Relevant bibliographies by topics / User Defined Functions (UDF)

Academic literature on the topic 'User Defined Functions (UDF)'

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Published: 10 December 2022
Last updated: 19 February 2023

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Journal articles on the topic "User Defined Functions (UDF)"

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Zou, Jia, Amitabh Das, Pratik Barhate, Arun Iyengar, Binhang Yuan, Dimitrije Jankov, and Chris Jermaine. "Lachesis." Proceedings of the VLDB Endowment 14, no. 8 (April 2021): 1262–75. http://dx.doi.org/10.14778/3457390.3457392.

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Partitioning is effective in avoiding expensive shuffling operations. However, it remains a significant challenge to automate this process for Big Data analytics workloads that extensively use user defined functions (UDFs), where sub-computations are hard to be reused for partitionings compared to relational applications. In addition, functional dependency that is widely utilized for partitioning selection is often unavailable in the unstructured data that is ubiquitous in UDF-centric analytics. We propose the Lachesis system, which represents UDF-centric workloads as workflows of analyzable and reusable sub-computations. Lachesis further adopts a deep reinforcement learning model to infer which sub-computations should be used to partition the underlying data. This analysis is then applied to automatically optimize the storage of the data across applications to improve the performance and users' productivity.
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Song, Shuan Jun, and Dan Feng Shen. "Synthetic Flow-Field Analysis of Main and Auxiliary Nozzles in Air-Jet Looms." Advanced Materials Research 411 (November 2011): 16–20. http://dx.doi.org/10.4028/www.scientific.net/amr.411.16.

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The synthetic flow-field model of main and auxiliary nozzle flow-field in air-jet loom is introduced. The software of computational fluid dynamics FLUENT is used for the first time to simulate synthetic flow-field, and velocity vector is analyzed. To different spray angles of auxiliary nozzle, the velocity and total pressure of central air are compared in brief. The boundary conditions are changed by User Defined Functions (UDF) and the comparison analysis is done before and after using UDF.
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Gu, Yunhong, and Robert L. Grossman. "Sector and Sphere: the design and implementation of a high-performance data cloud." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367, no. 1897 (June 28, 2009): 2429–45. http://dx.doi.org/10.1098/rsta.2009.0053.

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Cloud computing has demonstrated that processing very large datasets over commodity clusters can be done simply, given the right programming model and infrastructure. In this paper, we describe the design and implementation of the Sector storage cloud and the Sphere compute cloud. By contrast with the existing storage and compute clouds, Sector can manage data not only within a data centre, but also across geographically distributed data centres. Similarly, the Sphere compute cloud supports user-defined functions (UDFs) over data both within and across data centres. As a special case, MapReduce-style programming can be implemented in Sphere by using a Map UDF followed by a Reduce UDF. We describe some experimental studies comparing Sector/Sphere and Hadoop using the Terasort benchmark. In these studies, Sector is approximately twice as fast as Hadoop. Sector/Sphere is open source.
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Saur, Karla, Tara Mirmira, Konstantinos Karanasos, and Jesús Camacho-Rodríguez. "Containerized execution of UDFs." Proceedings of the VLDB Endowment 15, no. 11 (July 2022): 3158–71. http://dx.doi.org/10.14778/3551793.3551860.

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User-defined functions (UDFs) have long been used as the de facto way to extend the capabilities of data management systems. However, they are restricted to the specificities of each DBMS, and recent demands for advanced analytics have increased the need for complex UDFs that may require execution of arbitrary computation written in any programming language, management of library dependencies, portability across environments and engines, and resource isolation. These requirements go beyond what traditional UDFs were designed for, and have given rise to containerized UDFs that enable encapsulation and portability. However, this approach is nascent and can result in significant performance penalties and usability issues. In this paper, we present the first study that spans all stages of containerized UDFs' life cycle, performance bottlenecks in their execution, and extensibility to support different engines. Our experiments show that the performance of containerized UDF execution can be greatly affected by system design choices and that there are many trade-offs to consider. For example, regarding the method of communication with the containerized UDF, we show that binary-based implementations minimize overheads and are more than 2.4x faster than widely used text-based ones. Adopting a newer general-purpose communication method such as Arrow Flight can improve performance dramatically, causing a minimal ~10% slowdown compared to non-containerized UDFs. Additionally, containerized UDF start times vary wildly due to program size and complexity, from .07s to 7s in our experiments. Our insights can help DBMS developers make appropriate choices based on individual use cases when designing their systems.
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Foufoulas, Yannis, Alkis Simitsis, and Yannis Ioannidis. "YeSQL." Proceedings of the VLDB Endowment 15, no. 12 (August 2022): 3730–33. http://dx.doi.org/10.14778/3554821.3554886.

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The diversity and complexity of modern data management applications led to the extension of the relational paradigm with syntactic and semantic support for User-Defined Functions (UDFs). Although well-established in traditional DBMS settings, UDFs have become even more central in many applications spanning data science, data analytics, etc. Still, a critical limitation of UDFs, which to some extent has turned data scientists towards NoSQL systems, is the impedance mismatch between their evaluation and relational processing. We present YeSQL, an SQL extension with rich UDF support along with a pluggable architecture to easily integrate it with either server-based or embedded database engines. We currently support UDFs written in Python, which are fully integrated with relational queries as scalar functions, aggregators, or table returning functions. Key novel characteristics of YeSQL include easy implementation of complex algorithms, tracing JIT compilation of Python UDFs, and seamless integration with a database engine. Our demonstration will showcase (a) the usability and expressiveness of our approach, and (b) that our techniques of minimizing context switching between the relational engine and the Python VM are very effective and achieve significant speedups in common, practical use cases.
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Zhang, Guoqiang, Yuanchao Xu, Xipeng Shen, and Işıl Dillig. "UDF to SQL translation through compositional lazy inductive synthesis." Proceedings of the ACM on Programming Languages 5, OOPSLA (October 20, 2021): 1–26. http://dx.doi.org/10.1145/3485489.

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Many data processing systems allow SQL queries that call user-defined functions (UDFs) written in conventional programming languages. While such SQL extensions provide convenience and flexibility to users, queries involving UDFs are not as efficient as their pure SQL counterparts that invoke SQL’s highly-optimized built-in functions. Motivated by this problem, we propose a new technique for translating SQL queries with UDFs to pure SQL expressions. Unlike prior work in this space, our method is not based on syntactic rewrite rules and can handle a much more general class of UDFs. At a high-level, our method is based on counterexample-guided inductive synthesis (CEGIS) but employs a novel compositional strategy that decomposes the synthesis task into simpler sub-problems. However, because there is no universal decomposition strategy that works for all UDFs, we propose a novel lazy inductive synthesis approach that generates a sequence of decompositions that correspond to increasingly harder inductive synthesis problems. Because most realistic UDF-to-SQL translation tasks are amenable to a fine-grained decomposition strategy, our lazy inductive synthesis method scales significantly better than traditional CEGIS. We have implemented our proposed technique in a tool called CLIS for optimizing Spark SQL programs containing Scala UDFs. To evaluate CLIS, we manually study 100 randomly selected UDFs and find that 63 of them can be expressed in pure SQL. Our evaluation on these 63 UDFs shows that CLIS can automatically synthesize equivalent SQL expressions in 92% of the cases and that it can solve 2.4× more benchmarks compared to a baseline that does not use our compositional approach. We also show that CLIS yields an average speed-up of 3.5× for individual UDFs and 1.3× to 3.1× in terms of end-to-end application performance.
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Foufoulas, Yannis, Alkis Simitsis, Lefteris Stamatogiannakis, and Yannis Ioannidis. "YeSQL." Proceedings of the VLDB Endowment 15, no. 10 (June 2022): 2270–83. http://dx.doi.org/10.14778/3547305.3547328.

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The diversity and complexity of modern data management applications have led to the extension of the relational paradigm with syntactic and semantic support for User-Defined Functions (UDFs). Although well-established in traditional DBMS settings, UDFs have become central in many application contexts as well, such as data science, data analytics, and edge computing. Still, a critical limitation of UDFs is the impedance mismatch between their evaluation and relational processing. In this paper, we present YeSQL, an SQL extension with rich UDF support along with a pluggable architecture to easily integrate it with either server-based or embedded database engines. YeSQL currently supports Python UDFs fully integrated with relational queries as scalar, aggregator, or table functions. Key novel characteristics of YeSQL include easy implementation of complex algorithms and several performance enhancements, including tracing JIT compilation of Python UDFs, parallelism and fusion of UDFs, stateful UDFs, and seamless integration with a database engine. Our experimental analysis showcases the usability and expressiveness of YeSQL and demonstrates that our techniques of minimizing context switching between the relational engine and the Python VM are very effective and achieve significant speedups up to 68x in common, practical use cases compared to earlier approaches and alternative implementation choices.
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Pitchurov, George, Detelin Markov, Iskra Simova, Rositsa Velichkova, Peter Stankov, and Radostina Angelova. "Modelling indoor pollutant distribution via passive scalar and virtual box approach." E3S Web of Conferences 327 (2021): 05001. http://dx.doi.org/10.1051/e3sconf/202132705001.

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The distribution of PM2.5 around a thermal manikin with realistic female body shape in a naturally ventilated room has been modelled. The health risk (HR) due to inhalation of the PM2.5 has been quantified by integrating the pollutants mass flux over the boundaries of a virtual box around the mannequin’s head (the breathing zone). By the same approach HR is evaluated over the boundaries of another virtual box that surrounds the manikins body and defines the occupied zone. The paper focuses on the peculiarities of creating and meshing a virtual geometry, as well as on the application of user-defined functions (UDF) for defining a pollutant source within the room using Ansys Fluent modelling package.
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Kheloufi, Karim, and El Hachemi Amara. "Simulation of Geometry and Heat Transfer in a Thin Wall Produced by Direct Laser Powder Deposition." Advanced Materials Research 227 (April 2011): 134–37. http://dx.doi.org/10.4028/www.scientific.net/amr.227.134.

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A three dimensional model for direct laser powder deposition process is developed to simulate the geometry and the thermal field in building a single-bead wall (thin-wall). This model was employed using the Fluent commercial code to which several modules were appended (User Defined Functions UDF). The temperature distribution, the geometrical features of the generated structure, and thermal cycles have been carried out. We show that the results analysis can provide guidance for the process parameter selection in LPD. , and develop a base for further residual stress analysis.
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Ali, Syed Muhammad Fawad, Johannes Mey, and Maik Thiele. "Parallelizing user–defined functions in the ETL workflow using orchestration style sheets." International Journal of Applied Mathematics and Computer Science 29, no. 1 (March 1, 2019): 69–79. http://dx.doi.org/10.2478/amcs-2019-0005.

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Abstract Today’s ETL tools provide capabilities to develop custom code as user-defined functions (UDFs) to extend the expressiveness of the standard ETL operators. However, while this allows us to easily add new functionalities, it also comes with the risk that the custom code is not intended to be optimized, e.g., by parallelism, and for this reason, it performs poorly for data-intensive ETL workflows. In this paper we present a novel framework, which allows the ETL developer to choose a design pattern in order to write parallelizable code and generates a configuration for the UDFs to be executed in a distributed environment. This enables ETL developers with minimum expertise in distributed and parallel computing to develop UDFs without taking care of parallelization configurations and complexities. We perform experiments on large-scale datasets based on TPC-DS and BigBench. The results show that our approach significantly reduces the effort of ETL developers and at the same time generates efficient parallel configurations to support complex and data-intensive ETL tasks.
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Dissertations / Theses on the topic "User Defined Functions (UDF)"

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Große, Philipp, Norman May, and Wolfgang Lehner. "A Study of Partitioning and Parallel UDF Execution with the SAP HANA Database." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-144026.

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Large-scale data analysis relies on custom code both for preparing the data for analysis as well as for the core analysis algorithms. The map-reduce framework offers a simple model to parallelize custom code, but it does not integrate well with relational databases. Likewise, the literature on optimizing queries in relational databases has largely ignored user-defined functions (UDFs). In this paper, we discuss annotations for user-defined functions that facilitate optimizations that both consider relational operators and UDFs. We believe this to be the superior approach compared to just linking map-reduce evaluation to a relational database because it enables a broader range of optimizations. In this paper we focus on optimizations that enable the parallel execution of relational operators and UDFs for a number of typical patterns. A study on real-world data investigates the opportunities for parallelization of complex data flows containing both relational operators and UDFs.
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Gumulya, Monica. "The settling of spheres in viscoplastic fluids." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/2163.

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In this thesis, several significant contributions have been made towards the understanding of the flow behaviour of viscoplastic fluids and the settling behaviour of particles in these fluids. The attainment of this knowledge is highly crucial for the development of large-scale simulations of the movement of particles in tertiary grinding circuits, through which effective cost and resource saving strategies for the design and operation of these highly resource-demanding unit processes could be developed.To achieve the underlying objective of this thesis, the settling-sphere problem was approached using both experimental and numerical techniques. Experimentally, the flow behaviour of the viscoplastic slurries was represented by viscoplastic (aqueous) solutions of polyacrylamide. The settling behaviour of two spheres, using two different configurations of initial sphere positions, was then examined. In the first configuration, the two spheres are vertically-aligned, i.e. one sphere is released following the flow path of another sphere that has been released some time earlier into the fluid medium. In the second configuration, the two spheres are horizontally aligned, with a set distance apart, and released simultaneously into the viscoplastic solution. One of the major accomplishments achieved during the design of these experiments was the development of a stereo-photogrammetry sensor system, through which the 3D movement of spheres falling through the fluid could be determined to within ~ 1.5 mm accuracy.The numerical part of this study was conducted using Computational Fluid Dynamics (CFD) technique. Based on the Volume of Fluid (VOF) method, the settling particles were represented by fluids of very high viscosity (~ 400 – 1000 Pa.s). By implementing appropriate discretisation and approximation methods, the effects of numerical smearing and diffusion, as well as the level of deformation in the settling particles, could be minimised. A time-dependent estimation of the flow behaviour of the test fluids was then developed and implemented into this numerical scheme, using a series of User Defined Functions (UDFs).The development of the UDFs in the CFD analysis was based on the results of the rheometric assessment of the test fluids, through which it was found that these solutions possess a level of time dependency resulting from both thixotropy and elasticity. A new fluid model was thus developed, based on a scalar parameter that represents the integrity of the structural network configuration, resulting from the hydrogen bonding between the polyacrylamide and water molecules in the fluid. Although the resulting fluid model does not exclusively feature a yield stress value, the results of a series of dynamic analyses conducted on this model were found to be similar to those found experimentally, in which fluids that were initially ‘undisturbed’ or intact in structure have been found to require the application of stresses that are significantly larger in magnitude for the initiation of its deformation than in cases where the structure of the fluid is already deformed. Due to these dynamic characteristics, in which the fluid model seems to feature yield stress-like quality that dissipates once the ‘structure’ of the fluid has been deformed due to the application of shear, this fluid model was termed ‘semi-viscoplastic’.Using the analytical techniques outlined above, two significant contributions were made towards the understanding of the settling behaviour of particles in viscoplastic fluids. First, the settling velocity of particles falling in the fluid medium was found to be highly dependent on the structural condition of the fluid, i.e. whether it has recently been subjected to shear or whether sufficient time has been allowed for the fluid to recover its original viscous parameters. Based on this finding, a new generalised correlation was developed, through which predictions of the settling velocity of particles falling in fluids of various structural conditions can be made with much greater accuracy than before. The second contribution was in the understanding of the interaction tendencies between spheres that are settling in close proximity to each other. Through experimental and numerical analyses, it was found that the interaction tendencies of the particles are highly dependent on the elastic properties of the fluids. Correlations relating the tendencies of the spheres to interact with the elastic and viscous properties of the fluid were then developed. Through both of these contributions, aspects that are critical for the understanding of the motion of solid bodies in grinding circuits have been addressed.
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Zhang, Chao. "Optimization of User-Defined Aggregate Functions : Parallization and Sharing." Thesis, Université Clermont Auvergne‎ (2017-2020), 2019. http://www.theses.fr/2019CLFAC100.

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Les applications des agrégations pour la synthèse d’informations sont significatives dans de nombreux domaines. Les agrégations incorporées par défaut dans les systèmes ne sont pas suffisantes pour satisfaire les besoins qui émergent avec les progrès de l’analyse de données. Les UDAFs (User-Defined Aggregate Functions ou, en français, fonctions d’agrégation définies par l’utilisateur) sont en train de devenir un des opérateurs fondamentaux en analyse de données avancée. Le mécanisme UDAF fourni par la plupart des systèmes modernes souffre cependant d’au moins deux défauts : la définition d’UDAFs nécessite le codage en dur de la routine qui calcule la fonction d’agrégation, et la sémantique des UDAFs est totalement ou partiellement inconnue des processeurs de requêtes, empêchant leur optimisation. Cette thèse présente SUDAF (Sharing User-Defined Aggregate Functions), un cadre framework déclaratif qui permet aux utilisateurs de formuler des UDAFs sous la forme d’expressions mathématiques et de les utiliser dans des déclarations SQL. SUDAF est capable de générer automatiquement des implémentations parallèles efficientes à partir des UDAFs des utilisateurs, et supporte la mise en cache dynamique et la réutilisation des agrégats partiels. Nos expérimentations montrent que la technique de partage proposée permet des gains d’un à deux ordres de magnitude sur les temps d’exécution des requêtes
Applications of aggregations for information summary have great meanings in variousfields. System built-in aggregations are not sufficient to cover the needs of new applicationsin the age of analytics. UDAFs (user-defined aggregate functions) are becoming atype of fundamental operators in advanced data analytics. The UDAF mechanism providedby most of the modern systems suffers however from at least two severe drawbacks:defining UDAFs requires hardcoding the routine that computes the aggregationfunction, and the semantics of UDAFs is totally or partially unknown to the query processorwhich hampers the optimization possibilities. This thesis presents SUDAF (SharingUser-Defined Aggregate Functions), a declarative framework that allows users toformulate UDAFs as mathematical expressions and use them in SQL statements. SUDAFcomes equipped with the ability to generate efficient parallel implementation from users’UDAFs automatically and supports dynamic caching and reusing of partial aggregates.Our experiments show that the proposed sharing technique can lead from one to twoorders of magnitude improvement in query execution times
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Boháček, Jan. "EFFECT OF FLOW PARAMETERS OF WATER AND AIR ATOMIZED SPRAYS ON COOLING INTENSITY OF HOT SURFACES." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233959.

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Práce komplexně popisuje vodní a vodovzdušné chlazení pomocí metod CFD (Computational Fluid Dynamics) konkrétně s využitím software ANSYS FLUENT. Skládá se ze dvou hlavních částí, z nichž první se zabývá numerickým popisem jediné vodní kapky a druhá popisem směsí kapek představující paprsek válcové a ploché trysky. Je založena převážně na vícefázových modelech proudění a vlastních uživatelsky definovaných funkcí (User Defined Functions, UDF) představujících stěžejní část práce. Uvedené výpočtové modely jsou ve většině případů verifikovány pomocí experimentálních dat nebo jiných numerických modelů. V první části práce jsou teoreticky postupně rozebrány všechny tři použité vícefázové modely proudění. První z nich, Volume Of Fluid model (VOF), byl použit pro modelování jediné kapky (mikromodel). Zatímco zbývající dva, Euler-Euler model a Euler-Lagrange model, byly aplikovány v modelu celého paprsku trysky (makromodel). Mikromodel popisuje dynamiku volného pádu vodní kapky. Pro malé průměry kapek (~100µm) standardní model povrchového napětí (Continuum Surface Force, CSF) způsoboval tzv. parazitní proudy. Z toho důvodu je v práci rozebrána problematika výpočtu normál, křivostí volných povrchů a povrchového napětí jako zdroje objemových sil v pohybových rovnicích. Makromodel se zabývá studiem dynamiky celého paprsku tj. oblastí od ústí trysky po dopad na horký povrch, bere v úvahu kompletní geometrii, tzn. např. podpůrné válečky, bramu, spodní část krystalizátoru apod. V práci je rozebrána 2D simulace dopadu paprsku válcové trysky pomocí VOF modelu Euler-Lagrange modelu na horký povrch. Pro případ s VOF modelem byl navržen model blánového varu. Euler-Euler model a Euler-Lagrange model byly využity pro simulaci paprsku ploché trysky horizontálně ostřikující horkou bramu přímo pod krystalizátorem nad první řadou válečků. Pro Euler-Euler model byl navržen model sekundárního rozpadu paprsku založený na teorii nejstabilnější vlnové délky (Blob jet model). Jelikož diskrétní Lagrangeovy částice tvořily v určitých místech spíše kontinuální fázi, byl navržen a otestován model pro konverzi těchto částic do VOF.
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Tian, Hao. "A methodology for domain-specific conceptual data modeling and querying." restricted, 2007. http://etd.gsu.edu/theses/available/etd-02272007-140033/.

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Thesis (Ph. D.)--Georgia State University, 2007.
Rajshekhar Sunderraman, committee chair; Paul S. Katz, Yanqing Zhang, Ying Zhu, committee members. Electronic text (128 p. : ill.) : digital, PDF file. Description based on contents viewed Oct. 15, 2007; title from file title page. Includes bibliographical references (p. 124-128).
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Tokarski, Mieszko. "Computational and experimental analysis of a condensation hood." Rozprawa doktorska, 2021. https://repolis.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=73071.

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Tokarski, Mieszko. "Computational and experimental analysis of a condensation hood." Rozprawa doktorska, 2021. https://delibra.bg.polsl.pl/dlibra/docmetadata?showContent=true&id=73071.

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MARHOUN, Lukáš. "Návrh databáze pro připojení systému SAP jako zdroje dat pro webovou aplikaci." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-261068.

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The thesis deals with connecting SAP ERP system via local database system MS SQL Server using the tools SAP BI, data synchronization between systems and advanced usage of T-SQL language for preparing data for web applications and reports written in PHP. The thesis contains a brief overview of the SAP system and the possibility of connecting to the SAP system. The general principles of described solution can be used in conjunction with other systems and programming languages.
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Books on the topic "User Defined Functions (UDF)"

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Philip, Steele. 66 FoxBASE+ user-defined functions. Blue Ridge Summit, PA: TAB Books Inc., 1989.

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64 Clipper user-defined functions. Blue Ridge Summit, PA: TAB Books, 1988.

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Philip, Steele. 101+ FoxPro and dBase IV user-defined functions. Blue Ridge Summit, PA: Windcrest/McGraw-Hill, 1992.

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Philip, Steele. 101+ FoxPro and dBase IV user-defined functions. Blue Ridge Summit, Pennsylvania: Windcrest/McGraw-Hill, 1992.

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Steele, Philip. 85 dBASE IV user-defined functions and procedures. Blue Ridge Summit, PA: Windcrest, 1989.

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Sdvizhkov, Oleg, and Nikolay Macnev. Physics: a workshop in Excel. ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1014621.

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In the workshop, the program codes of user-defined VBA Excel functions are presented; it is shown how these functions are used to solve typical problems of elementary physics on a computer. The textbook includes problems in kinematics, dynamics, statics, molecular kinetic theory, thermal phenomena and electrodynamics. Each chapter includes: brief information on physics; code for one or more user functions and their description; step-by-step solutions to typical problems using user functions, illustrated with drawings of dialog boxes, fragments of worksheets, etc., made using screenshots. Meets the requirements of the federal state educational standards of secondary vocational education of the latest generation. It is intended for students of secondary vocational education institutions studying physics, but it will be useful for anyone who wants to learn how to solve problems in elementary physics at a modern level — on a computer using Excel.
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Novick, Andrew. Transact SQL User Defined Functions. Wordware Publishing, Inc., 2004.

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Stored Procedures, Triggers And User Defined Functions on DB2 Universal Database for Iseries. IBM.Com/Redbooks, 2004.

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Stored Procedures, Triggers, and User-defined Functions on DB2 Universal Database for iSeries. Vervante, 2006.

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Leuenberger, Christine, and Izhak Schnell. The Politics of Maps. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190076238.001.0001.

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This book traces how the geographical sciences have become entwined with politics, territorial claim-making, and nation-building in Israel/Palestine. In particular, the focus is on the history of geographical sciences before and after the establishment of the state of Israel in 1948, and how surveying, mapping, and naming the new territory became a crucial part of its making. With the 1993 Oslo Interim Agreement, Palestinians also surveyed and mapped the territory allocated to a future State of Palestine, with the expectation that they would, within five years, gain full sovereignty. In both cases, maps served to evoke a sense of national identity, facilitated a state’s ability to govern, and helped delineate territory. Besides maps’ geopolitical functions for nation-state building, they also became weapons in map wars. Before and after the 1967 war between Israel and its Arab neighbors, maps of the region became one of the many battlefields in which political conflicts over land claims and the ethno-national identity of this contested land were being waged. Aided by an increasingly user-defined mapping environment, Israeli and Palestinian governmental and non-governmental organizations increasingly relied on the rhetoric of maps to put forth their geopolitical visions. Such struggles over land and its rightful owners in Israel/Palestine exemplify processes under way in other states across the globe, whether in South Africa or Ukraine, which are engaged in disputes over territorial boundaries, national identities, and the territorial integrity of nation-states. Maps, no less, have become crucial tools in these struggles.
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Book chapters on the topic "User Defined Functions (UDF)"

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Schabacker, Michael. "User Defined Features (UDF)." In Solid Edge ST9 für Fortgeschrittene ‒ kurz und bündig, 90–93. Wiesbaden: Springer Fachmedien Wiesbaden, 2017. http://dx.doi.org/10.1007/978-3-658-18510-7_10.

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Wünsch, Andreas. "User Defined Features (UDF)." In NX 11 für Fortgeschrittene ‒ kurz und bündig, 67–84. Wiesbaden: Springer Fachmedien Wiesbaden, 2017. http://dx.doi.org/10.1007/978-3-658-18617-3_4.

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Wünsch, Andreas. "User Defined Feature (UDF)." In NX 10 für Fortgeschrittene - kurz und bündig, 48–63. Wiesbaden: Springer Fachmedien Wiesbaden, 2015. http://dx.doi.org/10.1007/978-3-658-09189-7_4.

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Wünsch, Andreas, and Fabian Pilz. "User Defined Features (UDF)." In Siemens NX für Fortgeschrittene ‒ kurz und bündig, 89–107. Wiesbaden: Springer Fachmedien Wiesbaden, 2020. http://dx.doi.org/10.1007/978-3-658-31561-0_5.

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Schabacker, Michael. "User Defined Features (UDF)." In Solid Edge 2020 für Fortgeschrittene – kurz und bündig, 90–93. Wiesbaden: Springer Fachmedien Wiesbaden, 2020. http://dx.doi.org/10.1007/978-3-658-29912-5_10.

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Wünsch, Andreas, Fabian Pilz, and Sándor Vajna. "User Defined Features (UDF)." In NX 12 für Fortgeschrittene ‒ kurz und bündig, 89–107. Wiesbaden: Springer Fachmedien Wiesbaden, 2019. http://dx.doi.org/10.1007/978-3-658-24773-7_5.

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Korotkevitch, Dmitri. "User-Defined Functions." In Pro SQL Server Internals, 227–40. Berkeley, CA: Apress, 2016. http://dx.doi.org/10.1007/978-1-4842-1964-5_11.

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Kalb, Irv. "User-Defined Functions." In Learn to Program with Python 3, 67–102. Berkeley, CA: Apress, 2018. http://dx.doi.org/10.1007/978-1-4842-3879-0_4.

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Natarajan, Jay, Rudi Bruchez, Scott Shaw, and Michael Coles. "User-Defined Functions." In Pro T-SQL 2012 Programmer’s Guide, 79–109. Berkeley, CA: Apress, 2012. http://dx.doi.org/10.1007/978-1-4302-4597-1_4.

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Cebollero, Miguel, Jay Natarajan, and Michael Coles. "User-Defined Functions." In Pro T-SQL Programmer's Guide, 79–110. Berkeley, CA: Apress, 2015. http://dx.doi.org/10.1007/978-1-4842-0145-9_4.

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Conference papers on the topic "User Defined Functions (UDF)"

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Poulton, Luke, Oyuna Rybdylova, Sergei S. Sazhin, Cyril Crua, Mansour Qubeissi, and Ahmed E. Elwardany. "A model for mono- and multi-component droplet heating and evaporation and its implementation into ANSYS Fluent." In ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems. Valencia: Universitat Politècnica València, 2017. http://dx.doi.org/10.4995/ilass2017.2017.4759.

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A model for heating and evaporation of mono- and multi-component droplets, based on analytical solutions to the heat transfer and species diffusion equations in the liquid phase, is summarised. The implementation of the model into ANSYS Fluent via User-Defined Functions (UDF) is described. The model is applied to the analysis of pure acetone, ethanol, and mixtures of acetone/ethanol droplet heating/cooling and evaporation. The predictions of the customised version of ANSYS Fluent with the newly implemented UDF model are verified against the results predicted by the previously developed in house, one-dimensional code.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4759
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Sen, Baris A., Yanhu Guo, Randal G. McKinney, Federico Montanari, and Frederick C. Bedford. "Pratt and Whitney Gas Turbine Combustor Design Using ANSYS Fluent and User Defined Functions." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-70145.

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This paper summarizes work conducted at Pratt & Whitney to incorporate ANSYS Fluent into the computational fluid dynamics-based combustor design process. As a first step, turbulence, combustion and spray models that already exist and have been validated in the Pratt & Whitney legacy computational fluid dynamics (CFD) solver ALLSTAR were converted into user defined functions (UDFs) for usage with the core ANSYS Fluent solver. In this manner, a baseline solver was established that allowed a systematic testing of the ANSYS Fluent native models. The baseline solver was validated against computational results as well as experimental data obtained for (i) liquid jet in cross-flow (LJICF), (ii) ambient spray injector tests and (iii) Pratt & Whitney next generation product family configurations. These test cases established a thorough evaluation of ANSYS Fluent with UDFs on a spectrum of simple to complex geometries and flow physics relevant to the conditions encountered in aeroengine combustors. Results show that Fluent produces calculated results obtained by ALLSTAR with similar level of agreement to the experiments. Furthermore, Fluent provides better convergence compared to the legacy ALLSTAR solver with a similar computational resource requirement. The ANSYS Fluent native spray break-up models were also tested for the liquid jet in cross flow configuration, demonstrating the importance of modeling the stripping and primary break-up regime of a spray jet. This capability is currently available only via the use of UDFs.
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Karimanal, Kamal V., Michael J. Ellsworth, and Gamal Refai-Ahmed. "A Numerical Technique for Modeling Thermoelectric Cooler With Temperature Controller for Steady State CFD Applications." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42068.

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A Thermo Electric Cooler (TEC) model was incorporated to a CFD software program by imposing heat absorption, heat rejection and Joule heat generation source terms to the appropriate geometric regions. The above-mentioned source terms are functions of current input and local temperature. These functions were incorporated as User Defined Functions (UDF) to the software program. If the objective is to achieve a desired temperature at the centroid location of the heat absorption side (cold side), the current input to the TEC is an unknown that depends on the boundary conditions. Hence the current parameter was posed as an unknown variable in the UDF and was iteratively solved so that the set point temperature is attained. The source terms and the feedback control were implemented in Finite Volume Method (FVM) based CFD software Icepak. FVM simulation predictions were compared with the results from a 1-D global energy balance model that was solved using TK solver program. Acceptable agreement between the two approaches is reported. While the 1-D model can be used for quick calculation under assumed simplistic scenarios, the CFD implementation can be applied to system level flow and energy simulations.
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Ge, Jian, Dalin Zhang, Wenxi Tian, Suizheng Qiu, and G. H. Su. "Coupled Analysis of Thermal Hydraulics and Neutronics for a Molten Salt Reactor." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-67042.

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As one of the six selected optional innovative nuclear reactor in the generation IV International Forum (GIF), the Molten Salt Reactor (MSR) adopts liquid salt as nuclear fuel and coolant, which makes the characteristics of thermal hydraulics and neutronics strongly intertwined. Coupling analysis of neutronics and thermal hydraulics has received considerable attention in recent years. In this paper, a new coupling method is introduced based on the Finite Volume Method (FVM), which is widely used in the Computational Fluid Dynamics (CFD) methodology. Neutron diffusion equations and delayed neutron precursors balance equations are discretized and solved by the commercial CFD package FLUENT, along with continuity, momentum and energy equations simultaneously. A Temporal And Spatial Neutronics Analysis Model (TASNAM) is developed using the User Defined Functions (UDF) and User Defined Scalar (UDS) in FLUENT. A neutronics benchmark is adopted to demonstrate the solution capability for neutronics problems using the method above. Furthermore, a steady state coupled analysis of neutronics and thermal hydraulics for the Molten Salt Advanced Reactor Transmuter (MOSART) is performed. Two groups of neutrons and six groups of delayed neutron precursors are adopted. Distributions of the liquid salt velocity, temperature, neutron flux and delayed neutron precursors in the core are obtained and analyzed. This work can provide some valuable information for the design and research of MSRs.
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Zhang, Liting, and Xiuling Wang. "Numerical Simulation of Three-Dimensional Ocean Wave." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71995.

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Abstract At present, caused by a large amount of wave energy resources and huge energy capacity, the development and utilization of wave energy have come to be an essential development focus of wave energy manufacturing. The purpose of this research is to simulate the ocean in an offshore environment. A three-dimensional Computational Fluid Dynamics (CFD) model was used to analyze the propagation of ocean waves. The Volume of Fluid (VOF) multiphase model and laminar model were used to analyze wave propagation in offshore conditions. Function Methodology and Mobile Methodology were implemented by applying User Defined Function (UDF) code which characterizes transient velocity profile. The parametric study was performed to analyze how velocity and amplitude change. The models were first validated by comparing them with previous analytical wave solutions. To prevent the reflection of the wave, a damping term was added by using User Define Function to define the viscosity of the water phase.
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Mehdizadeh, Minoo, and Goodarz Ahmadi. "Two-Dimensional Computer Simulation of Salinity Gradient Solar Pond Operation." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21811.

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This study is concerned with computer modeling of flow and thermal analysis of solar ponds with a salinity gradient. Solar ponds have been used as an efficient and environmentally friendly approach for collection of solar energy for low temperature thermal applications. A two-dimensional unsteady computational fluid dynamic (CFD) model was developed and used for numerical study of stability analysis of the pond, as well as heat and mass transfer in the salt gradient solar ponds. Salinity gradient was created in order to stabilize the pond and to restrict convective motions induced by buoyancy driven solar radiation heating during the period of operation. Fluent® commercial software was enhanced with the implementation of User Defined Functions (UDF) and was used in these simulations. The user defined scalar model was included for analyzing the convection and diffusion of the salt concentration in the solar pond. In addition, user defined functions were developed for relating the water density to temperature and salt concentration, as well as, the amount of solar radiation absorption in the solar pond as functions of thermo-physical properties. In the absence of flow exchange, the natural convection in the pond was simulated and the stability of the pond was verified. Development of salt concentration was also studied, and time evolution of temperature distribution in a small scale salinity gradient solar pond was analyzed. For the case of flow exchange at the bottom of the pond, the energy production was evaluated, and the temperature, concentration and flow field were simulated.
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Shen, Wenjun, Yougang Tang, and Liqin Liu. "Study on the Hydrodynamic Characteristics for Heave Plate Structure of Truss Spar." In ASME 2010 29th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/omae2010-21166.

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The hydrodynamic characteristics of heave plates are studied in this paper. Firstly, different motion amplitudes and plate spacing influencing hydrodynamic coefficients are considered. Secondly, heave plates with different thicknesses are calculated, the case of edges with inclined form for heave plate is also taken into account. Numerical simulations are made for the plate forced oscillation, employing the dynamic mesh method and UDF (User defined functions). The values of Cm and Cd for heave plate are calculated. It is found that, in a certain amplitude range, Cm increases with increasing of amplitudes, Cd decreases with increasing of amplitudes. The values of Cm and Cd increase with increasing of plate spacing. Furthermore with the same effective thickness, the hydrodynamic performance of heave plate with inclined form is improved greatly.
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Liu, Xiaojing, and Biao Zhou. "Liquid Water Removal Process in PEM Fuel Cell Cathode." In ASME 2009 7th International Conference on Fuel Cell Science, Engineering and Technology. ASMEDC, 2009. http://dx.doi.org/10.1115/fuelcell2009-85123.

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In this paper, water behaviors in both the gas flow channels and porous layer at the cathode side of a PEMFC are studied. VOF (Volume of Fluid) method and UDF (User-Defined-Function) are applied. A multi-phase three-dimensional fuel cell cathode side model is constructed with a serpentine shape channel and a porous layer attached to it. Fluid will be allowed to pass through both domains as it can in the real fuel cell system. Parameters of the porous layer will be introduced to the model by the user defined function. The detailed liquid water removal process in this model will be presented, and since the water behaviors in a fuel cell is proved to be one of the most important factors influencing the fuel cell performance, this model can be a good starting point to make more advanced models to investigate fuel cell performance.
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Mrinal, K. R., Md Hamid Siddique, and Abdus Samad. "A Transient 3D CFD Model of a Progressive Cavity Pump." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56599.

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A progressive cavity pump (PCP) is a positive displacement pump and has been used as an artificial lift method in the oil and gas industry for pumping fluid with solid content and high viscosity. In a PCP, a single-lobe rotor rotates inside a double-lobe stator. Articles on computational works for flows through a PCP are limited because of transient behavior of flow, complex geometry and moving boundaries. In this paper, a 3D CFD model has been developed to predict the flow variables at different operating conditions. The flow is considered as incompressible, single phase, transient, and turbulent. The dynamic mesh model in Ansys-Fluent for the rotor mesh movement is used, and a user defined function (UDF) written in C language defines the rotor’s hypocycloid path. The mesh deformation is done with spring based smoothing and local remeshing technique. The computational results are compared with the experiment results available in the literature. Thepump gives maximum flowrate at zero differential pressure.
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Liu, Li-qin, Jin-shuang Man, and Yu Qiu. "The Added Mass and Viscous Damping of a Spar Platform With Semi-Closed Moon Pool." In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41067.

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The CFD (Computational Fluent Dynamics) method was used to calculate the added mass and the viscous damping of the Spar platform considering the semi-closed moon pool in this paper. The three-dimensional models of the platform with water inside the semi-closed moon pool were established by the VOF (Volume of Fluid) method. The UDF (User Defined Function) was adopted to oscillate the platform. The added mass and the damping coefficients were calculated under different KC (Keulegan-Carpenter) number and flow velocity for different opening ratio of the moon pool. The viscous damping and natural period of the platform heaving were obtained by calculating the platform motion in the static water. The influences of water inside the moon pool on the Spar platform motion were analyzed.
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