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certainty.tex
| @@ -152,7 +152,7 @@ to drive the adaptation approaches discussed next. | @@ -152,7 +152,7 @@ to drive the adaptation approaches discussed next. | ||
| 152 | 152 | ||
| 153 | While large-scale split testing is intended to provide good coverage over all | 153 | While large-scale split testing is intended to provide good coverage over all |
| 154 | possible sources of uncertainty we have discussed, it still normally requires | 154 | possible sources of uncertainty we have discussed, it still normally requires |
| 155 | -that only one choice be made at any given time---implying that two | 155 | +that only one decision be made at any given time---implying that two |
| 156 | alternatives may never be evaluated under identical conditions. For | 156 | alternatives may never be evaluated under identical conditions. For |
| 157 | \texttt{maybe} statements, however, we are exploring the idea of performing | 157 | \texttt{maybe} statements, however, we are exploring the idea of performing |
| 158 | \textit{simultaneous} split testing. In this model the app forks at the top | 158 | \textit{simultaneous} split testing. In this model the app forks at the top |
| @@ -168,7 +168,7 @@ interference between alternatives executing in parallel. | @@ -168,7 +168,7 @@ interference between alternatives executing in parallel. | ||
| 168 | \subsection{\texttt{\large maybe} Endgames} | 168 | \subsection{\texttt{\large maybe} Endgames} |
| 169 | 169 | ||
| 170 | The entire \texttt{maybe} approach is predicated on the fact that there does | 170 | The entire \texttt{maybe} approach is predicated on the fact that there does |
| 171 | -exist, among the alternatives, a right choice, even if it depends on many | 171 | +exist, among the alternatives, a right decision, even if it depends on many |
| 172 | factors and uncertainties. We continue by discussing how the dataset | 172 | factors and uncertainties. We continue by discussing how the dataset |
| 173 | generated by post-deployment testing can be used to determine how to | 173 | generated by post-deployment testing can be used to determine how to |
| 174 | correctly choose \texttt{maybe} alternatives at runtime. | 174 | correctly choose \texttt{maybe} alternatives at runtime. |
| @@ -203,7 +203,7 @@ adaptation is time varying (dynamic) or not (static). We begin with the | @@ -203,7 +203,7 @@ adaptation is time varying (dynamic) or not (static). We begin with the | ||
| 203 | second, somewhat easier case. | 203 | second, somewhat easier case. |
| 204 | 204 | ||
| 205 | If the alternative is determined through static adaptation then the correct | 205 | If the alternative is determined through static adaptation then the correct |
| 206 | -choice is a function of some unchanging (or very-slowly changing) aspect of | 206 | +decision is a function of some unchanging (or very-slowly changing) aspect of |
| 207 | the deployed environment. Examples include the device model, average network | 207 | the deployed environment. Examples include the device model, average network |
| 208 | conditions, the other apps installed on the device, or user characteristics | 208 | conditions, the other apps installed on the device, or user characteristics |
| 209 | such as gender, age, or charging habits. In this case it is possible that the | 209 | such as gender, age, or charging habits. In this case it is possible that the |
| @@ -227,7 +227,7 @@ into the fragile decision-making we are trying to avoid. | @@ -227,7 +227,7 @@ into the fragile decision-making we are trying to avoid. | ||
| 227 | 227 | ||
| 228 | Instead, the \texttt{maybe} system allows developers to experiment with and | 228 | Instead, the \texttt{maybe} system allows developers to experiment with and |
| 229 | evaluate a variety of different dynamic adaptation strategies deployed in a | 229 | evaluate a variety of different dynamic adaptation strategies deployed in a |
| 230 | -companion library, with the choice guided by post-deployment testing. For | 230 | +companion library, with the decision guided by post-deployment testing. For |
| 231 | example, if the performance of an alternative is discovered to be correlated | 231 | example, if the performance of an alternative is discovered to be correlated |
| 232 | with a link providing a certain amount of bandwidth, then that adaptation | 232 | with a link providing a certain amount of bandwidth, then that adaptation |
| 233 | strategy can be connected with that particular \texttt{maybe} statement. | 233 | strategy can be connected with that particular \texttt{maybe} statement. |
| @@ -236,18 +236,18 @@ Observe that in some cases of dynamic adaptation, what begins as a | @@ -236,18 +236,18 @@ Observe that in some cases of dynamic adaptation, what begins as a | ||
| 236 | \texttt{maybe} statement may end as effectively \texttt{if-else} statement | 236 | \texttt{maybe} statement may end as effectively \texttt{if-else} statement |
| 237 | switching on a static threshold---the same approach we attacked to motivate | 237 | switching on a static threshold---the same approach we attacked to motivate |
| 238 | our system. However, through the process of arriving at this point we have | 238 | our system. However, through the process of arriving at this point we have |
| 239 | -determined several things that were initially unknown: what the alternatives | ||
| 240 | -accomplish, that a single threshold works for all users, and what that | ||
| 241 | -threshold is. And by maintaining the choice as a \texttt{maybe} statement, | ||
| 242 | -they can continue the adaptation process as devices, users, and networks | 239 | +determined several things that were initially unknown: (1) what the |
| 240 | +alternatives accomplish, (2) that a single threshold works for all users, and | ||
| 241 | +(3) what that threshold is. And by maintaining the choice as a \texttt{maybe} | ||
| 242 | +statement, they can continue adaptating as devices, users, and networks | ||
| 243 | change. | 243 | change. |
| 244 | 244 | ||
| 245 | Another benefit of this approach is that time-varying decisions can be | 245 | Another benefit of this approach is that time-varying decisions can be |
| 246 | -outsourced to developers with expertise in the particular area driving | ||
| 247 | -adaptation policy decisions. For example, by exposing an energy-performance | ||
| 248 | -tradeoff through a \texttt{maybe} statement, a developer allows it to be | ||
| 249 | -driven by a sophisticated machine learning algorithm written by an expert in | ||
| 250 | -energy adaptation, instead of their own ad-hoc approach. | 246 | +outsourced to developers with expertise in the particular area affecting |
| 247 | +adaptation decisions. For example, by exposing an energy-performance tradeoff | ||
| 248 | +through a \texttt{maybe} statement, a developer allows it to be connected to | ||
| 249 | +a sophisticated machine learning algorithm written by an expert in energy | ||
| 250 | +adaptation, instead of their own ad-hoc approach. | ||
| 251 | 251 | ||
| 252 | \subsubsection{Manual adaptation} | 252 | \subsubsection{Manual adaptation} |
| 253 | 253 | ||
| @@ -255,7 +255,7 @@ In some cases even our best efforts to automatically adapt may fail, and it | @@ -255,7 +255,7 @@ In some cases even our best efforts to automatically adapt may fail, and it | ||
| 255 | may be impossible to predict which alternative is best for a particular user | 255 | may be impossible to predict which alternative is best for a particular user |
| 256 | using a particular device at a particular time. If the differences between | 256 | using a particular device at a particular time. If the differences between |
| 257 | the alternatives are small, then it may be appropriate to simply fall back to | 257 | the alternatives are small, then it may be appropriate to simply fall back to |
| 258 | -a best-effort choice. However, if the differences between the alternatives | 258 | +a best-effort decision. However, if the differences between the alternatives |
| 259 | are significant then the \texttt{maybe} alternatives may need to be exposed | 259 | are significant then the \texttt{maybe} alternatives may need to be exposed |
| 260 | to the user through a settings menu. Fortunately, information obtained | 260 | to the user through a settings menu. Fortunately, information obtained |
| 261 | through testing can still be presented to the user to guide their decision. | 261 | through testing can still be presented to the user to guide their decision. |