21,955 research outputs found
Beyond Personalization: Research Directions in Multistakeholder Recommendation
Recommender systems are personalized information access applications; they
are ubiquitous in today's online environment, and effective at finding items
that meet user needs and tastes. As the reach of recommender systems has
extended, it has become apparent that the single-minded focus on the user
common to academic research has obscured other important aspects of
recommendation outcomes. Properties such as fairness, balance, profitability,
and reciprocity are not captured by typical metrics for recommender system
evaluation. The concept of multistakeholder recommendation has emerged as a
unifying framework for describing and understanding recommendation settings
where the end user is not the sole focus. This article describes the origins of
multistakeholder recommendation, and the landscape of system designs. It
provides illustrative examples of current research, as well as outlining open
questions and research directions for the field.Comment: 64 page
Fairs for e-commerce: the benefits of aggregating buyers and sellers
In recent years, many new and interesting models of successful online
business have been developed. Many of these are based on the competition
between users, such as online auctions, where the product price is not fixed
and tends to rise. Other models, including group-buying, are based on
cooperation between users, characterized by a dynamic price of the product that
tends to go down. There is not yet a business model in which both sellers and
buyers are grouped in order to negotiate on a specific product or service. The
present study investigates a new extension of the group-buying model, called
fair, which allows aggregation of demand and supply for price optimization, in
a cooperative manner. Additionally, our system also aggregates products and
destinations for shipping optimization. We introduced the following new
relevant input parameters in order to implement a double-side aggregation: (a)
price-quantity curves provided by the seller; (b) waiting time, that is, the
longer buyers wait, the greater discount they get; (c) payment time, which
determines if the buyer pays before, during or after receiving the product; (d)
the distance between the place where products are available and the place of
shipment, provided in advance by the buyer or dynamically suggested by the
system. To analyze the proposed model we implemented a system prototype and a
simulator that allow to study effects of changing some input parameters. We
analyzed the dynamic price model in fairs having one single seller and a
combination of selected sellers. The results are very encouraging and motivate
further investigation on this topic
Evolutionary Optimization of ZIP60: A Controlled Explosion in Hyperspace
The âZIPâ adaptive trading algorithm has been demonstrated to out-perform human traders in experimental studies of continuous double auction (CDA) markets. The original ZIP algorithm requires the values of eight control parameters to be set correctly. A new extension of the ZIP algorithm, called ZIP60, requires the values of 60 parameters to be set correctly. ZIP60 is shown here to produce significantly better results than the original ZIP (called âZIP8â hereafter), for negligable additional computational costs. A genetic algorithm (GA) is used to search the 60-dimensional ZIP60 parameter space, and it finds parameter vectors that yield ZIP60 traders with mean scores significantly better than those of ZIP8s. This paper shows that the optimizing evolutionary search works best when the GA itself controls the dimensionality of the search-space, so that the search commences in an 8-d space and thereafter the dimensionality of the search-space is gradually increased by the GA until it is exploring a 60-d space. Furthermore, the results from ZIP60 cast some doubt on prior ZIP8 results concerning the evolution of new âhybridâ auction mechanisms that appeared to be better than the CDA
A theoretical and computational basis for CATNETS
The main content of this report is the identification and definition of market mechanisms for Application Layer Networks (ALNs). On basis of the structured Market Engineering process, the work comprises the identification of requirements which adequate market mechanisms for ALNs have to fulfill. Subsequently, two mechanisms for each, the centralized and the decentralized case are described in this document. These build the theoretical foundation for the work within the following two years of the CATNETS project. --Grid Computing
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