16,074 research outputs found
Category-theoretical Semantics of the Description Logic ALC (extended version)
Category theory can be used to state formulas in First-Order Logic without
using set membership. Several notable results in logic such as proof of the
continuum hypothesis can be elegantly rewritten in category theory. We propose
in this paper a reformulation of the usual set-theoretical semantics of the
description logic ALC by using categorical language. In this setting, ALC
concepts are represented as objects, concept subsumptions as arrows, and
memberships as logical quantifiers over objects and arrows of categories. Such
a category-theore\-tical semantics provides a more modular representation of
the semantics of and a new way to design algorithms for
reasoning.Comment: 14 page
MODELING AND SIMULATION OF A LEAN SYSTEM. CASE STUDY OF A PAINT LINE IN A FURNITURE COMPANY
Since they were first developed, lean methodologies have grown in importance and scope and have been applied in both manufacturing and service. However, determining how to transform a common manufacturing company into a lean one, as well as how to evaluate the future company, are challenges for both researchers and manufacturers. This paper presents a case study of a lean manufacturing implementation for the paint line system in a furniture company. A systematic method for execution is shown. In addition, a simulation model is constructed to evaluate the new system in comparison with the MRP system. The new system promises much improvement in terms of a resource’s utility and the system’s productivity.Lean Techniques, Simulation Model, Paint Line, Furniture Company.
Supervised machine learning based multi-task artificial intelligence classification of retinopathies
Artificial intelligence (AI) classification holds promise as a novel and
affordable screening tool for clinical management of ocular diseases. Rural and
underserved areas, which suffer from lack of access to experienced
ophthalmologists may particularly benefit from this technology. Quantitative
optical coherence tomography angiography (OCTA) imaging provides excellent
capability to identify subtle vascular distortions, which are useful for
classifying retinovascular diseases. However, application of AI for
differentiation and classification of multiple eye diseases is not yet
established. In this study, we demonstrate supervised machine learning based
multi-task OCTA classification. We sought 1) to differentiate normal from
diseased ocular conditions, 2) to differentiate different ocular disease
conditions from each other, and 3) to stage the severity of each ocular
condition. Quantitative OCTA features, including blood vessel tortuosity (BVT),
blood vascular caliber (BVC), vessel perimeter index (VPI), blood vessel
density (BVD), foveal avascular zone (FAZ) area (FAZ-A), and FAZ contour
irregularity (FAZ-CI) were fully automatically extracted from the OCTA images.
A stepwise backward elimination approach was employed to identify sensitive
OCTA features and optimal-feature-combinations for the multi-task
classification. For proof-of-concept demonstration, diabetic retinopathy (DR)
and sickle cell retinopathy (SCR) were used to validate the supervised machine
leaning classifier. The presented AI classification methodology is applicable
and can be readily extended to other ocular diseases, holding promise to enable
a mass-screening platform for clinical deployment and telemedicine.Comment: Supplemental material attached at the en
Effects of stopping the Mediterranean Outflow on the southern polar region
The extent to which the southern polar region is sensitive to the stopping of the Mediterranean Outflow is investigated by using a global ocean-atmosphere coupled model. Two experimental runs, one(named the control run) with and the other(named the NMOW run) without exchanges of heat and salinity between the Mediterranean Sea and the Atlantic Ocean, are carried out in order to simulate the presence and absence of the outflow. Large responses in the sea surface temperature are found in both the northern North Atlantic and the Southern Ocean. For the NMOW run, the response in the Southern Ocean shows general decreases in sea surface temperature and salinity over a millenial timescale. Sea-ice thickness mostly increases, but is reduced in regions associated with increased sea surface temperature. The freshening of the Southern Ocean brings about a decrease in the density difference between the southern polar regions and the tropics. Consequently, the meridional overturning which transports Antarctic Bottom Water decreases
Line Bundles and Curves on a del Pezzo Order
Orders on surfaces provide a rich source of examples of noncommutative
surfaces. Other than some existence results, very little is known about the
various moduli spaces that can be associated to them. Even fewer examples have
been explicitly computed. In this paper we compute the Picard and Hilbert
schemes of an order on the projective plane ramified on a union of two conics.
Our main result is that, upon carefully selecting the right Chern classes, the
Hilbert scheme is a ruled surface over a genus two curve. Furthermore, this
genus two curve is, in itself, the Picard scheme of the order
A distributed multi-agent framework for shared resources scheduling
Nowadays, manufacturers have to share some of their resources with partners due to the competitive economic environment. The management of the availability periods of shared resources causes a problem because it is achieved by the scheduling systems which assume a local environment where all resources are on the same site. Therefore, distributed scheduling with shared resources is an important research topic in recent years. In this communication, we introduce the architecture and behavior of DSCEP framework (distributed, supervisor, customer, environment, and producer) under shared resources situation with disturbances. We are using a simple example of manufacturing system to illustrate the ability of DSCEP framework to solve the shared resources scheduling problem in complex systems
Identification of significant factors for air pollution levels using a neural network based knowledge discovery system
Artificial neural network (ANN) is a commonly used approach to estimate or forecast air pollution levels, which are usually assessed by the concentrations of air contaminants such as nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone, and suspended particulate matters (PMs) in the atmosphere of the concerned areas. Even through ANN can accurately estimate air pollution levels they are numerical enigmas and unable to provide explicit knowledge of air pollution levels by air pollution factors (e.g. traffic and meteorological factors). This paper proposed a neural network based knowledge discovery system aimed at overcoming this limitation in ANN. The system consists of two units: a) an ANN unit, which is used to estimate the air pollution levels based on relevant air pollution factors; b) a knowledge discovery unit, which is used to extract explicit knowledge from the ANN unit. To demonstrate the practicability of this neural network based knowledge discovery system, numerical data on mass concentrations of PM2.5 and PM1.0, meteorological and traffic data measured near a busy traffic road in Hangzhou city were applied to investigate the air pollution levels and the potential air pollution factors that may impact on the concentrations of these PMs. Results suggest that the proposed neural network based knowledge discovery system can accurately estimate air pollution levels and identify significant factors that have impact on air pollution levels
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