Beyond Just Money Transactions: Redesigning Digital Peer-to-Peer Payments for Social Connections

Financial activities, such as the exchange of money between individuals, have long been considered a crucial aspect of how people build and maintain their interpersonal relationships (i.e., a strong, deep, or close association/acquaintance between two or more people) with individuals they know because money is a sensitive social construct. In particular, over the past decade, how to conduct, manage, and experience money exchanges and processes between individuals has been dramatically transformed due to the increasing popularity of digital peer-to-peer (P2P) payment services (i.e., performing one to one online money transactions via a digital device). In this sense, digital P2P payments have shown the potential to affect how people pay and interact with each other regarding money, an important impact factor on various forms of interpersonal relationships, by facilitating direct money transactions between individuals through computer-mediated channels. Therefore, this dissertation research is motivated to leverage a sociotechnical approach to conduct an in-depth investigation of the nuanced human experiences of personal money exchanges mediated by digital P2P payments between people who know each other and the unique role of digital P2P payments in shaping these individuals\u27 social connections with each other online and offline. In doing so, this dissertation research aims to (i) reveal and elaborate the multidimensional influences of digital P2P payments on interpersonal relationships between people who already know each other in terms of both experiences of money exchanges and everyday social interactions; ii) advance our knowledge and understanding of how digital P2P payments systems can be redesigned to better support people\u27s social connections with individuals they know; and iii) envision the future landscape of digital P2P payments in our increasingly networked digital society. This dissertation research involves four studies. Grounded in 158 social media posts and 8 interviews, Study 1 explores how people perceive the increasing trend of integrating digital P2P payments with social media services (e.g., Facebook Messenger payment) and why they decide not to use this service in their daily lives. Study 2 reports findings of a qualitative study of 31 in-depth semi-structured interviews to investigate the influences of using digital P2P payments on people\u27s offline interpersonal relationships. Study 3 reports results of a large-scale anonymous online survey with 218 valid responses to measure the specific immediate social consequences and lasting impacts of using digital P2P payments on people\u27s interpersonal relationships. Study 4 adopts the research through design (RtD) approach with a specific emphasis on participatory design activities to both elicit and qualitatively investigate user needs and user-generated design solutions for digital P2P payment services that can better support people\u27s social connections. This dissertation research thus contributes to innovating financial technologies in the perspective of Human-Computer Interaction and Human-Centered Computing by better understanding new and more complicated social phenomena and dynamics emerging in today\u27s digital economy. First, this dissertation research offers one of the first empirical evidence to unpack and explicate the multidimensional influences of digital P2P payments on both financial experiences/processes and everyday social connections between known contacts, which is understudied in prior scholarship. In doing so, we provide new perspectives on today\u27s technology-mediated financial life and shed light on the intertwining financial and social relationships through technology. These insights also help re-conceptualize computer-mediated interpersonal relationships in today\u27s networked society. Second, we identify and further reflect on user-generated design recommendations and develop prototypes that highlight the importance of taking the interplay of financial and social engagement, in addition to security and privacy, into consideration when redesigning digital P2P payments platforms. Through this RtD approach, we thus rethink and envision the future landscape of digital P2P payments where such technologies can be designed, developed, and used in a more comfortable, innovative, and emotionally satisfactory way. As we are entering a post COVID-19 pandemic age, there is an increasing interest to make digital financial technologies not only secure but also more human-centered, interaction-centric, and culturally sensitive, which can be used to better support and maintain human connections through daily financial activities with or without face-to-face interaction. Therefore, in a broader sense, this dissertation research on the social values of digital P2P payments also contributes to building a more robust and inclusive digital economy in today\u27s changing society

Collaboration, Dedication, and Social Pressure: A Comparative Analysis of Virtual and Face-to-Face Game Jams

Game jams are virtual or face-to-face events where game developers (often non-professional or hobbyist) collaborate to make digital games within a limited time frame. As these events have become not only game-creation events but also social collaboration spaces, important questions emerge regarding how exactly different modes of game jams can offer different affordances for developers’ social collaboration. Using 24 semi-structured interviews, we provide a comparative analysis of virtual and face-to-face game jams, especially with regard to the different technological processes and social engagement in each mode of game jams. We contribute to the game jam community by highlighting game jams as novel social collaboration spaces and by providing empirical evidence of the unique affordances of different modes of game jams for social collaboration

Escaping from Consensus: Instantly Redactable Blockchain Protocols in Permissionless Setting

Blockchain technologies have received a great amount of attention, and its immutability is paramount to facilitate certain applications requiring persistent records. However, in many other use-cases, tremendous real-world incidents have exposed the harm of strict immutability. For example, illicit data stored in immutable blockchain poses numerous challenges for law enforcement agencies such as Interpol, and millions of dollars are lost due to the vulnerabilities of immutable smart contract. Moreover, ``Right to be Forgotten (a.k.a. data erasure) has been imposed in new European Union\u27s General Data Protection Regulation, thus causing immutable blockchains no longer compatible with personal data. Therefore, it is imperative (even legally required) to design efficient redactable blockchain protocols in a controlled way. In this paper, we propose a new redaction strategy to decouple the voting stage for redaction from the underlying consensus layer, where a committee with sufficient honest fraction is selected firstly and then the committee members would vote for the redaction. Based on this new strategy, we present a generic approach of designing redactable blockchain protocol in the permissionless setting with instant redaction, applied to both proof-of-stake (PoS) blockchain and proof-of-work (PoW) blockchain with just different instantiations to randomly select ``committee members\u27\u27 according to stake or computational power. Our protocol can maintain the same adversary bound requirements and security assumption as the underlying blockchain (e.g., 1/2 adversary bound and various network environments), which is compatible with most current blockchains requiring only minimal changes. It also offers public verifiability for redactable chains, where any edited block in the chain is publicly verifiable. Compared to previous solutions in permissionless setting, our redaction operation can be completed instantly, even only within one slot for the best-case scenario of PoS instantiation, which is desirable for redacting harmful or sensitive data. Correspondingly, our redaction verification in the blockchain is also instant. Furthermore, we define the first ideal protocol of redactable blockchain following the language of universal composition, and prove that our protocol can achieve the security property of redactable common prefix, chain quality, and chain growth. Finally, we develop a proof-of-concept implementation, and conduct extensive experiments to evaluate the overhead incurred by redactions. The experimental results show that the overhead remains minimal for both online nodes and re-spawning nodes, which demonstrates the high efficiency of our design

Tunable vortex Majorana zero modes in LiFeAs superconductor

The recent realization of pristine Majorana zero modes (MZMs) in vortices of iron-based superconductors (FeSCs) provides a promising platform for long-sought-after fault-tolerant quantum computation. A large topological gap between the MZMs and the lowest excitations enabled detailed characterization of vortex MZMs in those materials. Despite those achievements, a practical implementation of topological quantum computation based on MZM braiding remains elusive in this new Majorana platform. Among the most pressing issues are the lack of controllable tuning methods for vortex MZMs and inhomogeneity of the FeSC Majorana compounds that destroys MZMs during the braiding process. Thus, the realization of tunable vortex MZMs in a truly homogeneous compound of stoichiometric composition and with a charge neutral cleavage surface is highly desirable. Here we demonstrate experimentally that the stoichiometric superconductor LiFeAs is a good candidate to overcome these two obstacles. Using scanning tunneling microscopy, we discover that the MZMs, which are absent on the natural surface, can appear in vortices influenced by native impurities. Our detailed analysis and model calculations clarify the mechanism of emergence of MZMs in this material, paving a way towards MZMs tunable by controllable methods such as electrostatic gating. The tunability of MZMs in this homogeneous material offers an unprecedented platform to manipulate and braid MZMs, the essential ingredients for topological quantum computation.Comment: 21 pages, 10 figures. Suggestions and comments are welcom

Two distinct superconducting states controlled by orientation of local wrinkles in LiFeAs

We observe two types of superconducting states controlled by orientations of local wrinkles on the surface of LiFeAs. Using scanning tunneling microscopy/spectroscopy, we find type-I wrinkles enlarge the superconducting gaps and enhance the transition temperature, whereas type-II wrinkles significantly suppress the superconducting gaps. The vortices on wrinkles show a C2 symmetry, indicating the strain effects on the wrinkles. A discontinuous switch of superconductivity occurs at the border between two different wrinkles. Our results demonstrate that the local strain effect could affect superconducting order parameter of LiFeAs with a possible Lifshitz transition, by alternating crystal structure in different directions.Comment: 21 pages, 9 figure

Interaction Design to Enhance UX of University Timetable Plotting System on Mobile Version

Goal of this research is to introduce how the implementation of Interaction Design can solve problem of UI/UX in mobile devices. The method used here is Interaction Design, the study of designing interactive digital products with user-centered approach to deliver engaging and better user experiences (UX). One of interesting interactive product is University Timetable Plotting System, an application used to manage course scheduling that produces busy screen with large timetable. Problems occurred because this system have inadequate support for user with relatively low resolution (like smartphone) compared to desktop thus affect negative UX. Interaction design workflow begins with collecting data to establishing requirement, following with designing alternatives. Based on usability evaluation, Instruction approach proved to produce high satisfaction rating rather than direct manipulation approach. This research proved that Interaction Design could be utilize on the process of creating Interactive Products. In conclusion its challenging to convert plotting UI into mobile version and this paper demonstrate that Interaction design successfully guides developer and UI designer to design better UI/UX experiences

BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1

In this work, we present a constraint on the abundance of supergiant (SG) stars at redshift z ≈ 1, based on recent observations of astrongly lensed arc at this redshift. First we derived a free-form model of MACS J0416.1-2403 using data from the Beyond Ultradeep Frontier Fields and Legacy Observations (BUFFALO) program. The new lens model is based on 72 multiply lensed galaxies thatproduce 214 multiple images, making it the largest sample of spectroscopically confirmed lensed galaxies on this cluster. The largercoverage in BUFFALO allowed us to measure the shear up to the outskirts of the cluster, and extend the range of lensing constraintsup to ∼1 Mpc from the central region, providing a mass estimate up to this radius. As an application, we make predictions for thenumber of high-redshift multiply lensed galaxies detected in future observations with the James Webb Space Telescope (JWST).Then we focus on a previously known lensed galaxy at z = 1.0054, nicknamed Spock, which contains four previously reportedtransients. We interpret these transients as microcaustic crossings of SG stars and explain how we computed the probability of suchevents. Based on simplifications regarding the stellar evolution, we find that microlensing (by stars in the intracluster medium) ofSG stars at z = 1.0054 can fully explain these events. The inferred abundance of SG stars is consistent with either (1) a numberdensity of stars with bolometric luminosities beyond the Humphreys-Davidson (HD) limit (Lmax ≈ 6 × 105 L for red stars), whichis below ∼400 stars kpc−2, or (2) the absence of stars beyond the HD limit but with a SG number density of ∼9000 kpc−2 for starswith luminosities between 105 L and 6 × 105 L. This is equivalent to one SG star per 10 × 10 pc2. Finally, we make predictions forfuture observations with JWST’s NIRcam. We find that in observations made with the F200W filter that reach 29 mag AB, if cool red SG stars exist at z ≈ 1 beyond the HD limit, they should be easily detected in this arc

BUFFALO/Flashlights: Constraints on the abundance of lensed supergiant stars in the Spock galaxy at redshift 1

We present a constraint on the abundance of supergiant (SG) stars at redshift z approx. 1, based on recent observations of a strongly lensed arc at this redshift. First we derive a free-form model of MACS J0416.1-2403 using data from the BUFFALO program. The new lens model is based on 72 multiply lensed galaxies that produce 214 multiple images, making it the largest sample of spectroscopically confirmed lensed galaxies on this cluster. The larger coverage in BUFFALO allows us to measure the shear up to the outskirts of the cluster, and extend the range of lensing constraints up to ~ 1 Mpc from the central region, providing a mass estimate up to this radius. As an application, we make predictions for the number of high-redshift multiply-lensed galaxies detected in future observations with JWST. Then we focus on a previously known lensed galaxy at z=1.0054, nicknamed Spock, which contains four previously reported transients. We interpret these transients as microcaustic crossings of SG stars and compute the probability of such events. Based on simplifications regarding the stellar evolution, we find that microlensing (by stars in the intracluster medium) of SG stars at z=1.0054 can fully explain these events. The inferred abundance of SG stars is consistent with either (1) a number density of stars with bolometric luminosities beyond the Humphreys-Davidson (HD) limit (L ~ $6\times10^5 L_{\odot}$) that is below 400 stars per sq. kpc, or (2) the absence of stars beyond the HD limit but with a SG number density of ~ 9000 per sq. kpc for stars with luminosities between $10^5$ and $6\times10^5$. This is equivalent to one SG star per 10x10 pc$^2$. We finally make predictions for future observations with JWST's NIRcam. We find that in observations made with the F200W filter that reach 29 mag AB, if cool red SG stars exist at z~1 beyond the HD limit, they should be easily detected in this arcComment: 24 pages & 18 figure

Money vs. Social Life: Why People Choose Not to Use Facebook Messenger Payment

As money and mobile P2P payment experiences have become an emerging research agenda in HCI, prior studies have focused on the factors that promote the use of P2P payment services as well as related design implications. Yet, few have investigated why people decide not to use such services (e.g., technology non-use) and how people perceive the increasing trend of integrating P2P payments with social media services. To explore these issues, we identified factors that hindered people from using Facebook Messenger payment and their perceptions of integrating of P2P payments with social media based on 158 social media posts and eight interviews. This study not only extends our existing understanding of technology non-use through the lens of Facebook payment but also helps HCI researchers and designers innovate emerging financial technologies and better understand the global phenomenon of all-in-one design