Digital traces of our lives are now constantly produced by various connected devices, internet services and interactions. Our actions result in a multitude of heterogeneous data objects, or traces, kept in various locations in the cloud or on local devices. Users have very few tools to organize, understand, and search the digital traces they produce. We propose a simple but flexible data model to aggregate, organize, and find personal information within a collection of a user's personal digital traces. Our model uses as basic dimensions the six questions: what, when, where, who, why, and how. These natural questions model universal aspects of a personal data collection and serve as unifying features of each personal data object, regardless of its source. We propose indexing and search techniques to aid users in searching for their past information in their unified personal digital data sets using our model. Experiments performed over real user data from a variety of data sources such as Facebook, Dropbox, and Gmail show that our approach significantly improves search accuracy when compared with traditional search tools.
@cite_31: A major limitation of most existing retrieval models and systems is that the retrieval decision is made based solely on the query and document collection; information about the actual user and search context is largely ignored. In this paper, we study how to exploit implicit feedback information, including previous queries and clickthrough information, to improve retrieval accuracy in an interactive information retrieval setting. We propose several context-sensitive retrieval algorithms based on statistical language models to combine the preceding queries and clicked document summaries with the current query for better ranking of documents. We use the TREC AP data to create a test collection with search context information, and quantitatively evaluate our models using this test set. Experiment results show that using implicit feedback, especially the clicked document summaries, can improve retrieval performance substantially.
@cite_21: 
@cite_10: Purpose – This survey aims to study and analyze current techniques and methods for context‐aware web service systems, to discuss future trends and propose further steps on making web services systems context‐aware.Design methodology approach – The paper analyzes and compares existing context‐aware web service‐based systems based on techniques they support, such as context information modeling, context sensing, distribution, security and privacy, and adaptation techniques. Existing systems are also examined in terms of application domains, system type, mobility support, multi‐organization support and level of web services implementation.Findings – Supporting context‐aware web service‐based systems is increasing. It is hard to find a truly context‐aware web service‐based system that is interoperable and secure, and operates on multi‐organizational environments. Various issues, such as distributed context management, context‐aware service modeling and engineering, context reasoning and quality of context, se...
Contextual information has been considered in various computer science applications. Context-aware applications dynamically adapt to changes in the environment in which they are running: location, time, user profile, history. provide a thorough survey of context-aware models in @cite_21 . Truong and Dustdar survey context-aware Web-Service systems in @cite_10 . Context-awareness has become increasingly popular with the wide adoption of mobile devices. While the types of context these systems consider overlap with ours, the overall approach is different from ours, for instance a contextually-aware Information Retrieval system will use the current context (e.g., user location and time of day) to adjust search results @cite_31 . In contrast, we consider context as information that can be queried and used to guide the search.