An anytime approximation method for the inverse Shapley value problem

Coalition formation is the process of bringing together two or more agents so as to achieve goals that individuals on their own cannot, or to achieve them more efficiently. Typically, in such situations, the agents have conflicting preferences over the set of possible joint goals. Thus, before the agents realize the benefits of cooperation, they must find a way of resolving these conflicts and reaching a consensus. In this context, cooperative game theory offers the voting game as a mechanism for agents to reach a consensus. It also offers the Shapley value as a way of measuring the influence or power a player has in determining the outcome of a voting game. Given this, the designer of a voting game wants to construct a game such that a players Shapley value is equal to some desired value. This is called the inverse Shapley value problem. Solving this problem is necessary, for instance, to ensure fairness in the players voting powers. However, from a computational perspective, finding a players Shapley value for a given game is #p-complete. Consequently, the problem of verifying that a voting game does indeed yield the required powers to the agents is also #P-complete. Therefore, in order to overcome this problem we present a computationally efficient approximation algorithm for solving the inverse problem. This method is based on the technique of successive approximations; it starts with some initial approximate solution and iteratively updates it such that after each iteration, the approximate gets closer to the required solution. This is an anytime algorithm and has time complexity polynomial in the number of players. We also analyze the performance of this method in terms of its approximation error and the rate of convergence of an initial solution to the required one. Specifically, we show that the former decreases after each iteration, and that the latter increases with the number of players and also with the initial approximation error. Copyright © 2008, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaarnas.org). All rights reserved

On efficient procedures for multi-issue negotiation

This paper studies bilateral, multi-issue negotiation between self-interested agents with deadlines. There are a number of procedures for negotiating the issues and each of these gives a different outcome. Thus, a key problem is to decide which one to use. Given this, we study the three main alternatives: the package deal, the simultaneous procedure, and the sequential procedure. First, we determine equilibria for the case where each agent is uncertain about its opponent’s deadline. We then compare the outcomes for these procedures and determine the one that is optimal (in this case, the package deal is optimal for each party). We then compare the procedures in terms of their time complexity, the uniqueness and Pareto optimality of their solutions, and their time of agreement

Acceptance conditions in automated negotiation

In every negotiation with a deadline, one of the negotiating parties has to accept an offer to avoid a break off. A break off is usually an undesirable outcome for both parties, therefore it is important that a negotiator employs a proficient mechanism to decide under which conditions to accept. When designing such conditions one is faced with the acceptance dilemma: accepting the current offer may be suboptimal, as better offers may still be presented. On the other hand, accepting too late may prevent an agreement from being reached, resulting in a break off with no gain for either party. Motivated by the challenges of bilateral negotiations between automated agents and by the results and insights of the automated negotiating agents competition (ANAC), we classify and compare state-of-the-art generic acceptance conditions. We focus on decoupled acceptance conditions, i.e. conditions that do not depend on the bidding strategy that is used. We performed extensive experiments to compare the performance of acceptance conditions in combination with a broad range of bidding strategies and negotiation domains. Furthermore we propose new acceptance conditions and we demonstrate that they outperform the other conditions that we study. In particular, it is shown that they outperform the standard acceptance condition of comparing the current offer with the offer the agent is ready to send out. We also provide insight in to why some conditions work better than others and investigate correlations between the properties of the negotiation environment and the efficacy of acceptance condition

Assessment of Students Performances in Biology: Implication for Measurements and Evaluation of Learning

Scienceeducation is believed to be a vital tool for individual and societal development at large. The persistent low levels of students' achievement in sciences at the various public examinations in Nigeria have continued to draw the attention of major stakeholders in education. This study examined academic achievement of Senior Secondary School students in biology and gender difference in students' achievement was examined. Ex-post facto design of descriptive research was adopted for the study. A proforma was used to collect data from a sample of two hundred (200) students, selected using stratified random sampling procedure from the Science secondary schools in Kano state Nigeria. The data collected were the students' performances in biology achievement tests. The data were analysed using descriptive statistics and independent-sample t-test. Overall results showed that the test internal consistency reliability is low and unsatisfactory; the students performed below average (M=47.02, SD=16.493 (47%). Similarly, gender difference exists in biology performance with another significant difference between performance of urban and rural school students. The study concludes that, biology test used in Kano state qualifying examinations to assess students potential ability in biology is not a reliable measurement tool and that, academic performance of students in biology is unsatisfactory and evidence of differential performance between gender and schools locations. The implication for measurements and evaluation of learning as well as recommendations has been discussed

Pelecehan dan Kekerasan terhadap Perempuan dalam Siaran Radio Spfm Serta Dampaknya terhadap Perempuan Pendengar di Kota Makassar

Mass media well-known can influence public. This study aimed to describe and assess the impact of listening to broadcast “Derap Perempuan” in SPFM Radio against women listeners in Makassar City, which in terms of knowledge, attitudes, and behaviors. Data sourced from 16 female listeners, broadcast host and resource person who were selected through a purposive sample. The results showed that in terms of knowledge, there are some listeners who had understood from the start, half-understood, and there is even clueless about the fourth issue. In terms of attitude, there are listeners who showed preventive attitude, anxious, but there are also normal like usual days. In the terms of behavior, there are listeners who behave disseminate the information obtained, but there are also do not. In addition, the behavior shown, especially listeners who are single, is more selective in choosing a candidate companion of life. Thus, it was concluded that the impact of broadcast “Derap Perempuan” in SPFM Radio against women listeners in Makassar city is very variated

Hawking temperature of rotating charged black strings from tunneling

Thermal radiations from spherically symmetric black holes have been studied from the point of view of quantum tunneling. In this paper we extend this approach to study radiation of fermions from charged and rotating black strings. Using WKB approximation and Hamilton-Jacobi method we work out the tunneling probabilities of incoming and outgoing fermions and find the correct Hawking temperature for these objects. We show that in appropriate limits the results reduce to those for the uncharged and non-rotating black strings

Development of Regional Production and Logistic Networks in East Asia: the Case of the Philippines

Regional production networks and local production linkages are important not only for the generation of industrial activity through investment flows but also as essential sources of new information and technology. Complementing this are the so-called knowledge networks within or around industrial agglomerations that are equally important sources of technology for industrial upgrading and innovation. Both are present in the case study area of CALABARZON in the Philippines but the former seem to be more apparent than the latter as this has been characterized as weak based on secondary data and conduct of survey of establishments. With weaknesses in the S&T system in the country as part of the study's findings, policy suggestions were provided to strengthen the linkages that remain to be wanting but are important for stimulating innovation

Infrared spectroscopic studies of novel hydroxybisphosphonates and molecular modelling of their interaction with hydroxyapatite

Bisphosphonates (BPs) are a class of drugs widely used in the treatment of several metabolic bone disorders associated with increased bone resorption, including osteoporosis, Paget’s disease and metastic bone disease [1]. Although BPs can directly inhibit the cellular activity of osteoclasts, their ability to adsorb to bone mineral is also an important factor in determining their potency and duration of action [2]. In this study, we performed a molecular modelling analysis, by molecular mechanics, of the molecular structures of hydroxy(1H-indazol-3-yl)methylenediphosphonic acid (BP1; Figure 1a) and hydroxy(1-methyl-1H-indazol-3-yl)methylenediphosphonic acid (BP2; Figure 1b) and examined their interactions with hydroxyapatite (HA) by energy-minimising 50 different orientations for judiciously selected low energy conformers of each ligand at 10 Å from the mineral surface. We also calculated the vibrational spectra for each BP with semiempirical methods and compared then with FTIR spectra obtained experimentaly. The calculated interaction energies of the studied BPs with HA suggests that BP2 interacts stronger with hydroxyapatite than BP1. These results are in agreement with in vitro and in vivo studies of the 153Sm-BPs complexes. Complex 153Sm-BP2 showed, in vitro, higher HA binding than complex 153Sm-BP1. In vivo studies showed different farmacokinetics parameters with complex 153Sm-BP2 presenting initial higher levels of bone uptake than complex 153Sm-BP1, which concentration is increasing during the 24 h period studied