Estimates of the Aggregate Quarterly Capital Stock for the Post- War U.S. Economy

We construct quarterly aggregate gross and net capital stock series for the post-war U.S. economy using annual capital stock, capital depreciation, and capital discard figures along with quarterly investment series. We construct nominal and real measures of all three categories in the aggregate capital stock: consumer durable goods, producer durable goods, and business structures. In constructing the nominal series we take into account the changes in capital goods’ prices. The series are constructed using four different methods. Using time- and frequency domain techniques, we compare the constructed series and characterize their short-run, business cycle, and long-run cyclical properties. We find that the constructed series exhibit very different cyclical and shock persistence dynamics. Practical implications are discussed.Capital Stock, Consumer Durable Goods, Producer Durable Goods, Business Structures, Capital Depreciation and Discard, Capital Goods Prices, Frequency Domain, Cyclical Behavior, Linear Interpolation, Numerical Iteration

Advanced liquid crystal displays with supreme image qualities

Several metrics are commonly used to evaluate the performance of display devices. In this dissertation, we analyze three key parameters: fast response time, wide color gamut, and high contrast ratio, which affect the final perceived image quality. Firstly, we investigate how response time affects the motion blur, and then discover the 2-ms rule. With advanced low-viscosity materials, new operation modes, and backlight modulation technique, liquid crystal displays (LCDs) with an unnoticeable image blur can be realized. Its performance is comparable to an impulse-type display, like cathode ray tube (CRT). Next, we propose two novel backlight configurations to improve an LCD\u27s color gamut. One is to use a functional reflective polarizer (FRP), acting as a notch filter to block the unwanted light, and the other is to combine FRP with a patterned half-wave plate to suppress the crosstalk between blue and green/red lights. In experiment, we achieved 97.3% Rec. 2020 in CIE 1976 color space, which is approaching the color gamut of a laser projector. Finally, to enhance an LCD\u27s contrast ratio, we proposed a novel device configuration by adding an in-cell polarizer between LC layer and color filter array. The CR for a vertically-aligned LCD is improved from 5000:1 to 20,000:1, and the CR for a fringe field switching LCD is improved from 2000:1 to over 3000:1. To further enlarge CR to fulfill the high dynamic range requirement, a dual-panel LCD system is proposed and the measured contrast ratio exceeds 1,000,000:1. Overall speaking, such an innovated LCD exhibits supreme image qualities with motion picture response time comparable to CRT, vivid color to laser projector, and contrast ratio to OLED. Along with other outstanding features, like high peak brightness, high resolution density, long lifetime, and low cost, LCD would continue to maintain its dominance in consumer electronics in the foreseeable future

Rethinking Image Forgery Detection via Contrastive Learning and Unsupervised Clustering

Image forgery detection aims to detect and locate forged regions in an image. Most existing forgery detection algorithms formulate classification problems to classify pixels into forged or pristine. However, the definition of forged and pristine pixels is only relative within one single image, e.g., a forged region in image A is actually a pristine one in its source image B (splicing forgery). Such a relative definition has been severely overlooked by existing methods, which unnecessarily mix forged (pristine) regions across different images into the same category. To resolve this dilemma, we propose the FOrensic ContrAstive cLustering (FOCAL) method, a novel, simple yet very effective paradigm based on contrastive learning and unsupervised clustering for the image forgery detection. Specifically, FOCAL 1) utilizes pixel-level contrastive learning to supervise the high-level forensic feature extraction in an image-by-image manner, explicitly reflecting the above relative definition; 2) employs an on-the-fly unsupervised clustering algorithm (instead of a trained one) to cluster the learned features into forged/pristine categories, further suppressing the cross-image influence from training data; and 3) allows to further boost the detection performance via simple feature-level concatenation without the need of retraining. Extensive experimental results over six public testing datasets demonstrate that our proposed FOCAL significantly outperforms the state-of-the-art competing algorithms by big margins: +24.3% on Coverage, +18.6% on Columbia, +17.5% on FF++, +14.2% on MISD, +13.5% on CASIA and +10.3% on NIST in terms of IoU. The paradigm of FOCAL could bring fresh insights and serve as a novel benchmark for the image forgery detection task. The code is available at https://github.com/HighwayWu/FOCAL

Modeling and Application of Passenger Transport Network Capacity in New Town Based on Control Indicators

AbstractIn order to reflect the uncertainty of traffic demand and the orienting of planning schemes in new town, a bi-level programming model of passenger transport network capacity is proposed here based on travel choice behavior model. In the model, the objective function is to maximize the road network capacity. The saturation of road sections, the community development intensity and the public transit trip contribution rate are defined as control indicators, among which the interactive control relationships are revealed. Furthermore, a corresponding solution algorithm is also presented. At last, a numeric example is studied to verify the effectiveness of the model and the algorithm. The results show that the model and the algorithm are of highly effective and available in practice

Effect of engine thrust on nonlinear flutter of wings

The propulsion of wing-mounted engine is a typical follower force and may cause significant influences upon wing flutter characteristics. An integrated flutter analysis method has been presented, within which the effects of engine thrusts and geometrical nonlinearities are both considered. Firstly the method has been applied to evaluate the effects of thrusts on the flutter boundary of a high-altitude, long-endurance aircraft wing. The numerical results have an excellent agreement with the published ones. Furthermore the finite element model of a wing carrying two engines has been established, and the influences of propulsion magnitude and position on wing flutter speed are mainly investigated. The results indicated that the effects of engine thrusts are indispensable for wing flutter analysis

A Framework for Diffusion Fiber-based Analysis of T1w/T2w Ratio Maps

Purpose: To develop, test, evaluate and apply a novel tool for the diffusion fiber-based analysis of T1w/T2w ratio maps quantifying myelin content. Background: The cerebral white matter in the human brain develops from a mostly non-myelinated state to a nearly fully mature white matter myelination within the first few years of life. The study of myelination is of interests in a number of brain development studies. High resolution T1w/T2w ratio maps are believed to be effective in quantitatively estimating myelin content on a voxel-wise basis. I propose the use of a fiber-tract-based analysis of such T1w/T2w ratio data, as it allows us to separate fiber bundles that regional analysis imprecisely groups together, and to associate effects to specific tracts rather than large, broad regions. Methods: I developed an intuitive tool to facilitate such fiber-based studies of T1w/T2w ratio maps. Via its Graphical User Interface (GUI) the tool is accessible to non-technical users. The framework uses calibrated T1w/T2w ratio maps and a prior fiber atlas as an input to generate profiles of T1w/T2w values using a version of the UNC atlas-based fiber analysis toolkit that I adapted to handle non-diffusion data. The resulting fiber profiles are used in a statistical analysis that performs along-tract functional statistical analysis. We applied this approach to a study of early brain development in neonates. Results: I implemented a publicly available tool for the fiber based analysis of T1w/T2w ratio maps and tested it in a study of brain development.Bachelor of Scienc

Low voltage polymer network liquid crystal for infrared spatial light modulators

We report a low-voltage and fast-response polymer network liquid crystal (PNLC) infrared phase modulator. To optimize device performance, we propose a physical model to understand the curing temperature effect on average domain size. Good agreement between model and experiment is obtained. By optimizing the UV curing temperature and employing a large dielectric anisotropy LC host, we have lowered the 2 pi phase change voltage to 22.8V at 1.55 mu m wavelength while keeping response time at about 1 ms. Widespread application of such a PNLC integrated into a high resolution liquid-crystal-on-silicon (LCoS) for infrared spatial light modulator is foreseeable

Tuning the correlated color temperature of white LED with a guest-host liquid crystal

We demonstrate an electro-optic method to tune the correlated color temperature (CCT) of white light-emitting-diode (WLED) with a color conversion film, consisting of fluorescent dichroic dye doped in a liquid crystal host. By controlling the molecular reorientation of dichroic dyes, the power ratio of the transmitted blue and red lights of the white light can be accurately manipulated, resulting in different CCT. In a proof-of-concept experiment, we showed that the CCT of a yellow phosphor-converted WLED can be tuned from 3200 K to 4100 K. With further optimizations, the tuning range could be enlarged to 2500 K with fairly good color performance: luminous efficacy of radiation (LER) \u3e 300 lm/W, color rendering index (CRI) \u3e 75, and Duv \u3c 0.005. Besides, the operation voltage is lower than 5 V and good angular color uniformity is achieved with remote-phosphor coating. This approach is promising for next generation smart lighting