Confronting Misconceptions and Acknowledging Imperfections: A Response to Khaled Abou El Fadl\u27s Islam and Democracy

Professor Abou El Fadl\u27s Article, Islam and the Challenge of Democracy, demonstrates the need to move forward with knowledge of the nuance and depth of the historic, philosophic, legal, and theological foundations of both political stasis and political change in Muslim countries. The author comments on three aspects of Khaled Abou El Fadl\u27s paper. First, the author will juxtapose the discourse that Professor Abou El Fadl is stimulating with other perspectives in order to delineate the sets of actors in this debate among Muslims. The author will also argue that “Islamic exceptionalism,” so prominent in post-modern critiques, is unhelpful. Second, the author will comment on the centrality of Shari‘ah to the internal debate, and discuss widespread misconceptions about Shari‘ah among non-Muslims. Third, the author will comment on the problem of human agency and imperfect institutions. This imperfection becomes a critical issue when sacred texts are codified into secular law

A polarization identity for multilinear maps

Given linear spaces $E$ and $F$ over the real numbers or a field of characteristic zero, a simple argument is given to represent a symmetric multilinear map $u(x_1, x_2, \ldots, x_n)$ from $E^n$ to $F$ in terms of its restriction to the diagonal. As an application, a probabilistic expression for Gaussian variables used by Nelson and by Schetzen is derived. An Appendix by Tom H. Koornwinder notes an even further simplification by Bochnak and Siciak (1971) of the proof of the main result.Comment: 7 pages, with an Appendix by Tom Koornwinder; v4: minor changes corresponding to journal version in Indag. Mat

Fingerprinting-Based Positioning in Distributed Massive MIMO Systems

Location awareness in wireless networks may enable many applications such as emergency services, autonomous driving and geographic routing. Although there are many available positioning techniques, none of them is adapted to work with massive multiple-in-multiple-out (MIMO) systems, which represent a leading 5G technology candidate. In this paper, we discuss possible solutions for positioning of mobile stations using a vector of signals at the base station, equipped with many antennas distributed over deployment area. Our main proposal is to use fingerprinting techniques based on a vector of received signal strengths. This kind of methods are able to work in highly-cluttered multipath environments, and require just one base station, in contrast to standard range-based and angle-based techniques. We also provide a solution for fingerprinting-based positioning based on Gaussian process regression, and discuss main applications and challenges.Comment: Proc. of IEEE 82nd Vehicular Technology Conference (VTC2015-Fall

Introduced Purple Loosestrife as Host of Native Saturniidae (Lepidoptera)

Purple loosestrife (Lythrum salicaria,Lythraceae) arrived in North America nearly 200 years ago. In 1969 we first found larvae of the native Cecropia (Hyalophora cecropia) and Polyphemus (Antheraea polyphemus) moths (Lepidoptera: Saturniidae) on loosestrife in the Hudson River Valley, New York, and we have since found Io (Automeris io) on this plant. A census of 4th and 5th instar saturniids in four 0.25 ha plots in purple loosestrife-gray dogwood (Cornus racemosa) wet meadows near Saugerties in 1984 indicated that Polyphemus and Cecropia larvae occurred much more frequently on loosestrife than on dogwood, a native host. The switch from native woody hosts to an introduced herb may have been facilitated by the dense shrub- like habit, high productivity, and high tannin content of loosestrife

Sum Throughput Maximization in Multi-Tag Backscattering to Multiantenna Reader

Backscatter communication (BSC) is being realized as the core technology for pervasive sustainable Internet-of-Things applications. However, owing to the resource-limitations of passive tags, the efficient usage of multiple antennas at the reader is essential for both downlink excitation and uplink detection. This work targets at maximizing the achievable sum-backscattered-throughput by jointly optimizing the transceiver (TRX) design at the reader and backscattering coefficients (BC) at the tags. Since, this joint problem is nonconvex, we first present individually-optimal designs for the TRX and BC. We show that with precoder and {combiner} designs at the reader respectively targeting downlink energy beamforming and uplink Wiener filtering operations, the BC optimization at tags can be reduced to a binary power control problem. Next, the asymptotically-optimal joint-TRX-BC designs are proposed for both low and high signal-to-noise-ratio regimes. Based on these developments, an iterative low-complexity algorithm is proposed to yield an efficient jointly-suboptimal design. Thereafter, we discuss the practical utility of the proposed designs to other application settings like wireless powered communication networks and BSC with imperfect channel state information. Lastly, selected numerical results, validating the analysis and shedding novel insights, demonstrate that the proposed designs can yield significant enhancement in the sum-backscattered throughput over existing benchmarks.Comment: 17 pages, 5 figures, accepted for publication in IEEE Transactions on Communication

PAR-Aware Large-Scale Multi-User MIMO-OFDM Downlink

We investigate an orthogonal frequency-division multiplexing (OFDM)-based downlink transmission scheme for large-scale multi-user (MU) multiple-input multiple-output (MIMO) wireless systems. The use of OFDM causes a high peak-to-average (power) ratio (PAR), which necessitates expensive and power-inefficient radio-frequency (RF) components at the base station. In this paper, we present a novel downlink transmission scheme, which exploits the massive degrees-of-freedom available in large-scale MU-MIMO-OFDM systems to achieve low PAR. Specifically, we propose to jointly perform MU precoding, OFDM modulation, and PAR reduction by solving a convex optimization problem. We develop a corresponding fast iterative truncation algorithm (FITRA) and show numerical results to demonstrate tremendous PAR-reduction capabilities. The significantly reduced linearity requirements eventually enable the use of low-cost RF components for the large-scale MU-MIMO-OFDM downlink.Comment: To appear in IEEE Journal on Selected Areas in Communication