Community Structure in the United States House of Representatives

We investigate the networks of committee and subcommittee assignments in the United States House of Representatives from the 101st--108th Congresses, with the committees connected by ``interlocks'' or common membership. We examine the community structure in these networks using several methods, revealing strong links between certain committees as well as an intrinsic hierarchical structure in the House as a whole. We identify structural changes, including additional hierarchical levels and higher modularity, resulting from the 1994 election, in which the Republican party earned majority status in the House for the first time in more than forty years. We also combine our network approach with analysis of roll call votes using singular value decomposition to uncover correlations between the political and organizational structure of House committees.Comment: 44 pages, 13 figures (some with multiple parts and most in color), 9 tables, to appear in Physica A; new figures and revised discussion (including extra introductory material) for this versio

Scather: programming with multi-party computation and MapReduce

We present a prototype of a distributed computational infrastructure, an associated high level programming language, and an underlying formal framework that allow multiple parties to leverage their own cloud-based computational resources (capable of supporting MapReduce [27] operations) in concert with multi-party computation (MPC) to execute statistical analysis algorithms that have privacy-preserving properties. Our architecture allows a data analyst unfamiliar with MPC to: (1) author an analysis algorithm that is agnostic with regard to data privacy policies, (2) to use an automated process to derive algorithm implementation variants that have different privacy and performance properties, and (3) to compile those implementation variants so that they can be deployed on an infrastructures that allows computations to take place locally within each participant’s MapReduce cluster as well as across all the participants’ clusters using an MPC protocol. We describe implementation details of the architecture, discuss and demonstrate how the formal framework enables the exploration of tradeoffs between the efficiency and privacy properties of an analysis algorithm, and present two example applications that illustrate how such an infrastructure can be utilized in practice.This work was supported in part by NSF Grants: #1430145, #1414119, #1347522, and #1012798

Totally secure classical networks with multipoint telecloning (teleportation) of classical bits through loops with Johnson-like noise

First, we show a new inexpensive defense against intruders and the man-in-the-middle attack in the Kirchhoff's-loop-Johnson-like-noise (KLJN) cipher. Then instead of point-to-point communication, we propose a high efficiency, secure network. The (in the idealistic case totally secure) classical network is based on an improved version of the KLJN cipher. The network consists of two parallel networks: i) a chain-like network of securely communicating, electrically isolated Kirchhoff-loops with Johnson-like noise and driven by a specific switching process of the resistances; ii) and a regular non-secure data network with a Coordinator-server. If the classical network is fast enough, the chain-like network of N communicators can generate and share an N bit long secret key within a single clock period of the ciphers and that implies a significant speed-up compared to the point-to-point key exchanges used by quantum communication or RSA-like key exchange methods. This is a teleportation-type multiple telecloning of the classical information bit because the information transfer can take place without the actual presence of the information bit at the intermediate points of the network. With similar quantum schemes the telecloning of classical bits via quantum communicator networks without telecloning the quantum states is also possible.Comment: Quantum-based network application added. 13 page