1,720,973 research outputs found
Economic and Operational Considerations in Cloud Computing
No full textThis dissertation consists of three main chapters that examine economic and operational
issues in cloud computing market using analytical modeling.
Chapter 2 studies the problem of selecting computing resources from a cloud provider with
the goal to minimize the total rental cost of completing a computing task in the presence of
a time constraint. The problem is formulated as a scheduling problem that assigns computing resources to time periods of the planning horizon (time available to complete a single
computing task). This (NP-hard) preemptive-resume type scheduling problem – new to
the scheduling literature – has not been carefully addressed in practice to provide an implementable solution. Typically, the approach taken in practice is to use a single resource
(a single virtual machine instance, or a cluster of identical virtual machine instances) to
complete a computing task.
The main insight of this study is that rather than completing a computing task using a
single computing resource, rental costs can be significantly lowered by using a few resources
(sometimes, even just two) to complete the task. Thus, the computing task is switched from
one resource to another to exploit the cloud provider’s price-performance schedule. Cloud
computing has been recognized as an economically attractive computing environment whose
adoption has been growing over time. However, providers (such as Amazon Web Services)
offer a confusing and diverse set of computing resources with different configurations and
unit rental costs.
Our near-optimal solution is based on switching the computing task from one resource to
another in way that leverages the relationship between the price and performance of the
available computing resources. The performance of a given resource can vary randomly as
well as be correlated with the performance of another (stronger or weaker) resource. We
present a worst-case performance guarantee of the proposed solution. In addition, we study
the performance using a detailed computational study and a real-world example of an actual
company that can benefit from our proposed solution. In the computational study as well as
the real-world example, the cost of our solution is usually about 15% – 25% lower than the
benchmark solution of using the best single computing resource to process the computing
task. Practicing IT managers can use our approach to migrate in-house solutions to the
cloud in a cost-effective manner.
In Chapter 3, we consider an ad-firm that acts on behalf of advertisers to execute mobile,
in-app, ad campaigns. The firm commits to provide an advertiser a specified number of
ad placements (impressions) on mobile apps, usually in a specified location, and within a
specified time horizon. The supply for ad space arrives – in real-time – in the form of bid requests from one or more mobile ad-exchanges. The ad-firm needs to bid on each impression
in such a way that the goals of several on-going campaigns are met at minimum cost.
The ad-firm needs to execute multiple campaigns simultaneously and get its supply (for
ad space, or impressions) from multiple mobile ad-exchanges. By working with more than
one ad-exchange, the direct cost of procuring the necessary impressions can be lowered.
However, this lower cost needs to be balanced with the cost of the additional computing
resources needed to work with multiple mobile ad-exchanges, as well as the (possible) extra
cost of meeting the minimum spend (or participation fee) imposed by each ad-exchange.
In this study, we propose a cloud-based architecture to procure impressions for an ad-firm.
There are two key decisions that the firm needs to make. First, it needs to select the set
of mobile ad-exchanges to obtain its supply. Each mobile ad-exchange is characterized by
specific supply uncertainties, location dependent win-curves, and a participation fee. Second,
for each ad-exchange and location, the ad-firm needs to determine its bidding policy, i.e.,
how much to bid for each bid-request. We show that the proposed near-optimal bidding
strategy – the strategy to bid at each exchange-location combination – is state independent.
We first analyze a special case with identical mobile ad-exchanges and show that, depending
on the particular parameter setting, the near-optimal number of ad-exchanges and the near optimal bid amount can be weak complements or substitutes. We next solve the general
problem of selecting among multiple non-identical ad exchanges.
Finally, we propose a supply flexibility architecture that can further lower procurement costs.
The ideas of this paper are applied to a real problem and the savings from our approach
(about 33% lower cost) are demonstrated.
In Chapter 4, we analyze the webspeed competition between two electronic retailing firms.
As of 2018 (2010), Google has been using a new ranking algorithm designed for mobile
(desktop) search that uses webspeed (or equivalently, website response time) as a ranking
factor. The emerge of Google Speed Update makes firms aware about a new possible decision
process to manage the performance of their websites, namely, response-based. The response based decision process starts with choosing a desired level of webspeed (or equivalently,
website response time) which in turn determines the cloud computing capacity level. Before
Google Speed Update, firms were aware about capacity-based decision process that starts
with choosing the cloud computing capacity level which in turn determines the website
response time. We consider a duopoly where two electronic retailing firms compete for
customer traffic from Google search result page and make capacity or website response
time decisions in equilibrium. Our analysis shows that the emerge of Google Speed Update
intensifies the competition. In other words, capacity-based competition generates higher
profits for both firms than those generated in response-based competition. However, when
the firms are free to choose the decision process, a response-based decision process is chosen
by both firms in equilibrium. We recommend that managers of a focal firm should adopt a
response-based decision process if the rival firm employs a capacity-based decision process
Essays on Commercialization of Information Technology Products
No full textThis dissertation addresses two important issues in software demonstrations — (i) the design of a feature-limited software demonstration, and (ii) the role of data demonstration when firms bargain over proprietary data. These aspects of software demonstrations are presented in three separate essays provided in chapters 2, 3, and 4 with an introduction in chapter 1.
In the first essay we focus on feature-limited demonstration versions where some of the features are provided free of charge while the remaining features are charged by the vendor. As the specific features included in the feature-limited version influence whether the full product is purchased or not, it is essential that the features included in the feature-limited version be selected judiciously. This study fills the gap in the literature by providing an objective approach to the design of demonstration software.
The second essay investigates the data monetization issue through a negotiation process between a seller and a buyer and also considers the role of a data demonstration by the seller to mitigate the buyer side uncertainty in valuation. Both data sellers and buyers are often unclear about the true potential of the proprietary data, which in turn affects their pricing decision. This raises a fundamental question — how should the price of a unique and proprietary data be decided and is there a way to mitigate the uncertainty in valuation of the data? We model the pricing decision as a Nash bargaining problem where price of the data is mutually decided. The seller has an outside option and will negotiate with the buyer if they expect to gain from the negotiation. The seller also has an option to offer a data demonstration before the negotiation process to reduce the buyer side uncertainty in the valuation. Our results show that the presence of a moderately high outside option can trigger a demonstration. Interestingly, the seller is better off providing a noisy demonstration even when they do not have an outside option but the chances of a high value data is relatively high.
There are several instances where proprietary data can be quite rich and complex and extracting meaningful insights could require considerable effort in such situations. Sometimes the buyer may not always have the ability to effectively analyze the data and is willing to hire a consultant for this task. The consultant acts as a gatekeeper and works with the buyer. Once a decision is made to purchase the data, the buyer pays the seller for the data and the consultant for their services. The prices are arrived at through a negotiation process involving all three parties. The third essay investigates the outcome of the negotiation in the presence of a consultant and observes that proposing a demonstration is not beneficial for the seller in a three-party negotiation. However, it is interesting to find that if the consultant or the seller is aware of the true value while the buyer remains unaware as before, this does not help the consultant or the seller
Three Essays in Information Systems
No full textThis dissertation tackles three problems in information systems: In the first essay we investigate the value of a local showroom to online competition. An increasing number of online retailers are grappling with whether to expand their operations to offline local showrooms. In this study, we quantify the value of showrooms by investigating how the presence and absence of local showrooms may impact customers’ searching and purchasing behaviors with online competitors. By using an exogenous event of a large retailer’s offline market exit and a unique data set capturing customers’ online browsing and purchasing activities before and after the event, we empirically examine the changes in online search and sales made by customers who lived within neighborhoods where showrooms closed. We question the adequacy of conventional sales-based measures and devise several search-based measures in order to better quantify the value of a showroom from the perspective of customer experience online. Using a difference-in-difference approach, we find mixed results in terms of online competitors’ sales when a neighboring showroom closes. More importantly, we observe an increase in customers’ online search intensity in the absence of local showrooms. We discuss a wide range of implications both for online and offline retailers based on our results.
The second problem we analyze is the effect of worker collaboration on productivity and costs to a company. Although collaboration in the workplace is promoted as a silver bullet for increasing productivity and decreasing costs, there is little empirical evidence to show the effects of collaboration. Using a unique dataset and a field experiment we develop a framework to measure the effects of collaboration in a service delivery industry. Our results show that when collaboration is forced on employees, although productivity increases, costs also increase. Based on our conclusions we recommend management to allow employees to choose when to collaborate and when not to. On further analysis of the implementation of our recommendations, we find that productivity levels increase along with reduction in costs if employees are allowed to choose when to collaborate on tasks.
Finally, we investigate how to tackle the patching schedule of custom built enterprise systems. Keeping software systems safe from hackers is one of the most important goals for system operations managers. A system that has outstanding security patches is inherently risky and managers incur costs to keep the security of such systems at an acceptable level. Alternatively, they can choose to expend resources to apply outstanding patches and increase the security state of the system and thereby reducing the costs to maintain the system. In this research we study a motivating example from the Information and Communications Technology (ICT) industry and apply a control theoretic model to solve for optimal patching periods. The optimal patching policy is shown to have a bang-bang solution which explains common approaches practiced in the industry. The results in this research are valuable to operations and maintenance managers who strive to keep enterprise software systems safe while minimizing cost
Essays on Health Information Technology, Social Media, and Care Quality
No full textThis dissertation consists of five chapters. Chapter 1 provides introduction to the research
framework and questions examined in Chapters 2, 3 and 4. In Chapter 5, I conclude by
summarizing the key findings and implications. The main focus of this dissertation is
technology, such as health information technology (IT) and social media, and their relationship
with care quality and provider performance.
In Chapter 2, I examine the association between care quality (outcomes), health IT usage, and
Medicare reimbursements for congestive heart failure cases. This examination was done using a
three-year hospital-level panel dataset. The main finding is that hospitals with a higher level of
technology usage tend to experience higher reimbursements. Although this finding supports the
idea that technology improves efficiency, I do not observe any effectiveness gains, that is, there
is no reason to believe that improvements are happening because of improvements in clinical
outcomes. This is one of the first studies to look at reimbursements and how technology impacts
them in comprehensive way.
In Chapter 3, I study whether online reviews of physicians can provide reliable signals for the
actual clinical outcomes experienced by their patients. To study this question, I leveraged a
granular patient-admission-discharge dataset alongside physician reviews scraped from a public
website, Vitals.com. Contrary to findings in recent research, my study finds that there is no clear
relationship between online reviews of physicians and their patients’ clinical outcomes, such as
the readmission or the ER visit rate. Hence, online reviews may not be as helpful in the context
of healthcare services ridden with credence qualities as they usually are for experience goods
such as books, movies, or hotels. So, patients, providers, and policy makers should be careful
when inferring physician performance from online physician reviews.
In Chapter 4, I empirically investigate whether online reviews truly capture a physician’s
adherence to clinical guidelines. In addition, I examine whether the reviews indeed reflect the
benefits expected from using an electronic health records (EHR) system. The findings from this
investigation suggest that there is no significant relationship between adherence to clinical
guidelines by physicians and their online reviews, but there exists a positive relationship between
EHR usage and some dimensions of online reviews. The implication of these findings is that,
although the credence nature of healthcare services might obscure the quality of care delivery
and make online reviews somewhat unreliable, efficiency improvements from increased use of
health IT translates into positive patient perceptions, providing a natural motivation for a greater
adoption.
The above-mentioned findings have important implications for several stakeholders including
healthcare providers, patients, and policymakers. In Chapter 5, I summarize them alongside
conclusions that can be drawn from Chapters 2, 3 and 4
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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