Joe Corneli update recommender discussion  about 9 years ago

Commit id: 95f56b56594defaf3d3cdf44dbe77fb01d7b91d3

deletions | additions      

       

\paragraph{Minimally serendipitous systems.}  According to our standards, there are various ways to achieve a result  with \emph{low} serendipity: if the outcome observation  was likely to happen, likely,  if it further  developments  happenedby chance  with little skill, or and  if the the value of the result was low, then we would not say the outcome was serendipitous.  Campbell In Campbell's  \citeyear{campbell} describes description of  serendipity as ``the rational exploitation of chance observation, especially in the discovery of something useful or beneficial.'' beneficial'' one can see all the  components of our definition.  We would be prepared to attribute ``minimal serendipity'' to cases where the observation was  \emph{moderately} likely, \emph{some} skill or effort was involved,  and the result was only  \emph{fairly good}. For computational systems, if most of the skill involved lies with the user, then there is little reason to call the system's operation serendipitous -- even if it consistently does its job very well. For example, machines can ``learn'' to recognise instances of a given pattern quite  consistently, but it istypically  an interesting surprise if a computational system independently finds an entirely new kind of pattern. Furthermore, the position of the evaluator is important: A a  spell-checking system might suggest a particularly fortuitous  substitution, but we would not expect the spell-checker to know when  it was being clever. In such a case, we may say serendipity has 

As discussed in Section \ref{sec:related}, recommender systems are one  of the primary contexts in computing where serendipity is seen to play  a role. As we noted, these systems mostly focus on discovery.  Nevertheless, certain Although this describes the mainstream of recommender system  development, it seems that there are some  architectures that also take account of invention would match all invention. We have in mind Bayesian methods (surveyed in  Chapter 3  of criteria described by our model. Here we  draw \citeNP{shengbo-guo-thesis}). The current discussion  focuses on possibilities for serendipity on the system side, drawing  on the observation that recommender systems not \emph{stimulate} serendipitous discovery for the user: discovery:  they also have the task of \emph{simulating} when this is likely to occur. A recommendation is typically provided if the system suspects that the  item will be likely to introduce ideas that are close to what the user  knows, but that will be unexpected. In other words, the system aims  to stimulate Typical discussions of  serendipity for the user. For example, a museum in  recommender service might suggest a colourful medieval painting to a systems focus on this. However,  userwho seems to like colourful paintings by the modern artist Keith  Haring. User  behaviour (e.g.~following up on these recommendations)is outside of the direct control of the system and  may also  serve as a \textbf{serendipity trigger}, trigger} for the system,  and change the way it makes recommendations in the future. The Note that it is typically the  system's \emph{developers} who adapt the system; even in the Bayesian  case, the  system has limited responsibilities. Nevertheless, the  impetus to develop increasingly autonomous systems is present,  especially in complex domains where hand-tuning reaches its limits.  Current systems have at least the makings of  a \textbf{prepared mind}, including both a \emph{user model} and a \emph{domain model}, both of which can be updated dynamically.The connections through  which recommendations are made usually happen when the system notices  that elements of the domain have something in common via clustering or  faceting.  A \textbf{bridge} to a new kind of recommendation may be found if by pattern matching, and especially by  looking for exceptional cases:  new elements are introduced into the domain which do not cluster well, orif the user appears to know about  different clusters appear in the  user model  that do not have obvious connections between them. The intended outcome of recommendations depend depends  on the organisational mission  e.g.~to mission: to  make money, to provide a good user experience, etc.; at the  system level, the etc. The  serendiptious \textbf{result} would be learning a new approach that helps to address these goals better.  From the perspective of our model, \textbf{chance} goals.  \textbf{Chance}  will only have a significant role when in  the system if it  has the capacity to learn from user behaviour. In fact, Bayesian methods are used in contemporary  recommender systems (surveyed in Chapter 3 of  \citeNP{shengbo-guo-thesis}). %%  The typical commercial perspective on recommendations is related to %%  the process of ``conversion'' -- turning recommendations into %%  clicks and clicks into purchases. Combined with the ability to learn, \textbf{curiosity} could be described as the urge to make ``outside-the-box''\footnote{\citeA{abbassi2009getting}.} recommendations specifically for the purposes of learning more about  users, possibly to the detriment of other goals metrics  over the short term. Measures of \textbf{sagacity} would relate to the system's ability to  draw inferences from user behaviour that would update the  recommendation model. behaviour.  For example, the system might do A/B testing to decide how novel recommendation strategies influence conversion. Again, currently this would typically be organised by the  system's developers.  The \textbf{value} of recommendation strategies can be measured in terms of traditional business metrics or other organisational objectives. A \textbf{dynamic world} which nevertheless exhibits some regularity  is a precondition for useful A/B testing. As mentioned above the  primary \textbf{(multiple) contexts} are the user model and the domain  model. A system matching the description here would have  \textbf{multiple tasks}: making useful recommendations, generating new  experiments to learn about users, and building new models based on the  results of these experiments. models.  Such a system could avail itself of \textbf{multiple influences} related to experimental design, psychology, and domain understanding. % As a general comment, we would say that this is largely how  % \emph{research and development} of recommender systems works, but