypes, two of each and one prototype having two groups combined. All prototypes are developed based on a commonly used online payment application named Swish in Sweden. These prototypes are later been tested by ten participants. The results show both groups of solutions have a positive influence to reduce users’ overspending behavior and having them combined provides further complement effects. The study provides empirical data and practical design implications in addressing the overspending issue of an online payment solution.

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