Anchor-Free Localization in Mixed Wireless Sensor Network Systems

Recent technological advances have fostered the emergence of Wireless Sensor Networks (WSNs), which consist of tiny, wireless, battery-powered nodes that are expected to revolutionize the ways in which we understand and construct complex physical systems. A fundamental property needed to use and maintain these WSNs is ``localization\u27\u27, which allows the establishment of spatial relationships among nodes over time. This dissertation presents a series of Geographic Distributed Localization (GDL) algorithms for mixed WSNs, in which both static and mobile nodes can coexist. The GDL algorithms provide a series of useful methods for localization in mixed WSNs. First, GDL provides an approximation called ``hop-coordinates\u27\u27, which improves the accuracy of both hop-counting and connectivity-based measurement techniques. Second, GDL utilizes a distributed algorithm to compute the locations of all nodes in static networks with the help of the hop-coordinates approximation. Third, GDL integrates a sensor component into this localization paradigm for possible mobility and as a result allows for a more complex deployment of WSNs as well as lower costs. In addition, the development of GDL incorporated the possibility of manipulated communications, such as wormhole attacks. Simulations show that such a localization system can provide fundamental support for security by detecting and localizing wormhole attacks. Although several localization techniques have been proposed in the past few years, none currently satisfies our requirements to provide an accurate, efficient and reliable localization for mixed WSNs. The contributions of this dissertation are: (1) our measurement technique achieves better accuracy both in measurement and localization than other methods; (2) our method significantly improves the efficiency of localization in updating location in mixed WSNs by incorporating sensors into the method; (3) our method can detect and locate the communication that has been manipulated by a wormhole in a network without relying on a central server

The Power of Electronic Channels and Electronic Political Efficacy: Electronic Participation Discourse

Electronic participation (e-participation) has become an increasingly important phenomenon. Drawing from the information system success model and political efficacy, we built a research model that investigates how government feedback quality, information quality, and channel quality associated with an e-participating channel can affect people’s electronic political efficacy, which, in turn, can influence users’ post-adoption attitudes and behaviors. We also explored the relationship between offline political efficacy and electronic political efficacy. Based on data that we collected from a survey, we found that electronic political efficacy distinctly differs from offline political efficacy though the latter influences the former one. Four channel features (i.e., government feedback quality, information quality, media richness, and social presence of citizens) can affect electronic political efficacy, which, in turn, has a positive influence on e-participation continuance intention and positive word of mouth. We also found that government feedback quality negatively moderated the impact that offline political efficacy had on electronic political efficacy. This study provides useful insights for both researchers and practitioners on the power of electronic channels in electronic participation in public discourse

Health Service Access for Rural People Living with HIV/AIDS in China: A Critical Evaluation

The increasingly serious HIV/AIDS epidemic creates a significant burden for the public health system; however, little attention has been paid to the issue of health service access in rural China. Based on a qualitative study of 34 Chinese rural People Living with HIVIAIDS (PLWHA) and 13 health providers, this study fills a gap by examining health service access from both the demand and supply-side. Utilizing access theory, this study explores the availability, affordability and acceptability of health services in rural China. Moreover, this study focuses on access barriers and institutional obstacles that PLWHA meet during their illness and considers the influence of the current Chinese political philosophy of marketization and privatization of the health care systems

Corporate Application Integration: Challenges, Opportunities, and Implementation Strategies

In recent years, corporate applications such as enterprise resource planning (ERP) systems, supply chain management (SCM) systems, customer relationship management (CRM) systems, sales force automation (SFA), and other corporate-level information systems have received a great deal of attention from large business enterprises. These applications have been around for about a decade now, and in that time their producers have refined them and perfected them to the point where they can be considered developmentally mature. At the same time, vendors have continued to introduce new products that have moved corporate applications toward a higher level of integration, both technically and organizationally. However, these higher levels of integration have brought with them complex technical, organizational, cultural, political, and legal issues that have made the integration process a very challenging task. This paper reviews relevant current literature, discusses several perspectives of corporate application integration, and points out potential opportunities and cludlenges inherent in the integration process. Risk reduction strategies and opportunities provided by some newly developed technologies (e.g., software agents) are also discussed

CLIPC8: Face liveness detection algorithm based on image-text pairs and contrastive learning

Face recognition technology is widely used in the financial field, and various types of liveness attack behaviors need to be addressed. Existing liveness detection algorithms are trained on specific training datasets and tested on testing datasets, but their performance and robustness in transferring to unseen datasets are relatively poor. To tackle this issue, we propose a face liveness detection method based on image-text pairs and contrastive learning, dividing liveness attack problems in the financial field into eight categories and using text information to describe the images of these eight types of attacks. The text encoder and image encoder are used to extract feature vector representations for the classification description text and face images, respectively. By maximizing the similarity of positive samples and minimizing the similarity of negative samples, the model learns shared representations between images and texts. The proposed method is capable of effectively detecting specific liveness attack behaviors in certain scenarios, such as those occurring in dark environments or involving the tampering of ID card photos. Additionally, it is also effective in detecting traditional liveness attack methods, such as printing photo attacks and screen remake attacks. The zero-shot capabilities of face liveness detection on five public datasets, including NUAA, CASIA-FASD, Replay-Attack, OULU-NPU and MSU-MFSD also reaches the level of commercial algorithms. The detection capability of proposed algorithm was verified on 5 types of testing datasets, and the results show that the method outperformed commercial algorithms, and the detection rates reached 100% on multiple datasets. Demonstrating the effectiveness and robustness of introducing image-text pairs and contrastive learning into liveness detection tasks as proposed in this paper

Growth of high-quality CrI3 single crystals and engineering of its magnetic properties via V and Mn doping

CrI3, as a soft van der Waals layered magnetic material, has been widely concerned and explored for its magnetic complexity and tunability. In this work, high quality and large size thin CrI3, V and Mn doped single crystals were prepared by chemical vapor transfer method. A remarkable irreversible Barkhausen effect was observed in CrI3 and CrMn0.06I3, which can be attributed to the low dislocation density that facilitates movement of the domain walls. In addition, the introduction of the doping element Mn allows higher saturation magnetization intensity. Cr0.5V0.5I3 exhibits substantially increased coercivity force and larger magnetocrystalline anisotropy compared to CrI3, while kept similar Curie temperature and good environmental stability. The first principles calculations suggest direct and narrowed band gaps in Cr0.5V0.5I3 and VI3 comparing to CrI3. The smaller band gaps and good hard magnetic property make Cr0.5V0.5I3 an alternative choice to future research of spintronic devices