The floating-leaved plant Trapa japonica, one of the abundant aquatic plants in Lake Izunuma, was used for nutrient uptake and release tests. By comparing the nutrient elution rates from the sediment and the nutrient uptake rates by Trapa japonica, it was estimated that in Lake Izunuma the Trapa japonica communities could take up most of the nutrients eluted from the sediment during summer. It was also confirmed that NH 4 -N released from Trapa japonica changed to NO 3 -N via NO 2 -N. This result was quite similar to the NH 4 -N, NO 2 -N and NO 3 -N concentration changes in Lake Izunuma from autumn to winter. In Lake Izunuma, the dissolved inorganic nitrogen concentration was high in autumn and winter. On the basis of the results of the discharge experiment to determine the effect of the reduction in the water level by tilting the water gate of Lake Izunuma, we consider that the nutrients released by the aquatic plant from autumn to winter can be removed effectively by this water level reduction.

While responding to new cybersecurity threats such as cyber attacks, we will radically improve the efficiency of security operations by developing technologies for autonomous and automated security measures. Such technologies will enable operators to concentrate on countermeasures against advanced threats that cannot be handled mechanically and enhance overall security-response capabilities.

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This paper proposes a VPN configuration delivery system capable of reducing the configuration burden on users when making remote-access VPN connections and capable of supporting immediate VPN connections to VPN servers created on an ad hoc basis. The proposed system is able to lessen configuration inconvenience and create immediate VPN connections by means of a VPN configuration delivery server that links to the VPN server, generates the necessary VPN connection configuration data, and delivers the configuration data to the client. This paper also reports on the results of verifying the system's operation with an information-card prototype.

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