Modeling and optimization of production and distribution of drinking water at VMW

We develop and discuss an operational planning model aiming at minimizing production and distribution costs in large drinking water networks containing buffers with free inflow. Modeling drinking water networks is very challenging due of the presence of complex hydraulic constraints, such as friction losses and pump curves. Non-linear, non-convex constraints result from the relationships between pressure and flow in power terms. Also, binary variables are needed to model the possibility of free inflow or re-injection of water at reservoirs. The resulting model is thus a non-convex Mixed-Integer Non-Linear Program (MINLP). A discrete-time setting is proposed to solve the problem over a finite horizon made of several intervals. A commercial solver, BONMIN, suited for convex MINLP models is used to heuristically solve the problem. We are able to find a good solution for a small part of an existing network operated by the Vlaamse Maatschappij voor Watervoorziening (VMW), a major drinking water company in Flanders

Global haplotype partitioning for maximal associated SNP pairs

<p>Abstract</p> <p>Background</p> <p>Global partitioning based on pairwise associations of SNPs has not previously been used to define haplotype blocks within genomes. Here, we define an association index based on LD between SNP pairs. We use the Fisher's exact test to assess the statistical significance of the LD estimator. By this test, each SNP pair is characterized as associated, independent, or not-statistically-significant. We set limits on the maximum acceptable proportion of independent pairs within all blocks and search for the partitioning with maximal proportion of associated SNP pairs. Essentially, this model is reduced to a constrained optimization problem, the solution of which is obtained by iterating a dynamic programming algorithm.</p> <p>Results</p> <p>In comparison with other methods, our algorithm reports blocks of larger average size. Nevertheless, the haplotype diversity within the blocks is captured by a small number of tagSNPs. Resampling HapMap haplotypes under a block-based model of recombination showed that our algorithm is robust in reproducing the same partitioning for recombinant samples. Our algorithm performed better than previously reported models in a case-control association study aimed at mapping a single locus trait, based on simulation results that were evaluated by a block-based statistical test. Compared to methods of haplotype block partitioning, we performed best on detection of recombination hotspots.</p> <p>Conclusion</p> <p>Our proposed method divides chromosomes into the regions within which allelic associations of SNP pairs are maximized. This approach presents a native design for dimension reduction in genome-wide association studies. Our results show that the pairwise allelic association of SNPs can describe various features of genomic variation, in particular recombination hotspots.</p

Antihypertensive and antioxidant effects of dietary black sesame meal in pre-hypertensive humans

<p>Abstract</p> <p>Background</p> <p>It has been known that hypertension is an independent risk factor for cardiovascular disease (CVD). CVD is the major cause of morbidity and mortality in developed and developing countries. Elevation of blood pressure (BP) increases the adverse effect for cardiovascular outcomes. Prevention of increased BP plays a crucial role in a reduction of those outcomes, leading to a decrease in mortality. Therefore, the purpose of this study was to investigate the effects of dietary black sesame meal on BP and oxidative stress in individuals with prehypertension.</p> <p>Methods</p> <p>Twenty-two women and eight men (aged 49.8 ± 6.6 years) with prehypertension were randomly divided into two groups, 15 subjects per group. They ingested 2.52 g black sesame meal capsules or placebo capsules each day for 4 weeks. Blood samples were obtained after overnight fasting for measurement of plasma lipid, malondialdehyde (MDA) and vitamin E levels. Anthropometry, body composition and BP were measured before and after 4-week administration of black sesame meal or a placebo.</p> <p>Results</p> <p>The results showed that 4-week administration of black sesame meal significantly decreased systolic BP (129.3 ± 6.8 vs. 121.0 ± 9.0 mmHg, <it>P </it>< 0.05) and MDA level (1.8 ± 0.6 vs. 1.2 ± 0.6 μmol/L, <it>P </it>< 0.05), and increased vitamin E level (29.4 ± 6.0 vs. 38.2 ± 7.8 μmol/L, <it>P </it>< 0.01). In the black sesame meal group, the change in SBP tended to be positively related to the change in MDA (<it>R = 0.50, P </it>= 0.05), while the change in DBP was negatively related to the change in vitamin E (<it>R = -0.55, P </it>< 0.05). There were no correlations between changes in BP and oxidative stress in the control group.</p> <p>Conclusions</p> <p>These results suggest the possible antihypertensive effects of black sesame meal on improving antioxidant status and decreasing oxidant stress. These data may imply a beneficial effect of black sesame meal on prevention of CVD.</p

Design of framed structures: An integrated non-linear analysis and optimal minimum weight design

The aim of this paper is to develop a structural optimization algorithm based on optimality criterion approach to achieve a minimum weight structure that satisfies a set of displacement constraints. Optimal designs are found considering both linear and non-linear behaviour of the structure and compared through an example problem. Many algorithms have been developed to determine the optimal minimum weight design of framed structures under a set of displacement constraints; however, in almost all of them linear analyses are performed. This paper shows how the non-linear analysis will effect the optimal design of a structure. © 1998 John Wiley & Sons, Ltd

Data management for large-scale water-distribution optimization systems

This paper presents a technique to efficiently process data to supply the necessary in-puts to a large-scale water-distribution optimization model. The overall goal of this project is to develop an on-line optimal control strategy for a large municipal and industrial (M&I) water distribution system. That is, which pumps should be turned on to meet the demand and minimize cost? One of the problems in handling a large water-distribution system is managing the large database required for the optimization model. This paper presents an efficient algorithm to generate, store, and access the necessary data. Some of the characteristics of the method are illustrated through an example of a water-distribution system. © ASCE

Optimal design of structures with kinematic nonlinear behavior

This paper suggests an optimization-based methodology for the designof minimum weight structures with kinematic nonlinear behavior. Attention isfocused on three-dimensional reticulated structures idealized with beam elementsunder proportional static loadings. The algorithm used for optimization is basedon a classical optimality criterion approach using an active-set strategy for extremelimit constraints on the design variables. A first-order necessary condition is derivedand used as the basis of a fixed-point iteration method to search for the optimaldesign. A fixed-point iteration algorithm is used based on the criterion that atoptimum design the nonlinear strain energy is equal in all members. A nonlinearanalysis procedure for three-dimensional structures is discussed and used in developingthe optimization algorithm. Several examples are given to evaluate thevalidity of the underlying assumptions and to demonstrate some of the characteristicsof the proposed procedures. The procedure is verified using two well-knownexamples © ASCE

An improvement on the estimation of pseudoresponse spectral velocity using RVT method

The basic assumption in the prediction of peak ground acceleration (PGA), peak ground velocity (PGV), and pseudoresponse spectral values by the random vibration theory (RVT) method is that the ground motion process is a bandlimited Gaussian random process (BGRP). However, for the estimation of pseudoresponse spectral values, the process is the output of a single-degree-of-freedom (SDOF) system subjected to the input of a BGRP. The output process is a narrowband random process because a SDOF system acts a a narrow-bandpass filter. The property of a narrow-band process is significantly different from that of a bandlimited process. There is an obvious difference in the estimations of the pseudoresponse spectral values based on bandlimited or narrow-band process, especially in the lower frequency part. In this study, we propose an empirical method to improve the estimation of the pseudoresponse spectral values by the RVT based on the consideration of properties of a narrow-band Gaussian stationary process. Comparisons of our results with those of previous research studies and the time domain simulation (TDS) shows that our empirical approach improves the estimation of pseudoresponse spectral values in the long period range