Yuko Sakurai

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We examine the effect of false-name bids on combinatorial auction protocols. Falsename bids are bids submitted by a single bidder using multiple identifiers such as multiple e-mail addresses. The obtained results are summarized as follows: 1) The Vickrey-Clarke-Groves (VCG) mechanism, which is strategy-proof and Pareto efficient when there exists no(More)
Forming e ective coalitions is a major research challenge in AI and multi-agent systems. Coalition structure generation (CSG), which involves partitioning a set of agents into coalitions so that social surplus is maximized, is a central research topic due to its computational complexity. In this paper, we present new methods for CSG utilizing recently(More)
This paper presents a new combinatorial auction protocol (LDS protocol) that is robust against false-name bids. Internet auctions have become an integral part of Electronic Commerce (EC) and a promising field for applying agent and Artificial Intelligence technologies. Although the Internet provides an excellent infrastructure for combinatorial auctions, we(More)
Electronic Commerce (EC) has rapidly grown with the expansion of the Internet. Among these activities, auctions have recently achieved huge popularity, and have become a promising field for applying agent and Artificial Intelligence technologies. Although the Internet provides an infrastructure for much cheaper auctioning with many more sellers and buyers,(More)
A combinatorial auction mechanism consists of an allocation rule that defines the allocation of goods for each agent, and a payment rule that defines the payment of each winner. There have been several studies on characterizing strategyproof allocation rules. In particular, a condition called weakmonotonicity has been identified as a full characterization(More)
This paper presents a new multi-unit auction protocol (IR protocol) that is robust against false-name bids. Internet auctions have become an integral part of Electronic Commerce and a promising field for applying agent and Artificial Intelligence technologies. Although the Internet provides an excellent infrastructure for executing auctions, the possibility(More)
We analyzed lipids in liver diseases by agarose gel electrophoresis, and differential staining and simultaneous analysis of the cholesterol (Chol) and triglyceride (TG) fractions. Liver diseases were classified into chronic hepatitis (CH), liver cirrhosis (LC), hepatocellular carcinoma (HCC), and metastatic liver cancer, and each fraction was compared among(More)
Internet auctions have become an integral part of Electronic Commerce (EC) and a promising field for applying agent technologies. Although the Internet provides an excellent infrastructure for large-scale auctions, we must consider the possibility of a new type of cheating, i.e., a bidder trying to profit from submitting several bids under fictitious names(More)
This paper analyzes the worst-case efficiency ratio of falsename-proof combinatorial auction mechanisms. False-nameproofness generalizes strategy-proofness by assuming that a bidder can submit multiple bids under fictitious identifiers. Even the well-known Vickrey-Clarke-Groves mechanism is not false-name-proof. It has previously been shown that there is no(More)
OBJECTIVE Mounting evidence indicates that the gut microbiota are an important modifier of obesity and diabetes. However, so far there is no information on gut microbiota and "live gut bacteria" in the systemic circulation of Japanese patients with type 2 diabetes. RESEARCH DESIGN AND METHODS Using a sensitive reverse transcription-quantitative PCR(More)