Matching Items (7)
Filtering by
- All Subjects: Information Technology
- Creators: Davulcu, Hasan
- Creators: Schugurensky, Daniel, 1958-
- Member of: ASU Electronic Theses and Dissertations
- Status: Published
Description
The increasing popularity of Twitter renders improved trustworthiness and relevance assessment of tweets much more important for search. However, given the limitations on the size of tweets, it is hard to extract measures for ranking from the tweet's content alone. I propose a method of ranking tweets by generating a reputation score for each tweet that is based not just on content, but also additional information from the Twitter ecosystem that consists of users, tweets, and the web pages that tweets link to. This information is obtained by modeling the Twitter ecosystem as a three-layer graph. The reputation score is used to power two novel methods of ranking tweets by propagating the reputation over an agreement graph based on tweets' content similarity. Additionally, I show how the agreement graph helps counter tweet spam. An evaluation of my method on 16~million tweets from the TREC 2011 Microblog Dataset shows that it doubles the precision over baseline Twitter Search and achieves higher precision than current state of the art method. I present a detailed internal empirical evaluation of RAProp in comparison to several alternative approaches proposed by me, as well as external evaluation in comparison to the current state of the art method.
ContributorsRavikumar, Srijith (Author) / Kambhampati, Subbarao (Thesis advisor) / Davulcu, Hasan (Committee member) / Liu, Huan (Committee member) / Arizona State University (Publisher)
Created2013
Description
In this dissertation, two interrelated problems of service-based systems (SBS) are addressed: protecting users' data confidentiality from service providers, and managing performance of multiple workflows in SBS. Current SBSs pose serious limitations to protecting users' data confidentiality. Since users' sensitive data is sent in unencrypted forms to remote machines owned and operated by third-party service providers, there are risks of unauthorized use of the users' sensitive data by service providers. Although there are many techniques for protecting users' data from outside attackers, currently there is no effective way to protect users' sensitive data from service providers. In this dissertation, an approach is presented to protecting the confidentiality of users' data from service providers, and ensuring that service providers cannot collect users' confidential data while the data is processed or stored in cloud computing systems. The approach has four major features: (1) separation of software service providers and infrastructure service providers, (2) hiding the information of the owners of data, (3) data obfuscation, and (4) software module decomposition and distributed execution. Since the approach to protecting users' data confidentiality includes software module decomposition and distributed execution, it is very important to effectively allocate the resource of servers in SBS to each of the software module to manage the overall performance of workflows in SBS. An approach is presented to resource allocation for SBS to adaptively allocating the system resources of servers to their software modules in runtime in order to satisfy the performance requirements of multiple workflows in SBS. Experimental results show that the dynamic resource allocation approach can substantially increase the throughput of a SBS and the optimal resource allocation can be found in polynomial time
ContributorsAn, Ho Geun (Author) / Yau, Sik-Sang (Thesis advisor) / Huang, Dijiang (Committee member) / Ahn, Gail-Joon (Committee member) / Santanam, Raghu (Committee member) / Arizona State University (Publisher)
Created2012
Description
Cyber systems, including IoT (Internet of Things), are increasingly being used ubiquitously to vastly improve the efficiency and reduce the cost of critical application areas, such as finance, transportation, defense, and healthcare. Over the past two decades, computing efficiency and hardware cost have dramatically been improved. These improvements have made cyber systems omnipotent, and control many aspects of human lives. Emerging trends in successful cyber system breaches have shown increasing sophistication in attacks and that attackers are no longer limited by resources, including human and computing power. Most existing cyber defense systems for IoT systems have two major issues: (1) they do not incorporate human user behavior(s) and preferences in their approaches, and (2) they do not continuously learn from dynamic environment and effectively adapt to thwart sophisticated cyber-attacks. Consequently, the security solutions generated may not be usable or implementable by the user(s) thereby drastically reducing the effectiveness of these security solutions.
In order to address these major issues, a comprehensive approach to securing ubiquitous smart devices in IoT environment by incorporating probabilistic human user behavioral inputs is presented. The approach will include techniques to (1) protect the controller device(s) [smart phone or tablet] by continuously learning and authenticating the legitimate user based on the touch screen finger gestures in the background, without requiring users’ to provide their finger gesture inputs intentionally for training purposes, and (2) efficiently configure IoT devices through controller device(s), in conformance with the probabilistic human user behavior(s) and preferences, to effectively adapt IoT devices to the changing environment. The effectiveness of the approach will be demonstrated with experiments that are based on collected user behavioral data and simulations.
In order to address these major issues, a comprehensive approach to securing ubiquitous smart devices in IoT environment by incorporating probabilistic human user behavioral inputs is presented. The approach will include techniques to (1) protect the controller device(s) [smart phone or tablet] by continuously learning and authenticating the legitimate user based on the touch screen finger gestures in the background, without requiring users’ to provide their finger gesture inputs intentionally for training purposes, and (2) efficiently configure IoT devices through controller device(s), in conformance with the probabilistic human user behavior(s) and preferences, to effectively adapt IoT devices to the changing environment. The effectiveness of the approach will be demonstrated with experiments that are based on collected user behavioral data and simulations.
ContributorsBuduru, Arun Balaji (Author) / Yau, Sik-Sang (Thesis advisor) / Ahn, Gail-Joon (Committee member) / Davulcu, Hasan (Committee member) / Zhang, Yanchao (Committee member) / Arizona State University (Publisher)
Created2016
Description
Continuous advancements in biomedical research have resulted in the production of vast amounts of scientific data and literature discussing them. The ultimate goal of computational biology is to translate these large amounts of data into actual knowledge of the complex biological processes and accurate life science models. The ability to rapidly and effectively survey the literature is necessary for the creation of large scale models of the relationships among biomedical entities as well as hypothesis generation to guide biomedical research. To reduce the effort and time spent in performing these activities, an intelligent search system is required. Even though many systems aid in navigating through this wide collection of documents, the vastness and depth of this information overload can be overwhelming. An automated extraction system coupled with a cognitive search and navigation service over these document collections would not only save time and effort, but also facilitate discovery of the unknown information implicitly conveyed in the texts. This thesis presents the different approaches used for large scale biomedical named entity recognition, and the challenges faced in each. It also proposes BioEve: an integrative framework to fuse a faceted search with information extraction to provide a search service that addresses the user's desire for "completeness" of the query results, not just the top-ranked ones. This information extraction system enables discovery of important semantic relationships between entities such as genes, diseases, drugs, and cell lines and events from biomedical text on MEDLINE, which is the largest publicly available database of the world's biomedical journal literature. It is an innovative search and discovery service that makes it easier to search
avigate and discover knowledge hidden in life sciences literature. To demonstrate the utility of this system, this thesis also details a prototype enterprise quality search and discovery service that helps researchers with a guided step-by-step query refinement, by suggesting concepts enriched in intermediate results, and thereby facilitating the "discover more as you search" paradigm.
avigate and discover knowledge hidden in life sciences literature. To demonstrate the utility of this system, this thesis also details a prototype enterprise quality search and discovery service that helps researchers with a guided step-by-step query refinement, by suggesting concepts enriched in intermediate results, and thereby facilitating the "discover more as you search" paradigm.
ContributorsKanwar, Pradeep (Author) / Davulcu, Hasan (Thesis advisor) / Dinu, Valentin (Committee member) / Li, Baoxin (Committee member) / Arizona State University (Publisher)
Created2010
Description
The dissertation explores how participants view the relationships between democratic principles such as freedom, liberty, justice, and equality in work and home environments and their impact on the health and productivity of people living within these environments. This information can be used to determine the gap between legal democratic instruments established the published laws and rights and the participants understanding and awareness of these rights. The first step in effectively capturing information from the participants involved developing a virtual ethnographic research system architecture prototype that allowed participants to voice their opinions related to democracy and how the application of democratic principles in various lived environments such as the workplace and home can affect their health and productivity. The dissertation starts by first delving into what democracy is within the context of general social research and social contracts as related to everyday interactions between individuals within organizational environments. Second, it determines how democracy affects individual human rights and their well-being within lived environments such as their workplace and home. Third, it identifies how technological advances can be used to educate and improve democratic processes within various lived environments such that individuals are given an equal voice in decisions that affect their health and well-being, ensuring that they able to secure justice and fairness within their lives. The virtual ethnographic research system architecture prototype tested the ability of a web application and database technology to provide a more dynamic and longitudinal methodology allowing participants to voice their opinions related to the relationship of democracy in work and home environments to the health and productivity of the people who live within these environments. The technology enables continuous feedback as participants are educated about democracy and their lived environments, unlike other research methods that take a one-time view of situations and apply them to continuously changing environments. The analysis of the participant's answers to the various qualitative and quantitative questions indicated that the majority of participants agree that a positive relationship exists between democracy in work and home environments and the health and productivity of the individuals who live within these environments.
ContributorsBooze, Randall Ray (Author) / Romero, Mary (Thesis advisor) / Goul, Michael (Committee member) / Schugurensky, Daniel, 1958- (Committee member) / Arizona State University (Publisher)
Created2012
Description
Public organizations have been interested in tapping into the creativity and passion of the public through the use of open innovation, which emphasizes bottom-up ideation and collaboration. A challenge for organizational adoption of open innovation is that the quick-start, bottom-up, iterative nature of open innovation does not integrate easily into the hierarchical, stability-oriented structure of most organizations. In order to realize the potential of open innovation, organizations must be willing to change the way they operate. This dissertation is a case study of how Arizona State University (ASU), has adapted its organizational structure and created unique programming to incorporate open innovation. ASU has made innovation, inclusion, access, and real world impact organizational priorities in its mission to be the New American University. The primarily focus of the case study is the experiential knowledge of administrative leaders and administrative intermediaries who have managed open innovation programming at the university over the past five years. Using theoretical pattern matching, administrator insights on open innovation adoption are illustrated in terms of design stages, teamwork, and ASU's culture of innovation. It is found that administrators view iterative experimentation with goals of impact as organizational priorities. Institutional support for iterative, experimental programming, along with the assumption that not every effort will be successful, empowers administrators to push to be bolder in their implementation of open innovation. Theoretical pattern matching also enabled a detailed study of administrator alignment regarding one particular open innovation program, the hybrid participatory platform 10,000 Solutions. Creating a successful and meaningful hybrid platform is much more complex than administrators anticipated at the outset. This chapter provides administrator insights in the design, management, and evaluation of participatory platforms. Next, demographic assessment of student participation in open innovation programming is presented. Demographics are found to be reflective of the university population and provide indicators for how to improve existing programming. This dissertation expands understanding of the task facing administrators in an organization seeking to integrate open innovation into their work.
ContributorsKelley, Tanya M (Author) / Johnston, Erik W., 1977- (Thesis advisor) / Schugurensky, Daniel, 1958- (Committee member) / Mossberger, Karen (Committee member) / Longo, Justin (Committee member) / Arizona State University (Publisher)
Created2016
Description
Traditionally, emergency response is in large part the role and responsibility of formal organizations. Advances in information technology enable amateurs or concerned publics to play a meaningful role in emergency response. Indeed, in recent catastrophic disasters or crises such as the 2010 Haiti earthquake and the 2011 Japan earthquake and nuclear crisis, participatory online groups of the general public from both across the globe and the affected areas made significant contributions to the effective response through crowdsourcing vital information and assisting with the allocation of needed resources. Thus, a more integrative lens is needed to understand the responses of various actors to catastrophic crises or disasters by taking into account not only formal organizations with legal responsibilities, but also volunteer-based, participatory groups who actively participate in emergency response. In this dissertation, I first developed an “event-driven” lens for integrating both formal and volunteer-based, participatory emergency responses on the basis of a comprehensive literature review (chapter 1). Then I conducted a deeper analysis of one aspect of the event-driven lens: relationships between participatory online groups and formal organizations in crisis or disaster situations. Specifically, I explored organizational and technical determinants and outcomes of forming such relationships (chapter 2). As a consequence, I found out three determinants (resource dependence, shared understanding, and information technology) and two outcomes (inter-organizational alignment and the effectiveness of coordinated emergency response) of the relationship between participatory online groups and formal organizations and suggested seven hypotheses. Furthermore, I empirically tested these hypotheses, focusing on the 2015 Nepal earthquake case (chapter 3). As a result, I found empirical evidence that supports that shared understanding and information technology improve the development of the relationship between participatory online groups and formal organizations. Moreover, research findings support that the development of the relationship enhances inter-organizational coordination. Lastly, I provide implications for future research (chapter 4). This dissertation is expected to contribute to bridging the disconnect between the emergency management literature and the crisis informatics literature. The theoretical insight from inter-organizational relations (IOR) theory provides another contribution.
ContributorsPark, Chul Hyun (Author) / Johnston, Erik W., 1977- (Thesis advisor) / Schugurensky, Daniel, 1958- (Committee member) / Williams, Linda (Committee member) / Kapucu, Naim (Committee member) / Arizona State University (Publisher)
Created2016