Geographical Coarsegraining of Complex Networks

We perform the renormalization-group-like numerical analysis of geographically embedded complex networks on the two-dimensional square lattice. At each step of coarsegraining procedure, the four vertices on each $2 \times 2$ square box are merged to a single vertex, resulting in the coarsegrained system of the smaller sizes. Repetition of the process leads to the observation that the coarsegraining procedure does not alter the qualitative characteristics of the original scale-free network, which opens the possibility of subtracting a smaller network from the original network without destroying the important structural properties. The implication of the result is also suggested in the context of the recent study of the human brain functional network.Comment: To appear in Phys. Rev. Let

Teaching Scripture in Public High Schools

Special Religious Education is a ‘period allowance’ for religious education in public high schools. It is not only for Christian education, but also for other religious persuasions

Network Marketing on a Small-World Network

We investigate a dynamic model of network marketing in a small-world network structure artificially constructed similarly to the Watts-Strogatz network model. Different from the traditional marketing, consumers can also play the role of the manufacturer's selling agents in network marketing, which is stimulated by the referral fee the manufacturer offers. As the wiring probability $\alpha$ is increased from zero to unity, the network changes from the one-dimensional regular directed network to the star network where all but one player are connected to one consumer. The price $p$ of the product and the referral fee $r$ are used as free parameters to maximize the profit of the manufacturer. It is observed that at $\alpha=0$ the maximized profit is constant independent of the network size $N$ while at $\alpha \neq 0$, it increases linearly with $N$. This is in parallel to the small-world transition. It is also revealed that while the optimal value of $p$ stays at an almost constant level in a broad range of $\alpha$, that of $r$ is sensitive to a change in the network structure. The consumer surplus is also studied and discussed.Comment: 12 pages, to appear in Physica

Identifying generic features of borrower descriptions on Kiva. org

This paper describes the online platform of kiva.org, a microfinance site that enables people to contribute to the funding of microloans across the third world, and then describes an initial small-scale study to identify generic features of the borrower descriptions on the site. Future research will determine whether this is a developing genre, and whether the model is robust both within kiva.org and across other such platforms.ここでは、マイクロファイナンスを行う団体、kivaのオンライン・プラットフォームを取り上げてみました。それは第三世界に少額貸付を行うことを可能にするものであり、さらに、サイト上に登録された借り手側の記載内容に共通するものを見つけ出そうという試みを、わずかばかりのサンプル数ですが行ってみました。将来的には、これが発展的なジャンルであるのか、さらにはこのモデルがkivaや類似の他のサイトにおいて確固たるものか、確認作業を行いたいと思います

Online Business English : Enrichment components for elective university classes

This paper proposes a number of reasons that selected elements of English for online business should be included in instruction for elective university classes in Japan. Such elements include web presence and social media. Each element is discussed briefly before examples are given as to how the enrichment component can be incorporated into a number of elective classe

Comment on "Ising model on a small world network"

In the recent study of the Ising model on a small-world network by A. P\c{e}kalski [Phys. Rev. E {\bf 64}, 057104 (2001)], a surprisingly small value of the critical exponent $\beta \approx 0.0001$ has been obtained for the temperature dependence of the magnetization. We perform extensive Monte Carlo simulations of the same model and conclude, via the standard finite-size scaling of various quantities,that the phase transition in the model is of the mean-field nature, in contrast to the work by A. P\c{e}kalski but in accord with other existing studies.Comment: to be published in PR

What do we learn from correlations of local and global network properties?

In complex networks a common task is to identify the most important or "central" nodes. There are several definitions, often called centrality measures, which often lead to different results. Here we study extensively correlations between four local and global measures namely the degree, the shortest-path-betweenness, the random-walk betweenness and the subgraph centrality on different random-network models like Erdos-Renyi, Small-World and Barabasi-Albert as well as on different real networks like metabolic pathways, social collaborations and computer networks. Correlations are quite different between the real networks and the model networks questioning whether the models really reflect all important properties of the real world

E-learning : Issues and Choices

E-learning is becoming progressively more influential across the educational spectrum. Many schools and universities are instituting e-learning for students, some offering entire degree courses via the Internet. Developments in computer technologies have heralded a range of changes in possibilities both in the delivery of content and the implementation of methodologies, reflecting the situation vis-a-vis approaches to teaching that followed developments in audio and video content delivery systems. This paper outlines issues and choices that influence decision-making about the kind of e-learning program to be implemented. As computers become increasingly fast and powerful, available, and mobile ; interfaces more user-friendly; software more highly sophisticated; and students and faculty become increasingly familiar within the virtual environment, those involved in education are struggling with decisions regarding the best means in which to integrate computers into learning. However, the breadth of options for the utilization of computer technologies in education and the range of applications for which they may be used lead to conflicts of expectations and practice between school or program administrators, teachers, and students. These conflicts affect the choice of program as well as the ongoing success of any particular program once it has been implemented. The choices are not easy ; much depends on metaphors in which computer use is perceived, concepts of learning and teaching, the knowledge or skill set selected for e-learning focus, funding and other institutional constraints, as well as the skills and dedication of, and time constraints upon, those programming and managing the course. Success of an e-learning course is dependent upon a number of issues, including limitations of hardware and software; definitions of success and goals of the program; student access, confidence, and acceptance; teacher access, confidence, and acceptance; support for both students and teachers; and institutional factors. The issues and choices described first in this paper determine the type of program to be implemented. Options for the type of program are constrained by these initial choices, which are, in many cases, invisible in the decision-making process. It is argued that these factors should be examined prior to the point at which decisions regarding e-learning programs are made and should continue to be considered in the ongoing evaluations of any program

The fickle activity of a fly and a moth: variation in activity of two biocontrol agents of Chrysanthemoides monilifera

Biocontrol agents released to control exotic pests may not have the same spatial distribution as the pest species and may therefore vary in efficacy across the exotic range. These changes in distribution are unlikely to be known until species have had time to fill all preferred niches in the invasive habitat. However, studies of post-release activity of biocontrol agents rarely assess longer-term patterns of establishment in the landscape. Comostolopsis germana and Mesoclanis polana were released to control Chrysanthemoides monilifera spp. rotundata (bitou bush) between 29 and 32 years ago. We assessed their activity in foredune and hinddune habitats of coastal beaches across the major distribution of bitou bush and experimentally assessed the effectiveness of C. germana at preventing flowering and seed set. Both biocontrol agents were found to be distributed along the 870 km of coastline, representing the core area of infestation. Tip damage by C. germana was highly variable but was consistently more effective in the foredune. Comostolopsis germana was found to reduce flower production from 15 to 59% with tip damage increasing with latitude. Mesoclanis polana did not show differences in activity with latitude and only showed a marginal increase in activity in hinddunes. Comostolopsis germana and M. polana are reducing the reproductive output of bitou bush but are unlikely to be effective as a sole management strategy particularly in warmer latitudes where more seeds are released