CrowdBC: A blockchain-based decentralized framework for crowdsourcing

Crowdsourcing systems which utilize the human intelligence to solve complex tasks have gained considerable interest and adoption in recent years. However, the majority of existing crowdsourcing systems rely on central servers, which are subject to the weaknesses of traditional trust-based model, such as single point of failure. They are also vulnerable to distributed denial of service (DDoS) and Sybil attacks due to malicious users involvement. In addition, high service fees from the crowdsourcing platform may hinder the development of crowdsourcing. How to address these potential issues has both research and substantial value. In this paper, we conceptualize a blockchain-based decentralized framework for crowdsourcing named CrowdBC, in which a requester’s task can be solved by a crowd of workers without relying on any third trusted institution, users’ privacy can be guaranteed and only low transaction fees are required. In particular, we introduce the architecture of our proposed framework, based on which we give a concrete scheme. We further implement a software prototype on Ethereum public test network with real-world dataset. Experiment results show the feasibility, usability and scalability of our proposed crowdsourcing system

Indexing, browsing and searching of digital video

Video is a communications medium that normally brings together moving pictures with a synchronised audio track into a discrete piece or pieces of information. The size of a “piece ” of video can variously be referred to as a frame, a shot, a scene, a clip, a programme or an episode, and these are distinguished by their lengths and by their composition. We shall return to the definition of each of these in section 4 this chapter. In modern society, video is ver

Modeling interactive memex-like applications based on self-modifiable petri nets

This paper introduces an interactive Memex-like application using a self-modifiable Petri Net model – Self-modifiable Color Petri Net (SCPN). The Memex (“memory extender”) device proposed by Vannevar Bush in 1945 focused on the problems of “locating relevant information in the published records and recording how that information is intellectually connected.” The important features of Memex include associative indexing and retrieval. In this paper, the self-modifiable functions of SCPN are used to achieve trail recording and retrieval. A place in SCPN represents a website and an arc indicates the trail direction. Each time when a new website is visited, a place corresponding to this website will be added. After a trail is built, users can use it to retrieve the websites they have visited. Besides, useful user interactions are supported by SCPN to achieve Memex functions. The types of user interactions include: forward, backward, history, search, etc. A simulator has been built to demonstrate that the SCPN model can realize Memex functions. Petri net instances can be designed to model trail record, back, and forward operations using this simulator. Furthermore, a client-server based application system has been built. Using this system, a user can surf online and record his surfing history on the server according to different topics and share them with other users

NFriendConnector: Design and Evaluation of An Application for Integrating Offline and Online Social Networking

This paper describes the design and evaluation of NFriendConnector, a prototype application that allows for better integration between online and offline social networks. Online social networks are currently used to maintain and strengthen existing real-life social connections, rather than establishing ties that exist only online. However, users incur significant time and search related costs in replicating a naturally occurring social interaction using a social networking site (SNS). Therefore, there exists a gap between initiating social contact in real-life versus initiating social contact via an online social network. Using the design science paradigm, our research addresses this gap by introducing NFriendConnector. This application allows users to map their offline interactions, as and when they take place, onto their SNS presence, therefore making it possible to complement offline social interactions with SNS profile information. The prototype is implemented using Near Field Communication (NFC)-enabled mobile phones and Facebook. We evaluate the prototype in an experimental setting using expectation confirmation theory (ECT) as the theoretical framework. Findings show that NFriendConnector was able to satisfy users, therefore indicating a successful design exercise. We discuss the implications of this research in the context of current developments in online social networking

Information Technology Enabled Persuasion: An Experimental Investigation of the Role of Communication Channel, Strategy and Affect

With advances in information and communication technologies (ICT), organizations of various forms now deploy an increasing number of ICT-enabled persuasive systems in several domains. Traditional computer-mediated communication (CMC) theories mainly focus on the effectiveness of media in the synchronous/asynchronous spectrum for effectively matching medium with communication task. The contemporary communication environment is rich with asynchronous channels such as email, Web, and text messaging, which makes it important to go beyond synchronicity and determine the nuances among various asynchronous channels. No rigorous research has compared the effectiveness of these channels in the persuasive systems domain where organizations use technology to persuade users to modify their behavior in a direction that they mutually agree to be desirable. In this paper, we study the effectiveness of CMC and the strategy used to frame the persuasive message. We explore persuasive strategies of praising, reminding, suggesting, and rewarding for health behavior and promotion. We model user experience as a mediator between channel strategy combinations and persuasive effectiveness. Through controlled user studies, we compared sixteen combinations of communication channel and persuasive strategy with or without emoticons. We found that channel/strategy combinations affect persuasive effectiveness (mediated by user experience) in varying degrees. Our findings contribute to the body of CMC and persuasive system knowledge and have practical implications for online advertising, health promotion, and persuasive technology design

Considerations in Designing Human-Computer Interfaces for Elderly People

As computing devices continue to become more heavily integrated into our lives, proper design of human-computer interfaces becomes a more important topic of discussion. Efficient and useful human-computer interfaces need to take into account the abilities of the humans who will be using such interfaces, and adapt to difficulties that different users may face – such as the difficulties that elderly users must deal with. Interfaces that allow for user-specific customization, while taking into account the multiple difficulties that older users might face, can assist the elderly in properly using these newer computing devices, and in doing so possibly achieving a better quality of life through the advanced technological support that these devices offer. In this paper, we explore common problems the elderly face when using computing devices and solutions developed for these problems. Difficulties ultimately fall into several categories: cognition, auditory, haptic, visual, and motor-based troubles. We also present an idea for a new adaptive operating system with advanced customizations that would simplify computing for older users

SeePrivacy: Automated Contextual Privacy Policy Generation for Mobile Applications

Privacy policies have become the most critical approach to safeguarding individuals' privacy and digital security. To enhance their presentation and readability, researchers propose the concept of contextual privacy policies (CPPs), aiming to fragment policies into shorter snippets and display them only in corresponding contexts. In this paper, we propose a novel multi-modal framework, namely SeePrivacy, designed to automatically generate contextual privacy policies for mobile apps. Our method synergistically combines mobile GUI understanding and privacy policy document analysis, yielding an impressive overall 83.6% coverage rate for privacy-related context detection and an accuracy of 0.92 in extracting corresponding policy segments. Remarkably, 96% of the retrieved policy segments can be correctly matched with their contexts. The user study shows SeePrivacy demonstrates excellent functionality and usability (4.5/5). Specifically, participants exhibit a greater willingness to read CPPs (4.1/5) compared to original privacy policies (2/5). Our solution effectively assists users in comprehending privacy notices, and this research establishes a solid foundation for further advancements and exploration