The ultra-low-k dielectric material replacing the conventional SiO₂ dielectric medium in coupled multilayer graphene nanoribbon (MLGNR) interconnects is presented. An equivalent distributed transmission line model of coupled MLGNR interconnects is established to derive the analytical expressions of crosstalk delay, transfer gain, and noise output for 7.5 nm technology node at global level, which take the in-phase and out-of-phase crosstalk into account. The results show that by replacing the SiO₂ dielectric mediums with the nanoglass, the maximum reduction of delay time and peak noise voltage are 25.202 ns and 0.102 V for an interconnect length of 3000 µm, respectively. It is demonstrated that the ultra-low-k dielectric materials can significantly reduce delay time and crosstalk noise and increase transfer gain compared with the conventional SiO₂ dielectric medium. Moreover, it is found that the coupled MLGNR interconnect under out-of-phase mode has a larger crosstalk delay and a lesser transfer gain than that under in-phase mode, and the peak noise voltage increases with the increase of the coupled MLGNR interconnect length. The results presented in this paper would be useful to aid in the enhancement of performance of on-chip interconnects and provide guidelines for signal characteristic analysis of MLGNR interconnects.

This paper applies the carbon materials (i.e., SWCNT, MWCNT, and GNR) as new prospective filler materials of through silicon vias (TSV) for replacing the conventional copper (Cu) to improve the thermal performance of three-dimensional integrated circuits (3-D ICs). The thermal performance of 3-D ICs with integrated TSVs is investigated and the corresponding numerical calculation model is established in this work. Moreover, the thermal performance of 3-D ICs with integrated carbon materials based TSV is investigated by applying our proposed numerical calculation model. The calculation results illustrate that the 3D-ICs with integrated SWCNT based TSV have a greater thermal performance, as compared with the 3-D ICs integrated other materials (i.e., MWCNT, GNR, and Cu) based TSV. Furthermore, it is also manifested that the temperature of die layer in 3-D ICs can be reduced by increasing the thermal conductivity of package and heat sink, by increasing the radius of TSV and decreasing the spacing between TSV. In addition, it is found that the results of our proposed numerical calculation model are fairly consistent with COMSOL simulation and the maximum relative error for them is not exceeding 2%. The proposed new filler materials in this work has many potential applications in improving the heat dissipation performance of 3-D ICs, meanwhile the presented numerical calculation model can provide guidelines for thermal design of 3-D ICs.

Massively multiplayer online role-playing games create virtual communities that support heterogeneous “social roles” determined by gameplay interaction behaviors under a specific social context. For all social roles, formal roles are pre-defined, obvious, and explicitly ascribed to the people holding the roles, whereas informal roles are not well-defined and unspoken. Identifying the informal roles and understanding their subtle changes are critical to designing sociability mechanisms. However, it is nontrivial to understand the existence and evolution of such roles due to their loosely defined, interconvertible, and dynamic characteristics. We propose a visual analytics system, RoleSeer, to investigate informal roles from the perspectives of behavioral interactions and depict their dynamic interconversions and transitions. Two cases, experts’ feedback, and a user study suggest that RoleSeer helps interpret the identified informal roles and explore the patterns behind role changes. We see our approach’s potential in investigating informal roles in a broader range of social games.