Nowadays, a lot of e-Learning systems are widely deployed in educational schools. Typical e-Learning systems are implemented as client-server model. In the client-server model, the number of clients affects on the load of the server. In order to reduce the load on the server, we developed a P2P-based distributed e-Learning system. The proposed system consists of a lot of mobile agents which manage study contents and some functions such as scoring, showing questions, and correct answers. When a learner requests content, a mobile agent who has its content comes to the learner's computer, and then he/she can start the study. Here, a mobile agent has to manage multimedia data, which may be a huge size of data. Thus, a mobile agent has to migrates to the learner's node with a huge size of data. Then, the learner cannot start the study until the mobile agent finished to migrate. In order to solve this problem, we divide multimedia data into fragments and prepare mobile agents which manages each fragments. Since each mobile agents become small, a learner can start the study soon without waiting for the migration of a mobile agent which has a huge size of multimedia data. We, however, have to search a mobile agent which manages their fragments. Therefore, a mobile agent which manages nth fragments informs its location to the agent which manages (n+1)-th fragments, and vice versa. Since each agent knows the location of a mobile agent which manages next and previous fragment; and fragments are cached into learner's node, a learner can play multimedia data smoothly without finding the location of mobile agent which manages holding next fragment. Experiment results show the effectiveness of our method.

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Computer security has been getting more attention because a computer security incident may cause great damage on an organization. A quick and correct response against an incident is then important. One of the first possible responses is then locating and isolating a suspicious host. This isolation typically requires a manual operation that may cause a mistake or long delay. In order to solve these issues, this paper proposes a novel system to locate and isolate a suspicious host on an incident response adopting the Software Defined Network (SDN) approach. This SDN approach allows the proposed system to locate and isolate a suspicious host on-demand in a network that comprises different switches and routers of different makers. The proposed system then requires no host authentication configured, no IP address allocation/assignment database, no network topology map and no switch port list in advance. The proposed system, therefore, can reduce human manual operations. This paper then presents that human manual operations actually induce longer delays, more than 3 minutes on average, and also cause mistakes. This paper also presents that the proposed system can locate and isolate a suspicious host within 10 seconds right after an IP address of a suspicious host is given.

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