4,494 research outputs found
A comparative study of the AHP and TOPSIS methods for implementing load shedding scheme in a pulp mill system
The advancement of technology had encouraged mankind to design and create useful
equipment and devices. These equipment enable users to fully utilize them in various
applications. Pulp mill is one of the heavy industries that consumes large amount of
electricity in its production. Due to this, any malfunction of the equipment might
cause mass losses to the company. In particular, the breakdown of the generator
would cause other generators to be overloaded. In the meantime, the subsequence
loads will be shed until the generators are sufficient to provide the power to other
loads. Once the fault had been fixed, the load shedding scheme can be deactivated.
Thus, load shedding scheme is the best way in handling such condition. Selected load
will be shed under this scheme in order to protect the generators from being
damaged. Multi Criteria Decision Making (MCDM) can be applied in determination
of the load shedding scheme in the electric power system. In this thesis two methods
which are Analytic Hierarchy Process (AHP) and Technique for Order Preference by
Similarity to Ideal Solution (TOPSIS) were introduced and applied. From this thesis,
a series of analyses are conducted and the results are determined. Among these two
methods which are AHP and TOPSIS, the results shown that TOPSIS is the best
Multi criteria Decision Making (MCDM) for load shedding scheme in the pulp mill
system. TOPSIS is the most effective solution because of the highest percentage
effectiveness of load shedding between these two methods. The results of the AHP
and TOPSIS analysis to the pulp mill system are very promising
Semantic image retrieval using relevance feedback and transaction logs
Due to the recent improvements in digital photography and storage capacity, storing large amounts of images has been made possible, and efficient means to retrieve images matching a user’s query are needed. Content-based Image Retrieval (CBIR) systems automatically extract image contents based on image features, i.e. color, texture, and shape. Relevance feedback methods are applied to CBIR to integrate users’ perceptions and reduce the gap between high-level image semantics and low-level image features. The precision of a CBIR system in retrieving semantically rich (complex) images is improved in this dissertation work by making advancements in three areas of a CBIR system: input, process, and output. The input of the system includes a mechanism that provides the user with required tools to build and modify her query through feedbacks. Users behavioral in CBIR environments are studied, and a new feedback methodology is presented to efficiently capture users’ image perceptions. The process element includes image learning and retrieval algorithms. A Long-term image retrieval algorithm (LTL), which learns image semantics from prior search results available in the system’s transaction history, is developed using Factor Analysis. Another algorithm, a short-term learner (STL) that captures user’s image perceptions based on image features and user’s feedbacks in the on-going transaction, is developed based on Linear Discriminant Analysis. Then, a mechanism is introduced to integrate these two algorithms to one retrieval procedure. Finally, a retrieval strategy that includes learning and searching phases is defined for arranging images in the output of the system. The developed relevance feedback methodology proved to reduce the effect of human subjectivity in providing feedbacks for complex images. Retrieval algorithms were applied to images with different degrees of complexity. LTL is efficient in extracting the semantics of complex images that have a history in the system. STL is suitable for query and images that can be effectively represented by their image features. Therefore, the performance of the system in retrieving images with visual and conceptual complexities was improved when both algorithms were applied simultaneously. Finally, the strategy of retrieval phases demonstrated promising results when the query complexity increases
A Hybrid Web Recommendation System based on the Improved Association Rule Mining Algorithm
As the growing interest of web recommendation systems those are applied to
deliver customized data for their users, we started working on this system.
Generally the recommendation systems are divided into two major categories such
as collaborative recommendation system and content based recommendation system.
In case of collaborative recommen-dation systems, these try to seek out users
who share same tastes that of given user as well as recommends the websites
according to the liking given user. Whereas the content based recommendation
systems tries to recommend web sites similar to those web sites the user has
liked. In the recent research we found that the efficient technique based on
asso-ciation rule mining algorithm is proposed in order to solve the problem of
web page recommendation. Major problem of the same is that the web pages are
given equal importance. Here the importance of pages changes according to the
fre-quency of visiting the web page as well as amount of time user spends on
that page. Also recommendation of newly added web pages or the pages those are
not yet visited by users are not included in the recommendation set. To
over-come this problem, we have used the web usage log in the adaptive
association rule based web mining where the asso-ciation rules were applied to
personalization. This algorithm was purely based on the Apriori data mining
algorithm in order to generate the association rules. However this method also
suffers from some unavoidable drawbacks. In this paper we are presenting and
investigating the new approach based on weighted Association Rule Mining
Algorithm and text mining. This is improved algorithm which adds semantic
knowledge to the results, has more efficiency and hence gives better quality
and performances as compared to existing approaches.Comment: 9 pages, 7 figures, 2 table
The development, status and trends of recommender systems: a comprehensive and critical literature review
Recommender systems have been used in many fields of research and business applications. In this paper, a comprehensive and critical review of the literature on recommender systems is provided. A classification mechanism of recommender systems is proposed. The review pays attention to and covers the recommender system algorithms, application areas and data mining techniques published in relevant peer-reviewed journals between 2001 and 2013. The development of the field, status and trends are analyzed and discussed in the paper
A survey of data mining techniques for social media analysis
Social network has gained remarkable attention in the last decade. Accessing social network sites such as Twitter, Facebook LinkedIn and Google+ through the internet and the web 2.0 technologies has become more affordable. People are becoming more interested in and relying on social network for information, news and opinion of other users on diverse subject matters. The heavy reliance on social network sites causes them to generate massive data characterised by three computational issues namely; size, noise and dynamism. These issues often make social network data very complex to analyse manually, resulting in the pertinent use of computational means of analysing them. Data mining provides a wide range of techniques for detecting useful knowledge from massive datasets like trends, patterns and rules [44]. Data mining techniques are used for information retrieval, statistical modelling and machine learning. These techniques employ data pre-processing, data analysis, and data interpretation processes in the course of data analysis. This survey discusses different data mining techniques used in mining diverse aspects of the social network over decades going from the historical techniques to the up-to-date models, including our novel technique named TRCM. All the techniques covered in this survey are listed in the Table.1 including the tools employed as well as names of their authors
A new technique for intelligent web personal recommendation
Personal recommendation systems nowadays are very important in web applications
because of the available huge volume of information on the World Wide Web, and the
necessity to save users’ time, and provide appropriate desired information, knowledge,
items, etc. The most popular recommendation systems are collaborative filtering systems,
which suffer from certain problems such as cold-start, privacy, user identification, and
scalability. In this thesis, we suggest a new method to solve the cold start problem taking
into consideration the privacy issue. The method is shown to perform very well in
comparison with alternative methods, while having better properties regarding user privacy.
The cold start problem covers the situation when recommendation systems have not
sufficient information about a new user’s preferences (the user cold start problem), as well
as the case of newly added items to the system (the item cold start problem), in which case
the system will not be able to provide recommendations. Some systems use users’
demographical data as a basis for generating recommendations in such cases (e.g. the
Triadic Aspect method), but this solves only the user cold start problem and enforces user’s
privacy. Some systems use users’ ’stereotypes’ to generate recommendations, but
stereotypes often do not reflect the actual preferences of individual users. While some other
systems use user’s ’filterbots’ by injecting pseudo users or bots into the system and consider
these as existing ones, but this leads to poor accuracy.
We propose the active node method, that uses previous and recent users’ browsing targets
and browsing patterns to infer preferences and generate recommendations (node
recommendations, in which a single suggestion is given, and batch recommendations, in
which a set of possible target nodes are shown to the user at once). We compare the active
node method with three alternative methods (Triadic Aspect Method, Naïve Filterbots
Method, and MediaScout Stereotype Method), and we used a dataset collected from online
web news to generate recommendations based on our method and based on the three
alternative methods. We calculated the levels of novelty, coverage, and precision in these
experiments, and we found that our method achieves higher levels of novelty in batch
recommendation while achieving higher levels of coverage and precision in node
recommendations comparing to these alternative methods. Further, we develop a variant of
the active node method that incorporates semantic structure elements. A further
experimental evaluation with real data and users showed that semantic node
recommendation with the active node method achieved higher levels of novelty than nonsemantic
node recommendation, and semantic-batch recommendation achieved higher levels
of coverage and precision than non-semantic batch recommendation
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