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2022 ◽  
Vol 6 (POPL) ◽  
pp. 1-29
Anders Miltner ◽  
Adrian Trejo Nuñez ◽  
Ana Brendel ◽  
Swarat Chaudhuri ◽  
Isil Dillig

We present a novel bottom-up method for the synthesis of functional recursive programs. While bottom-up synthesis techniques can work better than top-down methods in certain settings, there is no prior technique for synthesizing recursive programs from logical specifications in a purely bottom-up fashion. The main challenge is that effective bottom-up methods need to execute sub-expressions of the code being synthesized, but it is impossible to execute a recursive subexpression of a program that has not been fully constructed yet. In this paper, we address this challenge using the concept of angelic semantics. Specifically, our method finds a program that satisfies the specification under angelic semantics (we refer to this as angelic synthesis), analyzes the assumptions made during its angelic execution, uses this analysis to strengthen the specification, and finally reattempts synthesis with the strengthened specification. Our proposed angelic synthesis algorithm is based on version space learning and therefore deals effectively with many incremental synthesis calls made during the overall algorithm. We have implemented this approach in a prototype called Burst and evaluate it on synthesis problems from prior work. Our experiments show that Burst is able to synthesize a solution to 94% of the benchmarks in our benchmark suite, outperforming prior work.

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 140
Huixiang Shao ◽  
Zhijiang Zhang ◽  
Xiaoyu Feng ◽  
Dan Zeng

Point cloud registration is used to find a rigid transformation from the source point cloud to the target point cloud. The main challenge in the point cloud registration is in finding correct correspondences in complex scenes that may contain many noise and repetitive structures. At present, many existing methods use outlier rejections to help the network obtain more accurate correspondences, but they often ignore the spatial consistency between keypoints. Therefore, to address this issue, we propose a spatial consistency guided network using contrastive learning for point cloud registration (SCRnet), in which its overall stage is symmetrical. SCRnet consists of four blocks, namely feature extraction block, confidence estimation block, contrastive learning block and registration block. Firstly, we use mini-PointNet to extract coarse local and global features. Secondly, we propose confidence estimation block, which formulate outlier rejection as confidence estimation problem of keypoint correspondences. In addition, the local spatial features are encoded into the confidence estimation block, which makes the correspondence possess local spatial consistency. Moreover, we propose contrastive learning block by constructing positive point pairs and hard negative point pairs and using Point-Pair-INfoNCE contrastive loss, which can further remove hard outliers through global spatial consistency. Finally, the proposed registration block selects a set of matching points with high spatial consistency and uses these matching sets to calculate multiple transformations, then the best transformation can be identified by initial alignment and Iterative Closest Point (ICP) algorithm. Extensive experiments are conducted on KITTI and nuScenes dataset, which demonstrate the high accuracy and strong robustness of SCRnet on point cloud registration task.

2022 ◽  
Vol 22 (1) ◽  
Guilherme S. Nunes ◽  
Samantha L. Adami ◽  
Maitê M. Pellenz ◽  
Daniela Rigo ◽  
Rafael A. Estivalet ◽  

Abstract Background The execution of undergraduate thesis is a period in which students have an opportunity to develop their scientific knowledge. However, many barriers could prevent the learning process. This cross-sectional study aimed to analyze the scientific dissemination of results from undergraduate theses in physical therapy programs and verify the existence of barriers and challenges in the preparation of undergraduate thesis. Second, to investigate whether project characteristics and thesis development barriers were associated with the dissemination of undergraduate thesis results. Methods Physical therapists who graduated as of 2015, from 50 different educational institutions, answered an online questionnaire about barriers faced during the execution of undergraduate thesis and about scientific dissemination of their results. Results Of 324 participants, 43% (n = 138) of participants disseminated their results, and the main form of dissemination was publishing in national journals (18%, n = 58). Regarding the barriers, 76% (n = 246) of participants reported facing some difficulties, and the main challenge highlighted was the lack of scientific knowledge (28%, n = 91). Chances of dissemination were associated with barriers related to scientific understanding and operational factors, such as the type of institution, institutional facilities, and involvement with other projects. Conclusion Scientific knowledge seems to be a determining factor for the good development of undergraduate theses. In addition, it is clear the need to stimulate more qualified dissemination that reaches a larger audience. Changes in operational and teaching factors may improve the undergraduate thesis quality. However, the importance of rethinking scientific education within physical therapy programs draws attention.

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Seyedehanahita Mousavi ◽  
Ashkan Hafezalkotob ◽  
Vahidreza Ghezavati ◽  
Farshid Abdi

Purpose This study aims to identify and accurately assess the risk factors of competitors’ cooperation in the NPD project. Design/methodology/approach New product development (NPD) is essential to the survival of companies and surpassing other competitors. A key prerequisite for the success of an NPD project is the timing of new product delivery to the market. The main challenge faced by many project managers is the delay in execution and completion phases due to the complex nature and uncertainty of these projects. Rival companies' cooperation reduces the time spent on an NPD project which is an excellent way to reduce the risk of losing the market, but it increases other risk factors. Findings Based on the results, the security and confidentiality of innovation, the competitors attracting human resources and the company’s brand credibility factors were ranked higher than other factors and should be predicted and managed before cooperating with competitors. Originality/value This paper proposed a new model to assess risk factors in cooperation with rival companies in NPD projects. This model takes into account new parameters, for example, negative and positive risks, negative and positive passable risks and risk-based multi-objective optimization by ratio analysis plus full multiplicative form methodology for the rival companies cooperation in NPD projects. To evaluate the efficiency of the proposed model, a real case of the R&D unit of Iran Khodro Company was studied.

2022 ◽  
Ernest Sayapov ◽  
Mathieu Molenaar ◽  
Alvaro Nunez ◽  
Ahmed Benchekor ◽  
Abdullah Hadhrami ◽  

Abstract Recent years and especially the coronavirus pandemic have been very challenging for the oil industry, resulting in a significant reduction in investment, forcing companies to review budgets and search for more efficient and economical technologies to achieve the target level of hydrocarbon production and revenue generation. In PDO, one of the most challenging fields is "AS", where extreme downhole conditions require a very well-engineered approach to become economical. This field has already seen some of the most advanced technology trials in PDO that are also covered in multiple SPE papers. Based on the new approaches and techniques that were successfully implemented on recently drilled wells, it was decided to review the older, previously fractured wells in the area and assess them for a refracturing opportunity. The main challenge in this project was that these older wells were previously hydraulically fractured in multiple target intervals, therefore both zonal isolation and successful placement of the new fracs were becoming the major concerns. As the planned coverage by the new fractures was to ensure no bypassed pay, the only applicable technology on the market was a pinpoint fracturing process, whereby the targeted placement is achieved through limited entry perforations and focused energy of the injected fluid. The subject pinpoint technology anticipates that the limited entry sandblasting perforation is created and then proppant laden fluid is pumped through a sandblasting nozzle which is part of either a coiled tubing (CT) or a jointed pipe (JP) Bottom Hole Assembly (BHA), and the backside (or the annulus of the injection path) is used to maintain the positive backpressure from the top. This technology allows for choosing a desirable order of target interval selection inside the well, unlike conventional plug and perf or a simplified multistage completion, where the treatments must be placed only in order from bottom to top. Another advantage of this approach is a faster frac cycle through the elimination of wellbore cleanout requirement. Being a unique and first-ever application in the Middle East, using CT for placing frac treatments through a jetting nozzle demonstrates the full scale potential of this approach not only in conventional wells but also in complex, sour and High Pressure (HP) environments that are often found in the Sultanate of Oman and in the Middle East. This paper will cover the advantages and disadvantages, complexity and requirements, opportunities and lessons learnt in relation to this approach.

2022 ◽  
Vol 7 (1) ◽  
pp. 299-312
Mohamad Fairuz Mat Ali ◽  
Mohammad Agus Yusoff

Prior to the 14th general election (GE-14), electoral practices in Malaysia have been often criticised as being obscure and biased since it was plagued with issues such as dubious voter registers and ballot paper fraud. Therefore, in its manifesto during GE-14, Pakatan Harapan (PH) promised to reform this electoral practice to make it more independent, transparent, and fair. PH then won the GE-14 on the strength of this vow, forcing it to keep its manifesto pledge. However, implementing the said promise is not easy as most of the proposals involve amendments to the Federal Constitution that require the support of at least a two-thirds majority. The fact that PH lacks such a majority has raised the issue of whether or not the objective to reform the electoral system can be materialised. Thus, this article examines the aspects of electoral reform implemented by PH during its 22 months in power and assesses the challenges faced in implementing such electoral system reform. The concept of electoral reform was used as an analytical tool in this article. This article mainly obtained its data from secondary sources including books, journals, theses, official government documents and websites, while primary data were collected from unstructured interviews with authoritative informants. Findings revealed that among the important reforms of the country's electoral system that have been accomplished by PH are improving the standard operating procedures of elections, enhancing election rules that do not require amendments, amending laws that require simple majority support in the parliament, and implementing ‘high-impact’ electoral reforms that require amendments to the Federal Constitution. Moreover, it was also discovered that the main challenge to reforming the electoral system was the constraint of electoral rule amendments that require the approval of a two-thirds majority of parliamentarians. Other obstacles included politicians' unwillingness to accept a new electoral system culture, barriers to accessing data and information owned by other agencies, discrepancies between federal and state legislation, and financial constraints on improving existing hardware and systems necessary for electoral reform success.

2022 ◽  
Vol 23 ◽  
pp. 84-103
Laimutė Žalimienė ◽  
Juratė Charenkova ◽  
Eglė Šumskienė ◽  
Donata Petružytė ◽  
Miroslavas Seniutis ◽  

This article explores the attitudes of Japanese and Lithuanian social work program teachers towards the challenges posed by modern technologies that may transform social work profession and studies. Study data revealed that scientists from both countries admit that “taming” technologies and optimally “cooperating” with them is the main challenge of social work practice and studies. On the one hand, belief that technological development will provide more opportunities to fulfil the mission of social work was prevalent among the study participants, on the other hand, they had expressed concern that eventually the use of technology will change the essence of social work as a profession of human relations or will create modified forms of social exclusion. Additionally, a niche for the new role of the social worker was identified: to help the world “occupied” by technology remain “social”. Attitudes of research participants from both Lithuania and Japan can be linked to traditional concept of sociality and vision of social work as profession that belongs exclusively to area of human relations. B. Latour’s asocial sociality concept can be applied for broader look into this situation. This concept states that efforts to trace the contribution of actors of an inhuman nature to what belongs in the human world may be more successful when one ceases to view the world exclusively through human eyes and tries to reveal the inner perspectives of phenomena of a mixed nature.

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 486
Carlos-Omar Rasgado-Moreno ◽  
Marek Rist ◽  
Raul Land ◽  
Madis Ratassepp

The sections of pipe bends are hot spots for wall thinning due to accelerated corrosion by fluid flow. Conventionally, the thickness of a bend wall is evaluated by local point-by-point ultrasonic measurement, which is slow and costly. Guided wave tomography is an attractive method that enables the monitoring of a whole bend area by processing the waves excited and received by transducer arrays. The main challenge associated with the tomography of the bend is the development of an appropriate forward model, which should simply and efficiently handle the wave propagation in a complex bend model. In this study, we developed a two-dimensional (2D) acoustic forward model to replace the complex three-dimensional (3D) bend domain with a rectangular domain that is made artificially anisotropic by using Thomsen parameters. Thomsen parameters allow the consideration of the directional dependence of the velocity of the wave in the model. Good agreement was found between predictions and experiments performed on a 220 mm diameter (d) pipe with 1.5d bend radius, including the wave-field focusing effect and the steering effect of scattered wave-fields from defects.

Buildings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 62
Anamaria Andreea Anghel ◽  
Diana Giurea ◽  
Irina Mohora ◽  
Alma-Dia Hapenciuc ◽  
Octavian Camil Milincu ◽  

Nature-based design process with its embedded concept of form that follows function can be materialized as products capable of incorporating aesthetics and functionality similar to the characteristics of its natural role models. The paper addresses the topic of green installations created through a design process that simulates nature’s smart developmental mechanisms. The aim is to create an interactive installation capable of receiving and interpreting external factors that would determine the ensemble’s behavior and influence its future development and evolution. The main challenge lies in the fact that the smart feature is often achieved by intensive use of technology, which often overshadows inventive ways in which the behavioral and aesthetic properties of the material can be reinterpreted. The interactive green installation “Modgrew” investigates the possibilities of obtaining smart features through the experimental testing of two main types of configurations. The results underline the fact that, by applying the principles of biomimetic design, technologies from different fields can be combined towards obtaining a smart product. The conclusions highlight the need for future studies cover subjects such as the efficiency of automation, the possible reconfiguration of modules, behavioral optimization over time, the identification of minimal tech alternatives and the reduction of maintenance necessities.

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 445
Kai-Uwe Zirk ◽  
Manuel Olze ◽  
Harald Pötzschke

This article presents a novel method for the detection of biofilms based on a heatable, capacitive sensor structure (CSS). Biofilms are capable of strongly binding large amounts of water to their extracellular biopolymer matrix, which is detectable via its dielectric properties. A main challenge is to determine the difference between the inherent occurring presence of moisture in the ecosystem, which is necessary to form a biofilm and an actual formed biofilm. Therefore, the CSS is carefully heated to evaporate unbound surface moisture and determine whether there is a remaining residual alternation of the capacitance in comparison to the dry state. As a reproduceable substitute for complex, real biofilms, a hygroscopic, medical hydrogel-based on polysaccharides was used and applied by spray coating. Printed circuit boards (PCB) in different geometries and materials were used as CSS and compared in terms of their performance. A layer-thickness of 20 µm for the hydrogel coating to be sufficiently detected was defined as a realistic condition based on known values for real biofilms cited in literature. For this thickness a double-meander structure proves to be preferable over interdigitating and spiral geometries. It does offer a 30% lower, yet sufficient sensitivity, but shows advantages in manufacturing (one layer instead of two) and conductive heating capability. In the experiments, free water showed virtually no residual change, while the hydrogel-coated CSS still shows an approx. 300% higher value compared to a dry capacity. Yet, the overall small capacities of about 6–30 pF in dry state are difficult to measure and therefore sensitive to interferences and noise, which results in a high deviation. The principle of measurement can be evaluated as proofed by the carried out experiments, though offering room for improvement in the design of the study. The new method might be especially useful for pipes (e.g., hydrodynamically ineffective sensors installed in a pipe wall) if they at least are not permanently flooded with an aqueous medium, but can occasionally dry. If the internal surface is still only moist, it can be dried by initial heating.

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