Search results for "Abstract data type"
showing 10 items of 1140 documents
Nonnegative signal factorization with learnt instrument models for sound source separation in close-microphone recordings
2013
Close-microphone techniques are extensively employed in many live music recordings, allowing for interference rejection and reducing the amount of reverberation in the resulting instrument tracks. However, despite the use of directional microphones, the recorded tracks are not completely free from source interference, a problem which is commonly known as microphone leakage. While source separation methods are potentially a solution to this problem, few approaches take into account the huge amount of prior information available in this scenario. In fact, besides the special properties of close-microphone tracks, the knowledge on the number and type of instruments making up the mixture can al…
Process parameters influence in additive manufacturing
2016
Additive manufacturing is a rapidly expanding technology. It allows the creation of very complex 3D objects by adding layers of material, in spite of the traditional production systems based on the removal of material. The development of additive technology has produced initially a generation of additive manufacturing techniques restricted to industrial applications, but their extraordinary degree of innovation has allowed the spreading of household systems. Nowadays, the most common domestic systems produce 3D parts through a fused deposition modeling process. Such systems have low productivity and make, usually, objects with no high accuracy and with unreliable mechanical properties. Thes…
Left-star order structure of Rickart *-rings
2015
Janowitz proved in 1983 that the initial segments of a Rickart *-ring with the star order are orthomodular posets. In this paper, the same result is proved for the left-star order , which was introduced by Marovtet al., by finding an orthogonality which corresponds to in a certain way and then applying a result proved by Cīrulis which states that the initial segments of any quasi-orthomodular set are orthomodular.
Square Ring Compression: Numerical Simulation and Experimental Tests
1996
In the upsetting process of square rings buckling problems often arise, depending on the geometry of the ring and on the frictional conditions at the punch-workpiece interface, yielding to the practical unacceptability of the forged component. Consequently in order to make up a set of rules to be introduced in an expert system able to assist the designer of cold forming sequences, a knowledge base has been built up, by means of a set of numerical simulations, the results of which have been validated by several experimental tests.
DECENTRALIZED SUBSPACE PROJECTION IN LARGE NETWORKS
2018
A great number of applications in wireless sensor networks involve projecting a vector of observations onto a subspace dictated by prior information. Accomplishing such a task in a centralized fashion entails great power consumption, congestion at certain nodes, and suffers from robustness issues. A sensible alternative is to compute such projections in a decentralized fashion. To this end, recent works proposed schemes based on graph filters, which compute projections exactly with a finite number of local exchanges among sensor nodes. However, existing methods to obtain these filters are confined to reduced families of projection matrices or small networks. This paper proposes a method tha…
What to Expect and What to Focus on in SQL Query Teaching
2019
In the process of learning a new computer language, writing erroneous statements is part of the learning experience. However, some errors persist throughout the query writing process and are never corrected. Structured Query Language (SQL) consists of a number of different concepts such as expressions, joins, grouping and ordering, all of which by nature invite different possible errors in the query writing process. Furthermore, some of these errors are relatively easy for a student to fix when compared to others. Using a data set from three student cohorts with the total of 744 students, we set out to explore which types of errors are persistent, i.e., more likely to be left uncorrected by…
An Information Aggregation and Analytics System for ATLAS Frontier
2019
International audience; ATLAS event processing requires access to centralized database systems where information about calibrations, detector status and data-taking conditions are stored. This processing is done on more than 150 computing sites on a world-wide computing grid which are able to access the database using the Squid-Frontier system. Some processing workflows have been found which overload the Frontier system due to the Conditions data model currently in use, specifically because some of the Conditions data requests have been found to have a low caching efficiency. The underlying cause is that non-identical requests as far as the caching are actually retrieving a much smaller num…
The Effects of Database Complexity on SQL Query Formulation
2020
In Structured Query Language (SQL) education, students often execute queries against a simple exercise database. Recently, databases that are more realistic have been utilized to the effect that students find exercises more interesting and useful, as these databases more accurately mimic databases students are likely to encounter in their future work environments. However, using even the most engaging database can be counterproductive to learning, if a student is not able to formulate correct queries due to the complexity of the database schema. Scientific evidence on the effects of database complexity on student’s query formulation is limited, and with queries from 744 students against thr…
Layer thickness optimisation in a laminated composite
1997
Abstract The paper describes a method to optimise the thickness balance within a composite laminate with layers oriented according to a limited set of angles. The laminate must be symmetric, balanced and loaded in-plane. The optimisation process is particularly suited to be used in conjunction with a finite element program. It provides the designer with the optimal overall engineering characteristics anda list of all the possible orientation combinations ranked with respect to their safety factor. The optimisation method is based on the first order gradient optimum search method and operates iteratively in the engineering elastic characteristics field. The cost function implemented up to no…
Development of a process for the treatment of synthetic wastewater without energy inputs using the salinity gradient of wastewaters and a reverse ele…
2019
Abstract Electrochemical processes are considered very effective methods for the treatment of wastewater contaminated by organics resistant to conventional biological processes and various inorganic pollutants. Large sites that treat wastewaters usually deal with a large number of waters often characterized by different salinity contents, that could be potentially used to provide the energy necessary for the electrochemical remediation. Hence, in this work a reverse electrodialysis (RED) process for the treatment of synthetic wastewaters contaminated by organics, without energy inputs, using the salinity gradient of different wastewaters, was studied, for the first time. It was found that t…