Measuring in-plane deflections and strains through visual sensing techniques for civil infrastructure applications

Maintaining the integrity and safety of civil infrastructures such as bridges, dams, tunnels and high-rise buildings is an essential task for civil engineers. Collapse or damage of these civil infrastructures may lead to a tremendous amount of injuries and casualties. To alleviate this situation, a real-time surveillance method enabled by visual sensing techniques is proposed in this thesis. The advances of applying visual sensing techniques, for instance, are allowing practical deployment for large extended systems in a more cost-effective way. Also, the image or video data can be easily used for long-term condition assessments.;The proposed method entails applying visual sensing techniques to measure in-plane deflections and strains of structural members for civil infrastructure applications. In specific, it employs visual sensors (digital/industrial cameras) to capture and record a series of continuous image frames of the targets. Then automated feature detection and matching algorithms are applied to detect and match object features in the consecutive image frames. Based on the location information of the detected features, the in-plane object displacement can be accurately calculated through keeping tracking those features in the continuous image frames. Next, an optimized interpolation procedure is conducted to obtain dense displacement field for the object. And the strains can be consequently recovered from the displacement field through computing its derivatives.;In this research, firstly, the work of evaluating the optimum feature detection and matching algorithm is reported, which is the key task to achieve accurate surveillance. A series of experiments were conducted to compare the three algorithms: DIC (Digital Image Correlation), SIFT (Scale Invariant Feature Transform), and SURF (Speeded-Up Robust Features). The experimental result indicated that the DIC algorithm reveals superiority among the three algorithms and holds the most potential for measuring in-plane deflections and strains of civil infrastructures. To further validate our method, we employed high-speed industrial camera (Manta G223B) to capture a series of continuous image frames of deformed real-world scenarios. The DIC algorithm was adopted for the feature detection and matching process. As the output, the displacement and strains were calculated and then compared with the ground truth in order to evaluate the accuracy performance of the method. Colored strain maps were generated by using different colors to reflect different strain levels in an intuitive way. The experimental result indicated that our method can achieve highly accurate measuring performance of computing in-plane displacements and strains for civil infrastructure applications. The proposed method has several advantages when compared to pre-existing methods (such as sensor networks). It can generate accurate full-field deflections and strains of the target. Besides, the cost-effective equipment and much more convenient set-up procedures will enable engineers to operate periodically and apply for different scales of civil infrastructure applications

Intermolecular Failure of L-type Ca(2+) Channel and Ryanodine Receptor Signaling in Hypertrophy

Pressure overload–induced hypertrophy is a key step leading to heart failure. The Ca(2+)-induced Ca(2+) release (CICR) process that governs cardiac contractility is defective in hypertrophy/heart failure, but the molecular mechanisms remain elusive. To examine the intermolecular aspects of CICR during hypertrophy, we utilized loose-patch confocal imaging to visualize the signaling between a single L-type Ca(2+) channel (LCC) and ryanodine receptors (RyRs) in aortic stenosis rat models of compensated (CHT) and decompensated (DHT) hypertrophy. We found that the LCC-RyR intermolecular coupling showed a 49% prolongation in coupling latency, a 47% decrease in chance of hit, and a 72% increase in chance of miss in DHT, demonstrating a state of “intermolecular failure.” Unexpectedly, these modifications also occurred robustly in CHT due at least partially to decreased expression of junctophilin, indicating that intermolecular failure occurs prior to cellular manifestations. As a result, cell-wide Ca(2+) release, visualized as “Ca(2+) spikes,” became desynchronized, which contrasted sharply with unaltered spike integrals and whole-cell Ca(2+) transients in CHT. These data suggested that, within a certain limit, termed the “stability margin,” mild intermolecular failure does not damage the cellular integrity of excitation-contraction coupling. Only when the modification steps beyond the stability margin does global failure occur. The discovery of “hidden” intermolecular failure in CHT has important clinical implications

Development and evaluation of the first high-throughput SNP array for common carp (Cyprinus carpio)

BACKGROUND: A large number of single nucleotide polymorphisms (SNPs) have been identified in common carp (Cyprinus carpio) but, as yet, no high-throughput genotyping platform is available for this species. C. carpio is an important aquaculture species that accounts for nearly 14% of freshwater aquaculture production worldwide. We have developed an array for C. carpio with 250,000 SNPs and evaluated its performance using samples from various strains of C. carpio. RESULTS: The SNPs used on the array were selected from two resources: the transcribed sequences from RNA-seq data of four strains of C. carpio, and the genome re-sequencing data of five strains of C. carpio. The 250,000 SNPs on the resulting array are distributed evenly across the reference C.carpio genome with an average spacing of 6.6 kb. To evaluate the SNP array, 1,072 C. carpio samples were collected and tested. Of the 250,000 SNPs on the array, 185,150 (74.06%) were found to be polymorphic sites. Genotyping accuracy was checked using genotyping data from a group of full-siblings and their parents, and over 99.8% of the qualified SNPs were found to be reliable. Analysis of the linkage disequilibrium on all samples and on three domestic C.carpio strains revealed that the latter had the longer haplotype blocks. We also evaluated our SNP array on 80 samples from eight species related to C. carpio, with from 53,526 to 71,984 polymorphic SNPs. An identity by state analysis divided all the samples into three clusters; most of the C. carpio strains formed the largest cluster. CONCLUSIONS: The Carp SNP array described here is the first high-throughput genotyping platform for C. carpio. Our evaluation of this array indicates that it will be valuable for farmed carp and for genetic and population biology studies in C. carpio and related species

Optimal pricing and production control in an assembly system with a general stockout cost

We study the optimal control of an assembly system used to produce an assemble-to-order end product. We determine how to manage component production and end product price in order to maximize total discounted profit over an infinite horizon. We show the optimal production control is a state dependent base-stock policy and the optimal price adjustment is given by a threshold switching policy.6 page(s

Optimal Starting Times for End-of-Season Sales and Optimal Stopping Times for Promotional Fares

Many industries face the problem of selling a fixed stock of items over a finite horizon. These industries include airlines selling seats before planes depart, hotels renting rooms before midnight, theaters selling seats before curtain time, and retailers selling seasonal goods such as air-conditioners or winter coats before the end of the season. Given a fixed number of seats, rooms, or coats, the objective for these industries is to maximize revenues in excess of salvage value. When demand is price sensitive and stochastic, pricing is an effective tool to maximize revenues. In this paper we address the problem of deciding the optimal timing of a single price change from a given initial price to either a given lower or higher second price. Under mild conditions, we show that it is optimal to decrease (resp., to increase) the initial price as soon as the time-to-go falls below (resp., above) a time threshold that depends on the number of yet unsold items.dynamic pricing, yield management, stopping times, intensity control, martingales, finite horizon, optimal policies

Two Pricing Mechanisms in Sponsored Search Advertising

Sponsored search advertising has grown rapidly since the last decade and is now a significant revenue source for search engines. To ameliorate revenues, search engines often set fixed or variable reserve price to in influence advertisers’ bidding. This paper studies and compares two pricing mechanisms: the generalized second-price auction (GSP) where the winner at the last ad position pays the larger value between the highest losing bid and reserve price, and the GSP with a posted reserve price (APR) where the winner at the last position pays the reserve price. We show that if advertisers’ per-click value has an increasing generalized failure rate, the search engine’s revenue rate is quasi-concave and hence there exists an optimal reserve price under both mechanisms. While the number of advertisers and the number of ad positions have no effect on the selection of reserve price in GSP, the optimal reserve price is affected by both factors in APR and it should be set higher than GSP

Two Pricing Mechanisms in Sponsored Search Advertising

Sponsored search advertising has grown rapidly since the last decade and is now a significant revenue source for search engines. To ameliorate revenues, search engines often set fixed or variable reserve price to in influence advertisers’ bidding. This paper studies and compares two pricing mechanisms: the generalized second-price auction (GSP) where the winner at the last ad position pays the larger value between the highest losing bid and reserve price, and the GSP with a posted reserve price (APR) where the winner at the last position pays the reserve price. We show that if advertisers’ per-click value has an increasing generalized failure rate, the search engine’s revenue rate is quasi-concave and hence there exists an optimal reserve price under both mechanisms. While the number of advertisers and the number of ad positions have no effect on the selection of reserve price in GSP, the optimal reserve price is affected by both factors in APR and it should be set higher than GSP