Integration of Low-Impact Development into the International Stormwater BMP Database

Low impact development (LID) strategies are being encouraged in many communities as an approach to reduce potential adverse impacts of development on receiving streams. Many questions exist regarding how well various LID strategies perform in different settings, just as similar questions have been raised regarding performance of traditional stormwater best management practices (BMPs). Whereas historical focus on BMP performance has been water quality concentrations or loads, characterization of volume reduction benefits for both conventional and LID practices is increasingly an objective of researchers and stormwater managers. More than a decade ago, Urban Water Resources Research Council (UWRRC) members worked to develop a set of standardized monitoring and reporting protocols for traditional BMPs and to establish a master database for the purpose of evaluating BMP performance and the factors affecting performance. This effort culminated in the International Stormwater BMP Database (www.bmpdatabase.org), which contains data for more than 360 BMPs and continues to operate as a clearinghouse for stormwater BMP data and performance analyses. During 2008–2009, the International Stormwater BMP Database project expanded to better integrate LID into the database and develop a set of metrics that can be used to characterize BMP performance with regard to surface runoff volume reduction. This paper provides a condensed overview and progress report on the LID-focused effort, including the following topics: (1)?monitoring guidance for LID at the overall site development level, (2)?an overview of recent changes to the International Stormwater BMP Database to better accommodate LID studies, (3)?a summary of LID studies currently included in the database, and (4)?a proposed approach for evaluating performance of LID studies with regard to reducing surface runoff volumes.     

Consideration of the BDNF gene in relation to two phenotypes: Hoarding and obesity.

The gene coding for the brain derived neurotrophic factor (BDNF) has emerged as an interesting candidate for multiple brain and brain disorder-related phenomena. The primary aim of the present investigation was to consider the relationship between the BDNF Val66Met variant and two phenotypes: compulsive hoarding as a symptom dimension of obsessive–compulsive disorder (OCD), and body mass index (BMI). We examined the BDNF gene in a large (N = 301) clinical sample of probands with OCD. Participants were classified as hoarding or nonhoarding using a strict, multimeasure grouping approach. Results revealed that the Val/Val genotype was linked with hoarding classification and more severe hoarding behaviors, as well as greater BMI levels. Hoarding status was also associated with greater BMI scores, with individuals in the hoarding group being far more likely to be classified as obese compared with the nonhoarding group. Our findings may provide a distinct avenue through which hoarding and BMI could be linked. These findings are suggestive of a complex gene, body weight, and psychopathology relationship wherein a primitive, survival “thrifty gene” strategy may be conserved and represented in a subgroup of humans manifesting severe hoarding symptoms. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Conservative interpolation on unstructured polyhedral meshes: An extension of the supermesh approach to cell-centered finite-volume variables

A method is presented for conservatively transferring, or remapping, cell-centered variable fields from one mesh to another with second-order accuracy. The method is generally applicable to any polyhedral source or target mesh. Like the work of Farrell et al. [1], which was designed for finite-element computations, the proposed methodology uses a logical supermesh consisting of the intersections of polyhedra from both meshes. The resulting transfer process is well-suited for finite-volume methods that rely on cell-centered variables. The accuracy and efficacy of the new remapping process is demonstrated with numerical experiments and a computational fluid dynamics test.     

Efficient shape optimization for certain and uncertain aerodynamic design

In this paper, we present novel developments in aerodynamic shape optimization based on shape calculus as well as the proper treatment of aleatoric uncertainties in the field of aerodynamic design.     

Unconstrained model predictive control and suboptimality estimates for nonlinear continuous-time systems

This paper presents a continuous-time version of recent results on unconstrained nonlinear model predictive control (MPC) schemes. Based on a controllability assumption and a corresponding infinite-dimensional optimization problem, performance estimates and stability conditions are derived in terms of the prediction horizon and the sampling time of the MPC controller. Moreover, improved estimates for small sampling times are discussed and a comparison to the application of the discrete-time results in a sampled-data context is provided.     

New high-speed bipolar XOR gate with absolutely symmetrical circuit configuration

A new monolithic integrated exclusive OR gate (XOR) in E/sup 2/CL circuit design is presented. The symmetry with respect to both inputs makes it superior to the standard XOR gates in ECL or E/sup 2/CL for several applications. The circuit was realised using a conservative 2 mu m standard silicon bipolar technology.<>     

Optimal block-type-decodable encoders for constrained systems

A constrained system is presented by a finite-state labeled graph. For such systems, we focus on block-type-decodable encoders, comprising three classes known as block, block-decodable, and deterministic encoders. Franaszek (1968) gives a sufficient condition which guarantees the equality of the optimal rates of block-decodable and deterministic encoders for the same block length. We introduce another sufficient condition, called the straight-line condition, which yields the same result. Run-length limited RLL(d,k) and maximum transition run MTR(j,k) constraints are shown to satisfy both conditions. In general, block-type-decodable encoders are constructed by choosing a subset of states of the graph to be used as encoder states. Such a subset is known as a set of principal states. For each type of encoder and each block length, a natural problem is to find a set of principal states which maximizes the code rate. We show how to compute the asymptotically optimal sets of principal states for deterministic encoders and how they are related to the case of large but finite block lengths. We give optimal sets of principal states for MTR(j,k)-block-type-decodable encoders for all codeword lengths. Finally we compare the code rate of nonreturn to zero inverted (NRZI) encoders to that of corresponding nonreturn to zero (NRZ) and signed NRZI encoders.     

On cosets of the generalized first-order reed-muller code with low PMEPR

Golay sequences are well suited for use as codewords in orthogonal frequency-division multiplexing (OFDM), since their peak-to-mean envelope power ratio (PMEPR) in q-ary phase-shift keying (PSK) modulation is at most 2. It is known that a family of polyphase Golay sequences of length 2^m organizes in m!/2 cosets of a q-ary generalization of the first-order Reed-Muller code, RM_q(1,m). In this paper, a more general construction technique for cosets of RM _q(1,m) with low PMEPR is established. These cosets contain so-called near-complementary sequences. The application of this theory is then illustrated by providing some construction examples. First, it is shown that the m!/2 cosets of RM_q(1,m) comprised of Golay sequences just arise as a special case. Second, further families of cosets of RM_q(1,m) with maximum PMEPR between 2 and 4 are presented, showing that some previously unexplained phenomena can now be understood within a unified framework. A lower bound on the PMEPR of cosets of RM_q(1,m) is proved as well, and it is demonstrated that the upper bound on the PMEPR is tight in many cases. Finally, it is shown that all upper bounds on the PMEPR of cosets of RM_q(1,m) also hold for the peak-to-average power ratio (PAPR) under the Walsh-Hadamard transform (WHT)     

Large deviation theorems for empirical types of Markov chainsconstrained to thin sets

An irreducible Markov chain with stationary transition probabilities on a finite directed graph is considered. The probability of large deviations of the random variable denoting the empirical type of the first n transitions is investigated