bluuebunny/crossref_metadata_2025 huggingface dataset:
A comprehensive review on surface modifications of polymer‐based 3D‐printed structures: Metal coating prospects and challenges
Authors: Gautam Khagendra , Gogoi Debashish , Kongnyui Tanyu Donarld , Devi Sangjukta , Kumar Chandan , Kumar Manjesh
Published: April 2024

The production of complex structures out of a variety of materials has undergone a revolution due to the rapid development of additive manufacturing (AM) technology. Initially confined to applications such as magnetic actuators and two‐dimensional electric or electronic circuits, the convergence of 3D printing and metallization methods has emerged as a revolutionary approach. This synergy facilitates the creation of functional and customizable metal‐polymer hybrid structures characterized by high strength, lightweight properties, intricate geometric designs, and superior surface finish. These structures also exhibit enhanced electrical and thermal conductivity, as well as optical reflectivity. This paper reviews techniques to improve the effectiveness of 3D‐printed polymer antennas and structures by using various techniques of metallization. The metallization processes are examined, and a classification based on the materials employed is presented to facilitate comparisons that highlight the optimal utilization of materials for the fabrication of 3D‐printed polymer structures. The main emphasis here is on the effectiveness of different processes in terms of deposition, bonding strength, electrical conductivity, and various characteristics of metallic coatings developed on polymers. This review contributes an in‐depth analysis of the latest developments in 3D printing and metallization techniques specifically applied to polymer antennas and structures. The exploration extends to potential applications, challenges encountered, and future prospects within this dynamic field. As AM and metallization continue to evolve, this study aims to provide a comprehensive understanding of the state‐of‐the‐art methodologies and their implications for the future of polymer‐based structures and antennas.
Promise of Composite Pain Index as a single pain outcome for sickle cell disease across the lifespan
Authors: Kashif Reema , Wallace‐Farquharson Tanya , Adams‐Mitchell Candice , Yao Yingwei , Molokie Robert E. , Wilkie Diana J. , Mack A. Kyle
Published: April 2024

Background

This study aimed to validate a Composite Pain Index (CPI) as a single pain outcome measure for sickle cell disease (SCD) across the lifespan from 8 years of age.

Procedure

This prospective, cross‐sectional study included 55 participants with SCD who completed the PAINReportIt tool and Adolescent Pediatric Pain Tool (APPT) in random order during outpatient visits to derive respective CPI scores for comparison.

Results

Of the 55 participants with SCD, 46 (84%) had HgbSS, eight (15%) HgbSC, and one (2%) HgbSβ0+. The mean age of all participants was 17.5 ± 2.6 years, and 28 (51%) were female, 52 (95%) were Black, 42 (98%) were non‐Hispanic, and 39 (71%) had a ninth grade or higher education. Correlation analyses between the APPT and PAINReportIt revealed positive associations for the number of pain sites (r = .57, p < .001), pain intensity (r = .46, p < .001), pain quality (r = .74, p < .001), and pain pattern (r = .34, p = .01). Patients’ mean CPI scores derived from the PAINReportIt was slightly higher than the APPT; 34.2 (SD = 14.7) and 30.0 (SD = 19.0), respectively. Regression analyses showed that the APPT CPI significantly predicted the PAINReportIt CPI (B = .497, t(53) = 6.051, p < .001). This finding holds true even when accounting for the order of measurement or patient's age.

Conclusion

The initial validation of CPI as a single pain outcome measure represents a significant advancement in pain assessment for SCD. Further validation is warranted for the CPI as a measure is for both clinicians and researchers to enable longitudinal pain assessment from age 8 years across the lifespan as children age into adult care.
Fabrication of GNPs sprayed carbon fiber and its effects on the interfacial and mechanical behavior of reinforced epoxy multiscale laminated composite
Authors: Jain Vaibhav , Jaiswal Satish , Dasgupta Kinshuk , Lahiri Debrupa
Published: April 2024

The current research compares the effects of modifying carbon fiber [via spraying graphene nanoplates (GNPs)] and/or GNPs reinforcement on the mechanical and interfacial behavior of carbon fiber epoxy composites. Using a spraying method, the epoxy matrix was reinforced, and carbon fiber was modified with 0.2 and 1 wt% of GNPs, respectively. Tensile, interlaminar, and dynamic mechanical analyses (DMA) tests were conducted on the composite to assess the role of GNPs in enhancing mechanical, interfacial, and thermomechanical properties. The obtained results indicate that the spraying technique effectively enhanced the ultimate tensile strength (UTS) and interlaminar fracture toughness (ILFT) of the composite. The UTS improved by 31%, while the ILFT significantly improved by 38%. Additionally, assessing the modulus gradient through the interface shows improved interfacial interaction between modified carbon fiber and reinforced epoxy. Scanning electron microscopy examination of the fractured surfaces indicated that the existence of nanofillers with high surface area contributed to significant improvements in adhesion between the modified fiber and reinforced epoxy matrix, leading to enhanced interfacial, mechanical, and thermomechanical properties of CFRPs for structural applications.

Highlights

Incorporation of surface modified carbon fibers and GNPs reinforcement in the epoxy matrix to enhance the interfacial interaction.

Evaluation of the effects of GNP nanofiller on interfacial and mechanical performance of the composite.

Fracture surfaces in ILSS, tensile, and mode I test were analyzed using FESEM.

Utilization of nanoscale modulus mapping for the fiber‐matrix interface assessment.
Plasma‐catalytic CO2 methanation over NiO/bentonite catalysts prepared by solution combustion synthesis
Authors: Tang Shouxian , Qin Shiji , Wang Zhengduo , Sang Lijun , Cheng Jiushan , Liu Zhongwei
Published: April 2024

A solution combustion synthesis (SCS) process to prepare nickel catalyst over bentonite (NiO/Ben) is reported. Compared to the traditional impregnation method, NiO/ben produced by SCS has smaller nickel particle size and higher dispersion. With a metal loading of 20 wt%, the afforded NiO/Ben demonstrates excellent catalytic activity for CO2 methanation in a dielectric barrier discharge reactor. In certain discharge conditions (H2:CO2 ratio of 5 in feed gas, discharge input power of 45 W, and gas hourly space velocity of 11 320 h−1), CO2 conversion and CH4 selectivity are as high as 55.8% and 84.6%, respectively. Under the conditions of plasma configuration, the strong interaction between the nickel species and the support plays an important role in the CO2 methanation process.
Proteomic and metabolomic characterization of bone, liver, and lung metastases in plasma of breast cancer patients
Authors: Ye Hui , Shen Xiabo , Li Yaohan , Zou Weibin , Hassan Syed Shams ul , Feng Yue , Wang Xiaojia , Tian Jingkui , Shao Xiying , Tao Yi , Zhu Wei
Published: April 2024

Background

Breast cancer (BC) is the second leading cause of cancer‐related deaths among women, primarily due to metastases to other organs rather than the primary tumor.

Methods

In this study, a comprehensive analysis of plasma proteomics and metabolomics was conducted on a cohort of 51 BC patients. Potential biomarkers were screened by the Least Absolute Shrinkage and Selection Operator (LASSO) regression and Random Forest algorithm. Additionally, enzyme‐linked immunosorbent assay (ELISA) kits and untargeted metabolomics were utilized to validate the prognostic biomarkers in an independent cohort.

Results

In the study, extracellular matrix (ECM)‐related functional enrichments were observed to be enriched in BC cases with bone metastases. Proteins dysregulated in retinol metabolism in liver metastases and leukocyte transendothelial migration in lung metastases were also identified. Machine learning models identified specific biomarker panels for each metastasis type, achieving high diagnostic accuracy with area under the curve (AUC) of 0.955 for bone, 0.941 for liver, and 0.989 for lung metastases.

Conclusions

For bone metastasis, biomarkers such as leucyl‐tryptophan, LysoPC(P‐16:0/0:0), FN1, and HSPG2 have been validated. dUDP, LPE(18:1/0:0), and aspartylphenylalanine have been confirmed for liver metastasis. For lung metastasis, dUDP, testosterone sulfate, and PE(14:0/20:5) have been established.
Development and validation of an imageless machine‐learning algorithm for the initial screening of prostate cancer
Authors: Martelin Nicolas , De Witt Brian , Chen Benjamin , Eschwège Pascal
Published: April 2024

Purpose

Prostate specific antigen (PSA) testing is a low‐cost screening method for prostate cancer (PCa). However, its accuracy is limited. While progress is being made using medical imaging for PCa screening, PSA testing can still be improved as an easily accessible first step in the screening process. We aimed to develop and validate a new model by further personalizing the analysis of PSA with demographic, medical history, lifestyle parameters, and digital rectal examination (DRE) results.

Methods

Using data from 34,224 patients in the screening arm of the PLCO trial (22,188 for the training set and 12,036 for the validation set), we applied a gradient‐boosting model whose features (Model 1) were one PSA value and the personal variables available in the PLCO trial except those that signaled an ex‐ante assumption of PCa. A second algorithm (Model 2) included a DRE result. The primary outcome was the occurrence of PCa, while the aggressiveness of PCa was a secondary outcome. ROC analyses were used to compare both models to other initial screening tests.

Results

The areas under the curve (AUC) for Model 2 was 0.894 overall and 0.908 for patients with a suspicious DRE, compared to 0.808 for PSA for patients with a suspicious DRE. The AUC for Model 1 was 0.814 compared to 0.821 for PSA. Model 2 predicted 58% more high‐risk PCa than PSA ≥4 combined with an abnormal DRE and had a positive predictive value of 74.7% (vs. 50.6%).

Conclusion

Personalizing the interpretation of PSA values and DRE results with a gradient‐boosting model showed promising results as a potential novel, low‐cost method for the initial screening of PCa. The importance of DRE, when included in such a model, was also highlighted.
Ursodeoxycholic acid may protect from severe acute respiratory syndrome coronavirus 2 Omicron variant by reducing angiotensin‐converting enzyme 2
Authors: Lee Kyungmin , Na Yujeong , Kim Minjin , Lee Dongjin , Choi Jongseo , Kim Gwanyoung , Kim Min‐Soo
Published: April 2024

The SARS‐CoV‐2 caused COVID‐19 pandemic has posed a global health hazard. While some vaccines have been developed, protection against viral infection is not perfect because of the urgent approval process and the emergence of mutant SARS‐CoV‐2 variants. Here, we employed UDCA as an FXR antagonist to regulate ACE2 expression, which is one of the key pathways activated by SARS‐CoV‐2 Delta variant infection. UDCA is a well‐known reagent of liver health supplements and the only clinically approved bile acid. In this paper, we investigated the protective efficacy of UDCA on Omicron variation, since it has previously been verified for protection against Delta variant. When co‐housing with an Omicron variant‐infected hamster group resulted in spontaneous airborne transmission, the UDCA pre‐supplied group was protected from weight loss relative to the non‐treated group at 4 days post‐infection by more than 5%–10%. Furthermore, UDCA‐treated groups had a 3‐fold decrease in ACE2 expression in nasal cavities, as well as reduced viral expressing genes in the respiratory tract. Here, the data show that the UDCA serves an alternative option for preventive drug, providing SARS‐CoV‐2 protection against not only Delta but also Omicron variant. Our results of this study will help to propose drug‐repositioning of UDCA from liver health supplement to preventive drug of SARS‐CoV‐2 infection.
High Efficiency O‐band Preamplified Receiver Integrated with Semiconductor Optical Amplifier and Uni‐travelling Carrier Photodiode for Passive Optical Network
Authors: Gnanamani Risab , Bertin Hervé , Besancon Claire , Mekhazni Karim , Caillaud Christophe , Deng Marina , Mukherjee Chhandak , Maneux Cristell
Published: April 2024

With the continuous increase in data traffic and enormous consumption of data in terms of video on demand services and cloud computing, there is an increasing demand for high speed and high sensitivity short reach receivers for passive optical networks (PON) access network which are point to multi‐point networks. Avalanche photodiodes (APD) are the standard receivers in PON networks due to their high sensitivity and low cost. However, it is currently not clear if they can provide high bandwidth above 40 GHz with good performance (gain, noise, etc.). Furthermore, standard PIN photodiodes do not provide sufficient sensitivity for PON networks. Therefore, in this article a SOA‐UTC receiver is proposed, which is a photonic integrated circuit (PIC) comprising a semiconductor optical amplifier (SOA) for optical preamplification and a high‐speed uni‐travelling‐carrier (UTC) photodiode for opto‐electronic conversion. A very high responsivity of 140 A W−1is demonstrated, with a polarization dependent loss (PDL) around 1 dB and a 3 dB bandwidth of 48 GHz, which is very promising for future PON network with 50 Gbit s−1capacity and above.
Topological characterizations on hexagonal and rectangular tessellations of antikekulenes and its computed spectral, nuclear magnetic resonance and electron spin resonance characterizations
Authors: Prabhu S. , Arulperumjothi M. , Manimozhi V. , Balasubramanian Krishnan
Published: April 2024

Tessellations of antikekulenes are of interest from the standpoints of antiaromaticity, ring currents, unusual ‐electron characteristics, magnetism and their highly reactive nature. Although precursors of antikekulenes have been synthesized, up to now synthesis of antikekulenes has been proven to be formidably difficult. Yet they are predicted to have intriguing properties and their antiaromatic nature together with a combination of four and six‐membered rings makes them intriguing candidates for theoretical indices. In the present study, we have computed the topological indices of antikekulene by employing graph‐theoretical cut methods that simplify the parent tessellations of antikekulenes into simpler graphs. We have derived exact mathematical expressions of several topological descriptors for hexagonal and rectangular antikekulene structures. Furthermore we have obtained the graph‐spectral properties, algebraic structure counts, resonance stabilization and delocalization energies as well as nuclear magnetic resonance and electron spin resonance spectroscopic patterns of the two tessellations of antikekulenes.
Electrophilic descriptor from third‐order Taylor expansion: The role of hyperhardness
Authors: Figueredo Said Fernando , Quintero María Alejandra
Published: April 2024

In this study, we introduce a novel definition for the electrophilic descriptor. Following the proposal of other researchers, the foundation of our approach lies in expanding the change in the energy of an electronic system using a third‐order Taylor series, leading to the integration of hyperhardness into the formulation of the electrophilic descriptor. To validate our results, we conducted a comparative analysis of reactivity sequences among 35 electrophilic systems with known reactivities, as reported in external experimental studies. The electrophilic descriptor demonstrated a remarkable ability to accurately replicate the relative reactivities of the compounds under consideration, surpassing predictions based solely on the electrophilicity index. These findings underscore the significance of incorporating hyperhardness as a crucial reactivity descriptor. Additionally, our study provides interesting insights into the interpretation of this concept.
Designing Urchin‐Like S/SiO2 with Regulated Pores Toward Ultra‐Fast Room Temperature Sodium–Sulfur Battery
Authors: Wang Xi , Zeng Zihao , Dong Zeyu , Ge Peng , Yang Yue
Published: April 2024

Captured by high theoretical capacity and low‐cost, Sodium–Sulfur (Na‐S) batteries have been deemed as promising energy‐storage systems. However, their electrochemical properties, containing both cycling and rate properties, still suffer from the notorious “shuttle effect” of polysulfide. Herein, through the effective regulation of pore sizes, a series of S/SiO2 cathode materials are obtained. Benefitting from the abundant pore channels of SiO2 particles, the sulfur loading is as high as 76.3%. Importantly, a suitable pore size can lead to adequate reaction and rapid diffusion behaviors, resulting in excellent electrochemical performances. Specifically, at 2.0 A g−1, the initial capacity of the as‐optimized sample can be up to 1370.6 mAh g−1. Surprisingly, even after 1050 cycles, it could achieve a high reversible capacity of 1280.8 mAh g−1 with an attenuation rate of 0.089%. At 5.0 A g−1, after 500 cycles, the capacity can still remain ≈ 1132.6 mAh g−1 (capacity retention rate, 97.5%). Given this, the work is anticipated to offer an effective strategy for advanced electrodes for Na‐S batteries.
Temperature‐Induced Interface Hybridization of WC Boosts NiCu Activity for Alkaline Hydrogen Oxidation Reaction
Authors: Xie Zhenyang , Li Mengting , Zhou Yuanyuan , Feng Yong , Song Xiaoyun , Li Li , Ding Wei , Wei Zidong
Published: April 2024

The development of non‐precious hydrogen oxidation reaction (HOR) catalysts is a major challenge for the commercialization of Pt‐free fuel cells. Herein, a temperature‐induced phase hybridization method is reported that greatly improves the catalytic performance of NiCu alloy for the HOR. The migration of W atoms hybridizes the interface of tungsten oxide (WOx) and tungsten carbide (WC) at the onset reduction temperature of WOx, leading to a greatly weakened H binding energy and an optimized OH binding energy, which endows NiCuW/WOx‐WC@WC with favorable stability and CO resistance during HOR. The hybridization catalysts deliver a high mass activity of 29.37 mA mg−1Ni and reach a peak power of 298 mW.cm−2 in H2‐O2 anion exchange membrane fuel cells (AEMFCs).
Activating the Ni‐Contenting Carbon Nanotube by Covalent Triazine Frameworks to Form Atomically Dispersed Ni Sites with Curvature Effect for Electrocatalytic CO2 Reduction
Authors: Ao Kai , Zhao Pengwei , Zhang Qicheng , Fan Xiaobin , Fang Qing , Wang Guojing , Zhu Yuanzhi
Published: April 2024

N‐coordinated Ni sites (NiNx) are effective catalysts for the electrochemical reduction of CO2 to CO. In most researches, modulating the coordination environment of Ni atoms is focused on to improve electrochemical CO2 reduction (ECR) performance. However, the influence of the carbon substrate's structure on the intrinsic activity of NiNx is seldom investigated. The highly curved surface of carbon nanotubes (CNT) may provide a unique curvature effect on NiNx. It is found that the Ni residues in CNT can be atomized to form NiNx sites on the surface of CNT (Ni‐N/CNT@covalent triazine framework [CTF]) through high‐temperature pyrolysis, using a soluble CTF nanosheet as N precursor. The π‐conjugated and ultrathin 2D structure of CTF enables closer interfacial contact between CTF and CNT, which avoids the formation of a thick carbon layer to maximize the curvature effect. Theoretical data reveal that the NiN3 configuration may act as a highly active ECR site, and the curvature effect from CNT can further tune the electronic structure of NiN3, thus improving the ECR kinetics. The Ni‐N/CNT@CTF‐based flow‐cell electrolyzer exhibits a jCO of 201 mA cm−2 at −0.9 V with a high FECO of 98%.
Lead‐Free Perovskites and Metal Halides for Resistive Switching Memory and Artificial Synapse
Authors: Zhang Bo Wei , Lin Chun‐Ho , Nirantar Shruti , Han EQ , Zhang Yurou , Wang Zitong , Lyu Miaoqiang , Wang Lianzhou
Published: April 2024

Memristive devices such as resistive switching memories and artificial synapses have emerged as promising technologies to overcome the technological challenges associated with the von Neumann bottleneck. Recently, lead halide perovskites have drawn substantial research attention as the candidate material for memristors and artificial synapses due to their unique optoelectronic properties, solution processability, and mechanical flexibility. However, the toxicity of lead‐containing species has raised major concerns for health and the environment, which makes it crucial to transition from lead‐based to lead‐free materials for practical applications. Herein, the recent progress of lead‐free metal halides including perovskites and perovskite analogs for resistive memory and artificial synapse is reviewed. Initially, the fundamentals of lead‐free materials and switching mechanisms are introduced. Next, the material design, fabrication technique, and device performance are summarized and critically evaluated for each metal halide species. Finally, the challenges of the lead‐free metal halides toward memristors and artificial synapses are outlined and discussed, and some potential research directions for future study are proposed.
Effects of Dual Modification of HMT and Cross Linking on Morphological, Thermal, Digestibility, and Structural Properties of Wild Tuber (Amorphophallus abyssinicus) Starch
Authors: Tsehay Eden Genetu , Emire Shimelis Admassu , Admassu Habtamu , Minuye Masresha
Published: April 2024

To examine functional, morphological, pasting, and digestibility properties, native bagana starch is subjected to physical, chemical, and dual modification respectively through heat moisture treatment, crosslinking, and combination of heat moisture and crosslinking. Accordingly, all modified starches except cross‐linked starch has showed higher solubility (heat moisture treated [23.33–27.33%] and heat moisture‐cross‐linked [21.33–26%]) and lower swelling power (2.07–3.83 g g−1) and (2.22–3.86 g g−1) respectively than native bagana starch (16.33–25%) and (2.03–6.82 g g−1). Heat moisture treated and cross‐linked starches have showed similar morphology with native starch. The lower breakdown and setback viscosities for cross‐linked starch (68.67 and 182 cp) and heat moisture‐cross‐linked starches (38.67 and 194.67 cp) have resulted in adequate capability for good shear resistance and anti‐retrogradation properties than same viscosities of native starch (126.67 and 770 cp). The in vitro digestibility of dual modified starch has resulted in good resistant starch content (26.40%) than native bagana (17.89%), heat moisture treated (15.68%), and cross‐linked (24.93%) starches. The study reveals dual modification using heat moisture and cross‐linking is an effective method to improve the physicochemical and thermal properties of starch and can advantageously result in a good resistant starch content, which is the most emphasized health issue; thus, attention should be given to broaden its application in the food industry.
Bio‐inspired human network diagnostics: Ecological modularity and nestedness as quantitative indicators of human engineered network function
Authors: Blair Samuel , Hairston Garrett , Banks Henry , Kaat Claire , Linsey Julie , Layton Astrid
Published: April 2024

Analyzing interactions between actors from a systems perspective yields valuable information about the overall system's form and function. When this is coupled with ecological modeling and analysis techniques, biological inspiration can also be applied to these systems. The diagnostic value of three metrics frequently used to study mutualistic biological ecosystems (nestedness, modularity, and connectance) is shown here using academic engineering makerspaces. Engineering students get hands‐on usage experience with tools for personal, class, and competition‐based projects in these spaces. COVID‐19 provides a unique study of university makerspaces, enabling the analysis of makerspace health through the known disturbance and resultant regulatory changes (implementation and return to normal operations). Nestedness, modularity, and connectance are shown to provide information on space functioning in a way that enables them to serve as heuristic diagnostics tools for system conditions. The makerspaces at two large R1 universities are analyzed across multiple semesters by modeling them as bipartite student‐tool interaction networks. The results visualize the predictive ability of these metrics, finding that the makerspaces tended to be structurally nested in any one semester, however when compared to a “normal” semester the restrictions are reflected via a higher modularity. The makerspace network case studies provide insight into the use and value of quantitative ecosystem structure and function indicators for monitoring similar human‐engineered interaction networks that are normally only tracked qualitatively.
The impact of cholecystectomy on the symptom relief and quality of life of patients with gallbladder dysmotility
Authors: Alamin Nadeen , Iqbal Sara , Baumert Alizee , Fernandes Roland
Published: April 2024

Background

The aim of this study was to demonstrate the impact of laparoscopic cholecystectomy on the physical and mental health of patients with gallbladder dysmotility.

Methods

Retrospective data was collected from 314 patients who had undergone a hepatobiliary iminodiacetic acid (HIDA) scan between June 2012 and June 2022 in a District General Hospital in South East England. Sixty‐three patients who were diagnosed with gallbladder dysmotility were then contacted and asked to participate in a telephone interview regarding their symptoms. We measured their health‐related quality of life using the HRQoL SF‐12 v2 (Health Related Quality of Life Short Form‐12 version 2) questionnaire. Differences in the resolution of symptoms between those that had undergone a cholecystectomy and those who did not, were assessed using a chi square test. The two groups were then compared using the student t‐test to assess statistically significant differences.

Results

94% (n = 31/33) of the participants in the non‐cholecystectomy group demonstrated persistent biliary pain symptoms as opposed to the 6% (n = 2/30) in the cholecystectomy group. A statistically significant improvement in five out of the eight domains of the HRQoL SF‐12 questionnaire was demonstrated. These domains include PCS (physical component summary), MCS (mental component summary), mental health, general health and bodily pain.

Conclusion

The results of our retrospective analysis demonstrate an improvement in both the physical and mental health‐related quality of life symptoms in patients who underwent laparoscopic cholecystectomy. These findings support the use of laparoscopic cholecystectomy as an effective method for managing gallbladder dysmotility.
A physics‐informed machine learning prediction for thermal analysis in a convective‐radiative concave fin with periodic boundary conditions
Authors: Kumar Chandan , Srilatha Pudhari , Karthik Kalachar , Somashekar Channaiah , Nagaraja Kallur Venkat , Varun Kumar Ravikumar Shashikala , Shah Nehad Ali
Published: April 2024

The present research is focused on the inspection of unsteady heat dissipation through a radiative‐convective concave profiled fin along with the periodic boundary conditions. Additionally, the long‐short‐term memory machine learning (LSTM‐ML) approach is used in this study to examine the periodic fluctuation in the temperature of the fin. The current research is devoted to solving the highly non‐linear equation using a physics‐informed neural network (PINN) approach. Using the proper dimensionless terms, the associated fin problem is transformed into a non‐dimensional system, and the resulting partial differential equation (PDE) is then numerically solved using the finite difference method (FDM). Using the data‐driven LSTM‐ML technique, the time‐dependent periodic heat transmission in the concave fin is also examined. The impact of various factors on the temperature profile of the concave extended surface is explained, and the results are visually displayed. The temperature distribution in the concave fin diminishes as the convection‐conduction parameter and radiation‐conduction parameter rise. As the amplitude and thermal conductivity parameters improve, so does the temperature of the concave fin. Furthermore, it is demonstrated that although LSTM‐ML and PINN closely matched the FDM findings during the training domain, only PINN with designed characteristics has the potential to predict accurately beyond the trained region by capturing the physics of the problem.
Stochastic Window Mean-Payoff Games
Authors: Doyen Laurent , Gaba Pranshu , Guha Shibashis
Published: April 2024

Stochastic two-player games model systems with an environment that is both adversarial and stochastic. The environment is modeled by a player ($$\text {Player}~{2}$$Player2) who tries to prevent the system ($$\text {Player}~{1}$$Player1) from achieving its objective. We consider finitary versions of the traditional mean-payoff objective, replacing the long-run average of the payoffs by payoff average computed over a finite sliding window. Two variants have been considered: in one variant, the maximum window length is fixed and given, while in the other, it is not fixed but is required to be bounded. For both variants, we present complexity bounds and algorithmic solutions for computing strategies for$$\text {Player}~{1}$$Player1to ensure that the objective is satisfied with positive probability, with probability 1, or with probability at least p, regardless of the strategy of$$\text {Player}~{2}$$Player2. The solution crucially relies on a reduction to the special case of non-stochastic two-player games. We give a general characterization of prefix-independent objectives for which this reduction holds. The memory requirement for both players in stochastic games is also the same as in non-stochastic games by our reduction. Moreover, for non-stochastic games, we improve upon the upper bound for the memory requirement of$$\text {Player}~{1}$$Player1and upon the lower bound for the memory requirement of$$\text {Player}~{2}$$Player2.
Parity Games on Temporal Graphs
Authors: Austin Pete , Bose Sougata , Totzke Patrick
Published: April 2024

Temporal graphs are a popular modelling mechanism for dynamic complex systems that extend ordinary graphs with discrete time. Simply put, time progresses one unit per step and the availability of edges can change with time.

We consider the complexity of solving$$\omega $$ω-regular games played on temporal graphs where the edge availability is ultimately periodic and fixed a priori.

We show that solving parity games on temporal graphs is decidable in$$\textsf{PSPACE}$$PSPACE, only assuming the edge predicate itself is in$$\textsf{PSPACE}$$PSPACE. A matching lower bound already holds for what we callpunctualreachability games on static graphs, where one player wants to reach the target at a given, binary encoded, point in time. We further study syntactic restrictions that imply more efficient procedures. In particular, if the edge predicate is in and is monotonically increasing for one player and decreasing for the other, then the complexity of solving games is only polynomially increased compared to static graphs.
Pareto Curves for Compositionally Model Checking String Diagrams of MDPs
Authors: Watanabe Kazuki , van der Vegt Marck , Hasuo Ichiro , Rot Jurriaan , Junges Sebastian
Published: April 2024

Computing schedulers that optimize reachability probabilities in MDPs is a standard verification task. To address scalability concerns, we focus on MDPs that are compositionally described in a high-level description formalism. In particular, this paper considersstring diagrams, which specify an algebraic, sequential composition of subMDPs. Towards their compositional verification, the key challenge is to locally optimize schedulers on subMDPs without considering their context in the string diagram. This paper proposes to consider the schedulers in a subMDP which form aPareto curveon a combination of local objectives. While considering all such schedulers is intractable, it gives rise to a highly efficient sound approximation algorithm. The prototype on top of the model checker Storm demonstrates the scalability of this approach.
Learning Explainable and Better Performing Representations of POMDP Strategies
Authors: Bork Alexander , Chakraborty Debraj , Grover Kush , Křetínský Jan , Mohr Stefanie
Published: April 2024

Strategies for partially observable Markov decision processes (POMDP) typically require memory. One way to represent this memory is via automata. We present a method to learn an automaton representation of a strategy using a modification of the $$L^*$$

L
∗

-algorithm. Compared to the tabular representation of a strategy, the resulting automaton is dramatically smaller and thus also more explainable. Moreover, in the learning process, our heuristics may even improve the strategy’s performance. We compare our approach to an existing approach that synthesizes an automaton directly from the POMDP, thereby solving it. Our experiments show that our approach can lead to significant improvements in the size and quality of the resulting strategy representations.
Forward and Backward Constrained Bisimulations for Quantum Circuits
Authors: Jiménez-Pastor A. , Larsen K. G. , Tribastone M. , Tschaikowski M.
Published: April 2024

Efficient methods for the simulation of quantum circuits on classic computers are crucial for their analysis due to the exponential growth of the problem size with the number of qubits. Here we study lumping methods based on bisimulation, an established class of techniques that has been proven successful for (classic) stochastic and deterministic systems such as Markov chains and ordinary differential equations. Forward constrained bisimulation yields a lower-dimensional model which exactly preserves quantum measurements projected on a linear subspace of interest. Backward constrained bisimulation gives a reduction that is valid on a subspace containing the circuit input, from which the circuit result can be fully recovered. We provide an algorithm to compute the constraint bisimulations yielding coarsest reductions in both cases, using a duality result relating the two notions. As applications, we provide theoretical bounds on the size of the reduced state space for well-known quantum algorithms for search, optimization, and factorization. Using a prototype implementation, we report significant reductions on a set of benchmarks. Furthermore, we show that constraint bisimulation complements state-of-the-art methods for the simulation of quantum circuits based on decision diagrams.
Enhancing GenMC’s Usability and Performance
Authors: Kokologiannakis Michalis , Majumdar Rupak , Vafeiadis Viktor
Published: April 2024

GenMC is a state-of-the-art stateless model checker that can verify safety properties of concurrent C/C++ programs under a wide range of memory consistency models, such as SC, TSO, RC11, and IMM.

In this paper, we improve the performance and usability of GenMC: we provide a probabilistic estimate of the expected verification cost, we automate the porting of new memory models, and employ caching and other data structure optimizations to improve the tool’s performance.
Provable Preimage Under-Approximation for Neural Networks
Authors: Zhang Xiyue , Wang Benjie , Kwiatkowska Marta
Published: April 2024

Neural network verification mainly focuses on local robustness properties, which can be checked by bounding the image (set of outputs) of a given input set. However, often it is important to know whether a given property holds globally for the input domain, and if not then for what proportion of the input the property is true. To analyze such properties requires computing preimage abstractions of neural networks. In this work, we propose an efficient anytime algorithm for generating symbolic under-approximations of the preimage of any polyhedron output set for neural networks. Our algorithm combines a novel technique for cheaply computing polytope preimage under-approximations using linear relaxation, with a carefully-designed refinement procedure that iteratively partitions the input region into subregions using input and ReLU splitting in order to improve the approximation. Empirically, we validate the efficacy of our method across a range of domains, including a high-dimensional MNIST classification task beyond the reach of existing preimage computation methods. Finally, as use cases, we showcase the application to quantitative verification and robustness analysis. We present a sound and complete algorithm for the former, which exploits our disjoint union of polytopes representation to provide formal guarantees. For the latter, we find that our method can provide useful quantitative information even when standard verifiers cannot verify a robustness property.
OxiDD
Authors: Husung Nils , Dubslaff Clemens , Hermanns Holger , Köhl Maximilian A.
Published: April 2024

Decision diagrams (DDs) are an important data structure in computer science with applications ranging from circuit design and verification to machine learning. Most prominently, binary DDs are commonly used to succinctly represent Boolean functions. Due to the practical importance of DDs, there is an ongoing quest for high-performance software libraries supporting the construction and manipulation of DDs. With OxiDD, we present a new framework for DDs that focuses on safety, concurrency, and modularity. Following a highly modular design we implement OxiDD in Rust, which facilitates the integration of various kinds of DDs such as MTBDDs, ZBDDs, and TDDs, all within safe code also in a concurrent setting. Already in its initial release, OxiDD does not compromise performance, which we show to be on par with or even better than established highly optimized DD libraries.
State of the Art in Software Verification and Witness Validation: SV-COMP 2024
Authors: Beyer Dirk
Published: April 2024

The 13th edition of the Competition on Software Verification (SV-COMP 2024) was the largest competition of its kind so far: A total of 76 tools for verification and witness validation were compared. The competition evaluated 59 verification systems and 17 validation systems from 34 teams from 12 countries. This yields a good overview of the state of the art in tools for software verification. The competition was executed on a benchmark set with 30 300 verification tasks for C programs and 587 . verification tasks for Java programs. The specifications again included reachability, memory safety, overflows, and termination. This year was the second time that the competition had an extra competition track on witness validation. We introduced a new witness format 2.0, and a new scoring schema for the validation track. All meta data about the verification and validation tools are available in the FM-Tools repository.
EmergenTheta: Verification Beyond Abstraction Refinement (Competition Contribution)
Authors: Bajczi Levente , Szekeres Dániel , Mondok Milán , Ádám Zsófia , Somorjai Márk , Telbisz Csanád , Dobos-Kovács Mihály , Molnár Vince
Published: April 2024

Thetais a model checking framework conventionally based on abstraction refinement techniques. While abstraction is useful for a large number of verification problems, the over-reliance on the technique led toThetabeing unable to meaningfully adapt. Identifying this problem in previous years of SV-COMP has led us to createEmergenTheta, a sandbox for the new approaches we wantThetato support. By differentiating between mature and emerging techniques, we can experiment more freely without hurting the reliability of the overall framework. In this paper we detail the development route toEmergenTheta, and its first debut on SV-COMP’24 in the ReachSafety category.
Mopsa-C: Improved Verification for C Programs, Simple Validation of Correctness Witnesses (Competition Contribution)
Authors: Monat Raphaël , Milanese Marco , Parolini Francesco , Boillot Jérôme , Ouadjaout Abdelraouf , Miné Antoine
Published: April 2024

We present advances we brought to Mopsa for SV-Comp 2024. We significantly improved the precision of our verifier in the presence of dynamic memory allocation, library calls such as , -based loops, and integer abstractions. We introduced a witness validator for correctness witnesses. Thanks to these improvements, Mopsa won SV-Comp’sSoftwareSystemscategory by a large margin, scoring 2.5 times more points than the silver medalist, Bubaak-SpLit.
Ultimate Automizer and the Abstraction of Bitwise Operations
Authors: Schüssele Frank , Bentele Manuel , Dietsch Daniel , Heizmann Matthias , Jiang Xinyu , Klumpp Dominik , Podelski Andreas
Published: April 2024

The verification ofUltimate Automizerworks on an SMT-LIB-based model of a C program. If we choose an SMT-LIB theory of (mathematical) integers, the translation is not precise, because we overapproximate bitwise operations. In this paper we present a translation for bitwise operations that improves the precision of this overapproximation.
$${\textsc {HaliVer}}$$: Deductive Verification and Scheduling Languages Join Forces
Authors: van den Haak Lars B. , Wijs Anton , Huisman Marieke , van den Brand Mark
Published: April 2024

The HaliVer tool integrates deductive verification into the popular scheduling language Halide, used for image processing pipelines and array computations. HaliVer uses VerCors, a separation logic-based verifier, to verify the correctness of (1) the Halide algorithms and (2) the optimised parallel code produced by Halide when an optimisation schedule is applied to an algorithm. This allows proving complex, optimised code correct while reducing the effort to provide the required verification annotations. For both approaches, the same specification is used. We evaluated the tool on several optimised programs generated from characteristic Halide algorithms, using all but one of the essential scheduling directives available in Halide. Without annotation effort, HaliVer proves memory safety in almost all programs. With annotations HaliVer, additionally, proves functional correctness properties. We show that the approach is viable and reduces the manual annotation effort by an order of magnitude.
Most General Winning Secure Equilibria Synthesis in Graph Games
Authors: Nayak Satya Prakash , Schmuck Anne-Kathrin
Published: April 2024

This paper considers the problem of co-synthesis in k-player games over a finite graph where each player has an individual $$\omega $$
ω
-regular specification $$\phi _i$$

ϕ
i

. In this context, a secure equilibrium (SE) is a Nash equilibrium w.r.t. the lexicographically ordered objectives of each player to first satisfy their own specification, and second, to falsify other players’ specifications. A winning secure equilibrium (WSE) is an SE strategy profile $$(\pi _i)_{i\in [1;k]}$$

(

π
i

)

i
∈
[
1
;
k
]

that ensures the specification $$\phi :=\bigwedge _{i\in [1;k]}\phi _i$$

ϕ
:
=

⋀

i
∈
[
1
;
k
]

ϕ
i

if no player deviates from their strategy $$\pi _i$$

π
i

. Distributed implementations generated from a WSE make components act rationally by ensuring that a deviation from the WSE strategy profile is immediately punished by a retaliating strategy that makes the involved players lose.

In this paper, we move from deviation punishment in WSE-based implementations to a distributed, assume-guarantee based realization of WSE. This shift is obtained by generalizing WSE from strategy profiles to specification profiles$$(\varphi _i)_{i\in [1;k]}$$

(

φ
i

)

i
∈
[
1
;
k
]

with $$\bigwedge _{i\in [1;k]}\varphi _i = \phi $$

⋀

i
∈
[
1
;
k
]

φ
i

=
ϕ

, which we call most general winning secure equilibria (GWSE). Such GWSE have the property that each player can individually pick a strategy $$\pi _i$$

π
i

winning for $$\varphi _i$$

φ
i

(against all other players) and all resulting strategy profiles $$(\pi _i)_{i\in [1;k]}$$

(

π
i

)

i
∈
[
1
;
k
]

are guaranteed to be a WSE. The obtained flexibility in players’ strategy choices can be utilized for robustness and adaptability of local implementations.

Concretely, our contribution is three-fold: (1) we formalize GWSE for k-player games over finite graphs, where each player has an $$\omega $$
ω
-regular specification $$\phi _i$$

ϕ
i

; (2) we devise an iterative semi-algorithm for GWSE synthesis in such games, and (3) obtain an exponential-time algorithm for GWSE synthesis with parity specifications $$\phi _i$$

ϕ
i

.
Scoped Effects as Parameterized Algebraic Theories
Authors: Lindley Sam , Matache Cristina , Moss Sean , Staton Sam , Wu Nicolas , Yang Zhixuan
Published: April 2024

Notions of computation can be modelled by monads. Algebraic effects offer a characterization of monads in terms of algebraic operations and equational axioms, where operations are basic programming features, such as reading or updating the state, and axioms specify observably equivalent expressions. However, many useful programming features depend on additional mechanisms such as delimited scopes or dynamically allocated resources. Such mechanisms can be supported via extensions to algebraic effects including scoped effects and parameterized algebraic theories. We present a fresh perspective on scoped effects by translation into a variation of parameterized algebraic theories. The translation enables a new approach to equational reasoning for scoped effects and gives rise to an alternative characterization of monads in terms of generators and equations involving both scoped and algebraic operations. We demonstrate the power of our fresh perspective by way of equational characterizations of several known models of scoped effects.
Artifact report: Generic bidirectional typing for dependent type theories
Authors: Felicissimo Thiago
Published: April 2024

We report on the implementation of a generic bidirectional algorithm for dependent type theories, following the proposal of the paper "Generic bidirectional typing for dependent type theories".
The Session Abstract Machine
Authors: Caires Luís , Toninho Bernardo
Published: April 2024

We build on a fine-grained analysis of session-based interaction as provided by the linear logic typing disciplines to introduce the SAM, an abstract machine for mechanically executing session-typed processes. A remarkable feature of the SAM’s design is its ability to naturally segregate and coordinate sequential with concurrent session behaviours. In particular, implicitly sequential parts of session programs may be efficiently executed by deterministic sequential application of SAM transitions, amenable to compilation, and without concurrent synchronisation mechanisms. We provide an intuitive discussion of the SAM structure and its underlying design, and state and prove its correctness for executing programs in a session calculus corresponding to full classical linear logic$$\textsf{CLL}$$CLL. We also discuss extensions and applications of the SAM to the execution of linear and session-based programming languages.
Specifying and Verifying Persistent Libraries
Authors: Stefanesco Léo , Raad Azalea , Vafeiadis Viktor
Published: April 2024

We present a general framework for specifying and verifying persistent libraries, that is, libraries of data structures that provide some persistency guarantees upon a failure of the machine they are executing on. Our framework enables modular reasoning about the correctness of individual libraries (horizontal and vertical compositionality) and is general enough to encompass all existing persistent library specifications ranging from hardware architectural specifications to correctness conditions such as durable linearizability. As case studies, we specify the and libraries, verify their implementations over "Image missing", and use them to build higher-level durably linearizable libraries, all within our framework. We also specify and verify a persistent transaction library that highlights some of the technical challenges which are specific to persistent memory compared to weak memory and how they are handled by our framework.