Modeling Social Networks with Node Attributes using the Multiplicative Attribute Graph Model

Networks arising from social, technological and natural domains exhibit rich connectivity patterns and nodes in such networks are often labeled with attributes or features. We address the question of modeling the structure of networks where nodes have attribute information. We present a Multiplicative Attribute Graph (MAG) model that considers nodes with categorical attributes and models the probability of an edge as the product of individual attribute link formation affinities. We develop a scalable variational expectation maximization parameter estimation method. Experiments show that MAG model reliably captures network connectivity as well as provides insights into how different attributes shape the network structure.Comment: 15 pages, 7 figures, 7 table

Multiplicative Attribute Graph Model of Real-World Networks

Large scale real-world network data such as social and information networks are ubiquitous. The study of such social and information networks seeks to find patterns and explain their emergence through tractable models. In most networks, and especially in social networks, nodes have a rich set of attributes (e.g., age, gender) associated with them. Here we present a model that we refer to as the Multiplicative Attribute Graphs (MAG), which naturally captures the interactions between the network structure and the node attributes. We consider a model where each node has a vector of categorical latent attributes associated with it. The probability of an edge between a pair of nodes then depends on the product of individual attribute-attribute affinities. The model yields itself to mathematical analysis and we derive thresholds for the connectivity and the emergence of the giant connected component, and show that the model gives rise to networks with a constant diameter. We analyze the degree distribution to show that MAG model can produce networks with either log-normal or power-law degree distributions depending on certain conditions.Comment: 33 pages, 6 figure

Optimal inverter logic gate using 10-nm double gate-all-around (DGAA) transistor with asymmetric channel width

We investigate the electrical characteristics of a double-gate-all-around (DGAA) transistor with an asymmetric channel width using three-dimensional device simulation. The DGAA structure creates a siliconnanotube field-effect transistor (NTFET) with a core-shell gate architecture, which can solve the problem of loss of gate controllability of the channel and provides improved short-channel behavior. The channel width asymmetry is analyzed on both sides of the terminals of the transistors, i.e., source and drain. In addition, we consider both n-type and p-type DGAA FETs, which are essential to forming a unit logic cell, the inverter. Simulation results reveal that, according to the carrier types, the location of the asymmetry has a different effect on the electrical properties of the devices. Thus, we propose the N/P DGAA FET structure with an asymmetric channel width to form the optimal inverter. Various electrical metrics are analyzed to investigate the benefits of the optimal inverter structure over the conventional inverter structure. Simulation results show that 27% delay and 15% leakage power improvement are enabled in the optimum structure.ope

Dimensionality of social networks using motifs and eigenvalues

We consider the dimensionality of social networks, and develop experiments aimed at predicting that dimension. We find that a social network model with nodes and links sampled from an $m$-dimensional metric space with power-law distributed influence regions best fits samples from real-world networks when $m$ scales logarithmically with the number of nodes of the network. This supports a logarithmic dimension hypothesis, and we provide evidence with two different social networks, Facebook and LinkedIn. Further, we employ two different methods for confirming the hypothesis: the first uses the distribution of motif counts, and the second exploits the eigenvalue distribution.Comment: 26 page

Laser-Induced Fabrication of a Transsubstrate Microelectrode Array and Its Neurophysiological Performance

Technical problems associated with the monolithic integration of active circuitry into a high-density microelectrode array for neural recordings include passivation of the active circuit area, capacitive coupling of switching transients, and nonuniformity of the recording surface. These problems can be eliminated by implementing the passive and active elements on opposite planes of a substrate and interconnecting them with transsubstrate conductive channels. As the first step toward this integrated active transsubstrate microelectrode array (TMEA), a passive TMEA was fabricated and is reported in this paper. An array of six transsubstrate conductive channels, each 100 /tm in diameter and spaced on 100 Am centers, were made in a 7 mil thick silicon substrate using a laser-induced diffusion technique. The transsubstrate channels are metal doped p-type channels embedded in a n-type silicon wafer. The p-n junction thus formed provides good channel-to-substrate and channel-to-channel isolation. Excellent recordings were made from crayfish giant axons using TMEA. The signal-to-noise ratio was as large as 10 to 1 with no crosstalk observed between adjacent channels. The TMEA showed no degradation with long-term use.Most of the processing work has been done in the National Research and Resource Facility for Submicron Structures (NRRFSS) at Cornell University, Ithaca, NY. The authors would especially like to thank Prof. E. Wolf and Prof. G. Wolga for the use of the equipment in the facility. The first author also thanks Prof. C. A. Lee of Cornell University and Prof. B. C. Wheeler of the University of Illinois, Urbana-Champaign, for consultation and discussion on various aspects of this work

Light-guiding hydrogels for cell-based sensing and optogenetic synthesis in vivo

Polymer hydrogels are widely used as cell scaffolds for biomedical applications. While the biochemical and biophysical properties of hydrogels have been extensively investigated, little attention has been paid to their potential photonic functionalities. Here, we report cell-integrated polyethylene glycol-based hydrogels for in-vivo optical sensing and therapy applications. Hydrogel patches containing cells were implanted in awake, freely moving mice for several days and shown to offer long-term transparency, biocompatibility, cell-viability, and light-guiding properties (loss: <1 dB/cm). Using optogenetic, glucagon-like peptide-1 (GLP-1) secreting cells, we conducted light-controlled therapy using the hydrogel in a mouse model with type-2 diabetes and attained improved glucose homeostasis. Furthermore, real-time optical readout of encapsulated heat-shock-protein-coupled fluorescent reporter cells made it possible to measure the nanotoxicity of cadmium-based bare and shelled quantum dots (CdTe; CdSe/ZnS) in vivo

Differences in bedding material could alter the growth performance of White Pekin ducks raised for 42 days

The effect of different commercially available bedding materials on the growth performance and carcass characteristics of ducks for 42 days was investigated. 336 one-day-old White-Pekin ducklings (60.48 ± 0.16 g) were randomly allocated into 24-floor pens with one of the three beddings namely i) coco peat, ii) rice husks, or iii) sawdust. 14 ducklings per pen and 8 replicate pens per bedding material were used. Birds were fed a starter diet from days 1–21 and a grower diet from days 22–42. Weekly growth performance evaluation was conducted for the average body weight, weight gains, daily feed intake, and feed conversion efficiency. One bird per pen was sacrificed on day 42 for the evaluation of carcass characteristics including the carcass, breast, and leg muscle percentages. Breast and leg muscle samples were then collected and analyzed for their proximate and pH values. Higher body weights (p &lt; 0.05) were noticed with rice husks on day 42 only. Improved daily gains (p &lt; 0.05) were also noticed for birds raised with rice husks over the entire period (days 1–42). Concerning feed intake, higher values (p &lt; 0.05) were similarly noted with rice husks for the grower phase (days 22–42), and the entire experimental period (days 1–42). Marginally improved feed intake values were also noted with the use of rice husks as the bedding materials on day 42 (p = 0.092). Improved feed efficiency (p &lt; 0.05) was noticed with rice husks on day 35, the grower period, and the entire 42-day period. However, no significant differences were noticed for most of the carcass characteristics that were evaluated. Nevertheless, higher (p &lt; 0.05) pH values for the breast muscle were noticed with the use of coco peat and sawdust as the bedding. Conclusively, the bedding type could have a significant impact on the growth performance of ducks without adverse effects on carcass characteristics. The use of rice husks as bedding might be advantageous and is therefore recommended