Supporting privacy protection in personalized web search

Supporting Privacy Protection in Personalized
Web Search
ABSTRACT
Personalized web search (PWS) has demonstrated its effectiveness in improving the
quality of various search services on the Internet. However, evidences show that users’
reluctance to disclose their private information during search has become a major barrier for the
wide proliferation of PWS. We study privacy protection in PWS applications that model user
preferences as hierarchical user profiles. We propose a PWS framework called UPS that can
adaptively generalize profiles by queries while respecting userspecified privacy requirements.
Our runtime generalization aims at striking a balance between two predictive metrics that
evaluate the utility of personalization and the privacy risk of exposing the generalized profile.
We present two greedy algorithms, namely GreedyDP and GreedyIL, for runtime generalization.
We also provide an online prediction mechanism for deciding whether personalizing a query is
beneficial. Extensive experiments demonstrate the effectiveness of our framework. The
experimental results also reveal that GreedyIL significantly outperforms GreedyDP in terms of
efficiency.
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Existing System
The existing profile-based Personalized Web Search do not support runtime profiling. A
user profile is typically generalized for only once offline, and used to personalize all queries
from a same user indiscriminatingly. Such “one profile fits all” strategy certainly has drawbacks
given the variety of queries. One evidence reported in is that profile-based personalization may
not even help to improve the search quality for some ad hoc queries, though exposing user
profile to a server has put the user’s privacy at risk.
The existing methods do not take into account the customization of privacy requirements.
This probably makes some user privacy to be overprotected while others insufficiently protected.
For example, in, all the sensitive topics are detected using an absolute metric called surprisal
based on the information theory, assuming that the interests with less user document support are
more sensitive. However, this assumption can be doubted with a simple counterexample: If a
user has a large number of documents about “sex,” the surprisal of this topic may lead to a
conclusion that “sex” is very general and not sensitive, despite the truth which is opposite.
Unfortunately, few prior work can effectively address individual privacy needs during the
generalization.
Many personalization techniques require iterative user interactions when creating personalized
search results. They usually refine the search results with some metrics which require multiple
user interactions, such as rank scoring, average rank, and so on. This paradigm is, however,
infeasible for runtime profiling, as it will not only pose too much risk of privacy breach, but also
demand prohibitive processing time for profiling. Thus, we need predictive metrics to measure
the search quality and breach risk after personalization, without incurring iterative user
interaction.
Disadvantage:

All the sensitive topics are detected using an absolute metric called surprisal based on the
information theory.
Proposed System:
We propose a privacy-preserving personalized web search framework UPS, which can
generalize profiles for each query according to user-specified privacy requirements. Relying on
the definition of two conflicting metrics, namely personalization utility and privacy risk, for
hierarchical user profile, we formulate the problem of privacy-preserving personalized search as
Risk Profile Generalization, with itsNP-hardness proved.
We develop two simple but effective generalization algorithms, GreedyDP and GreedyIL,
to support runtime profiling. While the former tries to maximize the discriminating power (DP),
the latter attempts to minimize the information loss (IL). By exploiting a number of heuristics,
GreedyIL outperforms GreedyDP significantly.
We provide an inexpensive mechanism for the client to decide whether to personalize a
query in UPS. This decision can be made before each runtime profiling to enhance the stability
of the search results while avoid the unnecessary exposure of the profile.
Advantages:
1. It enhances the stability of the search quality.
2. It avoids the unnecessary exposure of the user profile.

Architecture:
Enhanced

MODULES”
1. Profile-Based Personalization.
2. Privacy Protection in PWS System.
3. Generalizing User Profile.
4. Online Decision.
Modules Description
1. Profile-Based Personalization
This paper introduces an approach to personalize digital multimedia content based on
user profile information. For this, two main mechanisms were developed: a profile
generator that automatically creates user profiles representing the user preferences, and a

content-based recommendation algorithm that estimates the user's interest in unknown
content by matching her profile to metadata descriptions of the content. Both features are
integrated into a personalization system.
2. Privacy Protection in PWS System
We propose a PWS framework called UPS that can generalize profiles in for each
query according to user-specified privacy requirements. Two predictive metrics are
proposed to evaluate the privacy breach risk and the query utility for hierarchical user
profile. We develop two simple but effective generalization algorithms for user profiles
allowing for query-level customization using our proposed metrics. We also provide an
online prediction mechanism based on query utility for deciding whether to personalize a
query in UPS. Extensive experiments demonstrate the efficiency and effectiveness of our
framework.
3. Generalizing User Profile
The generalization process has to meet specific prerequisites to handle the user
profile. This is achieved by preprocessing the user profile. At first, the process initializes
the user profile by taking the indicated parent user profile into account. The process adds
the inherited properties to the properties of the local user profile. Thereafter the process
loads the data for the foreground and the background of the map according to the
described selection in the user profile.
Additionally, using references enables caching and is helpful when considering an
implementation in a production environment. The reference to the user profile can be
used as an identifier for already processed user profiles. It allows performing the
customization process once, but reusing the result multiple times. However, it has to be
made sure, that an update of the user profile is also propagated to the generalization

process. This requires specific update strategies, which check after a specific timeout or a
specific event, if the user profile has not changed yet. Additionally, as the generalization
process involves remote data services, which might be updated frequently, the cached
generalization results might become outdated. Thus selecting a specific caching strategy
requires careful analysis.
4. Online Decision
The profile-based personalization contributes little or even reduces the search
quality, while exposing the profile to a server would for sure risk the user’s privacy. To
address this problem, we develop an online mechanism to decide whether to personalize a
query. The basic idea is straightforward. if a distinct query is identified during
generalization, the entire runtime profiling will be aborted and the query will be sent to
the server without a user profile.
System Configuration:-
H/W System Configuration:-
Processor - Pentium –III
Speed - 1.1 Ghz
RAM - 256 MB (min)
Hard Disk - 20 GB

Floppy Drive - 1.44 MB
Key Board - Standard Windows Keyboard
Mouse - Two or Three Button Mouse
Monitor - SVGA
S/W System Configuration:-
 Operating System :Windows95/98/2000/XP
 Application Server : Tomcat5.0/6.X
 Front End : HTML, Java, Jsp
 Scripts : JavaScript.
 Server side Script : Java Server Pages.
 Database : Mysql
 Database Connectivity : JDBC.
CONCLUSION
This paper presented a client-side privacy protection framework called UPS for
personalized web search. UPS could potentially be adopted by any PWS that captures user
profiles in a hierarchical taxonomy. The framework allowed users to specify customized privacy
requirements via the hierarchical profiles. In addition, UPS also performed online generalization
on user profiles to protect the personal privacy without compromising the search quality. We
proposed two greedy algorithms, namely GreedyDP and GreedyIL, for the online generalization.
Our experimental results revealed that UPS could achieve quality search results while preserving

user’s customized privacy requirements. The results also confirmed the effectiveness and
efficiency of our solution.
REFERENCES
[1] Z. Dou, R. Song, and J.-R. Wen, “A Large-Scale Evaluation and Analysis of Personalized
Search Strategies,” Proc. Int’l Conf. World Wide Web (WWW), pp. 581-590, 2007.
[2] J. Teevan, S.T. Dumais, and E. Horvitz, “Personalizing Search via Automated Analysis of
Interests and Activities,” Proc. 28th Ann. Int’l ACM SIGIR Conf. Research and Development in
Information Retrieval (SIGIR), pp. 449-456, 2005.
[3] M. Spertta and S. Gach, “Personalizing Search Based on User Search Histories,” Proc.
IEEE/WIC/ACM Int’l Conf. Web Intelligence (WI), 2005.
[4] B. Tan, X. Shen, and C. Zhai, “Mining Long-Term Search History to Improve Search
Accuracy,” Proc. ACM SIGKDD Int’l Conf. Knowledge Discovery and Data Mining (KDD),
2006.
[5] K. Sugiyama, K. Hatano, and M. Yoshikawa, “Adaptive Web Search Based on User Profile
Constructed without any Effort from Users,” Proc. 13th Int’l Conf. World Wide Web (WWW),
2004.
Scope:
To protect user privacy in profile-based PWS, researchers have to consider two
contradicting effects during the search process. On the one hand, they attempt to improve the
search quality with the personalization utility of the user profile. On the other hand, they need to
hide the privacy contents existing in the user profile to place the privacy risk under control. A
few previous studies , suggest that people are willing to compromise privacy if the

personalization by supplying user profile to the search engine yields better search quality. In an
ideal case, significant gain can be obtained by personalization at the expense of only a small (and
less-sensitive) portion of the user profile, namely a generalized profile. Thus, user privacy can be
protected without compromising the personalized search quality. In general, there is a tradeoff
between the search quality and the level of privacy protection achieved from generalization.

Supporting privacy protection in personalized web search

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