Solução rasterizada para o problema de empacotamento de fita irregular utilizando a Montanha Voronoi.

O empacotamento irregular de fita é um grupo de problemas na área de corte e empacotamento, cuja aplicação é observada nas indústrias têxtil, moveleira e construção naval. O problema consiste em definir uma configuração de itens irregulares de modo que o comprimento do contêiner retangular que contém o leiaute seja minimizado. A solução deve ser válida, isto é, não deve haver sobreposição entre os itens, que não devem extrapolar as paredes do contêiner. Devido a aspectos práticos, são admitidas até quatro orientações para o item. O volume de material desperdiçado está diretamente relacionado à qualidade do leiaute obtido e, por este motivo, uma solução eficiente pressupõe uma vantagem econômica e resulta em um menor impacto ambiental. O objetivo deste trabalho consiste na geração automática de leiautes de modo a obter níveis de compactação e tempo de processamento compatíveis com outras soluções na literatura. A fim de atingir este objetivo, são realizadas duas propostas de solução. A primeira consiste no posicionamento sequencial dos itens de modo a maximizar a ocorrência de posições de encaixe, que estão relacionadas à restrição de movimento de um item no leiaute. Em linhas gerais, várias sequências de posicionamentos são exploradas com o objetivo de encontrar a solução mais compacta. Na segunda abordagem, que consiste na principal proposta deste trabalho, métodos rasterizados são aplicados para movimentar itens de acordo com uma grade de posicionamento, admitindo sobreposição. O método é baseado na estratégia de minimização de sobreposição, cujo objetivo é a eliminação da sobreposição em um contêiner fechado. Ambos os algoritmos foram testados utilizando o mesmo conjunto de problemas de referência da literatura. Foi verificado que a primeira estratégia não foi capaz de obter soluções satisfatórias, apesar de fornecer informações importantes sobre as propriedades das posições de encaixe. Por outro lado, a segunda abordagem obteve resultados competitivos. O desempenho do algoritmo também foi compatível com outras soluções, inclusive em casos nos quais o volume de dados era alto. Ademais, como trabalho futuro, o algoritmo pode ser estendido de modo a possibilitar a entrada de itens de geometria genérica, o que pode se tornar o grande diferencial da proposta.

Lente de contacto híbrida de geometría inversa en córnea irregular con presencia de isla central tras cirugía LASIK

La lente híbrida de geometría inversa PS ofrece una mejoría de la calidad visual en pacientes con córneas irregulares tras cirugía refractiva miópica, mostrándose como una excelente opción en aquellos casos en que el insuficiente lecho corneal imposibilita retratamientos posteriores.

Wavefront-Guided Laser Treatment Using a High-Resolution Aberrometer to Measure Irregular Corneas: A Pilot Study

PURPOSE: To evaluate in a pilot study the visual, refractive, corneal topographic, and aberrometric changes after wavefront-guided LASIK or photorefractive keratectomy (PRK) using a high-resolution aberrometer to calculate the treatment for aberrated eyes. METHODS: Twenty aberrated eyes of 18 patients undergoing wavefront-guided LASIK or PRK using the VISX STARS4IR excimer laser and the iDesign aberrometer (Abbott Medical Optics, Inc., Santa Ana, CA) were enrolled in this prospective study. Three groups were differentiated: keratoconus post-CXL group including 11 keratoconic eyes (10 patients), post-LASIK group including 5 eyes (5 patients) with previous decentered LASIK treatments, and post-RK group including 4 eyes (3 patients) with previous radial keratotomy. Visual, refractive, contrast sensitivity, corneal topographic, and ocular aberrometric changes were evaluated during a 6-month follow-up. RESULTS: An improvement in uncorrected (UDVA) and corrected visual acuity (CDVA) associated with a reduction in the spherical equivalent was observed in the three groups, but was only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). All eyes gained one or more lines of CDVA after surgery. Improvements in contrast sensitivity were observed in the three groups, but they were only statistically significant in the keratoconus post-CXL and post-LASIK groups (P ≤ .04). Regarding aberrations, a reduction was observed in trefoil aberrations in the keratoconus post-CXL group (P = .05) and significant reductions in higher-order and primary coma aberrations in the post-LASIK group (P = .04). CONCLUSIONS: Wavefront-guided laser enhancements using the evaluated platform seem to be safe and effective to restore the visual function in aberrated eyes.

Accounts with Benjamin Huntington, 1785-1787

This folder contains two handwritten copies of the accounts between Reverend Andrew Croswell of Boston, and Croswell's executor William Croswell, and Benjamin Huntington, for money collected from Col. Gallup between 1785 and 1787.

Accounts related to maps and pamphlets, 1809-1823

This folder contains eight handwritten account statements and notes primarily related to the collection of subscriptions for Croswell's maps and pamphlets, as well as the disbursement and storage of his printed maps and pamphlets.

Student accounts in commons, 1772-1778

This small volume, sewn without a backing, contains student accounts in commons, with the dates students entered and left the College.

Audited accounts, 1713-1745

The parchment-bound hardcover folio volume contains the Steward's accounts with the College from March 20, 1712/13 through August 9, 1745. The accounts are arranged as Harvard College's debits to the Steward with entries listing the Steward's expenses for students, salaries, and provisions and equipment, and the Steward's credits collected from the quarterly bills, arranged by type of charge (such as study rent, payments from the Butler, and repairs).

Accounts with Harvard College, 1719-1722

The thin paper-covered notebook contains the Steward's accounts with Harvard College kept by Steward Andrew Bordman II from 1719-1722. Arranged by quarters, the entries list money collected by the Steward from students, and money paid for food supplies, household provisions, the Butler's salary, and for services provided to the College.

Accounts with Harvard College, 1733-1745

The paper covered notebook contains the Steward's accounts with Harvard College kept by Steward Andrew Bordman II from 1733-1745.

Accounts with Harvard College, 1745-1753, 1764

The folio-sized paper covered notebook contains Steward Andrew Bordman III's accounts with Harvard College from 1745-1753. The final page of text, signed on September 19, 1764 by Bordman's son, Andrew Bordman IV, settles the accounts.

Notebook describing scholars' and church fathers' accounts of the Resurrection, undated

This notebook contains prose entries about many different scholars' accounts of Jesus Christ's Resurrection. Prince apparently studied over fifty authors' writings concerning the Resurrection and recorded in this notebook what he considered to be the significant details of each authors' interpretation.

[Salary and Treasury calculations and accounts], 1801

Three leaves with handwritten calculations and account information related to faculty salaries, the assignments on delinquents, rents, and repairs. One leaf is inscribed "R. Hallowell Feb. 28 1801" and likely refers to Robert Hallowell (later Gardiner), a member of the Harvard Class of 1801.