From 61fa30d37740a434e8de1b48f6e9a40903e97443 Mon Sep 17 00:00:00 2001 From: Geoffrey Challen Date: Mon, 13 Oct 2014 19:46:38 -0400 Subject: [PATCH] Mine. --- usage.tex | 75 ++++++++++++++++++++++++++------------------------------------------------- 1 file changed, 26 insertions(+), 49 deletions(-) diff --git a/usage.tex b/usage.tex index 5cd478a..9ba2890 100644 --- a/usage.tex +++ b/usage.tex @@ -2,33 +2,17 @@ \label{sec-usage} To motivate the need for a value measure, we return to the questions posed in -the introduction. We explore each in more depth, providing a more detailed -description of how a value measure could be used. These use cases also help -us develop requirements for our metric, which are summarized at the end of -this section. We begin by exploring the basic question at the heart of the -problem: what is the value delivered by an app? +the introduction and explore each in more depth. These use cases also help us +develop requirements for our measure, which are summarized at the end of this +section. We begin by exploring the basic question at the heart of the +problem: what is the value of an app? -\subsection{What is Value?} - -\begin{comment} - -\begin{quote} -I shall not today attempt further to define the kinds of material I -understand to be embraced within that shorthand description; and perhaps I -could never succeed in intelligibly doing so. But I know it when I see it, -and the motion picture involved in this case is not that.\\ ----Justice Potter Stewart~\cite{jacobellisvohio}. -\end{quote} - -\end{comment} +\subsection{What is App Value?} All smartphone users intuitively realize that smartphone apps differ in value---an email client, for example, is probably more valuable than a app -that makes farting sounds, and a chat client is probably more valuable than a -chat client that only sends the message ``yo''. In Supreme Court Justice -Potter Steward's famous formulation, they know value when they see it. But is -it possible to quantify these subjective distinctions and produce a value -measure? +that makes farting sounds. But is it possible to quantify these subjective +distinctions and produce a value measure? To argue that this is possible we present two experiments that elucidate smartphone app value in the form of both ordinal and cardinal utilities, @@ -49,19 +33,15 @@ battery percentages to each app you use. % We plan to engage smartphone users in studies to explore in more detail which of these approaches is more effective, comparing them by comparing users' -levels of satisfaction under each scenario. As an alternate formulation of -the second experiment to make it more similar to the first, the adversary -could remove the apps consuming the least energy up to a given target. - -For our value measure we are hopeful that users will prove capable of -assigning cardinal utilities to apps---as in the second experiment---since -this matches most directly with our proposed value measure and could provide -ground truth for a value measure computed automatically. The second -experiment also engages users directly in the task of allocating energy, -which is one way that a value measure could be used. However, if ordinal -utilities prove more intuitive we can still compare the ordering generated by -our value metric with the ordering generated by users, although the specific -values of the measure will still require justification. +levels of satisfaction under each scenario. For our value measure we are +hopeful that users will prove capable of assigning cardinal utilities to +apps---as in the second experiment---since this matches most directly with +our proposed value measure and could provide ground truth for a value measure +computed automatically. The second experiment also engages users directly in +the task of allocating energy, which is one way that a value measure could be +used. However, if ordinal utilities prove more intuitive we can still compare +the ordering generated by our measure with the ordering generated by users, +although the values of the measure will still require justification. In either case, we believe that these experiments do suggest the existence of quantifiable value for smartphone apps. We are not claiming, however, that @@ -90,15 +70,14 @@ consumption. Unless it is terribly written, the chat client will consume less energy. But this does not mean that it is efficient, or that the videoconferencing app is not. Ultimately, all the energy consumption comparison truly reveals is that the two apps do different things---which we -knew. +already knew. Using energy consumption alone even makes apples-to-apples of the same app difficult. Given an app that consumes twice as much energy on Alice's smartphone than on Bob's, the question of why is left unanswered by pure energy measures. Even if usage time can be used to normalize the comparison to the power consumed, power consumption alone cannot incorporate differences -due to the different app features used by Alice and Bob or the different ways -that they have configured the app. +due to the different app features or configurations used by Alice and Bob. By computing value and, thus, energy efficiency, we can overcome these weaknesses. A value measure should allow us to compare the efficiency of two @@ -108,10 +87,10 @@ video players. Comparisons within the same app category should allow users to select the most efficient email client or web browser. Aggregating results over all users, differences in app energy efficiency should reflect how well the app is written and how well it predicts and adapts to users, not just -differences in the core features it provides. And when comparing two users -using the same app, differences in energy efficiency should reflect different -configurations or differences in how efficiently at app provides certain -features, not just that one user is using one feature and another is not. +differences in the core features it provides. When comparing two users using +the same app, differences in efficiency should reflect different +configurations or differences in how efficiently the app provides certain +features. \subsection{Evaluating App Changes} @@ -150,9 +129,9 @@ allocates a rate to each app and enforces that rate by slowing or stopping the app when it exceeds its allocation~\cite{odyssey-osr99,cinder-eurosys11,Zeng:2003,pixie-sensys08}. However, all of these previous efforts have ignored the critical question of -\textbf{how rates should be set}. No matter how effective the enforcement -mechanisms are, systems that rely on rates will fail if they provide the same -rate to Skype and Snapchat, or to a very efficient app and an energy virus. +how rates should be set. No matter how effective the enforcement mechanisms +are, systems that rely on rates will fail if they provide the same rate to +Skype and Snapchat, or to a very efficient app and an energy virus. A measure of value can be used alone or in conjunction with energy consumption to help prioritize limited energy resources. The simplest approach is to @@ -186,10 +165,8 @@ inputs, requiring that it be calculable given data from a single user. app generate value and what parts do not. \item It should be able to be efficiently computed to not overly consume the -very resource that it is designed to help manage. +resources that it is designed to help manage. \item It should be derived with little to no input from the user. \end{itemize} -% -We continue by discussing possible inputs to such a metric. -- libgit2 0.22.2