Due to rapid increases in the number of users and diversity of devices, temporal fluctuation of traffic on information communication network is becoming large and rapid recently. Especially, sudden traffic changes such as flash crowds often cause serious congestion on the network and result in nearly fatal slow down of date-communication speed. In order to keep communication quality high on the network, routing protocols that are scalable and able to quickly respond to rapid, and often unexpected, traffic fluctuation are highly desired. One of the promising approaches is the distributed routing protocol, which works without referring global information of the whole network but requires only limited informatin of it to realize route selection. These approaches include biologically inspired routing protocols based on the Adaptive Response by Attractor Selection model (ARAS), in which routing tables are updated along with only a scalar value reflecting communication quality measured on each router without evaluating communication quality over the whole network. However, the lack of global knowledge of the current status of the network often makes it difficult to respond promptly to traffic changes on the network that occurs at outside of the local scope of the protocol and causes inefficient use of network resources. In order to solve the essential problem of the local scope, we extend ARAS and propose a routing protocol with active and stochastic route exploration. The proposed protocol can obtain current communication quality of the network beyond its local scope and promptly responds to traffic changes occur on the network by utilizing the route exploration. In order to compensate destabilization of routing itself due to the active and stochastic exploration, we also introduce a short-term memory to the dynamics of the proposed attractor selection model. We conform by numerical simulations that the proposed protocol successfully balances rapid exploration with reliable routing owning to the memory term.
twitter、Facebook、mixi、そして地域ＳＮＳなどのソーシャルメディアが 普及してから数年がたち、それぞれ社会の中で浸透・定着しつつある。 その中で各サービス上で生じるコミュニケーションのあり方にもかなり 明確な差異が見られる。 本講演では、これらのサービスが採用しているアーキテクチャ とそこで生じるコミュニケーションのあり方の関係について考察する。
This article attempts to examine the characteristics of a social networking service managed locally as a communication space by using the website “Stacomi” as an example. Its management, the characteristics of its users, the social networks of the users, and network-related events hosted in real space were analyzed.
Stacomi was founded in Okayama Prefecture by a venture enterprise (Standard Co.) whose aim is to make local governance in Okayama more active. Most users live in Okayama City, probably because personal invitations sent by Standard Co. staff members, who are Okayama residents themselves, are a primary method of recruitment. Highly motivated users who require extensive social connections for their businesses use Stacomi primarily as a database for tracking regional news, as a medium for drawing participants to events, or as a tool for attracting new customers. Stacomi includes hubs that are divided into two types: groups of users who have ties to many popular users and are eager to recruit new participants, and groups of users who have ties to other hubs and wish to increase the number of their acquaintances.
The communities active on Stacomi include three types: those featuring users who form groups in real space devoted to a common interest or common goals and use Stacomi as a social medium; those featuring users who met on Stacomi and thereafter plan and manage events in real space,; and those featuring users whose primary aim is to share news related to the area in which they live. The “Okayama Culture Zone,” for example, provides a link between hubs that leads to links between different clusters in the same area. This cooperation between hubs and active users results in an enrichment of the activities held in real space.
Two types of events are hosted in real space: those that Standard Co. strategically plans and manages, and those that users facilitate to either engage in previously planned activities or plan new activities. The participants in these events are also divided into two types: users who need information for their businesses and are eager to form new social ties, and users who need information for their daily lives and wish to maintain contact with old acquaintances.