Haruhisa Hayashi

In controlling spam mails, it is important not only to reduce spam mails, but also to deliver non-spam mails. It is also important to lower the cost in small and medium enterprises. The anti-spam method using greylisting only after working hours and throttling was implemented at Technology Research Institute of Osaka Prefecture. And we tried to reduce spam mails without maintenance of white list and database. In this paper, we describe the usefullness of this method from questionnaire survey and mail log analysis. After that, we report the result that we tried to reduce spam mails in the university laboratory with this method.

By using the public/commercial wide-area and broadband network (EoMPLS and ATM-MPLS etc) as the campus intranet, it seems as though the scattered campuses are in the same Local Area Network. We constructed the computer network system using such a network, to receive the same service for all users in each campus. In the educational institution, the utilization of such network service is expected to apply the distance learning with high quality video and sound. Therefore we show two cases of the system implementation and operation using the wide-area and broadband network with the educational institution.

Greylisting is known as one of the highest effective method within anti-seam method. However, it has issues that requires the maintenance of the list, and forces delivery delay of e-mails. So, we tried to resolve those issues by transfering e-mails without retransmission request during working hours. And also we used throttling to try to reduce spam mails during working hours. In this paper, we report on the controlling spa mails with greylisting and throttling, and it's effectiveness.

"Modrast-P", which we have developed, has distinctive functions for displaying molecular models, especially, the capacity to display models clipped by single or double plane(s). This function is useful to show inner structures of inclusion complexes or active sites of bio-molecules, which are otherwise hidden by outer parts of molecules. However, Modrast-P was dependent on hardware and OS, so we improved this program using GTK+, which was one of the toolkits of the X Window System, and named it "Modrast-P with GTK+". For the clipping function, the operations to specify the clipping plane are facilitated with GUI (graphical user interface). In addition, some useful functions such as animation and numerical analysis for results of Molecular Dynamics (MD) simulation with AMBER have been implemented.

A support program for AMBER was developed on the basis of the biomolecular graphics program “Modrast-P". This program has three features, which are : 1) Setting up of input files for AMBER. It is easy and efficient to make input files for AMBER modules (Figure 1) by using interactive and graphical operations. 2) Molecular modeling for building the initial structure of the molecule for molecular dynamics calculation by use of the extended function of Modrast-P. 3) Animations of atomic trajectory files from molecular dynamics simulations, calculations of atom-to-atom distances and the extraction of potential energies from output files in order to draw graphs for getting quantitative information, are possible.As an example use of this program, the structure of DNA containing anthraquinone groups was simulated (Figures 2,3).This program runs on any UNIX workstations and personal computers where PC-UNIX, such as Linux, are installed.

Molecular dynamics simulations have been performed for liquid n-butane and ethylene glycol (1,2-ethanediol; EG) in order to understand liquid structures in terms of both inter- and intra-molecular interactions. Each n-butane molecule consists of four sites interacting with LJ potential, and with only one dihedral angle potential, while each EG molecule has six sites interacting through LJ and coulomb potentials together with three dihedral angle potentials. The flexible molecule has the tendency to be folded more intensely in the liquid state than that in the gas phase. Comparing aqueous solution of EG with Xe solution and gaseous state of EG, it is found that EG molecules more strongly favor the folded form by intramolecular interactions, especially by intramolecular hydrogen bond. © 1995.