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Sensor devices and the emergent networks that they enable are capable of transmitting information between data sources and a permanent data sink. Since these devices have low-power and intermittent connectivity, latency of the data may be tolerated in an effort to save energy for certain classes of data. The BUBBLE routing algorithm developed by Hui et al. in 2008 provides consistent routing by employing a model which computes individual nodes popularity from sets of nodes and then uses these popularity values for forwarding decisions. This thesis considers enhancements to BUBBLE based on the hypothesis that nodes do form groups and certain centrality values of nodes within these groups can be used to improve routing decisions further. Built on this insight, there are two algorithms proposed in this thesis. First is the Community-Based- Forwarding (CBF), which uses pairwise group interactions and pairwise node-to-group interactions as a measure of popularity for routing messages. By having a different measure of popularity than BUBBLE, as an additional factor in determining message forwarding, CBF is a more conservative routing scheme than BUBBLE. Thus, it provides consistently superior message transmission and delivery performance at an acceptable delay cost in resource constrained environments. To overcome this drawback, the concept of unique interaction pattern within groups of nodes is introduced in CBF and it is further renewed into an enhanced algorithm known as Hybrid-Community-Based- Forwarding (HCBF). Utilizing this factor will channel messages along the entire path with consideration for higher probability of contact with the destination group and the destination node. Overall, the major contribution of this thesis is to design and evaluate an enhanced social based routing algorithm for resource-constrained Pocket Switched Networks (PSNs), which will optimize energy consumption related to data transfer. It will do so by explicitly considering features of communities in order to reduce packet loss while maintaining high delivery ratio and reduced delay.

在DTN(Delay Tolerant Networks)這類的網路架構下，無線節點之 間的通訊連線是採非連續性建立的。DTN 路由協定中, 決定中繼節點 方式大致可以分成兩類:依地理位置考量的路由協定（Geographic Routing Protocal）和依社交模式考量的路由協定（Social-based Routing Portocal）。 由於人與人間的互動是透過社交關係, 但是真實的資訊傳遞又須 仰賴當時的地理位置。因此我們提出的演算法將網路拓墣分成社交層與地理層, 在社交層中利用Social Ally Selection Algorithm 挑選出合適的社交盟友(Social Ally)。在地理層中利用Geographic Messenger Forwarding Algorithm 挑選合適的節點將訊息傳送給朝向目的地或是社交中繼站的節點。根據實驗模擬結果, 我們的路由協定能有較佳的傳遞成功率, 並降低了延遲時間。 / Delay Tolerant networks (DTN) may lack continuous network connectivity. Most of these DTN routing protocol, which attempt to make better routing decision, could be divided in two categories: Geographic routing protocols and Social-based routing protocols. Due to the interaction between people through social behaviors and message transmissions rely on geographic position information, we proposed a routing protocol which network topology is divided into two sub layers: social layer and geographic layer. In social layer, we propose a Social Ally Selection Algorithm to decide social allies that are controlled to improve delivery performance. In geographic layer, we propose a Geographic Messenger Forwarding Algorithm to transmit message to the nodes moving toward to social ally or destination. According to the simulation results, we could show that our routing protocol have higher delivery ratio and lower delay latency compare to other protocols.

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The project elaborates design opportunities for a future practice that could promotealternative sustainable lifestyles on waste handling through up-cycling activities. It doesthis on a small scale through engagement in the local communities of the Hildaneighborhood and Segepark students’ accommodations in Sweden. To thesecommunities, creative-up-cycling is explored which it introduced here as an approachwhere neighbors can participate in making new things from leftover materials. Throughthis work creative-up-cycling is a proposed recommendation for a possible service systemon how to share the leftover materials in the local resident’s communities, as well as, howto remake the items no longer needed.The empirical studies explore maker culture lifestyles and include how to find leftovermaterials, tools, space, and skills in order to guide people in creative-up-cyclingalternatives. These creative activities also build social relationship via the integration ofmultidisciplinary citizens who are living in the same community and explorations weredone on how could we elicit the skill sets from those people? What is a useful skill set inthis area today? Values like mutual physical experience, reciprocity, and ownership couldalso be found along the empirical workshops in this project. Additionally, this reportshows some interesting findings pointing towards the design process and the suggestionsof design elements; ‘Co-storage’, ‘Mix and Match furniture shop’, and ‘Renovation andup-cycling’ concept elements.Participatory design (designing with people) has been the core approach in this project.Additionally, I have been influenced by user-centered design, as well as service designapproaches in order to comprehend the services, system and activities of recycling andup-cycling in cities like: SYSAV, STPLN, Cykelköket, Återskapa, Toolpool. The findingpresented here are examples of practices that could make up the composition of recyclingand up-cycling activities in future local communities.