Projection Reconstruction Research Articles

Comparative Analysis of Low-contrast Detectability (LCD) using a 4-AFC: Filtered Back Projection (FBP) and Iterative Reconstruction (IR) Images

Purpose: This study aims to evaluate low-contrast detectability (LCD) and investigate the effect of the filtered-back projection (FBP) and iterative reconstruction (IR) reconstruction algorithms on object size differences sing 4-alternative forced choice (4-AFC). Methods: Phantom images of the AAPM CT Performance Model 610 were scanned using GE Healthcare Revolution Evo 128 Slice CT scanner at 120 kV and 300 mA. Images are reconstructed using the FBP and IR 50%. A total of 6 radiographers served as observers in this study to assess low-contrast objects and small objects between 2.5 mm and 7.5 mm using the 4-AFC approach with a total of 440 questions. Results: It is found that the detection rate decreased for 3.5 mm objects with an overall decrease of 22% using FBP, and a decrease of 12% for 3.0 mm objects with IR. In terms of image reconstruction, IR out performed FBP with an 11% improvement in LCD. Conclusions: This study concludes that the 4-AFC method is effective for LCD on small objects. IR can be considered as a better image reconstruction approach to improve LCD, especially in small sized objects.

Analisis Informasi Citra Anatomi Ureter antara Safire dengan Filtered Back Projection pada Teknik Tracking CT Urologi Klinis Hidronefrosis

Background: Clinical CT-Scan Examination and Noise Reduction in Hydronephrosis. Non-contrast CT-Scan examination is used to diagnose hydronephrosis and enhance diagnostic information in CT Urology tracking. However, CT Urography images often contain high noise levels due to examination parameters and patient size variations, which can obscure small anatomical details like the ureter. To improve image quality, reconstruction algorithms such as Filtered Back Projection (FBP) and Iterative Reconstruction (IR), particularly SAFIRE, are used alongside denoising techniques to reduce noise while preserving diagnostic information.This research aims to find the most optimal reconstruction algorithm for processing images regarding ureter anatomical information in tracking CT Urology techniques for clinical hydronephrosis.Methods: This is a quasi-experiment using the static group comparison method. Non-contrast CT (NCCT) Urology examination images in hydronephrosis patients were processed with FBP and SAFIRE strength 3 reconstruction algorithms. Assessment of anatomical image information analysis was conducted quantitatively by measuring noise and assessing anatomical information by respondents.Results: The results of this study are differences in anatomical information on Urology CT tracking images with variations in FBP and SAFIRE reconstruction algorithms with a p-value of 0.00 (0.05 The study results showed significant differences in ureter anatomical information between CT Urology tracking images reconstructed with FBP and SAFIRE algorithms (p-value = 0.00 0.05). The alternative hypothesis was accepted, indicating that SAFIRE is more effective than FBP in reducing noise in CT Urology tracking images.Conclusions: SAFIRE produces higher image quality and lower noise in non-contrast CT Urology.

Expediting Recovery: Lessons and Challenges from the Great East Japan Earthquake to War-Torn Ukraine

The ongoing war in Ukraine poses an uncertain future, highlighting the need to prioritize reconstruction efforts even before the war ends. Japan’s recovery mechanisms have developed based on the experiences and lessons learned from natural disasters such as the Great Kanto Earthquake in 1923 and from war damage by World War II. This study aims to draw practical insights and lessons from the 2011 Great East Japan Earthquake for Ukraine’s postwar recovery and help achieve rapid and high-quality results. This study reviews the literature, policy documents, and reports on recovery from the disaster. It was found that streamlining environmental impact assessments, land use regulations, and land acquisition could accelerate recovery. Engaging the private sector promoted the reconstruction of critical infrastructure and housing projects. This Japanese case study highlights the importance of ensuring sustained commitment and avoiding setbacks in the recovery process by establishing legislative, planning, and institutional frameworks, as well as financial mechanisms. Protecting human health is paramount, even if more resources are needed to manage hazardous materials. Applying these valuable lessons to Ukraine requires careful consideration, including leveraging foreign investments to supplement limited domestic resources and establishing effective governance structures that promote transparency, accountability, and coordination.

Energy efficiency potential determination for an oil treatment and stabilization unit at the field

Relevance. The desire to increase the energy efficiency of industrial enterprises and reduce greenhouse gas emissions from their activities. Reducing specific energy consumption at large oil refineries and petrochemical plants is not new and is quite widely used. Dozens of monographs and thousands of articles are devoted to these areas. But it should be taken into account that in the oil refining industry, all crude oil, even that which does not reach the refinery, necessarily passes through oil preparation and stabilization units at the fields. Therefore, in order to create energy-efficient and environmentally friendly processes throughout the entire oil refining chain, it is necessary to increase the energy efficiency of the oil preparation and stabilization units located at the fields. There are very few research works on thermal energy integration of oil preparation and stabilization units. Aim. Determination of target design and energy values for an energy-efficient retrofit project of the heat exchange network for the surveyed oil preparation and stabilization units and of its energy efficiency potential. Methods. Pinch analysis methods are used to determine the target values of an energy-efficient retrofit project. Mathematical modeling of heat exchange processes in the heat exchange network and economic analysis were performed using the Pinch 2.02 software; the Aspen HYSYS software package was used to create a simulation engineering model of the oil preparation and stabilization units. Results. When determining the target values of the heat exchange network retrofit project, the cost of energy and heat exchange equipment, the cost of collectors for splitting process streams, and technical restrictions on the placement of heat exchanger sections were taken into account. The inclusion of fuel gas in the process stream table has allowed the definition of target parameters for the optimal unit heat exchange network design to evolve. In the process of evolution of target values, the energy efficiency potential of the surveyed oil preparation and stabilization units was determined, which shows the possibility of reducing specific energy consumption by 77%. Upon implementation of the heat exchange network retrofit project and achievement of target parameters, the following economic results will be obtained: IRR=42%, NPV=7425780 USD, DPP 4 years. Also, CO2 emissions can be reduced by 30 thousand tons per year. It should be noted that the evolution of target designation and all target values for the reconstruction project were obtained before the implementation of the heat exchange network oil preparation and stabilization units project itself.

“If we rebuild the kitchen, we rebuild the heart”: Post-relief transformational politics in the Isthmus of Tehuantepec, Mexico

In September 2017, the strongest earthquake in the last century shook the Isthmus of Tehuantepec, Mexico, the region hosting the largest concentration of wind turbines in Mexico. In the municipalities with over 1600 wind turbines, the seismic shock affected 70% of the dwellings. After the disaster, community organisations undertook efforts to foster collective processes of territorial autonomy in towns hosting wind projects or expected to host projects in the future. Drawing on participant ethnographic methods and long-term collaboration with social movements, this article provides insights into the processes whereby disaster recovery holds the potential for territorial practices that imply a shift away from capitalist norms to alternative practices of territorial autonomy, sufficiency and rebellion. To this end, the article analyses a women-led kitchen reconstruction project implemented by the Assembly of Indigenous People of the Isthmus in Defence of Land and Territory (APIIDTT) to re-activate local economies through endemic crops and traditional crafts in six towns of the region. While emphasising broader tensions, pressures and contradictions resulting from disaster capitalism, the article argues that the project fostered collective autonomy processes against present and future extractive projects through endemic crops, traditional crafts and the identification of female leadership within and across the communities. Therefore, the article spotlights the different forms of bottom-up emancipatory politics that emerge in post-disaster contexts while interlinking them with wind power expansion.

SHRP2 R21 Project Implementation: Two-Lift Concrete Paving on I-65, Nashville

Under Strategic Highway Research Program 2 (SHRP2) Project R21, detailed design and construction guidelines were developed for new composite pavement systems. These systems, consisting of either a hot-mix asphalt (HMA) or portland cement concrete (PCC) wearing course over a structural concrete layer (i.e., HMA/PCC or PCC/PCC), are promising technologies for providing sustainable roadways that can be constructed rapidly and rehabilitated (or renewed) with minimal disruption to the traveling public. New composite pavement systems have proven to provide long service life, excellent surface characteristics, exceptionally smooth ride quality, and high durability. As part of the SHRP2 Implementation Assistance Program, the Tennessee Department of Transportation (TDOT) integrated a two-lift (wet-on-wet) concrete composite pavement into a full-depth shoulder adjacent to a mainline reconstruction project on I-65 in Nashville. TDOT’s interest in the two-lift concrete pavement was driven by a recent specification change requiring a higher quality surface aggregate, and the I-65 project offered the opportunity to evaluate the viability and costcompetitiveness of the two-lift system. This paper describes the construction of the TDOT two-lift composite pavement, including critical aspects of the batching, transport, placement, and post-construction aspects of two-lift composite pavement construction.

Reconstructing Baʾathist Syria through Cultural Heritage and State Media

Abstract This article analyzes Syrian state media coverage on the reconstruction of the citadel, the Umayyad Mosque and the old souq in Aleppo to investigate how the Syrian Baʾathist state is using destruction and reconstruction of significant cultural heritage to construct a post-war narrative. This narrative promotes an understanding of the Baʾathist state as the protector of Syrian cultural heritage and thus the protector of Syrian nationhood and civilization. The article argues that it is of crucial importance to the Baʾathist state to control the symbolic meaning of the national cultural heritage in its endeavor to create a viable post-war narrative and understands the state media’s coverage of selected reconstruction projects in Aleppo as part of the ongoing battle over how to remember (or forget) the years of upheaval and war. This continued battle over the narrative is essentially a battle over the social memories of the Syrian people and the politically constructed memories of the state.

Polarization-controlled metasurface for simultaneous holographic display and three-dimensional depth perception

Abstract Simultaneous optical display and depth perception are crucial in many intelligent technologies but are usually realized by separate bulky systems unfriendly to integration. Metasurfaces, artificial two-dimensional optical surfaces with strong light–matter interaction capabilities at deep subwavelength scales, offer a promising approach for manufacturing highly integrated optical devices performing various complex functions. In this work, we report a polarization-multiplexed metasurface that can functionally switch between holographic display and Dammann gratings. By tailoring the incidence polarization, the metasurface can display high-quality holographic images in the Fresnel region or project a uniform spot cloud nearly covering the entire 180° × 180° transmissive space. For the latter, a projection and three-dimensional (3D) reconstruction experiment is conducted to elaborate the potential in retrieving 3D complex spatial information. The current results provide a prominent way to manufacture lightweight and highly-integrated comprehensive imaging systems especially vital for cutting-edge intelligent visual technologies.

Can CT Image Reconstruction Parameters Impact the Predictive Value of Radiomics Features in Grading Pancreatic Neuroendocrine Neoplasms?

The WHO grading of pancreatic neuroendocrine neoplasms (PanNENs) is essential in patient management and an independent prognostic factor for patient survival. Radiomics features from CE-CT images hold promise for the outcome and tumor grade prediction. However, variations in reconstruction parameters can impact the predictive value of radiomics. 127 patients with histopathologically confirmed PanNENs underwent CT scans with filtered back projection (B20f) and iterative (I26f) reconstruction kernels. 3190 radiomic features were extracted from tumors and pancreatic volumes. Wilcoxon paired tests assessed the impact of reconstruction kernels and ComBat harmonization efficiency. SVM models were employed to predict tumor grade using the entire set of radiomics features or only those identified as harmonizable. The models' performance was assessed on an independent dataset of 36 patients. Significant differences, after correction for multiple testing, were observed in 69% of features in the pancreatic volume and 51% in the tumor volume with B20f and I26f kernels. SVM models demonstrated accuracy ranging from 0.67 (95%CI: 0.50-0.81) to 0.83 (95%CI: 0.69-0.94) in distinguishing grade 1 cases from higher grades. Reconstruction kernels alter radiomics features and iterative kernel models trended towards higher performance. ComBat harmonization mitigates kernel impacts but addressing this effect is crucial in studies involving data from different kernels.

Design and Construction of Concrete Pavement On Interstate 66 in Fairfax County, Virginia Applications of New Technologies

The article details the implementation of innovative technologies in the design and construction of a 10.3-kilometer concrete pavement on Interstate 66 in Fairfax County, Virginia, as part of a $140 million reconstruction project. Key technologies employed include cement stabilization of subgrade soils, use of a stabilized open-graded drainage layer, recycling of the original concrete pavement, and the introduction of fast-track concrete paving techniques. The project faced challenges due to deteriorating conditions of the original pavement, constructed in the early 1960s, under increasing traffic volumes. A comprehensive study involving traffic analysis, soil surveys, and structural assessments informed the decision to replace the existing pavement entirely with a new structure designed for improved drainage and durability. Construction strategies prioritized minimizing traffic disruption and maximizing the use of recycled materials. The successful completion of the project on schedule, despite additional work and unforeseen conditions, illustrates the viability of rapid concrete pavement construction using advanced technologies and materials. (Abstract generated by AI tool ChatGPT 4)

CONCRETE PAVEMENT RECONSTRUCTION ON THE INTERSTATE SYSTEM

This article reviews and discusses the design and reconstruction of concrete pavement projects on the U.S. Interstate System, focusing on the use of Portland cement concrete. The adoption of the 1982 Surface Transportation Assistance Act's 4R fund has facilitated significant advancements in reconstruction methods. Various projects across different climates in the United States are examined, including complete replacements, full-depth unbonded and partial-depth bonded overlays, and the recycling of old concrete as aggregate for new pavements. The paper highlights innovative equipment and techniques that have emerged as a result of increased funding and legislative support, aimed at addressing the challenges posed by heavy commercial traffic and the need for durable road infrastructure. Economic factors, life-cycle costing, and material reuse are also discussed as critical considerations in the decision-making process for pavement reconstruction. The effectiveness of these projects is assessed in terms of technical feasibility and long-term economic benefits, emphasizing the importance of continued funding and research to support future infrastructure demands. (Abstract generated by AI tool ChatGPT 4)

Optimized filter functions for filtered back projection reconstructions

Optimized filter functions for filtered back projection reconstructions

재건축사업 단계별 소요시간에 영향을 미치는 요인 : 서울 동남권의 사례

Using a nonparametric approach and a semi-parametric estimation method of survival analysis, this study analyzed the characteristics of and factors affecting the time required for each stage of reconstruction projects in Southeast Seoul (the districts of Seocho-gu, Gangnam-gu, and Songpa-gu) over the past 20 years. According to the results, the physical and human scale of such projects does not have a statistically significant effect on the time required for each stage, whereas the indicator of profitability—related to floor area ratio—significantly shortens the time required to prepare for these projects. In addition, the public support introduced to facilitate reconstruction projects was found to be insufficient for shortening the time required for each stage. This suggests that relevant policies need to be reviewed and improved.

Deep Learning Reconstruction for Contrast Agent of Lower Concentration for Abdominal CT Between Filters Back Projection and Iterative Reconstruction on Improving Image Quality

Deep Learning Reconstruction for Contrast Agent of Lower Concentration for Abdominal CT Between Filters Back Projection and Iterative Reconstruction on Improving Image Quality

Study on the Influence and Deformation Control of Rich Water Foundation Excavation on Adjacent Buildings

Taking the foundation pit of the Suzhou Chunshenhu Road Expressway Reconstruction Project as an example, the excavation process of the foundation pit was numerically simulated using a three-dimensional finite element method. The measured data and simulated data of the lateral deformation of the enclosure structure, surface settlement deformation of the ground outside the pit, and settlement deformation of the building were compared to analyze the impact of foundation pit construction on adjacent buildings. The influence of foundation pit floor and diaphragm wall thickness on wall displacement, building settlement, and foundation pit uplift was also discussed. The results showed the following: (1) Adding a foundation pit floor has a significant effect on reducing the lateral displacement of the diaphragm wall, settlement of the building, and uplift of the foundation pit. Increasing the thickness of the foundation pit floor has a limited effect on reducing the displacement, while increasing the thickness of the diaphragm wall has a small effect. (2) The displacement curve of the underground diaphragm wall increases with depth. It reaches a maximum at the excavation surface and then decreases gradually. (3) The surface settlement increases first and then decreases with distance from the foundation pit, showing a concave shape. As the depth of excavation increases, the settlement value increases. (4) Through analysis of the monitoring data of vertical displacement of buildings, it can be seen that during foundation pit excavation, buildings undergo five stages: initial slow descent, steep descent, mid-term slow descent, late steep descent, and stable deformation. The buildings are dominated by settlement deformation.

Nested compressive sensing for ECG signals using novel hybrid two-level approach of DWT and DCT sensing and sparsification

This paper demonstrates the merits of nested Compressive Sensing (CS) approach for Electrocardiogram (ECG) signals using discrete wavelet transform (DWT) and discrete cosine transform (DCT) as sensing matrix and sparsifying matrix. The implementation of CS framework is done using Gradient Projection for Sparse Reconstruction (GPSR). It is tested on 9 ECG signals of different arrhythmia categories obtained from MITBIH and BIDMC dataset. It is analysed for 3 different combinations, case (1) DCT sensing and DWT sparsification, case (2) DWT sensing and DCT sparsification and case (3) DWT sensing and DWT sparsification. A novel hybrid nested CS approach is proposed as case (4) which is a combination of case (2) in higher level and case (1) in lower level. This nested method yields the best PRD of 1.39 for CR = 0.2 and performs better than all proposed cases. This proposed approach involves a fair method of discarding the measurements in all frequency band and performs better than the state of the art work when the sampling rate is reduced by 4 times for ECG signal 100.dat from MIT-BIH (Massachusetts Institute of Technology-Beth Israel Hospital) database for CR = 0.2. It is shown that the reconstruction time of the proposed nested CS approach is lesser than non-nested CS approach.

Durability and Bearing Capacity Assessment of Existing Bridge Pile Foundations for Sustainable Highway Reconstruction

Conducting a reasonable assessment of whether the durability and bearing capacity of concrete used in existing bridge pile foundations can meet all requirements is an important prerequisite for ensuring the reuse of existing bridge pile foundations. With this in mind, this study evaluates the project of the Beijing–Taibei Highway in Shandong Province that must be restored and enlarged. Using static load and concrete durability testing methods, the bearing capacity characteristics and durability of seven existing bridge pile foundations were investigated. Using attribute identification theory, a systematic technique for determining the reuse value of existing piles is proposed. The test examination findings demonstrate that the change curve corresponding to the pile foundation’s ultimate bearing capacity matches the concrete compressive strength curve. The pile foundations had lower ultimate bearing capacity than average. The concrete compressive strengths of the three test piles were 18%, 16.3%, and 17.5% lower than the average compressive strengths of the seven test piles. A comprehensive durability evaluation method for assessing existing piles can effectively evaluate the reuse value of existing piles and promote sustainable highway reconstruction and expansion projects.

A study on CT detection image generation based on decompound synthesize method

Background Nuclear graphite and carbon components are vital structural elements in the cores of high-temperature gas-cooled reactors(HTGR), serving crucial roles in neutron reflection, moderation, and insulation. The structural integrity and stable operation of these reactors heavily depend on the quality of these components. Helical Computed Tomography (CT) technology provides a method for detecting and intelligently identifying defects within these structures. However, the scarcity of defect datasets limits the performance of deep learning-based detection algorithms due to small sample sizes and class imbalance. Objective Given the limited number of actual CT reconstruction images of components and the sparse distribution of defects, this study aims to address the challenges of small sample sizes and class imbalance in defect detection model training by generating approximate CT reconstruction images to augment the defect detection training dataset. Methods We propose a novel CT detection image generation algorithm called the Decompound Synthesize Method (DSM), which decomposes the image generation process into three steps: model conversion, background generation, and defect synthesis. First, STL files of various industrial components are converted into voxel data, which undergo forward projection and image reconstruction to obtain corresponding CT images. Next, the Contour-CycleGAN model is employed to generate synthetic images that closely resemble actual CT images. Finally, defects are randomly sampled from an existing defect library and added to the images using the Copy-Adjust-Paste (CAP) method. These steps significantly expand the training dataset with images that closely mimic actual CT reconstructions. Results Experimental results validate the effectiveness of the proposed image generation method in defect detection tasks. Datasets generated using DSM exhibit greater similarity to actual CT images, and when combined with original data for training, these datasets enhance defect detection accuracy compared to using only the original images. Conclusion The DSM shows promise in addressing the challenges of small sample sizes and class imbalance. Future research can focus on further optimizing the generation algorithm and refining the model structure to enhance the performance and accuracy of defect detection models.

Developing a community responsive resilient contractor selection model for post-disaster reconstruction projects: a build back better approach

Developing a community responsive resilient contractor selection model for post-disaster reconstruction projects: a build back better approach

The Preservation of Cultural Heritage in the City of Durrës as a Challenge for Local and Central Institutions, with a Focus on the Recognition and Practical Implementation of Legal Procedures and Normative Acts in Order to Preserve and Develop Cultural He

The damage done to the archaeological property of the city of Durrës is one of the major damages caused to our cultural heritage after the 90s. The reconstruction projects of buildings destroyed by the earthquake in Durrës, financed by the Albanian Development Fund, are being carried out without archaeological monitoring, destroying traces of ancient monuments. According to the law on cultural heritage, constructions that are carried out in areas with high archaeological intensity, such as the "Dyrrah" boulevard in Durrës, must be monitored by archaeologists, but in the case of the 6-story building, this control was missing. The creation of genuine scientific studies about all the archaeological materials and the very rich cultural heritage of the city of Durres, organizing publications, monographs, articles, inside and outside the country, of the cultural values that the city of Durres carries, the organization of joint workshops with universities different in the Balkans and wider, where the University of Durrës in cooperation with the relevant Departments to promote these studies, through the cooperation of pedagogues - specialists in the field of archeology and Cultural Heritage, in cooperation with the Institute of Albanian Albanology, to enrich the library of the city with studies Durrës and the National Library. According to the law on cultural heritage, constructions that are carried out in areas with high archaeological intensity, such as the "Dyrrah" boulevard in Durrës, must be monitored by archaeologists, but in the case of the 6-story building, this control was missing. Received: 12 August 2024 / Accepted: 30 October 2024 / Published: 3 December 2024