204985889
Regular graphs with excess one
Abstract It is shown that there exists no regular graph with excess e =1 and girth 2 r +1⩾5.
40274616
On the spectra of certain distance-regular graphs
Let r be an undirected graph whose vertex-set V(F) is the set (ZJ~ , u2 ,..., v,>. The adjacency matrix of I’ is the n x n matrix A = A(r), over the complex number field, whose entries aij are given by a,j = 1 if vi and vi are adjacent, = 0 otherwise. DEFINITION 1. The spectrum of r is the set of distinct eigenvalues 4l , 4 ,**-> Od of A(F), together with their multiplicities, written m(&), m(4),..., m(0,). Since r is undirected, A is symmetric, and so the Bi are all real numbers. We arrange the Bi in increasing order, namely, 0, < O1 < *.. < e dMany studies have been done on the spectra of graphs by many mathematicians. Some of them may be found, for instance, in Biggs [2].
10045838
Algorithms for finding distance-edge-colorings of graphs
For a bounded integer @?, we wish to color all edges of a graph G so that any two edges within distance @? have different colors. Such a coloring is called a distance-edge-coloring or an @?-edge-coloring of G. The distance-edge-coloring problem is to compute the minimum number of colors required for a distance-edge-coloring of a given graph G. A partial k-tree is a graph with tree-width bounded by a fixed constant k. We first present a polynomial-time exact algorithm to solve the problem for partial k-trees, and then give a polynomial-time 2-approximation algorithm for planar graphs.
8383423
A Support Method for Qualitative Simulation-Based Learning System
In this paper, we mainly present a support method of our proposed e-learning system. We employ qualitative simulations because this lets the learners understand the conceptual principles in economic dynamics. First, we define some qualitative values employed on simulation graph model that consists of nodes and arcs. Then, we show the support method using our learning system based on qualitative simulation.
35569886
A Bidders Cooperation Support System for Agent-Based Electronic Commerce
Internet is becoming an increasingly prosperous network for many types of commerce. Internet Auctions represent a particularly effective form of electronic commerce and have become a promising field for applying agent technologies. In many existing auction sites, some sellers deal in the same sort of goods or their imitations. Buyers bid for each item on sale. Buyers cannot always purchase goods at the lowest price because buyers compete, that is they do not cooperate with each other. Thus, buyers need to search hard to find items they can purchase. In this paper, we propose a bidders support system based on a mediated agent for auctions on the Internet. In our system, buyers can purchase goods at the lowest price by working in cooperation with each other. Each buyer selects an item based on his/her multi-attribute preferences. A mediated agent calculates the buyers' utilities, and determines the successful bidders. We consider an assumption of linear utility based on multi-attribute utility theory. The advantages of the bidder cooperation support system are as follows. (1) Each buyer can purchase an item at the lowest price. (2) The buyer's multi-attribute utilities are reflected. (3) The mechanism is robustness for buyer's anticipating. We conducted an experiment to investigate and compare buyers' utilities between existing auctions and our system. Our experiment shows that buyers utilities in our system are sufficiently higher than these in existing auctions.
18603528
A Qualitative-Quantitative Methods-Based e-Learning Support System in Economic Education
This paper describes a new qualitative-quantitative simulator to help buyers learn how to make decisions when they purchase goods. In this paper, we propose an e-learning support system (LSDM) for assisting user decision making by applying artificial intelligence technology. When buyers purchase expensive items, they must carefully select these items from many alternatives. The learning support system provides useful information that assists consumers in purchasing goods. We employ qualitative simulations because the output simulation results are useful. Our system consists of a qualitative processing system and a quantitative calculation system. When users use the system, they first input information on the goods they want to purchase. The information input by users is used in the qualitative simulation. Next, they supply the details of their budgets, the rate of loans, and several other factors, on a form. The system then integrates the results of simulation and the user's input data and proposes plans to aid in their decision process. The system has several advantages: it can be used by simple input, the process of simulation is easy to understand, users can learn how to make decisions by trial and error, and the users can base their decision making on synthetic results.
822028
An Approach to Coalition Formation Using Argumentation-Based Negotiation in Multi-agent Systems
In this paper, we propose an argumentation-based negotiation method for coalition formation. In existing argumentation method, it is difficult for an agent to calculate the effectiveness of each proposal, since agents are constructed based only on a logical framework. In our method, agents can calculate the effectiveness using a mechanism which can evaluate arguments. In order to evaluate the arguments, we prepare certain functions, so we employ the AHP. During the negotiation, agents can create the most effective proposal and change a negotiation strategy autonomously. An advantage of our method is that agents can reach an agreement reflecting user's multiple valuations, and the negotiation among agents is completed quickly. Another advantage is that if agents have no need to create proposals, each user's private data is not opened to others during the negotiation.