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Littérature scientifique sur le sujet « Views selection »

Auteur : Grafiati

Publié le 10 mars 2023

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Articles de revues sur le sujet "Views selection"

Haider, Mohammad, et T. V. Vijay Kumar. « Query Frequency based View Selection ». International Journal of Business Analytics 4, n^o 1 (janvier 2017) : 36–55. http://dx.doi.org/10.4018/ijban.2017010103.

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View selection deals with the selection of appropriate sets of views capable of improving the response times for queries while conforming to space constraints. Materializing all views is infeasible, as the number of possible views is exponential with respect to the number of dimensions and, thus, would not fit within the available storage space. Further, optimal view selection is an NP-Complete problem. Thus, the only remaining alternative is to select a subset of views that reduce the query response time and fit within the available space for materialization. The most fundamental greedy view selection algorithm HRUA considers the size parameter for computing the Top-K views for materialization. In each iteration, it computes the benefit, with respect to size, of all non-selected views, and selects the one entailing the highest benefit for materialization. Though these selected views may be beneficial in respect of their size, they may not be capable of answering large numbers of future queries thereby becoming an unnecessary space overhead. Existing query frequency based view selection algorithms, which address this problem, have been compared in this paper. Experimental results show that each of these algorithms, in comparison to HRUA, are able to select fairly good quality views that provide answers to comparatively greater numbers of queries. Materializing these selected views would facilitate the business decision making process.

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Arun, Biri, et T. V. Vijay Kumar. « Materialized View Selection using Marriage in Honey Bees Optimization ». International Journal of Natural Computing Research 5, n^o 3 (juillet 2015) : 1–25. http://dx.doi.org/10.4018/ijncr.2015070101.

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Data warehouse was designed to cater to the strategic decision making needs of an organization. Most queries posed on them are on-line analytical queries, which are complex and computation intensive in nature and have high query response times when processed against a large data warehouse. This time can be substantially reduced by materializing pre-computed summarized views and storing them in a data warehouse. All possible views cannot be materialized due to storage space constraints. Also, an optimal selection of subsets of views is shown to be an NP-Complete problem. This problem of view selection has been addressed in this paper by selecting a beneficial set of views, from amongst all possible views, using the swarm intelligence technique Marriage in Honey Bees Optimization (MBO). An MBO based view selection algorithm (MBOVSA), which aims to select views that incur the minimum total cost of evaluating all the views (TVEC), is proposed. In MBOVSA, the search has been intensified by incorporating the royal jelly feeding phase into MBO. MBOVSA, when compared with the most fundamental greedy based view selection algorithm HRUA, is able to select comparatively better quality views.

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Hurley, Catherine B. « Graphical Selection of Data Views ». Journal of Computational and Graphical Statistics 9, n^o 3 (septembre 2000) : 558. http://dx.doi.org/10.2307/1390946.

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Hurley, Catherine B. « Graphical Selection of Data Views ». Journal of Computational and Graphical Statistics 9, n^o 3 (septembre 2000) : 558–81. http://dx.doi.org/10.1080/10618600.2000.10474899.

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Prakash, Jay, et T. V. Vijay Kumar. « Multi-Objective Materialized View Selection Using Improved Strength Pareto Evolutionary Algorithm ». International Journal of Artificial Intelligence and Machine Learning 9, n^o 2 (juillet 2019) : 1–21. http://dx.doi.org/10.4018/ijaiml.2019070101.

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A data warehouse system uses materialized views extensively in order to speedily tackle analytical queries. Considering that all possible views cannot be materialized due to maintenance cost and storage constraints, the selection of an appropriate set of views to materialize that achieve an optimal trade-off among query response time, maintenance cost, and the storage constraint becomes an essential necessity. The selection of such an appropriate set of views for materialization is referred to as the materialized views selection problem, which is an NP-Complete problem. In the last two decades, several new selection approaches, based on heuristics, have been proposed. Most of these have used a single objective or weighted sum approach to address the various constraints. In this article, an attempt has been made to address the bi-objective materialized view selection problem, where the objective is to minimize the view evaluation cost of materialized views and the view evaluation cost of the non-materialized views, using the Improved Strength Pareto Evolutionary Algorithm. The experimental results show that the proposed multi-objective view selection algorithm is able to select the Top-K views that achieves a reasonable trade-off between the two objectives. Materializing these selected views would reduce the query response times for analytical queries and thereby facilitates the decision-making process.

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Mouna, Mustapha, Ladjel Bellatreche et Narhimene Boustia. « ProRes : Proactive re-selection of materialized views ». Computer Science and Information Systems, n^o 00 (2022) : 3. http://dx.doi.org/10.2298/csis210606003m.

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Materialized View Selection is one of the most studied problems in the database field, covering SQL and NoSQL technologies as well as different deployment infrastructures (centralized, parallel, cloud). This problem has become more complex with the arrival of data warehouses, being coupled with the physical de sign phase that aims at optimizing query performance. Selecting the best set of materialized views to optimize query performance is a challenging task. Given their importance and the complexity of their selection, several research efforts both from academia and industry have been conducted. Results are promising - some solutions are being implemented by commercial and open-source DBMSs -, but they do not factor in the following properties of nowadays analytical queries: (i) large scale queries, (ii) their dynamicity, and (iii) their high interaction. Studies to date fail to consider that complete set of properties. Considering the three properties simultaneously is crucial regarding today?s analytical requirements, which involve dynamic and interactive queries. In this paper, we first present a concise state of the art of the materialized view selection problem (VSP) by analyzing its ecosystem. Secondly, we propose a proactive re-selection approach that considers the three properties concurrently. It features twomain phases: offline and online. In the offline phase, we manage a set of the first queries based on a given threshold _ by selecting materialized views through a hypergraph structure. The second phase manages the addition of new queries by scheduling them, updates the structure of the hypergraph, and selects new views by eliminating the least beneficial ones. Finally, extensive experiments are conducted using the Star Schema Benchmark data set to evaluate the effectiveness and efficiency of our approach.

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Wu, Xiaoying, et Dimitri Theodoratos. « Template-Based Bitmap View Selection for Optimizing Queries Over Tree Data ». International Journal of Cooperative Information Systems 25, n^o 03 (septembre 2016) : 1650005. http://dx.doi.org/10.1142/s0218843016500052.

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Developing and exploiting flexible techniques for optimizing the evaluation of queries over loosely structured data (e.g. tree or graph databases) is of crucial importance for modern database applications. In this context, we consider a new type of views which can be materialized as compressed bitmaps over tree data. We introduce the concept of view structural template to define classes of views. We then define and address a novel view selection problem (called view class selection (VCS) problem) where the goal is to select classes of bitmap views in order to optimize the overall evaluation cost of all tree pattern queries (TPQs) that can be issued against a database while satisfying a space constraint and ensuring that all the TPQs can be answered using exclusively the materialized views. We show that the VCS problem is NP-hard and we design two heuristic greedy algorithms which iteratively generate new batches of candidate view classes and make them available for selection. Each algorithm uses a different view class expansion technique to enable the systematic generation of candidate view classes from classes with smaller templates. We run extensive experiments to evaluate both the effectiveness of the algorithms and their efficiency on real, benchmark and synthetic datasets. Our algorithms are able to suggest high quality selections of view classes in a reasonable amount of time.

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Arun, Biri, et T. V. Vijay Kumar. « Materialized View Selection using Artificial Bee Colony Optimization ». International Journal of Intelligent Information Technologies 13, n^o 1 (janvier 2017) : 26–49. http://dx.doi.org/10.4018/ijiit.2017010102.

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Data warehouse is an essential component of almost every modern enterprise information system. It stores huge amount of subject-oriented, time-stamped, non-volatile and integrated data. It is highly required of the system to respond to complex online analytical queries posed against its data warehouse in seconds for efficient decision making. Optimization of online analytical query processing (OLAP) could substantially minimize delays in query response time. Materialized view is an efficient and effective OLAP query optimization technique to minimize query response time. Selecting a set of such appropriate views for materialization is referred to as view selection, which is a nontrivial task. In this regard, an Artificial Bee Colony (ABC) based view selection algorithm (ABCVSA), which has been adapted by incorporating N-point and GBFS based N-point random insertion operations, to select Top-K views from a multidimensional lattice is proposed. Experimental results show that ABCVSA performs better than the most fundamental view selection algorithm HRUA. Thus, the views selected using ABCVSA on materialization would reduce the query response time of OLAP queries and thereby aid analysts in arriving at strategic business decisions in an effective manner.

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Zhou, Li Juan, Hai Jun Geng et Ming Sheng Xu. « Materialized View Selection in the Data Warehouse ». Applied Mechanics and Materials 29-32 (août 2010) : 1133–38. http://dx.doi.org/10.4028/www.scientific.net/amm.29-32.1133.

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A data warehouse stores materialized views of data from one or more sources, with the purpose of efficiently implementing decision-support or OLAP queries. Materialized view selection is one of the crucial decisions in designing a data warehouse for optimal efficiency. The goal is to select an appropriate set of views that minimizes sum of the query response time and the cost of maintaining the selected views, given a limited amount of resource, e.g., materialization time, storage space, etc. In this article, we present an improved PGA algorithm to accomplish the view selection problem; the experiments show that our proposed algorithm shows it’s superior.

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Bagale, Purushottam, et Shashidhar Ram Joshi. « Optimal Materialized View Management in Distributed Environment Using Random Walk Approach ». Journal of Advanced College of Engineering and Management 1 (13 mai 2016) : 67. http://dx.doi.org/10.3126/jacem.v1i0.14923.

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Materialized View selection and maintenance is a critical problem in many applications. In large databases particularly in distributed database, query response time plays an important role as timely access to information and it is the basic requirement of successful business application. The materialization of all views is not possible because of the space constraint and maintenance cost constraint. Materialized views selection is one of the crucial decisions in designing a data warehouse for optimal efficiency. Selecting a suitable set of views that minimizes the total cost associated with the materialized views is the key component in distributed database environment. Several solutions have been proposed in the literature to solve this problem. However, most studies do not encompass search time, storage constrains and maintenance cost. In this research work two algorithms are depicted; first for materialized view selection and maintenance in distributed environment where database is distributed, Second algorithm is for node selection in distributed environment. Journal of Advanced College of Engineering and Management, Vol.1, 2015, 69-75

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Thèses sur le sujet "Views selection"

Gupta, Shalu. « View Selection for Query-Evaluation Efficiency using Materialized Views ». NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-07142005-142452/.

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The purpose of this research is to show the use of derived data such as materialized views for run time optimization of aggregate queries. In this thesis, we show the trade off between the time taken to design the views Vs the query run time. We have designed a system called Query Performance Enhancement by Tuning (QPET) which implements the idea of designing and using materialized views to answer frequent aggregate queries.

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Indelli, Pisano Valentina. « Reducing the View Selection Problem through Code Modeling : Static and Dynamic approaches ». Doctoral thesis, Universita degli studi di Salerno, 2017. http://hdl.handle.net/10556/2617.

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2015 - 2016
Data warehouse systems aim to support decision making by providing users with the appropriate information at the right time. This task is particularly challenging in business contexts where large amount of data is produced at a high speed. To this end, data warehouses have been equipped with Online Analytical Processing tools that help users to make fast and precise decisions througt the execution of complex queries. Since the computation of these queries is time consuming, data warehouses precompute a set of materialized views answering to the workload queries. This thesis work defines a process to determine the minimal set of workload queries and the set of views to materialize. The set of queries is represented by an optimized lattice structure used to select the views to be materialized according to the processing time costs and the view storage space. The minimal set of required Online Analytical Processing queries is computer by analyzing the data model defined with the visual language CoDe (Complexity Design). The latter allows to conceptually organizatio the visualization of data reports and to generate visualizations of data obtained from data-‐mart queries. CoDe adopts a hybrid modeling process combining two main methodologieser-‐driven and data- driven. The first aims to create a model according to the user knowledge, re-quirements, and analysis needs, whilst the latter has in charge to concretize data and their relationships in the model through Online Analytical Processing queries. Since the materialized views change over time, we also propose a dynamic process that allows users to upgrade the CoDe model with a context-‐aware editor, build an optimized lattice structure able to minimize the effort to recalculate it,and propose the new set of views to materialize Moreover, the process applies a Markov strategy to predict whether the views need to be recalculate or not according to the changes of the model. The effectiveness of the proposed techniques has been evaluated on a real world data warehouse. The results revealed that the Markov strategy gives a better set of solutions in term of storage space and total processing cost. [edited by author]
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Pistellato, Mara <1991&gt. « Robust Joint Selection of Camera Orientations and Feature Projections over Multiple Views ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2016. http://hdl.handle.net/10579/8799.

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A number of critical factors arises when a complex 3D scene is to be reconstructed by means of a large sequence of different views. Some of them are related to the ability to recover the correct identity and the accurate projection of each observed feature. Other sources of error are tied to the reliability of the orientation estimate for each view. Here we propose a method that tries to solve both problems at the same time, while being also inherently resilient to outliers. At the core of the approach stands a widely adopted game-theoretical selection technique, which has already been successfully adopted to address similar tasks. The original inception, however, has been further refined to allow both better accuracy and tighter selection, as well as a greatly reduced memory consumption and computation complexity. By exploiting these enhancements, we were able to apply our technique to real-wolrd scenarios involving several hundreds of view points and tens of thousands of independent observations.

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Helle, Valeria, Andra-Stefania Negus et Jakob Nyberg. « Improving armed conflict prediction using machine learning : ViEWS+ ». Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-354845.

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Our project, ViEWS+, expands the software functionality of the Violence EarlyWarning System (ViEWS). ViEWS aims to predict the probabilities of armed conflicts in the next 36 months using machine learning. Governments and policy-makers may use conflict predictions to decide where to deliver aid and resources, potentially saving lives. The predictions use conflict data gathered by ViEWS, which includes variables like past conflicts, child mortality and urban density. The large number of variables raises the need for a selection tool to remove those that are irrelevant for conflict prediction. Before our work, the stakeholders used their experience and some guesswork to pick the variables, and the predictive function with its parameters. Our goals were to improve the efficiency, in terms of speed, and correctness of the ViEWS predictions. Three steps were taken. Firstly, we made an automatic variable selection tool. This helps researchers use fewer, more relevant variables, to save time and resources. Secondly, we compared prediction functions, and identified the best for the purpose of predicting conflict. Lastly, we tested how parameter values affect the performance of the chosen functions, so as to produce good predictions but also reduce the execution time. The new tools improved both the execution time and the predictive correctness of the system compared to the results obtained prior to our project. It is now nine times faster than before, and its correctness has improved by a factor of three. We believe our work leads to more accurate conflict predictions, and as ViEWS has strong connections to the European Union, we hope that decision makers can benefit from it when trying to prevent conflicts.
I detta projekt, vilket vi valt att benämna ViEWS+, har vi förbättrat olika aspekter av ViEWS (Violence Early-Warning System), ett system som med maskinlärning försöker förutsäga var i världen väpnade konflikter kommer uppstå. Målet med ViEWS är att kunna förutsäga sannolikheten för konflikter så långt som 36 månader i framtiden. Målet med att förutsäga sannoliketen för konflikter är att politiker och beslutsfattare ska kunna använda dessa kunskaper för att förhindra dem. Indata till systemet är konfliktdata med ett stort antal egenskaper, så som tidigare konflikter, barnadödlighet och urbanisering. Dessa är av varierande användbarhet, vilket skapar ett behov för att sålla ut de som inte är användbara för att förutsäga framtida konflikter. Innan vårt projekt har forskarna som använder ViEWS valt ut egenskaper för hand, vilket blir allt svårare i och med att fler introduceras. Forskargruppen hade även ingen formell metodik för att välja parametervärden till de maskinlärningsfunktioner de använder. De valde parametrar baserat på erfarenhet och känsla, något som kan leda till onödigt långa exekveringstider och eventuellt sämre resultat beroende på funktionen som används. Våra mål med projektet var att förbättra systemets produktivitet, i termer av exekveringstid och säkerheten i förutsägelserna. För att uppnå detta utvecklade vi analysverktyg för att försöka lösa de existerande problemen. Vi har utvecklat ett verktyg för att välja ut färre, mer användbara, egenskaper från datasamlingen. Detta gör att egenskaper som inte tillför någon viktig information kan sorteras bort vilket sparar exekveringstid. Vi har även jämfört prestandan hos olika maskinlärningsfunktioner, för att identifiera de bäst lämpade för konfliktprediktion. Slutligen har vi implementerat ett verktyg för att analysera hur resultaten från funktionerna varierar efter valet av parametrar. Detta gör att man systematiskt kan bestämma vilka parametervärden som bör väljas för att garantera bra resultat samtidigt som exekveringstid hålls nere. Våra resultat visar att med våra förbättringar sänkes exekveringstiden med en faktor av omkring nio och förutsägelseförmågorna höjdes med en faktor av tre. Vi hoppas att vårt arbete kan leda till säkrare föutsägelser och vilket i sin tur kanske leder till en fredligare värld.

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MACHIRAJU, SIRISHA. « SPACE ALLOCATION FOR MATERIALIZED VIEWS AND INDEXES USING GENETIC ALGORITHMS ». University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1029435112.

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Mami, Imene. « A Declarative Approach to Modeling and Solving the View Selection Problem ». Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20194/document.

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La matérialisation de vues est une technique très utilisée dans les systèmes de gestion bases de données ainsi que dans les entrepôts de données pour améliorer les performances des requêtes. Elle permet de réduire de manière considérable le temps de réponse des requêtes en pré-calculant des requêtes coûteuses et en stockant leurs résultats. De ce fait, l'exécution de certaines requêtes nécessite seulement un accès aux vues matérialisées au lieu des données sources. En contrepartie, la matérialisation entraîne un surcoût de maintenance des vues. En effet, les vues matérialisées doivent être mises à jour lorsque les données sources changent afin de conserver la cohérence et l'intégrité des données. De plus, chaque vue matérialisée nécessite également un espace de stockage supplémentaire qui doit être pris en compte au moment de la sélection. Le problème de choisir quelles sont les vues à matérialiser de manière à réduire les coûts de traitement des requêtes étant donné certaines contraintes tel que l'espace de stockage et le coût de maintenance, est connu dans la littérature sous le nom du problème de la sélection de vues. Trouver la solution optimale satisfaisant toutes les contraintes est un problème NP-complet. Dans un contexte distribué constitué d'un ensemble de noeuds ayant des contraintes de ressources différentes (CPU, IO, capacité de l'espace de stockage, bande passante réseau, etc.), le problème de la sélection des vues est celui de choisir un ensemble de vues à matérialiser ainsi que les noeuds du réseau sur lesquels celles-ci doivent être matérialisées de manière à optimiser les coût de maintenance et de traitement des requêtes.Notre étude traite le problème de la sélection de vues dans un environnement centralisé ainsi que dans un contexte distribué. Notre objectif est de fournir une approche efficace dans ces contextes. Ainsi, nous proposons une solution basée sur la programmation par contraintes, connue pour être efficace dans la résolution des problèmes NP-complets et une méthode puissante pour la modélisation et la résolution des problèmes d'optimisation combinatoire. L'originalité de notre approche est qu'elle permet une séparation claire entre la formulation et la résolution du problème. A cet effet, le problème de la sélection de vues est modélisé comme un problème de satisfaction de contraintes de manière simple et déclarative. Puis, sa résolution est effectuée automatiquement par le solveur de contraintes. De plus, notre approche est flexible et extensible, en ce sens que nous pouvons facilement modéliser et gérer de nouvelles contraintes et mettre au point des heuristiques pour un objectif d'optimisation.Les principales contributions de cette thèse sont les suivantes. Tout d'abord, nous définissons un cadre qui permet d'avoir une meilleure compréhension des problèmes que nous abordons dans cette thèse. Nous analysons également l'état de l'art des méthodes de sélection des vues à matérialiser en en identifiant leurs points forts ainsi que leurs limites. Ensuite, nous proposons une solution utilisant la programmation par contraintes pour résoudre le problème de la sélection de vues dans un contexte centralisé. Nos résultats expérimentaux montrent notre approche fournit de bonnes performances. Elle permet en effet d'avoir le meilleur compromis entre le temps de calcul nécessaire pour la sélection des vues à matérialiser et le gain de temps de traitement des requêtes à réaliser en matérialisant ces vues. Enfin, nous étendons notre approche pour résoudre le problème de la sélection de vues à matérialiser lorsque celui-ci est étudié sous contraintes de ressources multiples dans un contexte distribué. A l'aide d'une évaluation de performances extensive, nous montrons que notre approche fournit des résultats de qualité et fiable
View selection is important in many data-intensive systems e.g., commercial database and data warehousing systems to improve query performance. View selection can be defined as the process of selecting a set of views to be materialized in order to optimize query evaluation. To support this process, different related issues have to be considered. Whenever a data source is changed, the materialized views built on it have to be maintained in order to compute up-to-date query results. Besides the view maintenance issue, each materialized view also requires additional storage space which must be taken into account when deciding which and how many views to materialize.The problem of choosing which views to materialize that speed up incoming queries constrained by an additional storage overhead and/or maintenance costs, is known as the view selection problem. This is one of the most challenging problems in data warehousing and it is known to be a NP-complete problem. In a distributed environment, the view selection problem becomes more challenging. Indeed, it includes another issue which is to decide on which computer nodes the selected views should be materialized. The view selection problem in a distributed context is now additionally constrained by storage space capacities per computer node, maximum global maintenance costs and the communications cost between the computer nodes of the network.In this work, we deal with the view selection problem in a centralized context as well as in a distributed setting. Our goal is to provide a novel and efficient approach in these contexts. For this purpose, we designed a solution using constraint programming which is known to be efficient for the resolution of NP-complete problems and a powerful method for modeling and solving combinatorial optimization problems. The originality of our approach is that it provides a clear separation between formulation and resolution of the problem. Indeed, the view selection problem is modeled as a constraint satisfaction problem in an easy and declarative way. Then, its resolution is performed automatically by the constraint solver. Furthermore, our approach is flexible and extensible, in that it can easily model and handle new constraints and new heuristic search strategies for optimization purpose. The main contributions of this thesis are as follows. First, we define a framework that enables to have a better understanding of the problems we address in this thesis. We also analyze the state of the art in materialized view selection to review the existing methods by identifying respective potentials and limits. We then design a solution using constraint programming to address the view selection problem in a centralized context. Our performance experimentation results show that our approach has the ability to provide the best balance between the computing time to be required for finding the materialized views and the gain to be realized in query processing by materializing these views. Our approach will also guarantee to pick the optimal set of materialized views where no time limit is imposed. Finally, we extend our approach to provide a solution to the view selection problem when the latter is studied under multiple resource constraints in a distributed context. Based on our extensive performance evaluation, we show that our approach outperforms the genetic algorithm that has been designed for a distributed setting

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Brigo, Matteo <1984&gt. « Cost Effective Semi-Automatic Algorithm for Materialized Views Selection in Data Warehousing in distribuite environment ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2016. http://hdl.handle.net/10579/8372.

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L'analisi dei dati attraverso un sistema datawarehouse è sempre più presente e necessaria per permettere alle aziende una corretta politica decisionale. Con l'aumentare della quantità di informazioni presenti nei sistemi informativi è cruciale concentrarsi sulla ottimizzazione delle query per il recupero di informazioni dai sistemi aziendali, inoltre sempre più spesso le aziende dispongono di sistemi distribuiti eterogenei. Scopo di questa tesi è proporre un metodo per ottimizzare la velocità di reperimento delle informazioni, attraverso l'uso di viste materializzate, tenendo conto dei vincoli spaziali e della possibilità di avere sistemi con velocità di calcolo non omogenee. Per far ciò abbiamo dapprima analizzato alcuni algoritmi già presenti in letteratura, concentrandoci su pregi e difetti, in secondo luogo abbiamo presentato una versione modificata di un algoritmo per tener conto dei vincoli aggiuntivi da noi premessi. Infine abbiamo dato un esempio dell'algoritmo proposto e ne abbiamo confrontato il risultato con gli altri algoritmi descritti.

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Katsifodimos, Asterios. « Scalable view-based techniques for web data : algorithms and systems ». Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00870456.

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XML was recommended by W3C in 1998 as a markup language to be used by device- and system-independent methods of representing information. XML is nowadays used as a data model for storing and querying large volumes of data in database systems. In spite of significant research and systems development, many performance problems are raised by processing very large amounts of XML data. Materialized views have long been used in databases to speed up queries. Materialized views can be seen as precomputed query results that can be re-used to evaluate (part of) another query, and have been a topic of intensive research, in particular in the context of relational data warehousing. This thesis investigates the applicability of materialized views techniques to optimize the performance of Web data management tools, in particular in distributed settings, considering XML data and queries. We make three contributions.We first consider the problem of choosing the best views to materialize within a given space budget in order to improve the performance of a query workload. Our work is the first to address the view selection problem for a rich subset of XQuery. The challenges we face stem from the expressive power and features of both the query and view languages and from the size of the search space of candidate views to materialize. While the general problem has prohibitive complexity, we propose and study a heuristic algorithm and demonstrate its superior performance compared to the state of the art.Second, we consider the management of large XML corpora in peer-to-peer networks, based on distributed hash tables (or DHTs, in short). We consider a platform leveraging distributed materialized XML views, defined by arbitrary XML queries, filled in with data published anywhere in the network, and exploited to efficiently answer queries issued by any network peer. This thesis has contributed important scalability oriented optimizations, as well as a comprehensive set of experiments deployed in a country-wide WAN. These experiments outgrow by orders of magnitude similar competitor systems in terms of data volumes and data dissemination throughput. Thus, they are the most advanced in understanding the performance behavior of DHT-based XML content management in real settings.Finally, we present a novel approach for scalable content-based publish/subscribe (pub/sub, in short) in the presence of constraints on the available computational resources of data publishers. We achieve scalability by off-loading subscriptions from the publisher, and leveraging view-based query rewriting to feed these subscriptions from the data accumulated in others. Our main contribution is a novel algorithm for organizing subscriptions in a multi-level dissemination network in order to serve large numbers of subscriptions, respect capacity constraints, and minimize latency. The efficiency and effectiveness of our algorithm are confirmed through extensive experiments and a large deployment in a WAN.

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Karanasos, Konstantinos. « View-Based techniques for the efficient management of web data ». Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00755328.

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Data is being published in digital formats at very high rates nowadays. A large share of this data has complex structure, typically organized as trees (Web documents such as HTML and XML being the most representative) or graphs (in particular, graph-structured Semantic Web databases, expressed in RDF). There is great interest in exploiting such complex data, whether in an Open Data access model or within companies owning it, and efficiently doing so for large data volumes remains challenging. Materialized views have long been used to obtain significant performance improvements when processing queries. The principle is that a view stores pre-computed results that can be used to evaluate (possibly part of) a query. Adapting materialized view techniques to the Web data setting we consider is particularly challenging due to the structural and semantic complexity of the data. This thesis tackles two problems in the broad context of materialized view-based management of Web data. First, we focus on the problem of view selection for RDF query workloads. We present a novel algorithm, which, based on a query workload, proposes the most appropriate views to be materialized in the database, in order to minimize the combined cost of query evaluation, view maintenance and view storage. Although RDF query workloads typically feature many joins, hampering the view selection process, our algorithm scales to hundreds of queries, a number unattained by existing approaches. Furthermore, we propose new techniques to account for the implicit data that can be derived by the RDF Schemas and which further complicate the view selection process. The second contribution of our work concerns query rewriting based on materialized XML views. We start by identifying an expressive dialect of XQuery, corresponding to tree patterns with value joins, and study some important properties for these queries, such as containment and minimization. Based on these notions, we consider the problem of finding minimal equivalent rewritings of a query expressed in this dialect, using materialized views expressed in the same dialect, and provide a sound and complete algorithm for that purpose. Our work extends the state of the art by allowing each pattern node to return a set of attributes, supporting value joins in the patterns, and considering rewritings which combine many views. Finally, we show how our view-based query rewriting algorithm can be applied in a distributed setting, in order to efficiently disseminate corpora of XML documents carrying RDF annotations.

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Doubek, Petr. « Multi-view tracking and viewpoint selection ». Konstanz : Hartung-Gorre Verlag, 2005. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16071.

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Livres sur le sujet "Views selection"

Dore, Ashton, dir. Picasso on art : A selection of views. New York, N.Y : Da Capo, 1988.

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Carlson, Stephen P. Saugus memories : A selection of postcard views. Saugus, Mass : Saugus Historical Society, 1986.

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1951-, Engelbert Arthur, Pagel Maike et Borchers Wolf, dir. Cultrans : Ansichts-Sachen der Kunst = views of art. Würzburg : Königshausen & Neumann, 2005.

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A, Cornish Colin, dir. Royal Kingston's heritage : A selection of illustrations with captions. Nelson : Hendon, 1987.

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Murray, Thomas. Memorable Meath views : A selection of photographic views of Meath from the Lawrence and other collections. Trim ((4 Summerhill Rd., Trim, Co. Meath)) : T. Murray, 1986.

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Libraries, Newcastle City, dir. Gone-but not forgotten : A selection of photographs of Newcastle upon Tyne in the 1960's. 3^e éd. Newcastle upon Tyne : Newcastle City Libraries, 1985.

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Picasso, Pablo. Picasso on art : A selection of views [compiled by] Dore Ashton. New York, N.Y : Da Capo, 1988.

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Relations, United States Congress Senate Committee on Foreign. Nomination of Robert S. Gelbard : Report together with additional views. [Washington, D.C. ? : U.S. G.P.O., 1988.

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Hodler, Ferdinand. Ferdinand Hodler : Views & visions. Zurich : Swiss Institute for Art Research, 1994.

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Drymen and District Local History Society. Strathendrick in old photographs : A selection from Drymen and District Local History Society's collection. (Stirling) : Stirling District Libraries, 1990.

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Chapitres de livres sur le sujet "Views selection"

Vijay Kumar, T. V., et Mohammad Haider. « Materialized Views Selection for Answering Queries ». Dans Lecture Notes in Computer Science, 44–51. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-27872-3_7.

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Vázquez, Pere-Pau, et Mateu Sbert. « Fast Adaptive Selection of Best Views ». Dans Computational Science and Its Applications — ICCSA 2003, 295–305. Berlin, Heidelberg : Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-44842-x_31.

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Vijay Kumar, T. V., Mohammad Haider et Santosh Kumar. « A View Recommendation Greedy Algorithm for Materialized Views Selection ». Dans Information Intelligence, Systems, Technology and Management, 61–70. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19423-8_7.

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Kumar, Akshay, et T. V. Vijay Kumar. « Selection of Candidate Views for Big Data View Materialization ». Dans Lecture Notes in Electrical Engineering, 113–26. Singapore : Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-3067-5_10.

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Vijay Kumar, T. V., et Mohammad Haider. « Greedy Views Selection Using Size and Query Frequency ». Dans Communications in Computer and Information Science, 11–17. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-18440-6_2.

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Baril, Xavier, et Zohra Bellahséne. « Selection of Materialized Views : A Cost-Based Approach ». Dans Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 665–80. Cham : Springer International Publishing, 2003. http://dx.doi.org/10.1007/3-540-45017-3_44.

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Franconi, Enrico, et Paolo Guagliardo. « Translatable Updates of Selection Views under Constant Complement ». Dans Lecture Notes in Computer Science, 295–309. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-10085-2_27.

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Gupta, Himanshu. « Selection of views to materialize in a data warehouse ». Dans Lecture Notes in Computer Science, 98–112. Berlin, Heidelberg : Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/3-540-62222-5_39.

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Hlaváč, Václav, Aleš Leonardis et Tomáš Werner. « Automatic selection of reference views for image-based scene representations ». Dans Lecture Notes in Computer Science, 526–35. Berlin, Heidelberg : Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/bfb0015563.

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Deinzer, Frank, Joachim Denzler et Heinrich Niemann. « Viewpoint Selection – Planning Optimal Sequences of Views for Object Recognition ». Dans Computer Analysis of Images and Patterns, 65–73. Berlin, Heidelberg : Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-45179-2_9.

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Actes de conférences sur le sujet "Views selection"

Mokhtarian, F., et S. Abbasi. « Automatic Selection of Optimal Views in Multi-view ObjectRecognition ». Dans British Machine Vision Conference 2000. British Machine Vision Association, 2000. http://dx.doi.org/10.5244/c.14.28.

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Zhang, Baili, Le Yang, Zhikai Zhou, Hongjian Jiang, Ruizhao Liu et Jianxiong Han. « Preprocessor of Materialized Views Selection ». Dans 2018 1st International Cognitive Cities Conference (IC3). IEEE, 2018. http://dx.doi.org/10.1109/ic3.2018.00010.

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Tosic, Ivana, et Pascal Frossard. « Omnidirectional Views Selection for Scene Representation ». Dans 2006 International Conference on Image Processing. IEEE, 2006. http://dx.doi.org/10.1109/icip.2006.313009.

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Lei, Yingchun, Litang Yang, Qi Jiang et Chanle Wu. « Experimental Views on Neighbor Selection in BitTorrent ». Dans 2007 IFIP International Conference on Network and Parallel Computing Workshops (NPC 2007). IEEE, 2007. http://dx.doi.org/10.1109/npc.2007.122.

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Li, Xin, Xu Qian, Junlin Jiang et Ziqiang Wang. « Shuffled Frog Leaping Algorithm for Materialized Views Selection ». Dans 2010 Second International Workshop on Education Technology and Computer Science. IEEE, 2010. http://dx.doi.org/10.1109/etcs.2010.480.

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Werner, T., et A. Zisserman. « Model selection for automated reconstruction from multiple views ». Dans British Machine Vision Conference 2002. British Machine Vision Association, 2002. http://dx.doi.org/10.5244/c.16.3.

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Zhang, Qingzhou, Xia Sun et Ziqiang Wang. « An Efficient MA-Based Materialized Views Selection Algorithm ». Dans 2009 IITA International Conference on Control, Automation and Systems Engineering, CASE 2009. IEEE, 2009. http://dx.doi.org/10.1109/case.2009.111.

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Werner, T., V. Hlavac, A. Leonardis et T. Pajdla. « Selection of reference views for image-based representation ». Dans Proceedings of 13th International Conference on Pattern Recognition. IEEE, 1996. http://dx.doi.org/10.1109/icpr.1996.545994.

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Zhou, Lijuan, Chi Liu, Hongfeng Wang et Daixin Liu. « Selection of views to materialize using simulated annealing algorithms ». Dans AeroSense 2002, sous la direction de Belur V. Dasarathy. SPIE, 2002. http://dx.doi.org/10.1117/12.460207.

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Rapports d'organisations sur le sujet "Views selection"

McDonald, Catherine W., William Riddle et Christine Youngblut. STARS (Software Technology for Adaptable and Reliable Systems) Methodology Area Summary. Volume 2. Preliminary Views on the Software Life Cycle and Methodology Selection. Fort Belvoir, VA : Defense Technical Information Center, mars 1985. http://dx.doi.org/10.21236/ada163271.

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SAPOZHNIKOVA, S. M., et N. V. REICHERT. CONDITIONS FOR THE IMPLEMENTATION OF IMPORT SUBSTITUTION IN THE AGRICULTURAL SECTOR OF THE ECONOMY. Science and Innovation Center Publishing House, avril 2022. http://dx.doi.org/10.12731/2070-7568-2022-11-2-3-27-37.

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The article discusses different modern points of view on the problem of import substitution in the domestic agro-industrial complex. The authors outlined the necessary conditions for the implementation of import substitution in the seed sector: the creation of specialized companies for the selection of seed varieties necessary for agribusiness and a special agrarian zone, where a complete production chain will be organized from seed selection to their sale, as well as support and assistance in the form of subsidies from the state.

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Huang, Haohang, Erol Tutumluer, Jiayi Luo, Kelin Ding, Issam Qamhia et John Hart. 3D Image Analysis Using Deep Learning for Size and Shape Characterization of Stockpile Riprap Aggregates—Phase 2. Illinois Center for Transportation, septembre 2022. http://dx.doi.org/10.36501/0197-9191/22-017.

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Riprap rock and aggregates are extensively used in structural, transportation, geotechnical, and hydraulic engineering applications. Field determination of morphological properties of aggregates such as size and shape can greatly facilitate the quality assurance/quality control (QA/QC) process for proper aggregate material selection and engineering use. Many aggregate imaging approaches have been developed to characterize the size and morphology of individual aggregates by computer vision. However, 3D field characterization of aggregate particle morphology is challenging both during the quarry production process and at construction sites, particularly for aggregates in stockpile form. This research study presents a 3D reconstruction-segmentation-completion approach based on deep learning techniques by combining three developed research components: field 3D reconstruction procedures, 3D stockpile instance segmentation, and 3D shape completion. The approach was designed to reconstruct aggregate stockpiles from multi-view images, segment the stockpile into individual instances, and predict the unseen side of each instance (particle) based on the partial visible shapes. Based on the dataset constructed from individual aggregate models, a state-of-the-art 3D instance segmentation network and a 3D shape completion network were implemented and trained, respectively. The application of the integrated approach was demonstrated on re-engineered stockpiles and field stockpiles. The validation of results using ground-truth measurements showed satisfactory algorithm performance in capturing and predicting the unseen sides of aggregates. The algorithms are integrated into a software application with a user-friendly graphical user interface. Based on the findings of this study, this stockpile aggregate analysis approach is envisioned to provide efficient field evaluation of aggregate stockpiles by offering convenient and reliable solutions for on-site QA/QC tasks of riprap rock and aggregate stockpiles.

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Gurevitz, Michael, Michael E. Adams, Boaz Shaanan, Oren Froy, Dalia Gordon, Daewoo Lee et Yong Zhao. Interacting Domains of Anti-Insect Scorpion Toxins and their Sodium Channel Binding Sites : Structure, Cooperative Interactions with Agrochemicals, and Application. United States Department of Agriculture, décembre 2001. http://dx.doi.org/10.32747/2001.7585190.bard.

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Integrated pest management in modern crop protection may combine chemical and biological insecticides, particularly due to the risks to the environment and livestock arising from the massive use of non-selective chemicals. Thus, there is a need for safer alternatives, which target insects more specifically. Scorpions produce anti-insect selective polypeptide toxins that are biodegradable and non-toxic to warm-blooded animals. Therefore, integration of these substances into insect pest control strategies is of major importance. Moreover, clarification of the molecular basis of this selectivity may provide valuable information pertinent to their receptor sites and to the future design of peptidomimetic anti-insect specific substances. These toxins may also be important for reducing the current overuse of chemical insecticides if they produce a synergistic effect with conventional pesticides. Based on these considerations, our major objectives were: 1) To elucidate the three-dimensional structure and toxic-site of scorpion excitatory, "depressant, and anti-insect alpha toxins. 2) To obtain an initial view to the sodium channel recognition sites of the above toxins by generating peptide decoys through a phage display system. 3) To investigate the synergism between toxins and chemical insecticides. Our approach was to develop a suitable expression system for toxin production in a recombinant form and for elucidation of toxin bioactive sites via mutagenesis. In parallel, the mode of action and synergistic effects of scorpion insecticidal toxins with pyrethroids were studied at the sodium channel level using electrophysiological methods. Objective 1 was achieved for the alpha toxin, LqhaIT Zilberberg et al., 1996, 1997; Tugarinov et al., 1997; Froy et al., 2002), and the excitatory toxin, Bj-xtrIT (Oren et al., 1998; Froy et al., 1999; unpublished data). The bioactive surface of the depressant toxin, LqhIT2, has been clarified and a crystal of the toxin is now being analyzed (unpublished). Objective 2 was not successful thus far as no phages that recognize the toxins were obtained. We therefore initiated recently an alternative approach, which is introduction of mutations into recombinant channels and creation of channel chimeras. Objective 3 was undertaken at Riverside and the results demonstrated synergism between LqhaIT or AaIT and pyrethroids (Lee et al., 2002). Furthermore, negative cross-resistance between pyrethroids and scorpion toxins (LqhaIT and AaIT) was demonstrated at the molecular level. Although our study did not yield a product, it paves the way for future design of selective pesticides by capitalizing on the natural competence of scorpion toxins to distinguish between sodium channels of insects and vertebrates. We also show that future application of anti-insect toxins may enable to decrease the amounts of chemical pesticides due to their synergism.

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Katzir, Nurit, James Giovannoni, Marla Binzel, Efraim Lewinsohn, Joseph Burger et Arthur Schaffer. Genomic Approach to the Improvement of Fruit Quality in Melon (Cucumis melo) and Related Cucurbit Crops II : Functional Genomics. United States Department of Agriculture, janvier 2010. http://dx.doi.org/10.32747/2010.7592123.bard.

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Background: Genomics tools for enhancement of melon research, with an emphasis on fruit, were developed through a previous BARD project of the PIs (IS -333-02). These included the first public melon EST collection, a database to relay this information to the research community and a publicly available microarray. The current project (IS-3877- 06) aimed to apply these tools for identification of important genes for improvement of melon (Cucumis melo) fruit quality. Specifically, the research plans included expression analysis using the microarray and functional analyses of selected genes. The original project objectives, as they appeared in the approved project, were: Objective 1: Utilization of a public melon microarray developed under the existing project to characterize melon transcriptome activity during the ripening of normal melon fruit (cv. Galia) in order to provide a basis for both a general view of melon transcriptome activity during ripening and for comparison with existing transcriptome data of developing tomato and pepper fruit. Objective 2: Utilization of the same public melon microarray to characterize melon transcriptome activity in lines available in the collection of the Israeli group, focusing on sugar, organic acids and aroma metabolism, so as to identify potentially useful candidates for functional analysis and possible manipulation, through comparison with the general fruit development profile resulting from (1) above. Objective 3: Expansion of our existing melon EST database to include publicly available gene expression data and query tools, as the US group has done with tomato. Objective 4: Selection of 6-8 candidate genes for functional analysis and development of DNA constructs for repression or over-expression. Objective 5: Creation of transgenic melon lines, or transgenic heterologous systems (e.g. E. coli or tomato), to assess putative functions and potential as tools for molecular enhancement of melon fruit quality, using the candidate gene constructs from (4).

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Aharoni, Asaph, Zhangjun Fei, Efraim Lewinsohn, Arthur Schaffer et Yaakov Tadmor. System Approach to Understanding the Metabolic Diversity in Melon. United States Department of Agriculture, juillet 2013. http://dx.doi.org/10.32747/2013.7593400.bard.

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Fruit quality is determined by numerous genetic factors that affect taste, aroma, ‎color, texture, nutritional value and shelf life. To unravel the genetic components ‎involved in the metabolic pathways behind these traits, the major goal of the project was to identify novel genes that are involved in, or that regulate, these pathways using correlation analysis between genotype, metabolite and gene expression data. The original and specific research objectives were: (1) Collection of replicated fruit from a population of 96 RI lines derived from parents distinguished by great diversity in fruit development and quality phenotypes, (2) Phenotypic and metabolic profiling of mature fruit from all 96 RI lines and their parents, (3) 454 pyrosequencing of cDNA representing mRNA of mature fruit from each line to facilitate gene expression analysis based on relative EST abundance, (4) Development of a database modeled after an existing database developed for tomato introgression lines (ILs) to facilitate online data analysis by members of this project and by researchers around the world. The main functions of the database will be to store and present metabolite and gene expression data so that correlations can be drawn between variation in target traits or metabolites across the RI population members and variation in gene expression to identify candidate genes which may impact phenotypic and chemical traits of interest, (5) Selection of RI lines for segregation and/or hybridization (crosses) analysis to ascertain whether or not genes associated with traits through gene expression/metabolite correlation analysis are indeed contributors to said traits. The overall research strategy was to utilize an available recombinant inbred population of melon (Cucumis melo L.) derived from phenotypically diverse parents and for which over 800 molecular markers have been mapped for the association of metabolic trait and gene expression QTLs. Transcriptomic data were obtained by high throughput sequencing using the Illumina platform instead of the originally planned 454 platform. The change was due to the fast advancement and proven advantages of the Illumina platform, as explained in the first annual scientific report. Metabolic data were collected using both targeted (sugars, organic acids, carotenoids) and non-targeted metabolomics analysis methodologies. Genes whose expression patterns were associated with variation of particular metabolites or fruit quality traits represent candidates for the molecular mechanisms that underlie them. Candidate genes that may encode enzymes catalyzingbiosynthetic steps in the production of volatile compounds of interest, downstream catabolic processes of aromatic amino acids and regulatory genes were selected and are in the process of functional analyses. Several of these are genes represent unanticipated effectors of compound accumulation that could not be identified using traditional approaches. According to the original plan, the Cucurbit Genomics Network (http://www.icugi.org/), developed through an earlier BARD project (IS-3333-02), was expanded to serve as a public portal for the extensive metabolomics and transcriptomic data resulting from the current project. Importantly, this database was also expanded to include genomic and metabolomic resources of all the cucurbit crops, including genomes of cucumber and watermelon, EST collections, genetic maps, metabolite data and additional information. In addition, the database provides tools enabling researchers to identify genes, the expression patterns of which correlate with traits of interest. The project has significantly expanded the existing EST resource for melon and provides new molecular tools for marker-assisted selection. This information will be opened to the public by the end of 2013, upon the first publication describing the transcriptomic and metabolomics resources developed through the project. In addition, well-characterized RI lines are available to enable targeted breeding for genes of interest. Segregation of the RI lines for specific metabolites of interest has been shown, demonstrating the utility in these lines and our new molecular and metabolic data as a basis for selection targeting specific flavor, quality, nutritional and/or defensive compounds. To summarize, all the specific goals of the project have been achieved and in many cases exceeded. Large scale trascriptomic and metabolomic resources have been developed for melon and will soon become available to the community. The usefulness of these has been validated. A number of novel genes involved in fruit ripening have been selected and are currently being functionally analyzed. We thus fully addressed our obligations to the project. In our view, however, the potential value of the project outcomes as ultimately manifested may be far greater than originally anticipated. The resources developed and expanded under this project, and the tools created for using them will enable us, and others, to continue to employ resulting data and discoveries in future studies with benefits both in basic and applied agricultural - scientific research.

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Motel-Klingebiel, Andreas, et Gerhard Naegele. Exclusion and inequality in late working life in the political context of the EU. Linköping University Electronic Press, novembre 2022. http://dx.doi.org/10.3384/9789179293215.

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European societies need to increase the participation in work over the life course to support the provision of qualified labour and to meet the challenges for social security systems under the condition of their ageing populations. One of the key ambitions is to extend people’s working lives and to postpone labour market exit and retirement where possible. This requires informed policies, and the research programme EIWO – ‘Exclusion and Inequality in Late Working Life: Evidence for Policy Innovation towards Inclusive Extended Work and Sustainable Working Conditions in Sweden and Europe’ – aims to push the boundaries of knowledge about late working life and the potential of its inclusive and equal prolongation via a theoretically driven, gender-sensitive combination of multi-level perspectives. EIWO takes a life course approach on exclusion and inequality by security of tenure, quality of work, workplaces, and their consequences. It identifies life course policies, promoting lifelong learning processes and flexible adaptation to prolong working lives and to avoid increased exclusion and inequality. Moreover, it provides evidence for policies to ensure both individual, company and societal benefits from longer lives. To do so, EIWO orientates its analyses systematically to the macro-political contexts at the European Union level and to the policy goals expressed in the respective official statements, reports and plans. This report systematizes this ambitious approach. Relevant documents such as reports, green books and other publications of the European Commission (EC), the European Parliament (EP), the Organisation for Economic Co-operation and Development (OECD), as well as those of social partners and research institutions, have been systematically scanned and evaluated. In addition, relevant decisions of European summits have been considered. The selection of documents claims completeness regarding relevant and generally available publication, while relevance is defined from the point of view of EIWO’s interests. It is the aim of this report to provide a sound knowledge base for EIWO’s analyses and impact strategies and to contribute to the emerging research on the connection between population ageing and the European policies towards productivity, inclusiveness, equity, resilience and sustainability. This report aims to answer the following questions: How are EIWO’s conceptual classification and programme objectives reflected in the European Union’s policy programming? How can EIWO’s analyses and impact benefit from a reference to current EU policy considerations, and how does this focus support the outline of policy options and the formulating of possible proposals to Swedish and European stakeholders? The present report was written during early 2022; analyses were finalized in February 2022 and represent the status until this date.

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Mizrach, Amos, Sydney L. Spahr, Ephraim Maltz, Michael R. Murphy, Zeev Schmilovitch, Jan E. Novakofski, Uri M. Peiper et al. Ultrasonic Body Condition Measurements for Computerized Dairy Management Systems. United States Department of Agriculture, 1993. http://dx.doi.org/10.32747/1993.7568109.bard.

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The body condition (BC) score is recognized in the dairy industry as an essential tool for managing the energy reserves of the dairy cow, which is essential for sustaining optimal and efficient production over several lactations. The current use of BC scoring depends on the accuracy of subjective visual estimates, and this limits its kusefulness as a management aid in the dairy industry. A measuring tool that would frequently provide objective data on the cow's body reserves would be a major contribution to efficient dairy herd management. Ultrasonic sensors have the potential to be developed into an efficient BC measuring device, and the experimental use of such sensors for subcutaneous fat thickness (SDFT) estimates, as an indication for BC in beef cattle, supports this assumption. The purposes of this project were: 1. To compare visual BC scoring and ultrasonic fat thickness with on-line automated body weight (BW) measurements as monitors of nutritional adequacy of dairy cows at various stages of lactation. 2. To determine the effects of variation in digestive fill in early and late lactation on the accuracy of body weight measurements in lactating cows. 3. To modify an existing ultrasonic system and develop a specialized, low-cost sensor for repeatable determination of body condition scores by users with minimal training and skill. 4. To develop a standard for the assignment of body condition scores based on ultrasonic measurements of subdermal fat thickness. The procedure to execute these objectives involved: 1. Frequent measurement of BW, milk yield (MY), BC (visually scored) and subdermal fat thickness ultrasonically measured of dairy cows, and data analysis on average and individual basis. 2. Testing and selection of an appropriate special-purpose sensor, finding an optimum body location for working an ultrasonic measurement, prcessing the signals obtained, and correlating the resulting measurements with performance responses in lactating cows. Linking the ultrasonic signals to BC scores, and developing a BC scoring data acquisition system are the first steps towards fulfilling the necessary requirements for incorporating this device into an existing dairy herd management system, in order to provide the industry with a powerful managment tool. From the results obtained we could conclude that: 1. BC does not correlate with BW changes during all stages of lactation, although in general terms it does. These results were confirmed by individual cow BW and BC data obtained during the course of lactation, that were supported by individual objective ultrasonic measurement of SDFT. 2. BW changes reflect energy metabolism reliably ony after peak milk yield; early in lactation, a decrease in BW expresses mobilization of body reserves only qualitatively, and not quantitatively. 3. Gastrointestinal content increases throughout the whole period during which dry matter intake (DMI) increases. The drastic increase very early in lactation prevents the use of BW changes as a basis for quantitative estimatio of energy meatabolism; at this stage of lactation, konly a BC score or any other direct measurements willl provide a quantitative estimate of energy metabolism. 4. Ultrasonic measurements of subdermal fat thickness can be used to quantify changes that correlate with the actual condition of the cow, as assessed by performance and the traditional way of scoring. 5. To find the best site on the cow's body at which to obtain responses to BC and its changes in the course of lactation, additional sites have to be examined. From the present study, it seems that the sites between ribs 12 and 13 have the potential for this purpose. 6. The use of templates made it easier to repeat measurements at a desired site and spot. However, the convenient easy-to-handle way to standardize the measurement, described in this study, koffers scope for improvement. 7. The RF peak values of the A-mode are better indicators of the location of fat layer borders than image analysis, from the point of view of future commercial development. 8. The distances between the RF peaks of the A-mode can be automatically measured by suitable software, for future commercial development. 9. Proper analysis of daily body weight and milk yield data can provide the necessary information on body condition changes during lactation, until a direct BC measurement device is developed. 10. In any case, at least one visual BC assessment has to be done, preferably immediately after calving, for calibration purposes.

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