On the Possibility of Democracy and Rational Collective Choice

The paper challenges the 'orthodox doctrine' of collective choice theory according to which Arrow’s 'general possibility theorem' precludes rational decision procedures generally and implies that in particular all voting procedures must be flawed. I point out that all voting procedures are cardinal and that Arrow’s result, based on preference orderings cannot apply to them. All voting procedures that have been proposed, with the exception of approval voting, involve restrictions on voters expressions of their preferences. These restrictions, not any general impossibility, are the cause of various well known pathologies. In the class of unrestricted voting procedures I favor 'evaluative voting' under which a voter can vote for or against any alternative, or abstain. I give a historical/conceptual analysis of the origins of theorists’ aversion to cardinal analysis in collective choice and voting theories

On the Possibility of Democracy and Rational Collective Choice

The paper challenges the 'orthodox doctrine' of collective choice theory according to which Arrow’s 'general possibility theorem' precludes rational decision procedures generally and implies that in particular all voting procedures must be flawed. I point out that all voting procedures are cardinal and that Arrow’s result, based on preference orderings cannot apply to them. All voting procedures that have been proposed, with the exception of approval voting, involve restrictions on voters expressions of their preferences. These restrictions, not any general impossibility, are the cause of various well known pathologies. In the class of unrestricted voting procedures I favor 'evaluative voting' under which a voter can vote for or against any alternative, or abstain. I give a historical/conceptual analysis of the origins of theorists’ aversion to cardinal analysis in collective choice and voting theories.Arrow's paradox ; approval voting ; cardinal collective choice ; instant runoff voting ; voting paradoxes

High-Rate Space-Time Coded Large MIMO Systems: Low-Complexity Detection and Channel Estimation

In this paper, we present a low-complexity algorithm for detection in high-rate, non-orthogonal space-time block coded (STBC) large-MIMO systems that achieve high spectral efficiencies of the order of tens of bps/Hz. We also present a training-based iterative detection/channel estimation scheme for such large STBC MIMO systems. Our simulation results show that excellent bit error rate and nearness-to-capacity performance are achieved by the proposed multistage likelihood ascent search (M-LAS) detector in conjunction with the proposed iterative detection/channel estimation scheme at low complexities. The fact that we could show such good results for large STBCs like 16x16 and 32x32 STBCs from Cyclic Division Algebras (CDA) operating at spectral efficiencies in excess of 20 bps/Hz (even after accounting for the overheads meant for pilot based training for channel estimation and turbo coding) establishes the effectiveness of the proposed detector and channel estimator. We decode perfect codes of large dimensions using the proposed detector. With the feasibility of such a low-complexity detection/channel estimation scheme, large-MIMO systems with tens of antennas operating at several tens of bps/Hz spectral efficiencies can become practical, enabling interesting high data rate wireless applications.Comment: v3: Performance/complexity comparison of the proposed scheme with other large-MIMO architectures/detectors has been added (Sec. IV-D). The paper has been accepted for publication in IEEE Journal of Selected Topics in Signal Processing (JSTSP): Spl. Iss. on Managing Complexity in Multiuser MIMO Systems. v2: Section V on Channel Estimation is update

The decision tree approach to classification

A class of multistage decision tree classifiers is proposed and studied relative to the classification of multispectral remotely sensed data. The decision tree classifiers are shown to have the potential for improving both the classification accuracy and the computation efficiency. Dimensionality in pattern recognition is discussed and two theorems on the lower bound of logic computation for multiclass classification are derived. The automatic or optimization approach is emphasized. Experimental results on real data are reported, which clearly demonstrate the usefulness of decision tree classifiers

Human exposure limits to hypergolic fuels

Over the past four decades, many studies have been conducted on the toxicities of the rocket propellants hydrazine (HZ) and monomethylhydrazine (MH). Numerous technical challenges have made it difficult to unambiguously interpret the results of these studies, and there is considerable divergence between results obtained by different investigators on the inhalation concentrations (MAC's) for each toxic effect inducible by exposure to hypergolic fuels in spacecraft atmospheres, NASA undertook a critical review of published and unpublished investigations on the toxicities of these compounds. The current state of the art practices for similar studies. While many questions remain unanswered, MAC's were determined using the best available data for a variety of toxic endpoints for potential continuous exposure durations ranging from 1 hour to 180 days. Spacecraft MAC's (SMAC's) were set for each compound based on the most sensitive toxic endpoint at each exposure duration