Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
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Item The Use of Email in Establishment Surveys(2019) Langeland, Joshua Lee; Abraham, Katharine; Wagner, James; Survey Methodology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation evaluates the effectiveness of using Email for survey solicitation, nonresponse follow-up, and notifications for upcoming scheduled interviews in an establishment survey setting. Reasons for interest in the use of Email include the possibility that it could reduce printing and postage expenses, speed responses and encourage online reporting. To date, however, there has been limited research on the extent to which these benefits can in fact be realized in an establishment survey context. In order to send an Email for survey purposes, those administering a survey must have Email addresses for the units in the sample. One method for collecting Email addresses is to send a prenotification letter to sampled businesses prior to the initial survey invitation, informing respondents about the upcoming survey and requesting they provide contact information for someone within the organization who will have knowledge of the survey topic. Relatively little is known, however, about what makes a prenotification letter more or less effective. The first experiment on which this dissertation reports varies the content of prenotification letters sent to establishments selected for participation in a business survey in order to identify how different features affect the probability of obtaining a respondent's Email address. In this experiment, neither survey sponsorship, appeal type, nor a message about saving taxpayer dollars had a significant impact on response. The second experiment is a pilot study designed to compare the results of sending an initial Email invitation to participate in an establishment survey to the results of sending a standard postal invitation. Sampled businesses that provided an Email address were randomized into two groups. Half of the units in the experiment received the initial survey invitation by Email and the other half received the standard survey materials through postal mail; all units received the same nonresponse follow-up treatments. The analysis of this experiment focuses on response rates, timeliness of response, mode of response and cost per response. In this production environment, Email invitations achieved an equivalent response rate at reduced cost per response. Units receiving the Email invitation were more likely to report online, but it took them longer on average to respond. The third experiment built on the second and was an investigation into nonresponse follow-up procedures. In the second experiment, at the point when the cohort that received the initial survey invitation by Email received their first nonresponse follow-up, there was a large increase in response. The third experiment tests whether this large increase in response can be achieved by sending a follow-up Email instead of a postal reminder. Sampled units that provided an Email address were randomized into three groups. All units received the initial survey invitation by Email and all units also received nonresponse follow-ups by Email. The treatments varied in the point in the nonresponse follow-up period at which the Emails were augmented with a postal mailing. The analysis focuses on how this timing affects response rates and mode of response. The sequence that introduced postal mail early in nonresponse follow-up achieved the highest final response rate. All mode sequences were successful in encouraging online data reporting. The fourth and final experiment studies the use of Email in a monthly business panel survey conducted through Computer Assisted Telephone Interviewing (CATI). After the first month in which an interviewer in this survey collects data from a business, she schedules a date to call and collect data the following month. The current procedure is to send a postcard to the business a few days prior to the scheduled appointment to serve as a reminder of the upcoming interview. The fourth experiment investigates the effects of replacing this reminder postcard with an Email. Businesses in a sample that included both businesses for which the survey organization had an Email address and businesses for which no Email address was available were randomized into three groups. The first group acts as the control and received the standard postcard; the second group was designated to receive an Email reminder, provided an Email address was available, instead of the postcard; and the third group received an Email reminder with an iCalendar attachment instead of the postcard, again provided an Email address was available. Results focus on response rates, call length, percent of units reporting on time, and number of calls to respondents. The experiment found that the use of Email as a reminder for a scheduled interview significantly increased response rates and decreased the effort required to collect data.Item Risk assessment of email accounts: Difference between perception and reality(2012) Zinsou, Merine; Cukier, Michel; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The use of Internet is associated with a growing number of security threats. This thesis analyzes how users perceive the security of their email account based on the email account provider. With our study, we aim to contribute to the information security systems literature in three ways: First, by taking a more complete view on security online, and reviewing the concept of usable security, usability, human-computer interaction, trust and user perception. Second, by performing an analysis of providers of online services specifically emails. Third, by applying a renowned risk analysis method called Information Security Risk Analysis Method (ISRAM) for risk assessment. The ISRAM analysis revealed that Hotmail, Gmail and Yahoo email accounts have a medium risk level, while the reality analysis demonstrated no clearly more secure account provider with only low level risk counts.Item IDENTITY RESOLUTION IN EMAIL COLLECTIONS(2009) Elsayed, Tamer Mohamed; Oard, Douglas W; Computer Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Access to historically significant email collections poses challenges that arise less often in personal collections. Most notably, people exploring a large collection of emails, in which they were not sending or receiving, may not be very familiar with the discussions that exist in this collection. They would not only need to focus on understanding the topical content of those discussions, but would also find it useful to understand who the people sending, receiving, or mentioned in these discussions were. In this dissertation, the problem of resolving personal identity in the context of large email collections is tackled. In such collections, a common name (e.g., John) might easily refer to any one of several hundred people; when one of these people was mentioned in an email, the question then arises: "who is that John?'' To "resolve identity'' of people in an email collection, two problems need to be solved: (1) modeling the identity of the participants in that collection, and (2) resolving name-mentions (that appeared in the body of the messages) to these identities. To tackle the first problem, a simple computational model of identity, that is built on extracting unambiguous references (e.g., full names from headers, or nicknames from free-text signatures) to people from the whole collection, is presented. To tackle the second problem, a generative probabilistic approach that leverages the model of identity to resolve mentions is presented. The approach is motivated by intuitions about the way people might refer to others in an email; it expands the context surrounding a mention in four directions: the message where the mention was observed, the thread that includes that message, topically-related messages, and messages sent or received by the original communicating parties. It relies on less ambiguous references (e.g., email addresses or full names) that are observed in some context of a given mention to rank potential referents of that mention. In order to jointly resolve all mentions in the collection, a parallel implementation is presented using the MapReduce distributed-programming framework. The implementation decomposes the structure of the resolution process into subcomponents that fit the MapReduce task model well. At the heart of that implementation, a parallel algorithm for efficient computation of pairwise document similarity in large collections is proposed as a general solution that can be used for scalable context expansion of all mentions and other applications as well. The resolution approach compares favorably with previously-reported techniques on small test collections (sets of mention-queries that were manually resolved beforehand) that were used to evaluate the task in the literature. However, the mention-queries in those collections, besides being relatively few in number, are limited in that all refer to people for whom a substantial amount of evidence would be expected to be available in the collection thus omitting the "long tail'' of the identity distribution for which less evidence is available. This motivated the development of a new test collection that now is the largest and best-balanced test collection available for the task. To build this collection, a user study was conducted that also provided some insight into the difficulty of the task and how time-consuming it is when humans perform it, and the reliability of their task performance. The study revealed that at least 80% of the 584 annotated mentions were resolvable to people who had sent or received email within the same collection. The new test collection was used to experimentally evaluate the resolution system. The results highlight the importance of the social context (that includes messages sent or received by the original communicating parties) when resolving mentions in email. Moreover, the results show that combining evidence from multiple types of contexts yields better resolution than what can be achieved using any individual context. The one-best selection is correct 74% of the time when tested on the full set of the mention-queries, and 51% of the time when tested on the mention-queries labeled as "hard'' by the annotators. Experiments run with iterative reformulation of the resolution algorithm resulted in modest gains only for the second iteration in the social context expansion.