Vieira, Andre Mozart de Miranda
2008-07-01
In this work, absorbed dose to water produced by the radiation beam of a clinical linear accelerator - CLINAC 600C{sup TM} (Varian), with a photon beam of 6 MV, were evaluated both theoretically and experimentally. This determination includes square and circular field configurations, the last one obtained with a micro multi leaf collimator - mMLC m3{sup TM} (Brain Lab). Theoretical evaluation was performed throughout Monte Carlo method. Experimental measurements of Percentage Depth Dose - PDD and derived Tissue Maximum Ratio - TMR curves from CLINAC 600C were validated by comparison with reference values as well as with measurements using different detectors. The results indicate local differences smaller than 5% and average differences smaller than 1,5% for each evaluated field, if they are compared to the previous commissioning values (made in 1999) and to the values of literature. Comparisons of ionization chamber and diode result in an average local difference of -0,6% for PDD measurements, and within 1% for lateral dose profiles, at depth, in the flat region. Diode provides measurements with better spatial resolution. Current output factors of open fields agree with reference values within 1,03% of discrepancy level. Current absorbed dose distributions in water are, now, considered reference values and allow characterization of this CLINAC for patient dose calculation. The photon spectra resulting from simulations with PENELOPE and MCNP codes agree approximately in 80% of the sampled points, in what average energies of (1,6 {+-} 0,3)MeV, with MCNP, and of (1,72 {+-} 0,08)MeV, with PENELOPE, are coincident. The created simple source model of the CLINAC 600C, using the PENELOPE code, allows one to calculate dose distributions in water, for open fields, with discrepancies of the order of {+-} 1,0% in dose and of {+-} 0,1 cm in position, if they are compared to experimental measurements. These values met the initial proposed criteria to validate the simulation
Oliva, Jose de Jesus Rivero, E-mail: rivero@con.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Departamento de Engenharia Nuclear; Sousa, Fernando Nuno Carneiro de, E-mail: fernandonunosousa@gmail.com [Aceletron Irradiacao lndustrial, Rio de Janeiro, RJ (Brazil)
2013-07-01
The electron linear accelerators can be used in industrial applications that require powerful sources of ionizing radiation. They have the important characteristic of not representing a radiation hazard when the accelerators remain electrically disconnected. With the plant in operation, a high reliability defense in depth reduces the risk of radiological accidents to extremely small levels. It is practically impossible that a person could enter into the radiation bunker with the accelerators connected. Aceletron Irradiacao Industrial, located in Rio de Janeiro, offers services of irradiation by means of two powerful electron linear accelerators, with 15 kW power and 10 MeV electron energy. Despite the high level of existing radiation safety, a simplified risk study is underway to identify possible sequences of radiological accidents. The study is based on the combined application of the event and fault trees techniques. Preliminary results confirm that there is a very small risk of entering into the irradiation bunker with the accelerators in operation, but the risk of an operator entering into the bunker during a process interruption and remaining there without notice after the accelerators were restarted may be considerably larger. Based on these results the Company is considering alternatives to reduce the likelihood of human error of this type that could lead to a radiological accident. The paper describes the defense in depth of the irradiation process in Aceletron Irradiacao Industrial, as well as the models and preliminary results of the ongoing risk analysis, including the additional safety measures which are being evaluated. (author)
Sérgio Carlos Barros Esteves
2008-04-01
variables no statistically significant correlation was observed between occlusion and treatment complications.OBJETIVO: Analisar os resultados obtidos com radiocirurgia e as suas complicações do procedimento, no tratamento das malformações arteriovenosas com acelerador linear. MÉTODOS: Este é um estudo retrospectivo. Entre Outubro de 93 e Dezembro de 96, sessenta e um pacientes com malformações arteriovenosas foram tratados, utilizando um acelerador linear com 6MV de energia. As idades variaram de 6 a 54 anos (média: 28,3 anos, 32 pacientes mulheres e 29 pacientes homens. O sintoma inicial mais freqüente foi cefaléia (45,9%, seguido de déficit neurológico (36,1%. Hemorragia cerebral diagnostica por exame de imagem foi observada em 35 pacientes (57,3%. A maioria das malformações arteriovenosas (67,2% eram graus III e IV de Spetzler. Estenose venosa (21,3% e aneurisma (13,1% foram as mais freqüentes alterações da arquitetura vascular. A dose administrada variou de 12 a 27,5Gy na periferia da lesão. RESULTADOS: Dos vinte e oito pacientes que se submeteram a controle angiográfico conclusivo, 18 tiveram obliteração completa (72% e 7 falharam ao tratamento (ausência de oclusão com mais de três anos de seguimento. Quatro pacientes foram submetidos a uma segunda radiocirurgia, e um paciente deste grupo apresentou obliteração em 18 meses de seguimento. DISCUSSÃO: Vários fatores foram analisados em relação ao grau de oclusão (sexo, idade, volume, localização, Spetzler, fluxo, embolização, total de isocentros, dose prescrita e isodose escolhida e complicações (total de isocentros, localização, volume, dose máxima, dose prescrita e isodose escolhida. As variáveis analisadas não mostraram significância estatística para a obliteração do vaso, bem como para as complicações de tratamento. O maior diâmetro da malformação arteriovenosa, seu volume e a dose administrada não influenciaram no tempo de obliteração. CONCLUSÃO: Radiocirurgia
Lívia Almeida Fortunato
2015-12-01
Full Text Available A radioterapia é um tratamento eficaz contra o câncer de mama que tem a finalidade de destruir as células neoplásicas. Entretanto, pode produzir efeitos adversos causando alterações importantes na qualidade de vida (QV das pacientes durante e após o tratamento. Assim, essa pesquisa que tem por objetivo comparar a qualidade de vida de mulheres com câncer de mama no início e após se submeterem a radioterapia com acelerador linear. O estudo foi realizado no hospital denominado OncoBeda, na cidade de Campos dos Goytacazes - RJ. A amostra foi composta por 20 pacientes do gênero feminino, com idade entre 33 a 87 anos. As mesmas responderam nos momentos pré e pós tratamento ao Instrumento WHOQOL-bref, composto por 26 questões, sendo 2 questões gerais sobre auto avaliação da QV e as outras 24 questões que envolvem 4 domínios, sendo eles “físico”, “psicológico”, “relações sociais” e “meio ambiente”. Os resultados obtidos revelam que houve uma diferença ligeiramente significativa no domínio “físico”, influenciando na avaliação geral da QV dessas pacientes. Sendo assim, conclui-se que mesmo não tendo um valor elevado de diferença entre os dois momentos avaliados, as pacientes apresentaram alteração na sua QV durante o tratamento.
Sérgio Carlos Barros Esteves; Wladimir Nadalin; Ronie Leo Piske; Salomon Benabou; Evandro de Souza MD; Antonio Carlos Zuliani de Oliveira
2008-01-01
OBJECTIVE: To evaluate results achieved with radiosurgery and complications of the procedure when treating arteriovenous malformations with linear accelerator. METHODS: This retrospective study was conducted between October 1993 and December 1996. Sixty-one patients with arteriovenous malformations were treated with radiosurgery utilizing a 6MV energy linear accelerator. Ages of the 32 female and 29 male patients ranged from 6 to 54 years (mean: 28.3 years). The most frequent initial symptom ...
Maria da Penha Silva
2001-10-01
Full Text Available Um programa de garantia da qualidade é um pré-requisito obrigatório para a exatidão necessária em radioterapia. Este trabalho relata parte dos testes de rotina mensal do controle da qualidade dos aceleradores lineares do Instituto Nacional do Câncer, relativos à calibração dos feixes de fótons e elétrons, no período de dois anos. Os resultados foram comparados com as recomendações do protocolo AAPM TG-40. Na análise do fator de calibração para o feixe de fótons foi encontrado um desvio máximo de 12%; para o feixe de elétrons o maior desvio encontrado foi 10%. A flutuação observada no indicador da qualidade do feixe para os feixes de elétrons foi maior que para os feixes de fótons. Os resultados confirmam a importância de um programa de garantia da qualidade em um serviço de radioterapia, permitindo correções rápidas da dose administrada ao paciente.A quality assurance program is a mandatory prerequisite for obtaining the high level of accuracy required for radiotherapy. This paper reports the results of part of the routine quality control tests for linear accelerators at the National Cancer Institute, Brazil, performed monthly over a period of two years. These tests included dose output and beam quality indicator. The results were compared with the guidelines of the AAPM TG-40 protocol. The results for the photon beams have shown dose output variations of up to 12%; for electron beams, the largest deviation found was 10%. The fluctuations observed in the beam quality indicator for the electron beams were greater than for the photon beams. These results strongly emphasize the importance of a quality assurance program in radiotherapy services in order to allow prompt corrections of the dose delivered to the patient.
Goncalves, Leandro R.; Santos, Gabriela R.; Menegussi, Gisela; Silva, Marco A.; Passaro, Anderson M.; Rodrigues, Laura N., E-mail: leandrorg11@hotmail.com [Instituto do Cancer do Estado de Sao Paulo (ICESP), Sao Paulo, SP (Brazil)
2013-08-15
Radiotherapy techniques like VMAT allow complex dose distributions modulating the beam intensity within the irradiation field from the handling of multi-blade collimators, variations in dose rate, different speeds of rotation of the gantry and collimator angle allowing greater conformation of the dose to the tumor volume and a lower dose to healthy tissues. To ensure proper dose delivery, the linear particle accelerator must be able to monitor and perform all the variation in these parameters simultaneously. In this work dosimetric tests obtained in the literature that aims to commission, implement and ensure the quality of VMAT treatments were performed performed in the Institute of Cancer of Sao Paulo State (ICESP). From the results obtained it was established a program of quality control for the linear accelerator studied. The linearity and stability response of ionization chamber monitoring, leafs accuracy positioning, flatness and symmetry of beam to VMAT irradiations were evaluated. The obtained results are in agreement with the literature. It can be concluded that the accelerator studied is able to satisfactorily control the variation of all necessary parameters to perform the VMAT treatments. (author)
Soares, Alessandro Facure Neves de Salles
2006-04-15
Medical linear accelerators, with maximum photon energies above 10 MeV, are becoming of common use in Brazil. Although desirable in the therapeutic point of view, the increase in photon energies causes the generation of undesired neutrons, which are produced through nuclear reactions between photons and the high Z target nuclei of the materials that constitute the accelerator head. In this work, MCNP simulation was undertaken to examine the neutron equivalent doses around the accelerators head and at the entrance of medical linear accelerators treatment rooms, some of them licensed in Brazil by the National Regulatory Agency (CNEN). The simulated neutron dose equivalents varied between 2 e 26 {mu} Sv/Gy{sub RX}, and the results were compared with calculations performed with the use of some semi-empirical equations found in literature. It was found that the semi-empirical equations underestimate the simulated neutron doses in the majority of the cases, if compared to the simulated values, suggesting that these equations must be revised, due to the increasing number of high energy machines in the country. (author)
Gutt, F.; Silva, P.; Guerrero, R.; Diaz, J.; Colmenares, J. [Instituto Venezolano de Investigaciones Cientificas (IVIC), Laboratorio Secundario de Calibracion Dosimetrica (LSCD), Apartado 21827, Caracas 1020 A (Venezuela)
1998-12-31
The objective of the present work is to find a physical mathematical model based on the reason of the dose percentages at 10 and 20 cm depth, at 100 cm DFS and a 10 x 10 cm{sup 2} field. It was utilized literature data of new manufactured accelerators and those are in use in hospitals, which allow to prove the model under different conditions. Our objective consists only to obtain a model that verifies the nominal potential for a linear accelerator, but without pretending that such a model to be used to calculate any one factor to determination of absorbed dose. (Author)
Cruz, Jose Carlos da [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil). Servico de Radioterapia; Segreto, Roberto Araujo; Segreto, Helena R. Comodo [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. de Medicina. Setor de Radioterapia]. E-mail: josecarlos@einstein.br
2003-07-01
Three dosimetric systems were compared regarding dosimetry of small circular x ray fields used in radiosurgery. The dosimetric parameters for circular cones, with diameters ranging from 7 to 30 mm, were acquired using a 6 MV Clinac 600 C linear accelerator. For the measurement of tissue maximum ratios, total scatter factor and radiation field profile, Kodak X-Omat type V radiographic films, and ionization chamber of 0.1 cm{sup 3} and a plane parallel ionization chamber type Markus were used. The plane parallel ionization chamber showed satisfactory results for measurement of tissue maximum ratios and total scatter only for cone sizes larger than 11 mm in diameter. Beam profile showed better spatial resolution when films ere used. The main physical parameters of small circular fields used in radiosurgery can be obtained by combining the dosimetry results of radiation therapy equipment used in current clinical practice. (author)
Passaro, Bruno M.; Rodrigues, Laura N. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Videira, Heber S., E-mail: bruno.passaro@gmail.com [Universidade de Sao Paulo (HCFMRP/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas
2013-04-15
The aim of this study is to assess and analyze the stability of the calibration factor of three linear accelerators, as well as the other dosimetric parameters normally included in a program of quality control in radiotherapy. The average calibration factors of the accelerators for the period of approximately four years for the Clinac 600C and Clinac 6EX were (0.998±0.012) and (0.996±0.014), respectively. For the Clinac 2100CD 6 MV and 15 MV was (1.008±0.009) and (1.006±0.010), respectively, in a period of approximately four years. The data of the calibration factors were divided into four subgroups for a more detailed analysis of behavior over the years. Through statistical analysis of calibration factors, we found that for the 600C and Clinacs 2100CD, is an expected probability that more than 90% of cases the values are within acceptable ranges according to TG-142, while for the Clinac 6EX is expected around 85% since this had several exchanges of accelerator components. The values of TPR20,10 of three accelerators are practically constant and within acceptable limits according to the TG-142. It can be concluded that a detailed study of data from the calibration factor of the accelerators and TPR{sub 20},{sub 10} from a quantitative point of view, is extremely useful in a quality assurance program. (author)
Mafalda F. Berdaky
2001-10-01
Full Text Available Este trabalho apresenta a parte operacional do processo final envolvido na implantação de um programa de controle de qualidade por meio de testes rotineiros mecânicos e de radiação. O programa de controle de qualidade, durante 35 meses, mostrou a estabilidade excelente deste acelerador.This paper describes the operational characteristics of the final process of implementation of a quality control program using routine mechanical and radiation tests. The quality control program was performed during 35 months and demonstrated the excellent stability of this accelerator.
Ordiales, J. M.; Alvarez, F. J.; Falero, B.
2011-07-01
For quality control of the virtual wedge there are several systems on the market as arrays of detectors or ionization chambers, linear or 2D configuration, radiochromic films or digital imaging systems incorporated in electron linear accelerators (ALE ). The present work aims at implementing a system of Computed Radiography (CR) for a routine check of the virtual wedge.
Un ano de retraso para el acelerador europeo LHC
CERN. Geneva
2002-01-01
"Debido a las dificultades presupuestarias que sufre el Laboratorio Europeo de Fisica de Particulas (CERN) para construir el nuevo acelerador LHC, la puesta en marcha de esta gran instalacion se retrasara un ano, entrando en funcionamiento en 2007, segun el plan elaborado por la direccion del centro" (1/2 page).
Sanz Beltran, M.; Caballero Perea, B.; Rodriguez Rodriguez, C.; Arminio Diaz, E.; Lopez Fernandez, A.; Gomez Fervienza, J. R.; Crespo Diez, P.; Cantarero Valenzuela, N.; Alvarez Sanchez, M.; Martin Martin, G.; Gomez Fervienza, J. r.; Crespo Diez, P.; Cantarero Valenzuela, N.; Alvarez Sanchez, M.; Martin Martin, G.
2011-07-01
The objective is the realization of craniospinal treatment with a linear accelerator equipped with gantry based on MLC, carbon fiber table and Image Guided capability. The great length of treatment (patient l, 80m in height) was a great difficulty for want of full length of the longitudinal movement of the table to adequately cover the PTV, plus free metallic screws fastening the head of the table extender preventing further incidents.
Ordiales, J. M.; Falero, B.; Vazquez, M.; Alvarez, F. J.
2013-07-01
The use of bags of rice as dispersion medium in irradiation of blood products for medical use is less effective than the immersion from the point of view dosimetric water. However, given the wide range of dose values for a valid result and once subjected to quality control procedure, the method provides the necessary work for the irradiation of blood products in a linear electron accelerator. (Author)
Vega C, H.R. [Universidad Autonoma de Zacatecas, Cuerpo Academico de Radiobiologia, A.P. 336, 98000 Zacatecas (Mexico); Barquero, R. [Hospital Universitario Rio Hortega, Valladolid (Spain); Mendez, R.; Iniguez, M.P. [Depto. de Fisica Teorica, Atomica, Molecular y Nuclear, Universidad de Valladolid, 47011 Valladolid (Spain)
2003-07-01
By means of a series of measures and Monte Carlo calculations the dosimetric characteristics of the photoneutrons have been determined that take place in volume to a linear accelerator of radiotherapy of 18 MV, LINAC, mark Siemens Mevatron model. The measures were carried out with thermoluminescent dosemeters TLD 600 and TLD 700 that were naked exposed and confined with cover of Cd and Sn, inside a sphere of paraffin and inside spheres Bonner. (Author)
Barquero Sanz, R.; Anton, D. A.; Iniguez de la Torre, P. L.; Castillo Belmonte, A. C. del; Alonso, D. A.; Miguel, D. M. de; Lopez Lara-Martin, F. L.
2013-07-01
This paper describes how to use the reaction of thermal neutrons (n?) {sup 1}13Cd, {sup 1}14 Cd with the cadmium in an alloy of cadmium and zinc Telluride (CZT) semiconductor detector. 558 keV photons produced can be detected by the own semiconductor. In this way have an agile method for the measurement of the neutron flux transmitted by shielding and which provides an almost immediate reading of the result. This method applies three accelerators linear in that checks the correct shield on their respective treatment rooms. (Author)
Juste, B.; Miro, R.; Verdu, G.; Diez, S.; Campayo, J. M.
2010-07-01
Determining the spectral distribution of the emitted photon medical linear accelerator (linac) used in radiotherapy treatment is extremely important for performing dosimetry calculations as to accurately calculate the therapeutic dose distributions. Since directly measure the spectrum is very complicated, this paper presents an indirect technique to accurately calculate the spectra of Bremsstrahlung photons emitted by linacs.
Jatvia, J M
2002-01-01
"La Universidad de Valencia tiene avanzado el diseno de un acelerador lineal de protones, cuya culminacion depende del compromiso del Consell en sufragar la plantilla que necesitaria el centro para estar operativo" (1 page).
Apaza V, D.; Cardena R, R.; Cayllahua Q, F.; Vega R, J. [Universidad Nacional de San Agustin de Arequipa, Av. Independencia s/n, Hexagonos de Fisica, Arequipa (Peru); Urquizo B, R., E-mail: dgav02@gmail.com [Hospital Nacional Carlos Alberto Seguin Escobedo, Esquina de Peral y Filtro s/n, Arequipa (Peru)
2015-10-15
In systems of radiotherapy treatment for cancer, always looking to maximize the radiation dose on the target (tumor) and minimize to the organs at risk or healthy, so they resort to using electron beams that have properties and characteristics of higher dose deposition at fixed depths, directing and focusing the higher dose in the tumor, without harming healthy tissues to which seeks to radiate in the least possible. Simulating the interaction of electron beams with different equivalent tissues to the human body leads to a better dosimetric evaluation, improving the quality of treatment planning. The aim of this study is the comparison from the characterization of several equivalent tissues to the human body such as soft tissue, bone and lung. Based on the simulation of a calibration beam in water phantom with Penelope code and compared with the results of the calibration curves of beams in water vat by a linear accelerator Elekta Synergy of Hospital Nacional Carlos Alberto Seguin Escobedo EsSalud of Arequipa (Peru). From this to evaluate the behavior of electron beams in a homogeneous medium and then further evaluation in the human body homogeneities, for better evaluation and specific treatment planning. (Author)
Caballero G, C. A. [Southwest Oncology Centers, North Civic Center Plaza No. 2926, Scottsdale, Arizona (United States); Plascencia, J. C. [Centro Oncologico Louis and Lucille Grado, Republica del Peru No. 102-5, Col. Americas, Aguascalientes (Mexico); Vargas V, M. X.; Toledo J, P., E-mail: cabshm@msn.co [Centro Oncologico de Chihuahua, Hacienda de la Esperanza No. 6304, Fracc. Cima Comercial, Chihuahua (Mexico)
2010-09-15
The helicoid tomo therapy is an external radiotherapy system of modulated intensity, guided by image, in which the radiation is imparted to the patient using a narrow radiation beam in helicoid form, in a similar way to the scanning process with a computerized tomography. The tomo therapy equipment (Tomo Therapy Hi-Art) consists in an electrons linear accelerator with acceleration voltages of 6 MV for treatment and 3.5 MV for image, coupled to a ring that turn around the patient as this is transferred through this ring in perpendicular sense to the radiation beam. The radiation beam is narrow because has the maximum size of 5 x 40 cm{sup 2} in the isocenter. The intensity modulation of the beam is carried out with a binary dynamic collimator of 64 crisscross sheets, and the guide by image though a system of megavoltage computerized tomography. Opposed to the radiation beam, also coupled to the rotational ring, a group of lead plates exists with a total thickness of 13 cm that acts as barrier of the primary radiation beam. The special configuration of the tomography equipment makes to have the following characteristics: 1) the presence of the lead barrier of the equipment reduces the intensity of the primary beam that reaches the bunker walls in considerable way, 2) the disperse and leakage radiations are increased with regard to a conventional accelerator due to the increase in the necessary irradiation time to produce modulated intensity fields by means of the narrow radiation beam. These special characteristics of the tomo therapy equipment make that particularities exist in the application of the formulations for structural shielding calculations that appears in the NCRP reports 49, NCRP 151 and IAEA-SRS-47. For this reason, several researches have development analytic models based on geometric considerations of continuous rotation of the equipment ring to determine the shielding requirements for the primary beam, the dispersed and leakage radiation in tomo
Ginovart Cid, Clara
2015-01-01
Esta tesina analiza la localización al español y catalán de los aceleradores de los menús de LibreOffice a través de la compilación de un corpus multilingüe que recoge las opciones de su interfaz de usuario. Al explotar el corpus, se observa que la tendencia en localización de aceleradores es no alejarse del original. Consideramos que la directriz de ser fiel al carácter o ubicación originales no satisface las necesidades de los usuarios, puesto que provoca aceleradores con trazos bajos y rep...
Recent developments of the 1 MV AMS facility at the Centro Nacional de Aceleradores
Scognamiglio, G.; Chamizo, E.; López-Gutiérrez, J. M.; Müller, A. M.; Padilla, S.; Santos, F. J.; López-Lora, M.; Vivo-Vilches, C.; García-León, M.
2016-05-01
The Centro Nacional de Aceleradores (CNA) hosts a 1 MV accelerator mass spectrometry (AMS) apparatus since September 2005. In order to improve its overall performance, several updates have been made on the existing facility during the last 10 years of operation. In this paper, two modifications conducted in 2015 will be described. To increase the transmission of the ions through the accelerator, the stripping gas on the 1 MV CNA machine was changed from Ar to He. The measured maximum transmission for almost every isotope results to be higher, especially for heavy masses: for instance, in the case of uranium in the 3+ charge state, the transmission increased from 11% with Ar gas to about 38% with He gas. The second advance consisted of the substitution of the existing gas ionization chamber with a new one provided by ETH Zurich. The ETH detector features with its miniaturized design and is optimized for low energy AMS (i.e. very low electronic noise and efficient charge collection). As the electronic noise is the most important contribution to the resolution for light ions, the total energy resolution has been reduced by 15% in the case of 10Be, allowing a better discrimination against its isobar, 10B. For the heaviest radionuclides where the quality of the spectra is determined by the charge carrier production in the gas, the resolution for 2.7 MeV uranium ions was improved by 30%, probably due to a more efficient charge collection.
Accelerator-based research activities at 'Centro Nacional de Aceleradores', Seville (Spain)
Respaldiza, M.A. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Departmento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Sevilla (Spain)], E-mail: respaldiza@us.es; Ager, F.J. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Departmento de Fisica Aplicada I, Universidad de Sevilla, Sevilla (Spain); Carmona, A. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Laboratoire de Chimie Nucleaire Analytique et Bioenvironnementale, Universite de Bordeaux (France); Ferrer, J. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Garcia-Leon, M.; Garcia-Lopez, J. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Departmento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Sevilla (Spain); Garcia-Orellana, I. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Gomez-Tubio, B. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Departmento de Fisica Aplicada III, Universidad de Sevilla, Sevilla (Spain); Morilla, Y. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Ontalba, M.A. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Departmento de Fisica, Universidad de Extremadura, Caceres (Spain); Ortega-Feliu, I. [Centro Nacional de Aceleradores, Avd. Thomas A. Edison 7, E-41092 Sevilla (Spain); Departmento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Sevilla (Spain)
2008-05-15
In February 1998, almost 10 years ago, the set-up of the first IBA (ion beam analysis) facility in Spain took place with the arrival of a 3 MV tandem accelerator [J. Garcia-Lopez, F.J. Ager, M. Barbadillo-Rank, F.J. Madrigal, M.A. Ontalba, M.A. Respaldiza, M.D. Ynsa, Nucl. Instr. and Meth. B 161-163 (2000) 1137]. Since then, an intensive research program using IBA techniques has been carried out. Subsequently, a cyclotron for 18 MeV protons has been also installed at the 'Centro Nacional de Aceleradores' (CNA), devoted mainly to isotope production for PET (positron emission tomography) techniques, but possibly applied to material analysis and damage studies on a dedicated beam line. Moreover, a 1 MV tandem has been recently installed for AMS (accelerator mass spectrometry) {sup 14}C dating and environmental research with other isotopes. In the present paper we describe the new facilities and the developments of the 3 MV tandem beam lines occurred during the past years, as well as some examples of the most recent research activities in our Center in the fields of Material Science, Archaeometry, Biomedicine and Environment.
Accelerator-based research activities at 'Centro Nacional de Aceleradores', Seville (Spain)
In February 1998, almost 10 years ago, the set-up of the first IBA (ion beam analysis) facility in Spain took place with the arrival of a 3 MV tandem accelerator [J. Garcia-Lopez, F.J. Ager, M. Barbadillo-Rank, F.J. Madrigal, M.A. Ontalba, M.A. Respaldiza, M.D. Ynsa, Nucl. Instr. and Meth. B 161-163 (2000) 1137]. Since then, an intensive research program using IBA techniques has been carried out. Subsequently, a cyclotron for 18 MeV protons has been also installed at the 'Centro Nacional de Aceleradores' (CNA), devoted mainly to isotope production for PET (positron emission tomography) techniques, but possibly applied to material analysis and damage studies on a dedicated beam line. Moreover, a 1 MV tandem has been recently installed for AMS (accelerator mass spectrometry) 14C dating and environmental research with other isotopes. In the present paper we describe the new facilities and the developments of the 3 MV tandem beam lines occurred during the past years, as well as some examples of the most recent research activities in our Center in the fields of Material Science, Archaeometry, Biomedicine and Environment
Plutonium measurements on the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA)
Plutonium isotopes have been recently added to the list of radionuclides that can be measured with the new generation of compact AMS facilities. In this paper we present first experimental results concerning the development of the plutonium AMS technique at 680 kV on the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA) in Sevilla, Spain. This is the first compact AMS machine designed and manufactured by High Voltage Engineering Europa. As we demonstrate, the obtained backgrounds for 239,240Pu, of about 106 atoms, and the 239Pu/238U mass suppression factor, in the range of 10-9, compare to the ones achieved on other AMS facilities. With the measurement of reference materials provided by the International Atomic Energy Agency (IAEA-375, IAEA-Soil-6, IAEA-381) and samples already studied on the 600 kV compact ETH/PSI AMS system at Zuerich, we show that the CNA system can be perfectly used for the routine measurement of plutonium isotopes at environmental levels.
Status of the compact 1 MV AMS facility at the Centro Nacional de Aceleradores (Spain)
Since February 2006, the new 1 MV multielement compact AMS facility SARA (Spanish Accelerator for Radionuclides Analyses) at the Centro Nacional de Aceleradores (CNA) in Sevilla (Spain) is fully operative. During the first one and a half year of operation, the viability of the system for the measurement of 10Be, 14C, 129I and plutonium isotopes, 239Pu and 240Pu, has been evaluated. First results have demonstrated that, in terms of precision and detection limits, the performance of the device compares to other compact AMS facilities, although some progress can still be done in order to optimize its capacities. At this moment, background levels are in the order of 10-14 for 10Be/9Be, 10-13 for 129I/127I, 10-15 for 14C/12C (processed and unprocessed blank) and about 106 atoms for plutonium isotopes: 239Pu, 240Pu and 242Pu. In this work, the current status of the AMS measurements at CNA for the above mentioned radionuclides is described
Fuente de Alimentación para los Imanes Superconductores del Acelerador de Partículas Europeo XFEL
García, O.; Francés, A.; J.M. Fernández; Varela, Pablo; Catalanotto, Giuseppe; Alou Cervera, Pedro; Oliver Ramírez, Jesús Angel; Asensi Orosa, Rafael; Prieto López, Roberto; Uceda Antolín, Javier; Cobos Márquez, José Antonio
2013-01-01
En este artículo se presenta la fuente de alimentación que se está diseñando para alimentar los imanes superconductores del acelerador de partículas europeo XFEL que se está construyendo en Hamburgo, cuyas características le hacen el más avanzado del mundo. Un imán superconductor es una carga muy inductiva que debe ser controlada en corriente y que presenta una caída de tensión muy baja cuando está en modo superconductor. La fuente debe ser capaz de alimentar esta carga con una alta fiabilida...
The environmental research programme of the Centro Nacional de Aceleradores, Sevilla (Spain)
Full text: The Centro Nacional de Aceleradores (National Accelerator Center, CNA), the first and for the moment the only Spanish ion beam analysis (IBA) laboratory, was set up in 1998 in the University of Seville (Spain). This laboratory was created with the aim to fulfill the increasing demand for IBA techniques existing in Spain. This facility is based on a 3 MB pelletron tandem accelerator, which is being used for interdisciplinary studies concerning Material Science, Art, Archaeology, Biology, Medicine, Environmental Science, etc. In addition, the works for a cyclotron laboratory are commencing now. This paper reports on the most recent applications in the field of Environmental Science carried out in our laboratory. Remediation of metal-contaminated soils and waters poses a challenging problem due to its implications in the environment and the human health. A possible solution to this problem is the phytoremediation, i.e. the process of using plants for environmental restoration taking advantage of the ability of certain terrestrial plants to absorb and accumulate metals, removing them from soils and aqueous streams. These plants are called metal hyper accumulators if they accumulate for instance more than 0.01% of Cd, 0.1% of Ni or 1% of Zn per dry weight in their shoots. For example, Cd is readily transported and accumulated in the shoots of several plant species, being a favourable target metal for this technology. In recent works making use of nuclear microscopy techniques, we investigated the sites of metal localization within the leaves of metal hyper accumulator Arabidopsis thaliana, when plants are grown in a cadmium-rich environment, and we proved that cadmium is sequestered within the trichomes on the leaf surface. The Donana Natural Park is an internationally important wetland area of 280,000 ha in the Huelva-Seville-Cadiz triangle in Southern Spain, which includes natural beaches, dunes, pine forests and marshlands as the most relevant habitats. On
Measurement of 236U on the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA)
In this paper we present the first comprehensive analysis of the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA, Seville, Spain) for 236U studies in environmental samples. In the last years, this radionuclide has become key in the AMS community, due to the very demanding 236U/238U abundance sensitivities required for general applications. As we demonstrate, the AMS system at the CNA is able to achieve sensitivity for the 236U/238U ratio of about 3 × 10−11 despite its compact design. The use of “239Pu”/238U ratio as a proxy for “236U”/235U background correction is proposed and tested with natural samples that were also studied on the 600 kV Tandy AMS system at the ETH Zürich. This correction is significant in the CNA case, due to the low mass resolving power of the low-energy spectrometer and to the lack of a third filter on the high-energy side. With the measurement of reference solutions supplied by the Institute for Reference Materials and Methods (IRMM-075), and reference natural matrixes provided by the International Atomic Energy Agency (IAEA-Soil-6, IAEA-375; 384; 386 and IAEA-RGU), we show that the 1 MV AMS system at the CNA can be routinely used for determinations of anthropogenic 236U at environmental levels
In this work we present the most recent improvements performed by our group on 10Be measurements on the 1 MV AMS system recently set up at the CNA (Centro Nacional de Aceleradores), in Seville (Spain). Our efforts have been focused on the study of the viability of our system for BeO and BeF- measurements. To achieve this, different standard materials have been measured to demonstrate the reliability of the system for BeO measurements in a wide 10Be/9Be atomic ratio range and several environmental samples have been studied both at the 1 MV AMS CNA facility and at the 6 MV AMS ETH-PSI facility of Zurich to validate our measurements. The results show a good agreement between laboratories. New experiments also have been carried out selecting 1+ and 2+ charge states at the exit of the accelerator and inserting Si3N3.1 foils with different thicknesses to separate 10Be from its isobar, 10B. The influence of each foil on the overall transmission (detected 10Be compared to BeO- injected into the accelerator) and background level was also assessed. In addition some tests were also done to assess the viability of BeF2 and BaBeF4 measurements at our system. Several metal matrices and cathode preparation procedures for BeO samples were investigated to maximize current and cathode lifetime.
Measurement of {sup 236}U on the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA)
Chamizo, E. [Centro Nacional de Aceleradores (Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Junta de Andalucía), Thomas Alva Edison 7, 41092 Seville (Spain); Christl, M. [Laboratory of Ion Beam Physics, ETH Zurich, Otto Stern Weg 5, CH-8093 Zurich (Switzerland); Fifield, L.K. [Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 2601 (Australia)
2015-09-01
In this paper we present the first comprehensive analysis of the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA, Seville, Spain) for {sup 236}U studies in environmental samples. In the last years, this radionuclide has become key in the AMS community, due to the very demanding {sup 236}U/{sup 238}U abundance sensitivities required for general applications. As we demonstrate, the AMS system at the CNA is able to achieve sensitivity for the {sup 236}U/{sup 238}U ratio of about 3 × 10{sup −11} despite its compact design. The use of “{sup 239}Pu”/{sup 238}U ratio as a proxy for “{sup 236}U”/{sup 235}U background correction is proposed and tested with natural samples that were also studied on the 600 kV Tandy AMS system at the ETH Zürich. This correction is significant in the CNA case, due to the low mass resolving power of the low-energy spectrometer and to the lack of a third filter on the high-energy side. With the measurement of reference solutions supplied by the Institute for Reference Materials and Methods (IRMM-075), and reference natural matrixes provided by the International Atomic Energy Agency (IAEA-Soil-6, IAEA-375; 384; 386 and IAEA-RGU), we show that the 1 MV AMS system at the CNA can be routinely used for determinations of anthropogenic {sup 236}U at environmental levels.
El impacto de la política monetaria y la política fiscal en un modelo de acelerador financiero
Botero García, Jesús
2010-01-01
El presente artículo presenta un modelo sencillo de acelerador financiero, en el que a partir de la solución del problema de optimización intertemporal del flujo de renta del empresario en condiciones de competencia monopolística, es posible evaluar el impacto de dichos descuentos, así como también el impacto de la política monetaria, sobre el stock deseado de capital y la inversión deseada. El modelo es un modelo de equilibrio parcial, pero ilustra adecuadamente la forma como la política mon...
Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da, E-mail: asalgado@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Batista, Delano V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)
2009-07-01
This work demonstrates the complexity and the necessary cares for the realization of measurements of neutron fields in rooms for radiotherapy treatment containing clinical accelerators. The acquaintance of the technical characteristics of the monitors and the periodic calibration are actions and fundamental procedures to guarantee traceability and the reliability of measurements
Planes Meseguer, D.; Dorado Rodriguez, M. P.; Esposito, R. D.
2011-07-01
In this paper we present our solution for the realization of the monthly periodic quality control (CP) geometry - mechanical and multi leaf collimator (MLC), using the electronic system for portal imaging (EPI). We have developed specific programs created with free software. The monitoring results are automatically stored on our web server, along with other information generated in our service.
Leonardo de A. Monteiro
2011-06-01
Full Text Available A utilização correta de pneus em tratores, tanto em relação ao seu tipo quanto à calibração de sua pressão interna, e a lastragem ideal para cada condição de carga são fatores que influem significativamente no desempenho do trator. Esta pesquisa teve como objetivo comparar o desempenho de um trator equipado com pneus radiais e com pneus diagonais, para três condições de lastragem líquida (0%, 40% e 75% de água, em três condições superficiais de um Nitossolo Vermelho distrófico (superfície firme, preparada e com cobertura vegetal de resto de milho e em três velocidades teóricas de deslocamento (4 km h-1, 5 km h-1 e 7 km h-1, informadas no painel do trator, correspondendo às marchas B1, B2 e C1. O melhor desempenho do trator, equipado com pneu diagonal, ocorreu na condição de 75% de água nos pneus, apresentando maior velocidade de deslocamento, menor patinhagem do trator, menor consumo horário de combustível e gerando maior potência na barra de tração. Com pneus radiais, o melhor desempenho do trator ocorreu na condição de 40% de água nos pneus, proporcionando maiores velocidades de deslocamento do trator, menores patinhagens, menores consumos, horário e específico de combustível, e maiores potência e rendimento na barra de tração.The correct use of tires, as for its construction type as for internal pressure calibration and the optimal weighting for each load condition are factors that impact significantly on their performance. This study aimed to compare the performance of a tractor equipped with radial tires and bias ply tires in three conditions of liquid ballast (0%, 40% and 75% water, three surface conditions of a Dystrophic Red Alfisol (firm surface, tillage surface and surface with corn residues coverage and three theoretical traveling speeds (4 km h-1, 5 km h-1 and 7 km h-1, as indicated at the tractor display, related to the gear boxes B1, B2 and C1. The best tractor's performance, equipped with
Leonardo F. V. dos Santos
2011-01-01
Full Text Available O ZNIBU, acelerador de caráter lento foi avaliado neste trabalho em composições de polibutadieno. Este acelerador foi sintetizado com o objetivo de substituir, ou reduzir, o uso de alguns aceleradores comerciais muito utilizados em composições elastoméricas mas que, por serem formadores de nitrosaminas, podem ser prejudiciais à saúde. A fim de corrigir o caráter de acelerador lento do ZNIBU, este composto foi utilizado em conjunto com o acelerador comercial CBS (N-ciclohexil-2-benzotiazol-2-sulfenamida. Foi observado que pequenas quantidades dos dois aceleradores não são efetivas na aceleração da vulcanização nas composições do tipo goma pura. No entanto a presença de negro de fumo exerce um efeito positivo sobre a velocidade. As propriedades mecânicas estudadas mostram que o ZNIBU aumenta a resistência à tração da goma pura (35%, em comparação com a composição similar vulcanizada com CBS e, na presença do negro de fumo, este aumento é ainda mais expressivo (175%. Quanto à resistência ao rasgamento, a vulcanização com o ZNIBU forneceu o mais baixo valor da propriedade para a goma pura, enquanto que a composição com negro de fumo apresentou o mais alto valor.ZNIBU, a slow accelerator, was evaluated in polybutadiene compositions. This accelerator was synthesized intending to replace or reduce the use of some very used commercial accelerators in rubber compositions which, due to their nitrosamine-forming potential, can be harmful to health. In order to correct for the slow accelerating character ZNIBU was used in combination with the commercial accelerator CBS (N-cyclohexyl-2-benzothiazole-2-sulfenamide. It was observed that small amounts of the accelerators are not effective in the vulcanization accelerating process of gum type compositions. Nevertheless, the presence of carbon black exerts a positive effect on the reaction rate. The investigated mechanical properties show that ZNIBU improves stress strength of
The Neutrons and Reactors Laboratory (NYR) of CAB (Centro Atomico Bariloche) is equipped with a linear electron accelerator (LINAC) Linear particle accelerator). This LINAC is used as a neutron source from which two beams are extracted to perform neutron transmission and dispersion experiments. Through these experiments, structural and dynamic properties of materials can be studied. The neutron transmission experiments consist in a collimated neutron beam which interacts with a sample and a detector behind the sample. Important information about the microstructural characteristics of the material can be obtained from the comparison between neutron spectra before and after the interaction with the sample. This experimental technique has been extensively used to determine cross sections, lattice parameters of a crystalline solid, vibration frequencies of atoms or the strain field of a material. In the NYR Laboratory, cylindrical samples of one inch of diameter have been traditionally studied. Nonetheless, there is a great motivation for doing systematic research on smaller and with different geometries samples; particularly sheets and samples for tensile tests. In such cases, a reduction of the spot size of the beam and an increase of its intensity would have a direct impact on minimizing measurement times. Hence, in the NYR Laboratory it has been considered the possibility of incorporating a neutron guide into the existent transmission line. According to all mentioned above, the main objective of this work consisted in the optimization of the flight transmission tube optics of neutrons. This optimization not only improved the existent line but also contributed to an election criterion for the neutron guide acquisition. The optimization was directed towards maximize the neutron flux on samples of mentioned geometries and to form the divergence of the incident beam upon them. It was then necessary to study the instrument neutron optics, i.e. the characteristics of the
Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla C. de Souza; Fonseca, Evaldo S. da, E-mail: asalgado@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Batista, Delano V.S. [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil)
2009-07-01
The Neutron Laboratory of the Radioprotection and Dosimetry Institute - IRD/CNEN, Rio de Janeiro, Brazil, initiated studies on the process of calibration of neutron area monitors and the results of the measurements performed at radiotherapy treatment rooms, containing clinical accelerators
A linear gate providing a variable gate duration from 0,40μsec to 4μsec was developed. The electronic circuity consists of a linear circuit and an enable circuit. The input signal can be either unipolar or bipolar. If the input signal is bipolar, the negative portion will be filtered. The operation of the linear gate is controlled by the application of a positive enable pulse. (author)
Vretenar, M
2014-01-01
The main features of radio-frequency linear accelerators are introduced, reviewing the different types of accelerating structures and presenting the main characteristics aspects of linac beam dynamics.
From November 28 to December 9, the Stanford Linear Accelerator Center hosted an International Workshop on Next Generation Linear Colliders. The attendance, including delegations from CERN, Frascati (Italy), KEK (Japan), Livermore (US), Novosibirsk (USSR), Drsay (France) and SLAC itself reflected the international interest in this new approach to higher energies
Stoll, R R
1968-01-01
Linear Algebra is intended to be used as a text for a one-semester course in linear algebra at the undergraduate level. The treatment of the subject will be both useful to students of mathematics and those interested primarily in applications of the theory. The major prerequisite for mastering the material is the readiness of the student to reason abstractly. Specifically, this calls for an understanding of the fact that axioms are assumptions and that theorems are logical consequences of one or more axioms. Familiarity with calculus and linear differential equations is required for understand
Inauguran nuevo tunel de acelerador
Macedo, C
2003-01-01
"Contendra el Gran Colisionador de Hadrones del CERN. Ayer fue inaugurado el tunel subterraneo que acogera al experimento ATLAS, uno de los cuatro xperimentos que integraran el Gran Colisionador de Hadrones (LHC), que es construido en el Centro Europeo para la Investigacion Nuclear (CERN), en Ginebra" (1/3 page).
Liesen, Jörg
2015-01-01
This self-contained textbook takes a matrix-oriented approach to linear algebra and presents a complete theory, including all details and proofs, culminating in the Jordan canonical form and its proof. Throughout the development, the applicability of the results is highlighted. Additionally, the book presents special topics from applied linear algebra including matrix functions, the singular value decomposition, the Kronecker product and linear matrix equations. The matrix-oriented approach to linear algebra leads to a better intuition and a deeper understanding of the abstract concepts, and therefore simplifies their use in real world applications. Some of these applications are presented in detailed examples. In several ‘MATLAB-Minutes’ students can comprehend the concepts and results using computational experiments. Necessary basics for the use of MATLAB are presented in a short introduction. Students can also actively work with the material and practice their mathematical skills in more than 300 exerc...
Edwards, Harold M
1995-01-01
In his new undergraduate textbook, Harold M Edwards proposes a radically new and thoroughly algorithmic approach to linear algebra Originally inspired by the constructive philosophy of mathematics championed in the 19th century by Leopold Kronecker, the approach is well suited to students in the computer-dominated late 20th century Each proof is an algorithm described in English that can be translated into the computer language the class is using and put to work solving problems and generating new examples, making the study of linear algebra a truly interactive experience Designed for a one-semester course, this text adopts an algorithmic approach to linear algebra giving the student many examples to work through and copious exercises to test their skills and extend their knowledge of the subject Students at all levels will find much interactive instruction in this text while teachers will find stimulating examples and methods of approach to the subject
Allenby, Reg
1995-01-01
As the basis of equations (and therefore problem-solving), linear algebra is the most widely taught sub-division of pure mathematics. Dr Allenby has used his experience of teaching linear algebra to write a lively book on the subject that includes historical information about the founders of the subject as well as giving a basic introduction to the mathematics undergraduate. The whole text has been written in a connected way with ideas introduced as they occur naturally. As with the other books in the series, there are many worked examples.Solutions to the exercises are available onlin
Karloff, Howard
1991-01-01
To this reviewer’s knowledge, this is the first book accessible to the upper division undergraduate or beginning graduate student that surveys linear programming from the Simplex Method…via the Ellipsoid algorithm to Karmarkar’s algorithm. Moreover, its point of view is algorithmic and thus it provides both a history and a case history of work in complexity theory. The presentation is admirable; Karloff's style is informal (even humorous at times) without sacrificing anything necessary for understanding. Diagrams (including horizontal brackets that group terms) aid in providing clarity. The end-of-chapter notes are helpful...Recommended highly for acquisition, since it is not only a textbook, but can also be used for independent reading and study. —Choice Reviews The reader will be well served by reading the monograph from cover to cover. The author succeeds in providing a concise, readable, understandable introduction to modern linear programming. —Mathematics of Computing This is a textbook intend...
Bourlès, Henri
2013-01-01
Linear systems have all the necessary elements (modeling, identification, analysis and control), from an educational point of view, to help us understand the discipline of automation and apply it efficiently. This book is progressive and organized in such a way that different levels of readership are possible. It is addressed both to beginners and those with a good understanding of automation wishing to enhance their knowledge on the subject. The theory is rigorously developed and illustrated by numerous examples which can be reproduced with the help of appropriate computation software. 60 exe
Reduction of Linear Programming to Linear Approximation
Vaserstein, Leonid N.
2006-01-01
It is well known that every Chebyshev linear approximation problem can be reduced to a linear program. In this paper we show that conversely every linear program can be reduced to a Chebyshev linear approximation problem.
Fax, X.; Piro, N.; Sanchez, N.; Toribio, I.; Hermida, M.; Seioane, A.; Saez, J.; Beltran, M.
2011-07-01
We have studied the feasibility of Varian portal vision system AS500-II, dosimetry calibration mode, as a substitute for radiochromic plates in quality control tests that required the use of such film. Over a period of two months have been analyzed both the dosimetric characteristics of the system and the mechanical positioning. In addition there has been a financial estimate of annual savings that would result from replacing the radiochromic film by the portal system in a multi-energy accelerator.
Sierra Diaz, F.; Gonzalez Ruiz, C.; Garcia Marcos, R.; Gallego Franco, P.; Rodriguez Checa, M.; Gomez Calvar, R.; Lopez Bote, M. A.
2013-07-01
The objective is to show how the working procedures, have been defined unambiguously to ensure together with the structure of the installation, and optimally located elements of radiation protection, compliance with the classification of areas, occupation factors and rates expected according to them. (Author)
Velazquez Miranda, S.; Jimenez Domingiuez, M.; Mateos Perez, J. C.; Herrador Cordoba, M.
2011-07-01
The new design of carbon treatment tables for rotational IMRT application is being submitted in multiple publications, all dosimetric test to determine their influence on treatment. In most publications can be concluded that their influence is not negligible, especially in near-horizontal angles. In the case of IMRT its influence becomes non-intuitive and therefore difficult to estimate. These publications can not consider all the possibilities of clinical practice, so that its applicability is limited. We propose, therefore, a role-table with the exact geometry of the treatment and density adjusted to the experimental data, to resolve the estimation of their influence in each clinical case.
Torres Pozas, S.; Monja Rey, P. de la; Sanchez Carrasca, M.; Yanez Lopez, D.; Macias Verde, D.; Martin Oliva, R.
2011-07-01
In recent years, the progress experienced in cancer treatment with ionizing radiation can deliver higher doses to smaller volumes and better shaped, making it necessary to take into account new aspects in the calculation of structural barriers. Furthermore, given that forecasts suggest that in the near future will install a large number of accelerators, or existing ones modified, we believe a useful tool to estimate the thickness of the structural barriers of treatment rooms. The shielding calculation methods are based on standard DIN 6847-2 and the recommendations given by the NCRP 151. In our experience we found only estimates originated from the DIN. Therefore, we considered interesting to develop an application that incorporates the formulation suggested by the NCRP, together with previous work based on the rules DIN allow us to establish a comparison between the results of both methods. (Author)
Cortes Giraldo, M. A.; Miras, H.; Arrans, R.; Gallardo, M. I.; Quesada, J. M.
2011-07-01
The interest and motivation of this work lies in the ability to present GEANT4 to simulate neutron transport through the material, making it possible to make estimates of pollution existing neutron radiotherapy treatments to energies at which the neutron production is significant.
Linear Algebra and Smarandache Linear Algebra
Vasantha, Kandasamy
2003-01-01
The present book, on Smarandache linear algebra, not only studies the Smarandache analogues of linear algebra and its applications, it also aims to bridge the need for new research topics pertaining to linear algebra, purely in the algebraic sense. We have introduced Smarandache semilinear algebra, Smarandache bilinear algebra and Smarandache anti-linear algebra and their fuzzy equivalents. Moreover, in this book, we have brought out the study of linear algebra and ve...
Ginovart Cid, Clara
2015-01-01
Esta tesina analiza la localización al español y al catalán de las teclas aceleradoras de los menús de la interfaz de usuario de LibreOffice 4.4.0 a través de la compilación de un corpus multilingüe que recoge las opciones de los menús del software. A través de su explotación, se ha observado que la tendencia en localización de aceleradores es no alejarse del original. La directriz de no alejarse del inglés en lo que al carácter o a la ubicación se refiere no satisface, a nuestro criterio, la...
Santana, Emico Ferreira; Milian, Felix Mas; Paixao, Paulo Oliveira; Costa, Raranna Alves da; Velasco, Fermin Garcia, E-mail: efsantana@uesc.br, E-mail: f.mas.milian@gmail.com, E-mail: popaixao@uesc.br, E-mail: racosta@uesc.br, E-mail: fermingv@gmail.com [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil)
2015-07-01
In this paper is used a computational code of radiation transport simulation based on Monte Carlo technique, in order to model a linear accelerator of treatment by Radiotherapy. This work is the initial step of future proposals which aim to study several treatment of patient by Radiotherapy, employing computational modeling in cooperation with the institutions UESC, IPEN, UFRJ e COI. The Chosen simulation code is GATE/Geant4. The average accelerator is TrueBeam of Varian Company. The geometric modeling was based in technical manuals, and radiation sources on the phase space for photons, provided by manufacturer in the IAEA (International Atomic Energy Agency) format. The simulations were carried out in equal conditions to experimental measurements. Were studied photons beams of 6MV, with 10 per 10 cm of field, focusing on a water phantom. For validation were compared dose curves in depth, lateral profiles in different depths of the simulated results and experimental data. The final modeling of this accelerator will be used in future works involving treatments and real patients. (author)
Gaona, E.; Azorin N, J.; Perez, M.A.; Picon, C.; Castellanos, E.; Plazas, M.C.; Murcia, G.; Archundia, L. [Depto. El Hombre y su Ambiente. Universidad Autonoma Metropolitana, Calz. Del Hueso 1100, 04960 Mexico D.F. (Mexico)
1998-12-31
In Radiotherapy one of the objectives is to establish and to give follow up to quality assurance programs which make sure that the doses administered to the patients with cancer are a high probability of a success in external radiation. Likewise, one of the present preoccupations of the United Nations Agencies as well as the International Atomic Energy Agency and the Pan-American Health Organization is the optimal employment of the radiations in the treatment of cancer patients since the administered dose in Radiotherapy suffers considerable variations by the lack of quality assurance programs. The use of Electron linear accelerators requires a program of quality assurance that includes expert personnel, equipment and adequate facilities. The more used methodology for the dosimetry calibration and characterization of X-ray beams and high energy electrons for radiotherapy use is using a ionization chamber dosemeter calibrated in a regional secondary standardization laboratory. However, to establish and give follow up to the quality assurance programs it is necessary the dosimetric intercomparison through TLD. In this study it was designed plastic phantoms with TLD crystals and it was made its characterization to realize an absorbed dose analysis in the crystals exposed at X-ray beams 6 MV and high energy electrons 10 and 12 MeV to standardize the dosimetric procedures and proceeding to realize an International Pilot intercomparison of absorbed doses in TLD crystals in three Latin American countries: Mexico, Peru and Colombia with the participation of accelerators of five different institutions. The found results show that the majority of the measured doses with TLD in the different accelerators were in the 0.95-1.05 range though it had two cases outside of this range. The use of the phantoms with TLD crystals shows that they are of excellent aid to make analysis of the doses administered to the patients and an intercomparison of results to standardize procedures at
... News Physician Resources Professions Site Index A-Z Linear Accelerator A linear accelerator (LINAC) customizes high energy x-rays to ... ensured? What is this equipment used for? A linear accelerator (LINAC) is the device most commonly used ...
Linearly constrained minimax optimization
Madsen, Kaj; Schjær-Jacobsen, Hans
1978-01-01
We present an algorithm for nonlinear minimax optimization subject to linear equality and inequality constraints which requires first order partial derivatives. The algorithm is based on successive linear approximations to the functions defining the problem. The resulting linear subproblems are...
Paredes G, L.C. [Instituto Nacional de Investigaciones Nucleares, Direccion de Innovacion Tecnologica, A.P. 18-1027, 11801 Mexico D.F. (Mexico)
2001-07-01
An investigation was made on the theoretical fundamentals for the determination of the neutron fluence in a linear electron accelerator for radiotherapy applications and the limit values of leakage neutron radiation established by guidelines and standards in radiation protection for these type of accelerators. This investigation includes the following parts: a) Exhaustive bibliographical review on the topics mentioned above, in order to combine and to update the necessary basic information to facilitate the understanding of this subject; b) Analysis of the accelerator operation and identification of its main components, specially in the accelerator head; c) Study of different types of targets and its materials for the Bremsstrahlung production which is based on the electron initial energy, the thickness of the target, and its angular distribution and energy, which influences in the neutron generation by means of the photonuclear and electro disintegration reactions; d) Analysis of the neutron yield based on the target type and its thickness, the energy of electrons and photons; e) Analysis of the neutron energy spectra generated in the accelerator head, inside and outside the treatment room; f) Study of the dosimetry fundamentals for neutron and photon mixed fields, the dosimeter selection criteria and standards applied for these applications, specially the Panasonic U D-809 thermoluminescent dosemeter and C R-39 nuclear track dosimeter; g) Theoretical calculation of the neutron yield using a simplified geometric model for the accelerator head with spherical cell, which considers the target, primary collimator, flattener filter, movable collimators and the head shielding as the main components for radiation production. The cases with W and Pb shielding for closed movable collimators and an irradiation field of 20 x 20 cm{sup 2} were analyzed and, h) Experimental evaluation of the leakage neutron radiation from the patient and head planes, observing that the
Moreno, S. [Universidade da Beira Interior (UBI), Covilha (Portugal); Chaves, A.; Lopes, M.C. [Instituto Portugues de Oncologia Doutor Francisco Gentil (IPO), Coimbra (Portugal); Peralta, L. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas (LIP), Lisboa (Portugal)]|[Universidade de Lisboa (Portugal). Faculdade de Ciencias
2004-07-01
The advent of linear accelerators (linac) with computer-controlled dynamic collimation systems and functional and anatomical imaging techniques allowed a more exact delimitation and localisation of the target volume. These advanced treatment techniques inevitably increase the complexity level of dose calculation because of the introduction of the temporal variable. On account of this, it is mandatory the usage of more accurate modelling techniques of the collimator components, as it is the case of Monte Carlo (MC) simulation, which has created an enormous interest in research and clinical practice. Because the patients bodies are not homogenous nor are their body surfaces plane and regular, the dose distribution may differ significantly from the standard distribution from the linac calibration. It is in the treatment planning systems, which include algorithms that are usually measured in homogeneous water phantoms specific for each correction that the dose distributions from each case are obtained. In a real treatment, exception made to superficial lesions, two or more radiation fields are used in order to obtain the recommended dose distributions. The simplest arrangement is made from two parallel and opposed fields that originate a homogeneous dose distribution in almost all the irradiated volume. The available resources are, for example, different types of energies and of radiation, the application of bolus, the protection of healthy structures, the usage of wedged filters and the application of dynamic wedges. A virtual or dynamic wedge, modelled through the movement of one of the jaws, when compared with a set of physical wedges offers an alternative calculation method of an arbitrary number of wedged fields, instead of the four traditional fields of 15 deg, 30 deg, 45 deg and 60 deg angle and obtained with physical wedges. The goal of this work consists in the study of the application of dynamic wedges in tailoring the radiation field by the Varian Clinac 600
Foundations of linear and generalized linear models
Agresti, Alan
2015-01-01
A valuable overview of the most important ideas and results in statistical analysis Written by a highly-experienced author, Foundations of Linear and Generalized Linear Models is a clear and comprehensive guide to the key concepts and results of linear statistical models. The book presents a broad, in-depth overview of the most commonly used statistical models by discussing the theory underlying the models, R software applications, and examples with crafted models to elucidate key ideas and promote practical model building. The book begins by illustrating the fundamentals of linear models,
J. R. Garcia
2007-03-01
Full Text Available Um dos aspectos principais para o desenvolvimento de concretos refratários está no aprimoramento dos conhecimentos sobre o cimento de alta alumina ou cimento de aluminato de cálcio (CAC, já que esse ligante é o mais utilizado nesta classe de produtos. O objetivo desse trabalho foi o de analisar as informações disponíveis na literatura para se obter um conhecimento mais aprofundado dos mecanismos de ação dos aditivos retardadores e aceleradores da pega deste cimento. Da análise dos dados compilados pode-se concluir que os aditivos retardadores agem geralmente de duas maneiras: 1 dificultando o processo de dissolução do cimento, por meio da formação de barreiras insolúveis ao redor das suas partículas e 2 favorecendo a formação de hidratos mais solúveis, o que aumenta o tempo necessário para que se inicie a precipitação. Por outro lado, os aditivos aceleradores de pega podem atuar favorecendo a formação de hidratos menos solúveis, diminuindo assim o tempo necessário para a precipitação ou ainda pela formação de núcleos iniciadores do processo de crescimento dos cristais dos hidratos. A análise destas informações leva a constatação de que a ação de alguns aditivos retardadores e aceleradores ocorre em estágios distintos no processo de hidratação do CAC. Portanto, pode-se imaginar uma situação onde a combinação desses dois aditivos poderia conferir um tempo de trabalhabilidade adequado e seguro, aliado a um curto tempo de desmoldagem.One of the main aspects for the development of refractories castables is to master the knowledge regarding calcium aluminate cement (CAC, as this binder is the most applied in these products. The objective of this work was to analyze the available information in the literature in order to explain the understanding regarding the actions of retarder and accelerator additives in the setting mechanisms of CACs. The analysis of the compiled information pointed out that the
Switched linear encoding with rectified linear autoencoders
Johnson, Leif; Corcoran, Craig
2013-01-01
Several recent results in machine learning have established formal connections between autoencoders---artificial neural network models that attempt to reproduce their inputs---and other coding models like sparse coding and K-means. This paper explores in depth an autoencoder model that is constructed using rectified linear activations on its hidden units. Our analysis builds on recent results to further unify the world of sparse linear coding models. We provide an intuitive interpretation of ...
Young, T.
This book is intended to be used as a textbook in a one-semester course at a variety of levels. Because of self-study features incorporated, it may also be used by practicing electronic engineers as a formal and thorough introduction to the subject. The distinction between linear and digital integrated circuits is discussed, taking into account digital and linear signal characteristics, linear and digital integrated circuit characteristics, the definitions for linear and digital circuits, applications of digital and linear integrated circuits, aspects of fabrication, packaging, and classification and numbering. Operational amplifiers are considered along with linear integrated circuit (LIC) power requirements and power supplies, voltage and current regulators, linear amplifiers, linear integrated circuit oscillators, wave-shaping circuits, active filters, DA and AD converters, demodulators, comparators, instrument amplifiers, current difference amplifiers, analog circuits and devices, and aspects of troubleshooting.
Tuey, R. C.
1972-01-01
Computer solutions of linear programming problems are outlined. Information covers vector spaces, convex sets, and matrix algebra elements for solving simultaneous linear equations. Dual problems, reduced cost analysis, ranges, and error analysis are illustrated.
Kılıç, Selim
2013-01-01
Linear regression is an approach to modeling the association between a numeric dependent variable y and one or more independent variables denoted X. The case of one explanatory variable in regression model is called simple linear regression. For more than one explanatory variable, then the model is called multiple linear regression. The dependent variable should be a numeric variable in linear regression. It is recommended at least 10 times as many cases as the number of independent variables...
Greuel, Gert-Martin
2000-01-01
Inhalte der Grundvorlesungen Lineare Algebra I und II im Winter- und Sommersemester 1999/2000: Gruppen, Ringe, Körper, Vektorräume, lineare Abbildungen, Determinanten, lineare Gleichungssysteme, Polynomring, Eigenwerte, Jordansche Normalform, endlich-dimensionale Hilberträume, Hauptachsentransformation, multilineare Algebra, Dualraum, Tensorprodukt, äußeres Produkt, Einführung in Singular.
Lawson, C. L.; Krogh, F. T.; Gold, S. S.; Kincaid, D. R.; Sullivan, J.; Williams, E.; Hanson, R. J.; Haskell, K.; Dongarra, J.; Moler, C. B.
1982-01-01
The Basic Linear Algebra Subprograms (BLAS) library is a collection of 38 FORTRAN-callable routines for performing basic operations of numerical linear algebra. BLAS library is portable and efficient source of basic operations for designers of programs involving linear algebriac computations. BLAS library is supplied in portable FORTRAN and Assembler code versions for IBM 370, UNIVAC 1100 and CDC 6000 series computers.
Blyth, T S
2002-01-01
Basic Linear Algebra is a text for first year students leading from concrete examples to abstract theorems, via tutorial-type exercises. More exercises (of the kind a student may expect in examination papers) are grouped at the end of each section. The book covers the most important basics of any first course on linear algebra, explaining the algebra of matrices with applications to analytic geometry, systems of linear equations, difference equations and complex numbers. Linear equations are treated via Hermite normal forms which provides a successful and concrete explanation of the notion of linear independence. Another important highlight is the connection between linear mappings and matrices leading to the change of basis theorem which opens the door to the notion of similarity. This new and revised edition features additional exercises and coverage of Cramer's rule (omitted from the first edition). However, it is the new, extra chapter on computer assistance that will be of particular interest to readers:...
Wiedemann, H.
1981-11-01
Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center.
Linearity in Process Languages
Nygaard, Mikkel; Winskel, Glynn
2002-01-01
The meaning and mathematical consequences of linearity (managing without a presumed ability to copy) are studied for a path-based model of processes which is also a model of affine-linear logic. This connection yields an affine-linear language for processes, automatically respecting open-map bisi......The meaning and mathematical consequences of linearity (managing without a presumed ability to copy) are studied for a path-based model of processes which is also a model of affine-linear logic. This connection yields an affine-linear language for processes, automatically respecting open......-map bisimulation, in which a range of process operations can be expressed. An operational semantics is provided for the tensor fragment of the language. Different ways to make assemblies of processes lead to different choices of exponential, some of which respect bisimulation....
Shelah, Saharon
2011-01-01
We address the following question: Can we expand an NIP theory by adding a linear order such that the expansion is still NIP? Easily, if acl(A)=A for all A, then this is true. Otherwise, we give counterexamples. More precisely, there is a totally categorical theory for which every expansion by a linear order has IP. There is also an \\omega-stable NDOP theory for which every expansion by a linear order interprets bounded arithmetic.
Efficient Non Linear Loudspeakers
Petersen, Bo R.; Agerkvist, Finn T.
2006-01-01
Loudspeakers have traditionally been designed to be as linear as possible. However, as techniques for compensating non linearities are emerging, it becomes possible to use other design criteria. This paper present and examines a new idea for improving the efficiency of loudspeakers at high levels...... by changing the voice coil layout. This deliberate non-linear design has the benefit that a smaller amplifier can be used, which has the benefit of reducing system cost as well as reducing power consumption....
Deep Linear Discriminant Analysis
Dorfer, Matthias; Kelz, Rainer; WIDMER, Gerhard
2015-01-01
We introduce Deep Linear Discriminant Analysis (DeepLDA) which learns linearly separable latent representations in an end-to-end fashion. Classic LDA extracts features which preserve class separability and is used for dimensionality reduction for many classification problems. The central idea of this paper is to put LDA on top of a deep neural network. This can be seen as a non-linear extension of classic LDA. Instead of maximizing the likelihood of target labels for individual samples, we pr...
Faraway, Julian J
2014-01-01
A Hands-On Way to Learning Data AnalysisPart of the core of statistics, linear models are used to make predictions and explain the relationship between the response and the predictors. Understanding linear models is crucial to a broader competence in the practice of statistics. Linear Models with R, Second Edition explains how to use linear models in physical science, engineering, social science, and business applications. The book incorporates several improvements that reflect how the world of R has greatly expanded since the publication of the first edition.New to the Second EditionReorganiz
Carr, Joseph
1996-01-01
The linear IC market is large and growing, as is the demand for well trained technicians and engineers who understand how these devices work and how to apply them. Linear Integrated Circuits provides in-depth coverage of the devices and their operation, but not at the expense of practical applications in which linear devices figure prominently. This book is written for a wide readership from FE and first degree students, to hobbyists and professionals.Chapter 1 offers a general introduction that will provide students with the foundations of linear IC technology. From chapter 2 onwa
Generalized Linear Orthomorphisms
Haiqing Han
2013-05-01
Full Text Available In this study, we generalize the conception of orthomorphisms and obtain a counting formula on the generalized linear orthomorphisms over the Galois field with the arbitrary prime number p as the characteristic. Thus the partial generation algorithm of generalized linear orthomorphisms is achieved. The counting formula of the linear orthomorphisms over the finite field with characteristic 2 is the special case in our results. Furthermore, the generalized linear orthomorphisms generated and discussed in this study can gain the maximum branch number when they are designed as P-permutations.
Handbook on linear motor application
This book guides the application for Linear motor. It lists classification and speciality of Linear Motor, terms of linear-induction motor, principle of the Motor, types on one-side linear-induction motor, bilateral linear-induction motor, linear-DC Motor on basic of the motor, linear-DC Motor for moving-coil type, linear-DC motor for permanent-magnet moving type, linear-DC motor for electricity non-utility type, linear-pulse motor for variable motor, linear-pulse motor for permanent magneto type, linear-vibration actuator, linear-vibration actuator for moving-coil type, linear synchronous motor, linear electromagnetic motor, linear electromagnetic solenoid, technical organization and magnetic levitation and linear motor and sensor.
Linear Equations: Equivalence = Success
Baratta, Wendy
2011-01-01
The ability to solve linear equations sets students up for success in many areas of mathematics and other disciplines requiring formula manipulations. There are many reasons why solving linear equations is a challenging skill for students to master. One major barrier for students is the inability to interpret the equals sign as anything other than…
An improved recirculating electron beam linear accelerator of the racetrack type is described. The system comprises a beam path of four straight legs with four Pretzel bending magnets at the end of each leg to direct the beam into the next leg of the beam path. At least one of the beam path legs includes a linear accelerator. (UK)
Albici, Mihaela; Teselios, Delia; Prundeanu, Raluca; Popa, Ionela
2010-01-01
Any linear programming problem marked as P and called ”primal” can be seen in connection with another linear programming problem marked as D and called ”dual”. The economic interpretation of the dual model brings about new information when analyzing such phenomena and when substantiating decision making
Efficient Non Linear Loudspeakers
Petersen, Bo R.; Agerkvist, Finn T.
2006-01-01
Loudspeakers have traditionally been designed to be as linear as possible. However, as techniques for compensating non linearities are emerging, it becomes possible to use other design criteria. This paper present and examines a new idea for improving the efficiency of loudspeakers at high levels...
Linear models: permutation methods
Cade, B.S.
2005-01-01
Permutation tests (see Permutation Based Inference) for the linear model have applications in behavioral studies when traditional parametric assumptions about the error term in a linear model are not tenable. Improved validity of Type I error rates can be achieved with properly constructed permutation tests. Perhaps more importantly, increased statistical power, improved robustness to effects of outliers, and detection of alternative distributional differences can be achieved by coupling permutation inference with alternative linear model estimators. For example, it is well-known that estimates of the mean in linear model are extremely sensitive to even a single outlying value of the dependent variable compared to estimates of the median [7, 19]. Traditionally, linear modeling focused on estimating changes in the center of distributions (means or medians). However, quantile regression allows distributional changes to be estimated in all or any selected part of a distribution or responses, providing a more complete statistical picture that has relevance to many biological questions [6]...
Semidefinite linear complementarity problems
Semidefinite linear complementarity problems arise by discretization of variational inequalities describing e.g. elastic contact problems, free boundary value problems etc. In the present paper linear complementarity problems are introduced and the theory as well as the numerical treatment of them are described. In the special case of semidefinite linear complementarity problems a numerical method is presented which combines the advantages of elimination and iteration methods without suffering from their drawbacks. This new method has very attractive properties since it has a high degree of invariance with respect to the representation of the set of all feasible solutions of a linear complementarity problem by linear inequalities. By means of some practical applications the properties of the new method are demonstrated. (orig.)
Axler, Sheldon
2015-01-01
This best-selling textbook for a second course in linear algebra is aimed at undergrad math majors and graduate students. The novel approach taken here banishes determinants to the end of the book. The text focuses on the central goal of linear algebra: understanding the structure of linear operators on finite-dimensional vector spaces. The author has taken unusual care to motivate concepts and to simplify proofs. A variety of interesting exercises in each chapter helps students understand and manipulate the objects of linear algebra. The third edition contains major improvements and revisions throughout the book. More than 300 new exercises have been added since the previous edition. Many new examples have been added to illustrate the key ideas of linear algebra. New topics covered in the book include product spaces, quotient spaces, and dual spaces. Beautiful new formatting creates pages with an unusually pleasant appearance in both print and electronic versions. No prerequisites are assumed other than the ...
Santos, Maira R.; Silveira, Thiago B.; Garcia, Paulo L.; Trindade, Cassia; Martins, Lais P.; Batista, Delano V.S., E-mail: mairafisica@gmail.com [Instituto Nacional do Cancer (INCA), Rio de Janeiro, RJ (Brazil)
2013-08-15
Given the new methodology introduced in the shielding calculation due to recent modulated techniques in radiotherapy treatment, it became necessary to evaluate the impact of changes in the accelerator routine using such techniques. Based on a group of 30 patients from the National Cancer Institute (INCA) the workload multiplier factors for intensity modulated radiotherapy (IMRT factor) and for RapidArc™ (RA factor) were established. Four different routines in a 6 MV generic accelerator were proposed to estimate the impact of these modified workloads in the building cost of the secondary barriers. The results indicate that if 50% of patients are treating with IMRT, the secondary barrier becomes 14,1% more expensive than the barrier calculated for conformal treatments exclusive. While RA, in the same proportion, leads to a barrier only 3,7% more expensive. Showing that RA can, while reducing treatment time, increase the proportion of patients treated with modulation technique, without increasing the cost of the barrier, when compared with IMRT. (author)
Weisberg, Sanford
2005-01-01
Master linear regression techniques with a new edition of a classic text Reviews of the Second Edition: ""I found it enjoyable reading and so full of interesting material that even the well-informed reader will probably find something new . . . a necessity for all of those who do linear regression."" -Technometrics, February 1987 ""Overall, I feel that the book is a valuable addition to the now considerable list of texts on applied linear regression. It should be a strong contender as the leading text for a first serious course in regression analysis."" -American Scientist, May-June 1987
Linear Network Fractional Routing
S.ASOKAN,
2011-07-01
Full Text Available A Network is a finite directed acyclic graph with source messages from a fixed alphabet and message demands at sink nodes. Linear Programming is an algorithm design method. It can be used whenthe solution to a problem can be viewed as the result of a sequence of decisions. The Linear Programming model for the network problem where in every variable has a value one or zero. The problem is todetermine a method of transmitting the messages through the network such that all sink demands are satisfied. We will prove fractional routing capacity for some solvable network using Linear Programmingmodel.
Weisberg, Sanford
2013-01-01
Praise for the Third Edition ""...this is an excellent book which could easily be used as a course text...""-International Statistical Institute The Fourth Edition of Applied Linear Regression provides a thorough update of the basic theory and methodology of linear regression modeling. Demonstrating the practical applications of linear regression analysis techniques, the Fourth Edition uses interesting, real-world exercises and examples. Stressing central concepts such as model building, understanding parameters, assessing fit and reliability, and drawing conclusions, the new edition illus
Amir-Moez, A R; Sneddon, I N
1962-01-01
Elements of Linear Space is a detailed treatment of the elements of linear spaces, including real spaces with no more than three dimensions and complex n-dimensional spaces. The geometry of conic sections and quadric surfaces is considered, along with algebraic structures, especially vector spaces and transformations. Problems drawn from various branches of geometry are given.Comprised of 12 chapters, this volume begins with an introduction to real Euclidean space, followed by a discussion on linear transformations and matrices. The addition and multiplication of transformations and matrices a
Schneider, Hans
1989-01-01
Linear algebra is one of the central disciplines in mathematics. A student of pure mathematics must know linear algebra if he is to continue with modern algebra or functional analysis. Much of the mathematics now taught to engineers and physicists requires it.This well-known and highly regarded text makes the subject accessible to undergraduates with little mathematical experience. Written mainly for students in physics, engineering, economics, and other fields outside mathematics, the book gives the theory of matrices and applications to systems of linear equations, as well as many related t
Unsupervised Linear Discriminant Analysis
无
2006-01-01
An algorithm for unsupervised linear discriminant analysis was presented. Optimal unsupervised discriminant vectors are obtained through maximizing covariance of all samples and minimizing covariance of local k-nearest neighbor samples. The experimental results show our algorithm is effective.
Linear Integer Arithmetic Revisited
Bromberger, M.; Sturm, T.; Weidenbach, C.
2015-01-01
We consider feasibility of linear integer programs in the context of verification systems such as SMT solvers or theorem provers. Although satisfiability of linear integer programs is decidable, many state-of-the-art solvers neglect termination in favor of efficiency. It is challenging to design a solver that is both terminating and practically efficient. Recent work by Jovanovic and de Moura constitutes an important step into this direction. Their algorithm CUTSAT is sound, but does not term...
Callier, Frank M.; Desoer, Charles A.
1991-01-01
The aim of this book is to provide a systematic and rigorous access to the main topics of linear state-space system theory in both the continuous-time case and the discrete-time case; and the I/O description of linear systems. The main thrusts of the work are the analysis of system descriptions and derivations of their properties, LQ-optimal control, state feedback and state estimation, and MIMO unity-feedback systems.
Høskuldsson, Agnar
1996-01-01
Determination of the proper dimension of a given linear model is one of the most important tasks in the applied modeling work. We consider here eight criteria that can be used to determine the dimension of the model, or equivalently, the number of components to use in the model. Four of these...... the basic problems in determining the dimension of linear models. Then each of the eight measures are treated. The results are illustrated by examples....
Online Sparse Linear Regression
Foster, Dean; Kale, Satyen; Karloff, Howard
2016-01-01
We consider the online sparse linear regression problem, which is the problem of sequentially making predictions observing only a limited number of features in each round, to minimize regret with respect to the best sparse linear regressor, where prediction accuracy is measured by square loss. We give an inefficient algorithm that obtains regret bounded by $\\tilde{O}(\\sqrt{T})$ after $T$ prediction rounds. We complement this result by showing that no algorithm running in polynomial time per i...
Andrilli, Stephen
2010-01-01
Elementary Linear Algebra develops and explains in careful detail the computational techniques and fundamental theoretical results central to a first course in linear algebra. This highly acclaimed text focuses on developing the abstract thinking essential for further mathematical study. The authors give early, intensive attention to the skills necessary to make students comfortable with mathematical proofs. The text builds a gradual and smooth transition from computational results to general theory of abstract vector spaces. It also provides flexbile coverage of practical applications, expl
Systematized linear epidermolytic hyperkeratosis
Kumar, Piyush; Kumar, Rajesh; Mandal, Rajesh Kumar; Hassan, Shahid
2014-01-01
A 5-year-old boy presented with widespread asymptomatic hyperpigmented verrucous plaques since 3 months of age. The lesions were distributed in a linear manner along Blaschko's lines on trunk and extremities and were accentuated in flexures and around joints. There was no history of blistering or redness and no other family member was affected. Ichthyosis hystrix (of Curth and Macklin) and generalized linear/mosaic epidermolytic hyperkeratosis (EHK) were considered in the differential diagnos...
Preconditioning Parametrized Linear Systems
Grim-McNally, Arielle; de Sturler, Eric; Gugercin, Serkan
2016-01-01
Preconditioners are generally essential for fast convergence in the iterative solution of linear systems of equations. However, the computation of a good preconditioner can be expensive. So, while solving a sequence of many linear systems, it is advantageous to recycle preconditioners, that is, update a previous preconditioner and reuse the updated version. In this paper, we introduce a simple and effective method for doing this. Although our approach can be used for matrices changing slowly ...
Blyth, T S
2002-01-01
Most of the introductory courses on linear algebra develop the basic theory of finite dimensional vector spaces, and in so doing relate the notion of a linear mapping to that of a matrix. Generally speaking, such courses culminate in the diagonalisation of certain matrices and the application of this process to various situations. Such is the case, for example, in our previous SUMS volume Basic Linear Algebra. The present text is a continuation of that volume, and has the objective of introducing the reader to more advanced properties of vector spaces and linear mappings, and consequently of matrices. For readers who are not familiar with the contents of Basic Linear Algebra we provide an introductory chapter that consists of a compact summary of the prerequisites for the present volume. In order to consolidate the student's understanding we have included a large num ber of illustrative and worked examples, as well as many exercises that are strategi cally placed throughout the text. Solutions to the ex...
Classifications of Linear Controlled Systems
Li, Jing
2008-01-01
This paper is devoted to a study of linear, differential and topological classifications for linear controlled systems governed by ordinary differential equations. The necessary and sufficient conditions for the linear and topological equivalence are given. It is also shown that the differential equivalence is the same as the linear equivalence for the linear controlled systems.
Cooperstein, Bruce
2015-01-01
Advanced Linear Algebra, Second Edition takes a gentle approach that starts with familiar concepts and then gradually builds to deeper results. Each section begins with an outline of previously introduced concepts and results necessary for mastering the new material. By reviewing what students need to know before moving forward, the text builds a solid foundation upon which to progress. The new edition of this successful text focuses on vector spaces and the maps between them that preserve their structure (linear transformations). Designed for advanced undergraduate and beginning graduate stud
Green, Ben; Tao, Terence
2006-01-01
Consider a system \\Psi of non-constant affine-linear forms \\psi_1,...,\\psi_t: Z^d -> Z, no two of which are linearly dependent. Let N be a large integer, and let K be a convex subset of [-N,N]^d. A famous and difficult open conjecture of Hardy and Littlewood predicts an asymptotic, as N -> \\infty, for the number of integer points n in K for which the integers \\psi_1(n),...,\\psi_t(n) are simultaneously prime. This implies many other well-known conjectures, such as the Hardy-Littlewood prime tu...
Structured Stochastic Linear Bandits
Johnson, Nicholas; Sivakumar, Vidyashankar; Banerjee, Arindam
2016-01-01
The stochastic linear bandit problem proceeds in rounds where at each round the algorithm selects a vector from a decision set after which it receives a noisy linear loss parameterized by an unknown vector. The goal in such a problem is to minimize the (pseudo) regret which is the difference between the total expected loss of the algorithm and the total expected loss of the best fixed vector in hindsight. In this paper, we consider settings where the unknown parameter has structure, e.g., spa...
Hogben, Leslie
2013-01-01
With a substantial amount of new material, the Handbook of Linear Algebra, Second Edition provides comprehensive coverage of linear algebra concepts, applications, and computational software packages in an easy-to-use format. It guides you from the very elementary aspects of the subject to the frontiers of current research. Along with revisions and updates throughout, the second edition of this bestseller includes 20 new chapters.New to the Second EditionSeparate chapters on Schur complements, additional types of canonical forms, tensors, matrix polynomials, matrix equations, special types of
Linear quantum feedback networks
Gough, J. E.; Gohm, R.; Yanagisawa, M.
2008-12-01
The mathematical theory of quantum feedback networks has recently been developed [J. Gough and M. R. James, e-print arXiv:0804.3442v2] for general open quantum dynamical systems interacting with bosonic input fields. In this article we show, for the special case of linear dynamical Markovian systems with instantaneous feedback connections, that the transfer functions can be deduced and agree with the algebraic rules obtained in the nonlinear case. Using these rules, we derive the transfer functions for linear quantum systems in series, in cascade, and in feedback arrangements mediated by beam splitter devices.
Linear Logical Voting Protocols
DeYoung, Henry; Schürmann, Carsten
2012-01-01
Current approaches to electronic implementations of voting protocols involve translating legal text to source code of an imperative programming language. Because the gap between legal text and source code is very large, it is difficult to trust that the program meets its legal specification....... In response, we promote linear logic as a high-level language for both specifying and implementing voting protocols. Our linear logical specifications of the single-winner first-past-the-post (SW- FPTP) and single transferable vote (STV) protocols demonstrate that this approach leads to concise...
Linear Mappings of Quaternion Algebra
Kleyn, Aleks
2011-01-01
In the paper I considered linear and antilinear automorphisms of quaternion algebra. I proved the theorem that there is unique expansion of R-linear mapping of quaternion algebra relative to the given set of linear and antilinear automorphisms.
Non linear viscoelastic models
Agerkvist, Finn T.
2011-01-01
Viscoelastic eects are often present in loudspeaker suspensions, this can be seen in the displacement transfer function which often shows a frequency dependent value below the resonance frequency. In this paper nonlinear versions of the standard linear solid model (SLS) are investigated. The...
Dobbs, David E.
2013-01-01
A direct method is given for solving first-order linear recurrences with constant coefficients. The limiting value of that solution is studied as "n to infinity." This classroom note could serve as enrichment material for the typical introductory course on discrete mathematics that follows a calculus course.
Averin, D. V.
2003-01-01
Linear response theory describes quantum measurement with an arbitrary detector weakly coupled to a measured system. This description produces generic quantitative relation characterizing the detector that is analogous to the fluctuation-dissipation theorem for equilibrium systems. The detector characteristic obtained in this way shows how efficient the trade-off is between the back-action dephasing and information acquisition by the detector.
Linear Complete Differential Resultants and the Implicitization of Linear DPPEs
Rueda, Sonia L.; Sendra, J. Rafael
2007-01-01
The linear complete differential resultant of a finite set of linear ordinary differential polynomials is defined. We study the computation by linear complete differential resultants of the implicit equation of a system of $n$ linear differential polynomial parametric equations in $n-1$ differential parameters. We give necessary conditions to ensure properness of the system of differential polynomial parametric equations.
Ramirez-Ros, J.; Garcia-Marcos, R.; Huertas Martinez, M. c.; Hurtado Sanchez, A.
2015-07-01
We discuss the field factors obtained for a linear accelerator electron multi energetic with irradiation standard modes and flatter unfiltered. We compared the values obtained with several diodes, two chambers of ionization and film radiochromic We obtain correction factors for diodes and. Finally, we evaluate the Daisy-Chain method, depending on the detector and the field of step. (Author)
Goldowsky, Michael P. (Inventor)
1987-01-01
A reciprocating linear motor is formed with a pair of ring-shaped permanent magnets having opposite radial polarizations, held axially apart by a nonmagnetic yoke, which serves as an axially displaceable armature assembly. A pair of annularly wound coils having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils serially coupled together in mutual opposition and an inner cylindrical core positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils.
Nathanson, Melvyn B.
2006-01-01
The quantum integer $[n]_q$ is the polynomial $1 + q + q^2 + ... + q^{n-1}.$ Two sequences of polynomials $\\mathcal{U} = \\{u_n(q)\\}_{n=1}^{\\infty}$ and $\\mathcal{V} = \\{v_n(q)\\}_{n=1}^{\\infty}$ define a {\\em linear addition rule} $\\oplus$ on a sequence $\\mathcal{F} = \\{f_n(q)\\}_{n=1}^{\\infty}$ by $f_m(q)\\oplus f_n(q) = u_n(q)f_m(q) + v_m(q)f_n(q).$ This is called a {\\em quantum addition rule} if $[m]_q \\oplus [n]_q = [m+n]_q$ for all positive integers $m$ and $n$. In this paper all linear qua...
General linear chirplet transform
Yu, Gang; Zhou, Yiqi
2016-03-01
Time-frequency (TF) analysis (TFA) method is an effective tool to characterize the time-varying feature of a signal, which has drawn many attentions in a fairly long period. With the development of TFA, many advanced methods are proposed, which can provide more precise TF results. However, some restrictions are introduced inevitably. In this paper, we introduce a novel TFA method, termed as general linear chirplet transform (GLCT), which can overcome some limitations existed in current TFA methods. In numerical and experimental validations, by comparing with current TFA methods, some advantages of GLCT are demonstrated, which consist of well-characterizing the signal of multi-component with distinct non-linear features, being independent to the mathematical model and initial TFA method, allowing for the reconstruction of the interested component, and being non-sensitivity to noise.
The SLAC Linear Collider has begun a new era of operation with the SLD detector. During 1991 there was a first engineering run for the SLD in parallel with machine improvements to increase luminosity and reliability. For the 1992 run, a polarized electron source was added and more than 10,000 Zs with an average of 23% polarization have been logged by the SLD. This paper discusses the performance of the SLC in 1991 and 1992 and the technical advances that have produced higher luminosity. Emphasis will be placed on issues relevant to future linear colliders such as producing and maintaining high current, low emittance beams and focusing the beams to the micron scale for collisions. (Author) tab., 2 figs., 18 refs
Schmidt, Bruno E; Ernotte, Guilmot; Clerici, Matteo; Morandotti, Roberto; Ibrahim, Heide; Legare, Francois
2016-01-01
In the framework of linear optics, light fields do not interact with each other in a medium. Yet, when their field amplitude becomes comparable to the electron binding energies of matter, the nonlinear motion of these electrons emits new dipole radiation whose amplitude, frequency and phase differ from the incoming fields. Such high fields are typically achieved with ultra-short, femtosecond (1fs = 10-15 sec.) laser pulses containing very broad frequency spectra. Here, the matter not only couples incoming and outgoing fields but also causes different spectral components to interact and mix through a convolution process. In this contribution, we describe how frequency domain nonlinear optics overcomes the shortcomings arising from this convolution in conventional time domain nonlinear optics1. We generate light fields with previously inaccessible properties because the uncontrolled coupling of amplitudes and phases is turned off. For example, arbitrary phase functions are transferred linearly to the second har...
Extended linear chain compounds
Linear chain substances span a large cross section of contemporary chemistry ranging from covalent polymers, to organic charge transfer com plexes to nonstoichiometric transition metal coordination complexes. Their commonality, which coalesced intense interest in the theoretical and exper imental solid state physics/chemistry communities, was based on the obser vation that these inorganic and organic polymeric substrates exhibit striking metal-like electrical and optical properties. Exploitation and extension of these systems has led to the systematic study of both the chemistry and physics of highly and poorly conducting linear chain substances. To gain a salient understanding of these complex materials rich in anomalous aniso tropic electrical, optical, magnetic, and mechanical properties, the conver gence of diverse skills and talents was required. The constructive blending of traditionally segregated disciplines such as synthetic and physical organic, inorganic, and polymer chemistry, crystallog...
Relativistic Linear Restoring Force
Clark, D.; Franklin, J.; Mann, N.
2012-01-01
We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…
Combustion powered linear actuator
Fischer, Gary J.
2007-09-04
The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.
Sander, K F
1964-01-01
Linear Network Theory covers the significant algebraic aspect of network theory, with minimal reference to practical circuits. The book begins the presentation of network analysis with the exposition of networks containing resistances only, and follows it up with a discussion of networks involving inductance and capacity by way of the differential equations. Classification and description of certain networks, equivalent networks, filter circuits, and network functions are also covered. Electrical engineers, technicians, electronics engineers, electricians, and students learning the intricacies
Eberly, Lynn E
2007-01-01
This chapter describes multiple linear regression, a statistical approach used to describe the simultaneous associations of several variables with one continuous outcome. Important steps in using this approach include estimation and inference, variable selection in model building, and assessing model fit. The special cases of regression with interactions among the variables, polynomial regression, regressions with categorical (grouping) variables, and separate slopes models are also covered. Examples in microbiology are used throughout. PMID:18450050
The linear Grad-Shafranov equation for a toroidal, axisymmetric plasma is solved analytically. Exact solutions are given in terms of confluent hyper-geometric functions. As an alternative, simple and accurate WKBJ solutions are presented. With parabolic pressure profiles, both hollow and peaked toroidal current density profiles are obtained. As an example the equilibrium of a z-pinch with a square-shaped cross section is derived.(author)
Fundamentals of linear algebra
Dash, Rajani Ballav
2008-01-01
FUNDAMENTALS OF LINEAR ALGEBRA is a comprehensive Text Book, which can be used by students and teachers of All Indian Universities. The Text has easy, understandable form and covers all topics of UGC Curriculum. There are lots of worked out examples which helps the students in solving the problems without anybody's help. The Problem sets have been designed keeping in view of the questions asked in different examinations.
Miniature linear cooler development
An overview is presented of the status of a family of miniature linear coolers currently under development by Hughes Aircraft Co. for use in hand held, volume limited or power limited infrared applications. These coolers, representing the latest additions to the Hughes family of TOP trademark [twin-opposed piston] linear coolers, have been fabricated and tested in three different configurations. Each configuration is designed to utilize a common compressor assembly resulting in reduced manufacturing costs. The baseline compressor has been integrated with two different expander configurations and has been operated with two different levels of input power. These various configuration combinations offer a wide range of performance and interface characteristics which may be tailored to applications requiring limited power and size without significantly compromising cooler capacity or cooldown characteristics. Key cooler characteristics and test data are summarized for three combinations of cooler configurations which are representative of the versatility of this linear cooler design. Configurations reviewed include the shortened coldfinger [1.50 to 1.75 inches long], limited input power [less than 17 Watts] for low power availability applications; the shortened coldfinger with higher input power for lightweight, higher performance applications; and coldfingers compatible with DoD 0.4 Watt Common Module coolers for wider range retrofit capability. Typical weight of these miniature linear coolers is less than 500 grams for the compressor, expander and interconnecting transfer line. Cooling capacity at 80K at room ambient conditions ranges from 400 mW to greater than 550 mW. Steady state power requirements for maintaining a heat load of 150 mW at 80K has been shown to be less than 8 Watts. Ongoing reliability growth testing is summarized including a review of the latest test article results
Uhlmann, Armin
2016-03-01
This is an introduction to antilinear operators. In following Wigner the terminus antilinear is used as it is standard in Physics. Mathematicians prefer to say conjugate linear. By restricting to finite-dimensional complex-linear spaces, the exposition becomes elementary in the functional analytic sense. Nevertheless it shows the amazing differences to the linear case. Basics of antilinearity is explained in sects. 2, 3, 4, 7 and in sect. 1.2: Spectrum, canonical Hermitian form, antilinear rank one and two operators, the Hermitian adjoint, classification of antilinear normal operators, (skew) conjugations, involutions, and acq-lines, the antilinear counterparts of 1-parameter operator groups. Applications include the representation of the Lagrangian Grassmannian by conjugations, its covering by acq-lines. As well as results on equivalence relations. After remembering elementary Tomita-Takesaki theory, antilinear maps, associated to a vector of a two-partite quantum system, are defined. By allowing to write modular objects as twisted products of pairs of them, they open some new ways to express EPR and teleportation tasks. The appendix presents a look onto the rich structure of antilinear operator spaces.
Linearized Kernel Dictionary Learning
Golts, Alona; Elad, Michael
2016-06-01
In this paper we present a new approach of incorporating kernels into dictionary learning. The kernel K-SVD algorithm (KKSVD), which has been introduced recently, shows an improvement in classification performance, with relation to its linear counterpart K-SVD. However, this algorithm requires the storage and handling of a very large kernel matrix, which leads to high computational cost, while also limiting its use to setups with small number of training examples. We address these problems by combining two ideas: first we approximate the kernel matrix using a cleverly sampled subset of its columns using the Nystr\\"{o}m method; secondly, as we wish to avoid using this matrix altogether, we decompose it by SVD to form new "virtual samples," on which any linear dictionary learning can be employed. Our method, termed "Linearized Kernel Dictionary Learning" (LKDL) can be seamlessly applied as a pre-processing stage on top of any efficient off-the-shelf dictionary learning scheme, effectively "kernelizing" it. We demonstrate the effectiveness of our method on several tasks of both supervised and unsupervised classification and show the efficiency of the proposed scheme, its easy integration and performance boosting properties.
The Stanford Linear Collider (SLC) is the first and only high-energy e+e- linear collider in the world. Its most remarkable features are high intensity, submicron sized, polarized (e-) beams at a single interaction point. The main challenges posed by these unique characteristics include machine-wide emittance preservation, consistent high intensity operation, polarized electron production and transport, and the achievement of a high degree of beam stability on all time scales. In addition to serving as an important machine for the study of Z0 boson production and decay using polarized beams, the SLC is also an indispensable source of hands-on experience for future linear colliders. Each new year of operation has been highlighted with a marked improvement in performance. The most significant improvements for the 1994-95 run include new low impedance vacuum chambers for the damping rings, an upgrade to the optics and diagnostics of the final focus systems, and a higher degree of polarization from the electron source. As a result, the average luminosity has nearly doubled over the previous year with peaks approaching 1030 cm-2s-1 and an 80% electron polarization at the interaction point. These developments as well as the remaining identifiable performance limitations will be discussed
Linear capacity storage devices
The linearity of information storage in capacitor storage circuits is discussed. The paper describes two storage circuits whose operation is linear over a wide range of output-signal amplitudes. In one of the circuits the error signal is measured by a differential amplifier and, thanks to the high amplification factor of the amplifier, good linearity is obtained. The second circuit was designed for work in the nanosecond pulse-width range. Input pulses of standard width cut off a pentode, in the anode of which there is a memory capacitor. Since the capacitor is charged from the anode supply through a current generator, the charging current remains almost constant during measurement of the capacitor voltage. The pentode has a large internal resistance so that after the end of the input pulse the magnitude of the current through the pentode is almost equal to its initial value, and the charge stored by the capacitor is remembered. The width of the information memory is limited by the output resistance of the current generator and the internal resistance (Ri) of the pentode. To increase the memory width, a diode may be inserted before the capacitor. (author)
Springer, T A
1998-01-01
"[The first] ten chapters...are an efficient, accessible, and self-contained introduction to affine algebraic groups over an algebraically closed field. The author includes exercises and the book is certainly usable by graduate students as a text or for self-study...the author [has a] student-friendly style… [The following] seven chapters... would also be a good introduction to rationality issues for algebraic groups. A number of results from the literature…appear for the first time in a text." –Mathematical Reviews (Review of the Second Edition) "This book is a completely new version of the first edition. The aim of the old book was to present the theory of linear algebraic groups over an algebraically closed field. Reading that book, many people entered the research field of linear algebraic groups. The present book has a wider scope. Its aim is to treat the theory of linear algebraic groups over arbitrary fields. Again, the author keeps the treatment of prerequisites self-contained. The material of t...
Becker, Jörg D.
2015-01-01
In many European countries the growth of the real GDP per capita has been linear since 1950. An explanation for this linearity is still missing. We propose that in artificial intelligence we may find models for a linear growth of performance. We also discuss possible consequences of the fact that in systems with linear growth the percentage growth goes to zero.
Fermionic Linear Optics and Matchgates
Knill, E.
2001-01-01
Fermionic linear optics is efficiently classically simulatable. Here it is shown that the set of states achievable with fermionic linear optics and particle measurements is the closure of a low dimensional Lie group. The weakness of fermionic linear optics and measurements can therefore be explained and contrasted with the strength of bosonic linear optics with particle measurements. An analysis of fermionic linear optics is used to show that the two-qubit matchgates and the simulatable match...
Conceição, Ana; PEREIRA, José; Silva, Cátia; Simão, Cristina
2012-01-01
The article (see http://hdl.handle.net/10400.1/1105) was first presented in the 1st National Conference on Symbolic Computation in Education and Research, IST Portugal 2012, where distinguished with the Timberlake Award for Best Article by a Young Researcher. On how to work with the CDF format please see http://www.wolfram.com/cdf-player/. F-Linear is a F-Tool (see http://hdl.handle.net/10400.1/1105), that is, a visual, dynamic, and interactive teaching tool that allow to explore in an inn...
Wangler, Thomas P
2008-01-01
Thomas P. Wangler received his B.S. degree in physics from Michigan State University, and his Ph.D. degree in physics and astronomy from the University of Wisconsin. After postdoctoral appointments at the University of Wisconsin and Brookhaven National Laboratory, he joined the staff of Argonne National Laboratory in 1966, working in the fields of experimental high-energy physics and accelerator physics. He joined the Accelerator Technology Division at Los Alamos National Laboratory in 1979, where he specialized in high-current beam physics and linear accelerator design and technology. In 2007
Perkins, Gerald S. (Inventor)
1980-01-01
A linear actuator which can apply high forces is described, which includes a reciprocating rod having a threaded portion engaged by a nut that is directly coupled to the rotor of an electric motor. The nut is connected to the rotor in a manner that minimizes loading on the rotor, by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded rod portion, with an oilcarrying groove in the nut being interrupted.
Linear Probability Forecasting
Zhdanov, Fedor
2010-01-01
Multi-class classification is one of the most important tasks in machine learning. In this paper we consider two online multi-class classification problems: classification by a linear model and by a kernelized model. The quality of predictions is measured by the Brier loss function. We suggest two computationally efficient algorithms to work with these problems and prove theoretical guarantees on their losses. We kernelize one of the algorithms and prove theoretical guarantees on its loss. We perform experiments and compare our algorithms with logistic regression.
Lopez, Cesar
2014-01-01
MATLAB is a high-level language and environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spreadsheets or traditional programming languages, such as C/C++ or Java. MATLAB Linear Algebra introduces you to the MATLAB language with practical hands-on instructions and results, allowing you to quickly achieve your goals. In addition to giving an introduction to
El-Orany, Faisal A A
2009-01-01
In this paper, we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of them includes a localized and/or a trapped atom. These waveguides are placed close enough to allow exchanging energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way, i.e. as the Jaynes-Cummings model (JCM), and with the atom-mode in the second waveguide via evanescent wave. We present the Hamiltonian for the system and deduce the exact form for the wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional linear coupler, the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions, the system can yield the results of the two-m...
The purpose of the linear wind-power generator described in this article is to decrease the following disadvantages of the common wind-powered turbine: 1) large bending and twisting moments to the blades and the shaft, especially when strong winds and turbulence exist; 2) significant values of the natural oscillation period of the construction result in the possibility of occurrence of destroying resonance oscillations; 3) high velocity of the peripheral parts of the rotor creating a danger for birds; 4) difficulties, connected with the installation and the operation on the mountain ridges and passages where the wind energy potential is the largest. The working surfaces of the generator in questions driven by the wind are not connected with a joint shaft but each moves along a railway track with few oscillations. So the sizes of each component are small and their number can be rather large. The mechanical trajectory is not a circle but a closed outline in a vertical plain, which consists of two rectilinear sectors, one above the other, connected in their ends by semi-circumferences. The mechanical energy of each component turns into electrical on the principle of the linear electrical generator. A regulation is provided when the direction of the wind is perpendicular to the route. A possibility of effectiveness is shown through aiming of additional quantities of air to the movable components by static barriers
Pseudo Linear Gyro Calibration
Harman, Richard; Bar-Itzhack, Itzhack Y.
2003-01-01
Previous high fidelity onboard attitude algorithms estimated only the spacecraft attitude and gyro bias. The desire to promote spacecraft and ground autonomy and improvements in onboard computing power has spurred development of more sophisticated calibration algorithms. Namely, there is a desire to provide for sensor calibration through calibration parameter estimation onboard the spacecraft as well as autonomous estimation on the ground. Gyro calibration is a particularly challenging area of research. There are a variety of gyro devices available for any prospective mission ranging from inexpensive low fidelity gyros with potentially unstable scale factors to much more expensive extremely stable high fidelity units. Much research has been devoted to designing dedicated estimators such as particular Extended Kalman Filter (EKF) algorithms or Square Root Information Filters. This paper builds upon previous attitude, rate, and specialized gyro parameter estimation work performed with Pseudo Linear Kalman Filter (PSELIKA). The PSELIKA advantage is the use of the standard linear Kalman Filter algorithm. A PSELIKA algorithm for an orthogonal gyro set which includes estimates of attitude, rate, gyro misalignments, gyro scale factors, and gyro bias is developed and tested using simulated and flight data. The measurements PSELIKA uses include gyro and quaternion tracker data.
Bonding a linearly piezoelectric patch on a linearly elastic body
Licht, Christian; Orankitjaroen, Somsak; Viriyasrisuwattana, Patcharakorn; Weller, Thibaut
2014-04-01
A rigorous study of the asymptotic behavior of the system constituted by a very thin linearly piezoelectric plate bonded on a linearly elastic body supplies various models for an elastic body monitored by a piezoelectric patch. xml:lang="fr"
On the linear programming bound for linear Lee codes.
Astola, Helena; Tabus, Ioan
2016-01-01
Based on an invariance-type property of the Lee-compositions of a linear Lee code, additional equality constraints can be introduced to the linear programming problem of linear Lee codes. In this paper, we formulate this property in terms of an action of the multiplicative group of the field [Formula: see text] on the set of Lee-compositions. We show some useful properties of certain sums of Lee-numbers, which are the eigenvalues of the Lee association scheme, appearing in the linear programming problem of linear Lee codes. Using the additional equality constraints, we formulate the linear programming problem of linear Lee codes in a very compact form, leading to a fast execution, which allows to efficiently compute the bounds for large parameter values of the linear codes. PMID:27026939
Linear algebra, geometry and transformation
Solomon, Bruce
2014-01-01
Vectors, Mappings and Linearity Numeric Vectors Functions Mappings and Transformations Linearity The Matrix of a Linear Transformation Solving Linear Systems The Linear SystemThe Augmented Matrix and RRE Form Homogeneous Systems in RRE Form Inhomogeneous Systems in RRE Form The Gauss-Jordan Algorithm Two Mapping Answers Linear Geometry Geometric Vectors Geometric/Numeric Duality Dot-Product Geometry Lines, Planes, and Hyperplanes System Geometry and Row/Column Duality The Algebra of Matrices Matrix Operations Special Matrices Matrix Inversion A Logical Digression The Logic of the Inversion Alg
This paper examines a new layout for the injector and accelerating sectins of a linear induction accelerator. The sections are combined in a single housing: an induction system with a current-pulse generator based on double strip shaping lines laid over ferromagnetic cores; a multichannel spark discharger with forced current division among channels; and a system for core demagnetization and electron-beam formation and transport. The results of formation of an electron beam in the injector system and its acceleration in the first accelerating section of the accelerator for injection of beams with energies of 0.2-0.4 MeV, currents of 1-2 kA, and pulse durations of 60 nsec are given
Standing wave linear accelerator
Consideration is being given to standing wave linear accelerator containing generator, phase shifter, two accelerating resonator sections, charged particle injector and waveguide bridge. Its first arm is oined up with generator via the phase shifter, the second and the third ones-with accelerating sections and the fourth one - with HF-power absorber. HF-power absorber represents a section of circular diaphragmatic wavequide with transformer with input wave and intrawaveguide output load located between injector and the first accelerating section. The section possesses holes in side walls lying on accelerator axis. The distances between centers of the last cell of the fast accelerating section and the first cell of the second accelerating sectiOn equal (2n+3)lambda/4, where n=1, 2, 3..., lambda - wave length of generator. The suggested system enables to improve by one order spectral characteristics of accelerators as compared to the prototype in which magnetrons are used as generator
Linear electrochemical gel actuators
Goswami, Shailesh; McAdam, C. John; Hanton, Lyall R.; Moratti, Stephen C.
2012-04-01
By using electroactive monomers it is possible to produce gels that respond to oxidation or reduction by swelling and deswelling in the presence of solvent. By the inclusion of an appropriate biasing element such as a spring, it is possible to produce linear, reversible actuation. The process can be driven electrochemically in a standard cell, with driving voltages under +/- 1 V. For many systems, the intrinsic conductivity of the gel, leading to poor or no performance. This can be overcome by blending conductive carbon nanotubes at 1% concentration, which give reasonable conductivity without affecting mechanical performance. Extensions of up to 40% are possible, against an external pressure of 30 kPa. The process is slow, taking up to 160 minutes per cycle due to slow ionic diffusion. The electrochemical cell can be cycled many times without degradation.
Adaptive functional linear regression
Comte, Fabienne
2011-01-01
We consider the estimation of the slope function in functional linear regression, where scalar responses are modeled in dependence of random functions. Cardot and Johannes [2010] have shown that a thresholded projection estimator can attain up to a constant minimax-rates of convergence in a general framework which allows to cover the prediction problem with respect to the mean squared prediction error as well as the estimation of the slope function and its derivatives. This estimation procedure, however, requires an optimal choice of a tuning parameter with regard to certain characteristics of the slope function and the covariance operator associated with the functional regressor. As this information is usually inaccessible in practice, we investigate a fully data-driven choice of the tuning parameter which combines model selection and Lepski's method. It is inspired by the recent work of Goldenshluger and Lepski [2011]. The tuning parameter is selected as minimizer of a stochastic penalized contrast function...
Introduction to linear elasticity
Gould, Phillip L
2013-01-01
Introduction to Linear Elasticity, 3rd Edition, provides an applications-oriented grounding in the tensor-based theory of elasticity for students in mechanical, civil, aeronautical, and biomedical engineering, as well as materials and earth science. The book is distinct from the traditional text aimed at graduate students in solid mechanics by introducing the subject at a level appropriate for advanced undergraduate and beginning graduate students. The author's presentation allows students to apply the basic notions of stress analysis and move on to advanced work in continuum mechanics, plasticity, plate and shell theory, composite materials, viscoelasticity and finite method analysis. This book also: Emphasizes tensor-based approach while still distilling down to explicit notation Provides introduction to theory of plates, theory of shells, wave propagation, viscoelasticity and plasticity accessible to advanced undergraduate students Appropriate for courses following emerging trend of teaching solid mechan...
Salgado, Ana Paula
2011-07-01
The clinical importance and usage of linear accelerators in cancer treatment increased significantly in the last years. Coupled with this growth came the concern about the use of accelerators with energies over to 10 MeV which produce therapeutic beam contaminated with neutrons generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. At these facilities, measurements of the ambient dose equivalent for neutrons present difficulties owing to the existence of a mixed radiation field and possible electromagnetic interference near the accelerator. The Neutron Laboratory of the IRD - Brazilian Institute for Radioprotection and Dosimetry, aiming to evaluate the survey meters performance at these facilities, initiated studies of instrumentation response in the presence of different neutron spectra. Neutrons sources with average energies ranging from 0.55 to 4.2 MeV, four different survey meters and one ionization chamber to obtain the ratio between the dose due to neutrons and gamma radiation were used in this work. The evaluation of these measurements, performed in a 15 MV linear accelerator room is presented. This work presents results that demonstrate the complexity and care needed to make neutrons measurements in radiotherapy treatment rooms containing high energy clinical accelerators. (author)
Quaternion Linear Canonical Transform Application
Bahri, Mawardi
2015-01-01
Quaternion linear canonical transform (QLCT) is a generalization of the classical linear canonical transfom (LCT) using quaternion algebra. The focus of this paper is to introduce an application of the QLCT to study of generalized swept-frequency filter
Computer Program For Linear Algebra
Krogh, F. T.; Hanson, R. J.
1987-01-01
Collection of routines provided for basic vector operations. Basic Linear Algebra Subprogram (BLAS) library is collection from FORTRAN-callable routines for employing standard techniques to perform basic operations of numerical linear algebra.
Linear maps respecting unitary conjugation
Bhat, B V Rajarama
2011-01-01
We characterize linear maps on von Neumann algebras which leave every unital subalgebra invariant. We use this characterization to determine linear maps which respect unitary conjugation, answering a question of M. S. Moslehian.
Monahan, John F
2008-01-01
Preface Examples of the General Linear Model Introduction One-Sample Problem Simple Linear Regression Multiple Regression One-Way ANOVA First Discussion The Two-Way Nested Model Two-Way Crossed Model Analysis of Covariance Autoregression Discussion The Linear Least Squares Problem The Normal Equations The Geometry of Least Squares Reparameterization Gram-Schmidt Orthonormalization Estimability and Least Squares Estimators Assumptions for the Linear Mean Model Confounding, Identifiability, and Estimability Estimability and Least Squares Estimators F
Engberg, Uffe Henrik; Winskel, Glynn
This article shows how individual Petri nets form models of Girard's intuitionistic linear logic. It explores questions of expressiveness and completeness of linear logic with respect to this interpretation. An aim is to use Petri nets to give an understanding of linear logic and give some apprai...
The experiments described in this paper show that there are two types of non-linear three-wave processes: A. Disintegration of an electron plasma wave. In a plasma column of a density of 108 to 109 electrons/cm3, an electron temperature of the order of several eV, a length of 60 cm, a radius of 1 cm, which is confined by a magnetic field of 2500 G, a monochromatic electron plasma wave of frequency f1 is excited. A noise spectrum in a frequency band always below f1 due to the disintegration of this wave is observed. The resonance relations are verified. The threshold level and the energy transfer lengths are measured. The results of measurement show that the mechanism of disintegration should be interpreted without making use of the random-phase hypothesis. The shape of the spectrum is explained by varying the interaction coefficient as a function of the different phase velocities. In the same way, the parameter amplification of a wave pre-excited at one of the disintegration spectrum frequencies is studied. B. Non-linear generation of an electromagnetic wave. In a plasma with an electron density between 109 and 1011 electrons/cm3, which is confined by a magnetic field of the order of 4000 G and generated by a stationary high-frequency discharge, the interaction of two microwave beams propagated perpendicularly to the confining magnetic field and polarized both according to ordinary and extraordinary modes is brought about. The intersection of these beams defines the volume of interaction in which the third wave is generated. Two processes were studied, depending on the polarization of the two primary waves: (OX.O') and (OO', X). The measurements show that the conditions of resonance imposed on the frequencies and propagation vectors are satisfied. The power released is compared with the theoretical value. The polarization of the generated wave is in accordance with that expected from the structure of the interaction matrix. (author)
On constructing disjoint linear codes
ZHANG Weiguo; CAI Mian; XIAO Guozhen
2007-01-01
To produce a highly nonlinear resilient function,the disjoint linear codes were originally proposed by Johansson and Pasalic in IEEE Trans.Inform.Theory,2003,49(2):494-501.In this paper,an effective method for finding a set of such disjoint linear codes is presented.When n≥2k,we can find a set of[n,k] disjoint linear codes with joint linear codes exists with cardinality at least 2.We also describe a result on constructing a set of [n,k] disjoint linear codes with minimum distance at least some fixed positive integer.
Generalized Linear Covariance Analysis
Carpenter, James R.; Markley, F. Landis
2014-01-01
This talk presents a comprehensive approach to filter modeling for generalized covariance analysis of both batch least-squares and sequential estimators. We review and extend in two directions the results of prior work that allowed for partitioning of the state space into solve-for'' and consider'' parameters, accounted for differences between the formal values and the true values of the measurement noise, process noise, and textita priori solve-for and consider covariances, and explicitly partitioned the errors into subspaces containing only the influence of the measurement noise, process noise, and solve-for and consider covariances. In this work, we explicitly add sensitivity analysis to this prior work, and relax an implicit assumption that the batch estimator's epoch time occurs prior to the definitive span. We also apply the method to an integrated orbit and attitude problem, in which gyro and accelerometer errors, though not estimated, influence the orbit determination performance. We illustrate our results using two graphical presentations, which we call the variance sandpile'' and the sensitivity mosaic,'' and we compare the linear covariance results to confidence intervals associated with ensemble statistics from a Monte Carlo analysis.
Du, Yigang
The theory for modeling non-linear acoustic propagation is addressed in the dissertation. The solutions to both the linear and non-linear wave equations have been found by an angular spectrum approach (ASA), in which an analytical expression can be derived. This makes the calculation complete...... without iteration steps. The ASA is implemented in combination with Field II and extended to simulate the pulsed ultrasound fields. The simulated results from a linear array transducer are made by the ASA based on Field II, and by a released non-linear simulation program- Abersim, respectively. The...... calculation speed of the ASA is increased approximately by a factor of 140. For the second harmonic point spread function the error of the full width is 1.5% at -6 dB and 6.4% at -12 dB compared to Abersim. To further investigate the linear and non-linear ultrasound fields, hydrophone measurements are...
Studi Transformasi Bentuk Fuzzy Linear Programming Ke Bentuk Linear Programming
Josephine
2011-01-01
Since the emergence of Fuzzy Linear Programming in the 1940s, the assumption of certainty about the values of the parameters in the decision-making problem which is modeled with linear programming in real-world systems are too complex to be defined and imprecision is often involved. Then to resolve and accommodate this uncertainty, the using of Fuzzy Linear Programming has an essential role which can formulate the uncertainty in the real-world problems. This study aims to simpl...
Avaliação hidráulica de um canal de rega equipado com diferentes controladores
Rijo, M.; Arranja, C.
2005-01-01
Apresenta-se um estudo comparativo de três modos de controlo de um canal de rega: i) controlo local por montante (com descarregadores do tipo bico de pato; com comportas planas verticais associadas a controladores do tipo Proporcional (P) ou do tipo Proporcional e Integral (PI); ii) controlo local por jusante com comportas planas verticais associadas a controladores do tipo PI; iii) controlo por jusante à distância com comportas planas verticais associadas a controladores do tipo PI. O caso e...
Cardena R, A. R.; Vega R, J. L.; Apaza V, D. G., E-mail: cardroj@yahoo.es [Universidad Nacional de San Agustin, Av. Independencia s/n, Arequipa (Peru)
2015-10-15
The progress in cancer treatment systems in heterogeneities of human body has had obstacles by the lack of a suitable experimental model test. The only option is to develop simulated theoretical models that have the same properties in interfaces similar to human tissues, to know the radiation behavior in the interaction with these materials. In this paper we used the Monte Carlo method by Penelope code based solely on studies for the cancer treatment as well as for the calibration of beams and their various interactions in mannequins. This paper also aims the construction, simulation and characterization of an equivalent object to the tissues of the human body with various heterogeneities, we will later use to control and plan experientially doses supplied in treating tumors in radiotherapy. To fulfill the objective we study the ionizing radiation and the various processes occurring in the interaction with matter; understanding that to calculate the dose deposited in tissues interfaces (percentage depth dose) must be taken into consideration aspects such as the deposited energy, irradiation fields, density, thickness, tissue sensitivity and other items. (Author)
Vega R, J. L.; Cayllahua, F.; Apaza, D. G.; Javier, H., E-mail: josevegaramirez@yahoo.es [Universidad Nacional de San Agustin, Departamento de Fisica, Av. Independencia s/n, Arequipa (Peru)
2015-10-15
Percentage depth dose curves were obtained with TLD-100 dosimeters, EDR2 films and Penelope simulation at the interfaces in an inhomogeneous mannequin, composed by equivalent materials to the human body built for this study, consisting of cylindrical plates of solid water-bone-lung-bone-solid water of 15 cm in diameter and 1 cm in height; plates were placed in descending way (4-2-8-2-4). Irradiated with Co-60 source (Theratron Equinox-100) for small radiation fields 3 x 3 cm{sup 2} and 1 x 1 cm{sup 2} at a surface source distance of 100 cm from mannequin. The TLD-100 dosimeters were placed in the center of each plate of mannequin irradiated at 10 Gy. The results were compared between these measurement techniques, giving good agreement in interfaces better than 97%. This study was compared with the same characteristics of another study realized with other equivalent materials to human body not homogeneous acrylic-bone-cork-bone-acrylic. The percentage depth dose curves were obtained with mini-dosimeters L-alanine of 1 mm in diameter and 3 mm in height and 3.5 to 4.0 mg of mass with spectrometer band K (EPR). The mini-dosimeters were irradiated with a lineal accelerator PRIMUS Siemens 6 MV. The results of percentage depth dose of L-alanine mini-dosimeters show a good agreement with the percentage depth dose curves of Penelope code, better than 97.7% in interfaces of tissues. (Author)
Cleber Nogueira de Souza
2001-04-01
Full Text Available Os parâmetros dosimétricos de um feixe de raios X de pequeno diâmetro para um sistema de radiocirurgia comercial foram medidos em água com um detector de diodo de Si do tipo p. As razões tecido-máximo, o fator de espalhamento total e os perfis dos feixes a profundidades de 5 e 10 cm foram medidos para 17 feixes de diâmetros circulares de 5 mm a 50 mm, em incrementos de 2,5 mm. Os fatores de espalhamento totais caíram lentamente, de 0,947 para 0,888 entre os cones de 50 mm e 12,5 mm de diâmetro (variação de 7%; para os cones entre 10 mm e 5 mm de diâmetro, esta queda foi bem maior, de 0,854 para 0,666 (variação de 28%. Os valores obtidos para a relação tecido-máximo são consistentes com dados publicados. Os perfis dos feixes foram medidos nas direções x e y, e estão dentro de 0,2 mm para todos os cones entre as duas direções. A medida da largura à meia-altura se encontra dentro de 1 mm com o diâmetro nominal dos cones.The dosimetric parameters of small diameter photon beams of a commercially available radiosurgery system were measured in a water phantom using a p-type Si photon diode. Tissue maximum ratios, total scattering factor and beam profiles at 5 and 10 cm depth were measured for 17 circular beams ranging from 5 mm to 50 mm in diameter, in 1.5 mm steps. The total scattering factor decreased slowly from 0.947 to 0.888 for the cones with diameter between 50 mm and 12.5 mm (7% variation whereas for cones with diameter between 10 mm and 5 mm the factor decreased more steeply, from 0.854 to 0.666 (28% variation. These tissue maximum ratio data are consistent with the data published by other authors. The beam profiles measured in the x and y directions were aproximately 0.2 mm between the two directions for all cone sizes. The full widths at half maximum were within 1 mm of the nominal cone sizes.
Sparse Linear Identifiable Multivariate Modeling
Henao, Ricardo; Winther, Ole
2011-01-01
In this paper we consider sparse and identifiable linear latent variable (factor) and linear Bayesian network models for parsimonious analysis of multivariate data. We propose a computationally efficient method for joint parameter and model inference, and model comparison. It consists of a fully...... Bayesian hierarchy for sparse models using slab and spike priors (two-component δ-function and continuous mixtures), non-Gaussian latent factors and a stochastic search over the ordering of the variables. The framework, which we call SLIM (Sparse Linear Identifiable Multivariate modeling), is validated and...... computational complexity. We attribute this mainly to the stochastic search strategy used, and to parsimony (sparsity and identifiability), which is an explicit part of the model. We propose two extensions to the basic i.i.d. linear framework: non-linear dependence on observed variables, called SNIM (Sparse Non-linear...
Linear algebra and projective geometry
Baer, Reinhold
2005-01-01
Geared toward upper-level undergraduates and graduate students, this text establishes that projective geometry and linear algebra are essentially identical. The supporting evidence consists of theorems offering an algebraic demonstration of certain geometric concepts. These focus on the representation of projective geometries by linear manifolds, of projectivities by semilinear transformations, of collineations by linear transformations, and of dualities by semilinear forms. These theorems lead to a reconstruction of the geometry that constituted the discussion's starting point, within algebra
Partially linear censored quantile regression
Neocleous, T.; Portnoy, S.
2009-01-01
Censored regression quantile (CRQ) methods provide a powerful and flexible approach to the analysis of censored survival data when standard linear models are felt to be appropriate. In many cases however, greater flexibility is desired to go beyond the usual multiple regression paradigm. One area of common interest is that of partially linear models: one (or more) of the explanatory covariates are assumed to act on the response through a non-linear function. Here the CRQ approach of Portnoy (...
Perturbed linear rough differential equations
Coutin, Laure; Lejay, Antoine
2014-01-01
We study linear rough differential equations and we solve perturbed linear rough differential equation using the Duhamel principle. These results provide us with the key technical point to study the regularity of the differential of the Itô map in a subsequent article. Also, the notion of linear rough differential equations leads to consider multiplicative functionals with values in Banach algebra more general than tensor algebra and to consider extensions of classical results such as the Mag...
Correlation and simple linear regression.
Eberly, Lynn E
2007-01-01
This chapter highlights important steps in using correlation and simple linear regression to address scientific questions about the association of two continuous variables with each other. These steps include estimation and inference, assessing model fit, the connection between regression and ANOVA, and study design. Examples in microbiology are used throughout. This chapter provides a framework that is helpful in understanding more complex statistical techniques, such as multiple linear regression, linear mixed effects models, logistic regression, and proportional hazards regression. PMID:18450049
Linear Programming and Network Flows
Bazaraa, Mokhtar S; Sherali, Hanif D
2011-01-01
The authoritative guide to modeling and solving complex problems with linear programming-extensively revised, expanded, and updated The only book to treat both linear programming techniques and network flows under one cover, Linear Programming and Network Flows, Fourth Edition has been completely updated with the latest developments on the topic. This new edition continues to successfully emphasize modeling concepts, the design and analysis of algorithms, and implementation strategies for problems in a variety of fields, including industrial engineering, management science, operations research
LINEAR2007, Linear-Linear Interpolation of ENDF Format Cross-Sections
1 - Description of program or function: LINEAR converts evaluated cross sections in the ENDF/B format into a tabular form that is subject to linear-linear interpolation in energy and cross section. The code also thins tables of cross sections already in that form. Codes used subsequently need thus to consider only linear-linear data. IAEA1311/15: This version include the updates up to January 30, 2007. Changes in ENDF/B-VII Format and procedures, as well as the evaluations themselves, make it impossible for versions of the ENDF/B pre-processing codes earlier than PREPRO 2007 (2007 Version) to accurately process current ENDF/B-VII evaluations. The present code can handle all existing ENDF/B-VI evaluations through release 8, which will be the last release of ENDF/B-VI. Modifications from previous versions: - Linear VERS. 2007-1 (JAN. 2007): checked against all ENDF/B-VII; increased page size from 60,000 to 600,000 points 2 - Method of solution: Each section of data is considered separately. Each section of File 3, 23, and 27 data consists of a table of cross section versus energy with any of five interpolation laws. LINEAR will replace each section with a new table of energy versus cross section data in which the interpolation law is always linear in energy and cross section. The histogram (constant cross section between two energies) interpolation law is converted to linear-linear by substituting two points for each initial point. The linear-linear is not altered. For the log-linear, linear-log and log- log laws, the cross section data are converted to linear by an interval halving algorithm. Each interval is divided in half until the value at the middle of the interval can be approximated by linear-linear interpolation to within a given accuracy. The LINEAR program uses a multipoint fractional error thinning algorithm to minimize the size of each cross section table
Elementary linear programming with applications
Kolman, Bernard
1995-01-01
Linear programming finds the least expensive way to meet given needs with available resources. Its results are used in every area of engineering and commerce: agriculture, oil refining, banking, and air transport. Authors Kolman and Beck present the basic notions of linear programming and illustrate how they are used to solve important common problems. The software on the included disk leads students step-by-step through the calculations. The Second Edition is completely revised and provides additional review material on linear algebra as well as complete coverage of elementary linear program
Hood, John Linsley
2013-01-01
The Art of Linear Electronics presents the principal aspects of linear electronics and techniques in linear electronic circuit design. The book provides a wide range of information on the elucidation of the methods and techniques in the design of linear electronic circuits. The text discusses such topics as electronic component symbols and circuit drawing; passive and active semiconductor components; DC and low frequency amplifiers; and the basic effects of feedback. Subjects on frequency response modifying circuits and filters; audio amplifiers; low frequency oscillators and waveform generato
Linear collider development at SLAC
Linear collider R ampersand D at SLAC comprises work on the present Stanford Linear Collider (SLC) and work toward the next linear collider (NLC). Recent SLC developments are summarized. NLC studies are divided into hardware-based and theoretical. We report on the status of the NLC Test Accelerator (NLCTA) and the final focus test beam (FFTB), describe plans for ASSET, an installation to measure accelerator structure wakefields, and mention IR design developments. Finally we review recent NLC theoretical studies, ending with the author's view of next linear collider parameter sets
LINEAR AND NON-LINEAR CAMERA CALIBRATION TECHNIQUES
Manoj Gupta
2011-01-01
This Paper deals with calibrate a camera to find out the intrinsic and extrinsic camera parameters which are necessary to recover the depth estimation of an object in stereovision system. Keywords: Camera Calibration, Tsai’s algorithm, Stereovision, Linear Calibration, Non-Linear Calibration, Depth estimation
Linear and non-linear optics of condensed matter
Part I - Linear optics: 1. General introduction. 2. Frequency dependence of epsilon(ω, k vector). 3. Wave-vector dependence of epsilon(ω, k vector). 4. Tensor character of epsilon(ω, k vector). Part II - Non-linear optics: 5. Introduction. 6. A classical theory of non-linear response in one dimension. 7. The generalization to three dimensions. 8. General properties of the polarizability tensors. 9. The phase-matching condition. 10. Propagation in a non-linear dielectric. 11. Second harmonic generation. 12. Coupling of three waves. 13. Materials and their non-linearities. 14. Processes involving energy exchange with the medium. 15. Two-photon absorption. 16. Stimulated Raman effect. 17. Electro-optic effects. 18. Limitations of the approach presented here. (author)
Linear contextual modal type theory
Schack-Nielsen, Anders; Schürmann, Carsten
Abstract. When one implements a logical framework based on linear type theory, for example the Celf system [?], one is immediately con- fronted with questions about their equational theory and how to deal with logic variables. In this paper, we propose linear contextual modal type theory that gives...
Spatial Processes in Linear Ordering
von Hecker, Ulrich; Klauer, Karl Christoph; Wolf, Lukas; Fazilat-Pour, Masoud
2016-01-01
Memory performance in linear order reasoning tasks (A > B, B > C, C > D, etc.) shows quicker, and more accurate responses to queries on wider (AD) than narrower (AB) pairs on a hypothetical linear mental model (A -- B -- C -- D). While indicative of an analogue representation, research so far did not provide positive evidence for spatial…
Andersen, Steffen; Harrison, Glenn W.; Hole, Arne Risa;
2012-01-01
We develop an extension of the familiar linear mixed logit model to allow for the direct estimation of parametric non-linear functions defined over structural parameters. Classic applications include the estimation of coefficients of utility functions to characterize risk attitudes and discounting...
Linear Algebra and Image Processing
Allali, Mohamed
2010-01-01
We use the computing technology digital image processing (DIP) to enhance the teaching of linear algebra so as to make the course more visual and interesting. Certainly, this visual approach by using technology to link linear algebra to DIP is interesting and unexpected to both students as well as many faculty. (Contains 2 tables and 11 figures.)
Fuzzy linear regression forecasting models
吴冲; 惠晓峰; 朱洪文
2002-01-01
The fuzzy linear regression forecasting model is deduced from the symmetric triangular fuzzy number.With the help of the degree of fitting and the measure of fuzziness, the determination of symmetric triangularfuzzy numbers is changed into a problem of solving linear programming.
Campagnoli, Patrizia; Petris, Giovanni
2009-01-01
State space models have gained tremendous popularity in as disparate fields as engineering, economics, genetics and ecology. Introducing general state space models, this book focuses on dynamic linear models, emphasizing their Bayesian analysis. It illustrates the fundamental steps needed to use dynamic linear models in practice, using R package.
Introduction to RF linear accelerators
The basic features of RF linear accelerators are described. The concept of the 'loaded cavity', essential for the synchronism wave-particle, is introduced, and formulae describing the action of electromagnetic fields on the beam are given. The treatment of intense beams is mentioned, and various existing linear accelerators are presented as examples. (orig.)
Physics at Future Linear Colliders
Moenig, Klaus
2005-01-01
This article summarises the physics at future linear colliders. It will be shown that in all studied physics scenarios a 1 TeV linear collider in addition to the LHC will enhance our knowledge significantly and helps to reconstruct the model of new physics nature has chosen.
Linear Programming across the Curriculum
Yoder, S. Elizabeth; Kurz, M. Elizabeth
2015-01-01
Linear programming (LP) is taught in different departments across college campuses with engineering and management curricula. Modeling an LP problem is taught in every linear programming class. As faculty teaching in Engineering and Management departments, the depth to which teachers should expect students to master this particular type of…
Linear Patterns and Their Equations
2008-01-01
<正>A linear pattern,the points plotted all lie on the same straight line.In this section we will be looking further into such linear patterns. In this figure,by plotting the points B to F and joining them,
Efficient Searching with Linear Constraints
Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff;
2000-01-01
We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint. This...... problem is called halfspace range searching in the computational geometry literature. Our goal is to minimize the number of disk blocks required to store the data structure and the number of disk accesses (I/Os) required to answer a query. For d=2, we present the first data structure that uses linear...... space and answers linear-constraint queries using an optimal number of I/Os in the worst case. For d=3, we present a near-linear-size data structure that answers queries using an optimal number of I/Os on the average. We present linear-size data structures that can answer d-dimensional linear...
Ferencz, Donald C.; Viterna, Larry A.
1991-01-01
ALPS is a computer program which can be used to solve general linear program (optimization) problems. ALPS was designed for those who have minimal linear programming (LP) knowledge and features a menu-driven scheme to guide the user through the process of creating and solving LP formulations. Once created, the problems can be edited and stored in standard DOS ASCII files to provide portability to various word processors or even other linear programming packages. Unlike many math-oriented LP solvers, ALPS contains an LP parser that reads through the LP formulation and reports several types of errors to the user. ALPS provides a large amount of solution data which is often useful in problem solving. In addition to pure linear programs, ALPS can solve for integer, mixed integer, and binary type problems. Pure linear programs are solved with the revised simplex method. Integer or mixed integer programs are solved initially with the revised simplex, and the completed using the branch-and-bound technique. Binary programs are solved with the method of implicit enumeration. This manual describes how to use ALPS to create, edit, and solve linear programming problems. Instructions for installing ALPS on a PC compatible computer are included in the appendices along with a general introduction to linear programming. A programmers guide is also included for assistance in modifying and maintaining the program.
Linear and non-linear perturbations in dark energy models
Escamilla-Rivera, Celia; Casarini, Luciano; Fabris, Julio C.; Alcaniz, Jailson S.
2016-01-01
In this work we discuss observational aspects of three time-dependent parameterisations of the dark energy equation of state $w(z)$. In order to determine the dynamics associated with these models, we calculate their background evolution and perturbations in a scalar field representation. After performing a complete treatment of linear perturbations, we also show that the non-linear contribution of the selected $w(z)$ parameterisations to the matter power spectra is almost the same for all sc...
Linear and non-linear bias: predictions vs. measurements
Hoffmann, Kai; Bel, Julien; Gaztanaga, Enrique
2016-01-01
We study the linear and non-linear bias parameters which determine the mapping between the distributions of galaxies and the full matter density fields, comparing different measurements and predictions. Accociating galaxies with dark matter haloes in the MICE Grand Challenge N-body simulation we directly measure the bias parameters by comparing the smoothed density fluctuations of halos and matter in the same region at different positions as a function of smoothing scale. Alternatively we mea...
Linear and non-linear calculation of resistive magnetohydrodynamic instabilities
The time-dependent, linear and non-linear, resistive magnetohydrodynamic, numerical models that have been developed at MFECC are reviewed. The purpose of these codes is to compute growth rates, mode structure and saturation of tearing, rippling, and interchange modes in fusion experiments. Cartesian, cylindrical, helical, and toroidal geometries are used in the applications. The numerical methods are described and applications to reversed field configurations are presented
Convexity in Linear Fractional Programming Problem.
Anita Biswas; Smita Verma
2013-01-01
Linear programming is a mathematical programming technique to optimize performance under a set of resource constraints as specified by organization. Linear fractional programming is a generalization of linear programming. The objective functions in linear programs are linear functions while the objective function in a linear fractional program is a ratio of two linear functions. In his paper an attempt is made to solve the convexity in linear fractional programming problem by taking CCR model...
Primordial black holes in linear and non-linear regimes
Allahyari, Alireza; Abolhasani, Ali Akbar
2016-01-01
Using the concept of apparent horizon for dynamical black holes, we revisit the formation of primordial black holes (PBH) in the early universe for both linear and non-linear regimes. First, we develop the perturbation theory for spherically symmetric spacetimes to study the formation of spherical PBHs in linear regime and we fix two gauges. We also introduce a well defined gauge invariant quantity for the expansion. Using this quantity, we argue that PBHs do not form in the linear regime. Finally, we study the non-linear regime. We adopt the spherical collapse picture by taking a closed FRW model in the radiation dominated era to investigate PBH formation. Taking the initial condition of the spherical collapse from the linear theory of perturbations, we allow for both density and velocity perturbations. Our model gives a constraint on the velocity perturbation. This model also predicts that the apparent horizon of PBHs forms when $\\delta > 3$. Applying the sound horizon constraint, we have shown the threshol...
Practical approach to linear algebra
Choudhary, Prabhat
2009-01-01
""Linear Algebra is the heart of applied science but there are divergent views concerning its meaning. The field of Linear Algebra is more beautiful and more fundamental than its rather dull name may suggest. More beautiful because it is full of powerful ideas that are quite unlike those normally emphasized in a linear algebra course in a mathematics department. Throughout the book the author follows the practice of first presenting required background material, which is then used to develop the results. The book is divided in ten chapters. Relevant material is included in each chapter from ot
Optimal control linear quadratic methods
Anderson, Brian D O
2007-01-01
This augmented edition of a respected text teaches the reader how to use linear quadratic Gaussian methods effectively for the design of control systems. It explores linear optimal control theory from an engineering viewpoint, with step-by-step explanations that show clearly how to make practical use of the material.The three-part treatment begins with the basic theory of the linear regulator/tracker for time-invariant and time-varying systems. The Hamilton-Jacobi equation is introduced using the Principle of Optimality, and the infinite-time problem is considered. The second part outlines the
This book consists of control linear motor with DSP, which is composed of two parts. The title of the first part is control Algorithm and software with introduction and tracking controller, drive profile on decision of motion time, floating point DSP and quantization effect, motion override Algorithm and drive profile summary, design of digital controller on design for controller structure and analysis of PID control Loop and Motor turning, design for IIR digital filter and protocol structure for communication wit host. The second part describes control hardware, which mentions Linear motor and Amplifier, motor and power supply, DSP board and interface, control of Micro Linear Stepping Motor and conclusion.
Cellular Automata Rules and Linear Numbers
Nayak, Birendra Kumar; Sahoo, Sudhakar; Biswal, Sagarika
2012-01-01
In this paper, linear Cellular Automta (CA) rules are recursively generated using a binary tree rooted at "0". Some mathematical results on linear as well as non-linear CA rules are derived. Integers associated with linear CA rules are defined as linear numbers and the properties of these linear numbers are studied.
[New technology for linear colliders
McIntyre, P.M.
1992-08-12
This report discusses the following topics on research of microwave amplifiers for linear colliders: Context in current microwave technology development; gated field emission for microwave cathodes; cathode fabrication and tests; microwave cathode design using field emitters; and microwave localization.
Overdetermined Systems of Linear Equations.
Williams, Gareth
1990-01-01
Explored is an overdetermined system of linear equations to find an appropriate least squares solution. A geometrical interpretation of this solution is given. Included is a least squares point discussion. (KR)
Gyrokinetic linearized Landau collision operator
Madsen, Jens
2013-01-01
The full gyrokinetic electrostatic linearized Landau collision operator is calculated including the equilibrium operator, which represents the effect of collisions between gyrokinetic Maxwellian particles. First, the equilibrium operator describes energy exchange between different plasma species...
Forms and Linear Network Codes
Hansen, Johan P.
We present a general theory to obtain linear network codes utilizing forms and obtain explicit families of equidimensional vector spaces, in which any pair of distinct vector spaces intersect in the same small dimension. The theory is inspired by the methods of the author utilizing the osculating...... spaces of Veronese varieties. Linear network coding transmits information in terms of a basis of a vector space and the information is received as a basis of a possibly altered vector space. Ralf Koetter and Frank R. Kschischang introduced a metric on the set af vector spaces and showed that a minimal...... them suitable for linear network coding. The parameters of the resulting linear network codes are determined....
CERN balances linear collider studies
ILC Newsline
2011-01-01
The forces behind the two most mature proposals for a next-generation collider, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) study, have been steadily coming together, with scientists from both communities sharing ideas and information across the technology divide. In a support of cooperation between the two, CERN in Switzerland, where most CLIC research takes place, recently converted the project-specific position of CLIC Study Leader to the concept-based Linear Collider Study Leader. The scientist who now holds this position, Steinar Stapnes, is charged with making the linear collider a viable option for CERN’s future, one that could include either CLIC or the ILC. The transition to more involve the ILC must be gradual, he said, and the redefinition of his post is a good start. Though not very much involved with superconducting radiofrequency (SRF) technology, where ILC researchers have made significant advances, CERN participates in many aspect...
1988 linear accelerator conference proceedings
This report contains papers presented at the 1988 Linear Accelerator Conference. A few topics covered are beam dynamics; beam transport; superconducting components; free electron lasers; ion sources; and klystron research
The relativistic linear singular oscillator
Exactly solvable model of the linear singular oscillator in the relativistic configurational space is considered. We have found wavefunctions and energy spectrum for the model under study. It is shown that they have the correct non-relativistic limits
Klumpp, A. R.; Lawson, C. L.
1988-01-01
Routines provided for common scalar, vector, matrix, and quaternion operations. Computer program extends Ada programming language to include linear-algebra capabilities similar to HAS/S programming language. Designed for such avionics applications as software for Space Station.
[New technology for linear colliders
This report discusses the following topics on research of microwave amplifiers for linear colliders: Context in current microwave technology development; gated field emission for microwave cathodes; cathode fabrication and tests; microwave cathode design using field emitters; and microwave localization
Sparse Linear Identifiable Multivariate Modeling
Henao, Ricardo; Winther, Ole
2011-01-01
In this paper we consider sparse and identifiable linear latent variable (factor) and linear Bayesian network models for parsimonious analysis of multivariate data. We propose a computationally efficient method for joint parameter and model inference, and model comparison. It consists of a fully...... Bayesian hierarchy for sparse models using slab and spike priors (two-component δ-function and continuous mixtures), non-Gaussian latent factors and a stochastic search over the ordering of the variables. The framework, which we call SLIM (Sparse Linear Identifiable Multivariate modeling), is validated and......-linear Identifiable Multivariate modeling) and allowing for correlations between latent variables, called CSLIM (Correlated SLIM), for the temporal and/or spatial data. The source code and scripts are available from http://cogsys.imm.dtu.dk/ slim/. © 2011 Ricardo Henao and Ole Winther....
Topics in computational linear optimization
Hultberg, Tim Helge
2000-01-01
Linear optimization has been an active area of research ever since the pioneering work of G. Dantzig more than 50 years ago. This research has produced a long sequence of practical as well as theoretical improvements of the solution techniques avilable for solving linear optimization problems...... formulation has a tighter LP-relaxation than the original formulation. The first paper surveys the use of automatic reformulation techniques for general mixed 0-1 linear programs. An implementation, Spiky, of a direct method for solving large sparse unsymmetric systems of linear equations is presented in the...... factorization of an augmented system is computed. This involves the solution of a sparse triangular system with 's' right-hand sides. Solution sparsity is exploited in the sparse triangular solves of the block LU factorization. 3) a factorization of the Schur complement matrix, of order 's', is computed. The...
Preconditioning Complex Symmetric Linear Systems
Enrico Bertolazzi
2015-01-01
Full Text Available A new preconditioner for symmetric complex linear systems based on Hermitian and skew-Hermitian splitting (HSS for complex symmetric linear systems is herein presented. It applies to conjugate orthogonal conjugate gradient (COCG or conjugate orthogonal conjugate residual (COCR iterative solvers and does not require any estimation of the spectrum of the coefficient matrix. An upper bound of the condition number of the preconditioned linear system is provided. To reduce the computational cost the preconditioner is approximated with an inexact variant based on incomplete Cholesky decomposition or on orthogonal polynomials. Numerical results show that the present preconditioner and its inexact variant are efficient and robust solvers for this class of linear systems. A stability analysis of the inexact polynomial version completes the description of the preconditioner.
Linear Back-Drive Differentials
Waydo, Peter
2003-01-01
Linear back-drive differentials have been proposed as alternatives to conventional gear differentials for applications in which there is only limited rotational motion (e.g., oscillation). The finite nature of the rotation makes it possible to optimize a linear back-drive differential in ways that would not be possible for gear differentials or other differentials that are required to be capable of unlimited rotation. As a result, relative to gear differentials, linear back-drive differentials could be more compact and less massive, could contain fewer complex parts, and could be less sensitive to variations in the viscosities of lubricants. Linear back-drive differentials would operate according to established principles of power ball screws and linear-motion drives, but would utilize these principles in an innovative way. One major characteristic of such mechanisms that would be exploited in linear back-drive differentials is the possibility of designing them to drive or back-drive with similar efficiency and energy input: in other words, such a mechanism can be designed so that a rotating screw can drive a nut linearly or the linear motion of the nut can cause the screw to rotate. A linear back-drive differential (see figure) would include two collinear shafts connected to two parts that are intended to engage in limited opposing rotations. The linear back-drive differential would also include a nut that would be free to translate along its axis but not to rotate. The inner surface of the nut would be right-hand threaded at one end and left-hand threaded at the opposite end to engage corresponding right- and left-handed threads on the shafts. A rotation and torque introduced into the system via one shaft would drive the nut in linear motion. The nut, in turn, would back-drive the other shaft, creating a reaction torque. Balls would reduce friction, making it possible for the shaft/nut coupling on each side to operate with 90 percent efficiency.
Feedback Systems for Linear Colliders
Hendrickson, L.; Grossberg, P.; Himel, T.; Minty, M.; Phinney, N.; Raimondi, P.; Raubenheimer, T.; Shoaee, H.; Tenenbaum, P.
2001-01-01
Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have...
Linear isometries of Hardy spaces
Edoardo VESENTINI
2008-01-01
According to results established by DeLeeuw-Rudin-Wermer and by Forelli,all linear isometries of any Hardy space Hp (p ≥ 1,p ≠ 2) on the open unit disc △ of C are represented by weighted composition operators defined by inner functions on △.After reviewing (and completing when p = ∞) some of those results,the present report deals with a characterization of periodic and almost periodic semigroups of linear isometries of Hp.
Functional linear regression with derivatives
Mas, André; Pumo, Besnik
2006-01-01
International audience We introduce a new model of linear regression for random functional inputs taking into account the first order derivative of the data. We propose an estimation method which comes down to solving a special linear inverse problem. Our procedure tackles the problem through a double and synchronized penalization. An asymptotic expansion of the mean square prevision error is given. The model and the method are applied to a benchmark dataset of spectrometric curves and com...
Explorative methods in linear models
Høskuldsson, Agnar
2004-01-01
The author has developed the H-method of mathematical modeling that builds up the model by parts, where each part is optimized with respect to prediction. Besides providing with better predictions than traditional methods, these methods provide with graphic procedures for analyzing different feat...... features in data. These graphic methods extend the well-known methods and results of Principal Component Analysis to any linear model. Here the graphic procedures are applied to linear regression and Ridge Regression....
Several letters discuss the short-comings of the use of the linear quadratic model in fractionated radiotherapy and the validity of the prediction of hyperfractionation as the operational strategy for most human tumours. Particular points discussed are the absence of a time factor in the linear quadratic model, corrections in regard to OER and the clinical implications of isoeffect relationships for normal tissue damage. (U.K.)
Linear Response for Granular Fluids
Dufty, James; Baskaran, Aparna; Brey, J. Javier
2005-01-01
The linear response of an isolated, homogeneous granular fluid to small spatial perturbations is studied by methods of non-equilibrium statistical mechanics. The long wavelength linear hydrodynamic equations are obtained, with formally exact expressions for the susceptibilities and transport coefficients. The latter are given in equivalent Einstein-Helfand and Green-Kubo forms. The context of these results and their contrast with corresponding results for normal fluids are discussed.
LINEAR AND NONLINEAR SEMIDEFINITE PROGRAMMING
Walter Gómez Bofill
2014-12-01
Full Text Available This paper provides a short introduction to optimization problems with semidefinite constraints. Basic duality and optimality conditions are presented. For linear semidefinite programming some advances by dealing with degeneracy and the semidefinite facial reduction are discussed. Two relatively recent areas of application are presented. Finally a short overview of relevant literature on algorithmic approaches for efficiently solving linear and nonlinear semidefinite programming is provided.
Transformation matrices between non-linear and linear differential equations
Sartain, R. L.
1983-01-01
In the linearization of systems of non-linear differential equations, those systems which can be exactly transformed into the second order linear differential equation Y"-AY'-BY=0 where Y, Y', and Y" are n x 1 vectors and A and B are constant n x n matrices of real numbers were considered. The 2n x 2n matrix was used to transform the above matrix equation into the first order matrix equation X' = MX. Specially the matrix M and the conditions which will diagonalize or triangularize M were studied. Transformation matrices P and P sub -1 were used to accomplish this diagonalization or triangularization to return to the solution of the second order matrix differential equation system from the first order system.
Linear and non-linear bias: predictions vs. measurements
Hoffmann, Kai; Gaztanaga, Enrique
2016-01-01
We study the linear and non-linear bias parameters which determine the mapping between the distributions of galaxies and the full matter density fields, comparing different measurements and predictions. Accociating galaxies with dark matter haloes in the MICE Grand Challenge N-body simulation we directly measure the bias parameters by comparing the smoothed density fluctuations of halos and matter in the same region at different positions as a function of smoothing scale. Alternatively we measure the bias parameters by matching the probablility distributions of halo and matter density fluctuations, which can be applied to observations. These direct bias measurements are compared to corresponding measurements from two-point and different third-order correlations, as well as predictions from the peak-background model, which we presented in previous articles using the same data. We find an overall variation of the linear bias measurements and predictions of $\\sim 5 \\%$ with respect to results from two-point corr...
Boundedness and closedness of linear relations
Shi, Yuming; Xu, Guixin; Ren, Guojing
2016-01-01
This paper studies boundedness and closedness of linear relations, which include both single-valued and multi-valued linear operators. A new (single-valued) linear operator induced by a linear relation is introduced, and its relationships with other two important induced linear operators are established. Several characterizations for closedness, closability, bundedness, relative boundedness, and boundedness from below (above) of linear relations are given in terms of their induced linear oper...
Linear and non-linear perturbations in dark energy models
Escamilla-Rivera, Celia; Fabris, Julio C; Alcaniz, Jailson S
2016-01-01
In this work we discuss observational aspects of three time-dependent parameterisations of the dark energy equation of state $w(z)$. In order to determine the dynamics associated with these models, we calculate their background evolution and perturbations in a scalar field representation. After performing a complete treatment of linear perturbations, we also show that the non-linear contribution of the selected $w(z)$ parameterisations to the matter power spectra is almost the same for all scales, with no significant difference from the predictions of the standard $\\Lambda$CDM model.
From Linear to Non-linear Supersymmetry via Functional Integration
Kallosh, Renata; Murli, Divyanshu
2016-01-01
We derive a complete pure de Sitter supergravity action with non-linearly realized supersymmetry and its rigid limit, the Volkov-Akulov action, from the corresponding models with linear supersymmetry, by computing the path integral in the limit of infinite sgoldstino mass. In this, we use a non-Gaussian functional integration formula that was recently discovered in a derivation of de Sitter supergravity from the superconformal theory. We also present explicit examples of pure dS supergravity and the case with one matter multiplet. These two simple examples serve as a test and a demo of the universal action formula valid for de Sitter supergravities with general matter coupling.
Processing of nuclear medicine images is generally performed by essentially linear methods with the non-negativity condition being applied as the only non-linear process. The various methods used: matrix methods in signal space and Fourier or Hadamard transforms in frequency or sequency space are essentially equivalent. Further improvement in images can be obtained by the use of inherently non-linear methods. The recent development of an approximation to a least-difference method (as opposed to a least-square method) has led to an appreciation of the effects of data bounding and to the development of a more powerful process. Data bounding (modification of statistically improbable data values) is an inherently non-linear method with considerable promise. Strong bounding depending on two-dimensional least-squares fitting yields a reduction of mottling (buttermilk effect) not attainable with linear processes. A pre-bounding process removing very bad points is used to protect the strong bounding process from incorrectly modifying data points due to the weight of an extreme but yet unbounded point as the fitting area approaches it
Topics in quaternion linear algebra
Rodman, Leiba
2014-01-01
Quaternions are a number system that has become increasingly useful for representing the rotations of objects in three-dimensional space and has important applications in theoretical and applied mathematics, physics, computer science, and engineering. This is the first book to provide a systematic, accessible, and self-contained exposition of quaternion linear algebra. It features previously unpublished research results with complete proofs and many open problems at various levels, as well as more than 200 exercises to facilitate use by students and instructors. Applications presented in the book include numerical ranges, invariant semidefinite subspaces, differential equations with symmetries, and matrix equations. Designed for researchers and students across a variety of disciplines, the book can be read by anyone with a background in linear algebra, rudimentary complex analysis, and some multivariable calculus. Instructors will find it useful as a complementary text for undergraduate linear algebra courses...
Linear inflation from quartic potential
Kannike, Kristjan; Raidal, Martti
2016-01-01
We show that linear inflation appears as an attractor solution in the Coleman-Weinberg inflation provided the inflaton has a non-minimal coupling to gravity and the Planck scale is dynamically generated. Thus linear inflation appears in the context of a well-defined quantum field theory framework from quartic potentials without introducing any {\\it ad hoc} interaction or unbounded scalar potential by hand. The minimal scenario has only one free parameter -- the inflaton's non-minimal coupling to gravity -- that determines all physical parameters such as the tensor-to-scalar ratio and the reheating temperature of the Universe. Should the more precise future measurements of inflationary parameters point towards linear inflation, the dynamical origin of inflation would be strongly supported.
Linear Synchronous Motor Repeatability Tests
A cart system using linear synchronous motors was being considered for the Plutonium Immobilization Plant (PIP). One of the applications in the PIP was the movement of a stack of furnace trays, filled with the waste form (pucks) from a stacking/unstacking station to several bottom loaded furnaces. A system was ordered to perform this function in the PIP Ceramic Prototype Test Facility (CPTF). This system was installed and started up in SRTC prior to being installed in the CPTF. The PIP was suspended and then canceled after the linear synchronous motor system was started up. This system was used to determine repeatability of a linear synchronous motor cart system for the Modern Pit Facility
Andersen, O. Krogh
1975-01-01
Two approximate methods for solving the band-structure problem in an efficient and physically transparent way are presented and discussed in detail. The variational principle for the one-electron Hamiltonian is used in both schemes, and the trial functions are linear combinations of energy......-independent augmented plane waves (APW) and muffin-tin orbitals (MTO), respectively. The secular equations are therefore eigenvalue equations, linear in energy. The trial functions are defined with respect to a muffin-tin (MT) potential and the energy bands depend on the potential in the spheres through potential...... parameters which describe the energy dependence of the logarithmic derivatives. Inside the spheres, the energy-independent APW is that linear combination of an exact solution, at the arbitrary but fixed energy Eν, and its energy derivative which matches continuously and differentiably onto the plane...
Bayes linear statistics, theory & methods
Goldstein, Michael
2007-01-01
Bayesian methods combine information available from data with any prior information available from expert knowledge. The Bayes linear approach follows this path, offering a quantitative structure for expressing beliefs, and systematic methods for adjusting these beliefs, given observational data. The methodology differs from the full Bayesian methodology in that it establishes simpler approaches to belief specification and analysis based around expectation judgements. Bayes Linear Statistics presents an authoritative account of this approach, explaining the foundations, theory, methodology, and practicalities of this important field. The text provides a thorough coverage of Bayes linear analysis, from the development of the basic language to the collection of algebraic results needed for efficient implementation, with detailed practical examples. The book covers:The importance of partial prior specifications for complex problems where it is difficult to supply a meaningful full prior probability specification...
Linear programming foundations and extensions
Vanderbei, Robert J
2001-01-01
Linear Programming: Foundations and Extensions is an introduction to the field of optimization. The book emphasizes constrained optimization, beginning with a substantial treatment of linear programming, and proceeding to convex analysis, network flows, integer programming, quadratic programming, and convex optimization. The book is carefully written. Specific examples and concrete algorithms precede more abstract topics. Topics are clearly developed with a large number of numerical examples worked out in detail. Moreover, Linear Programming: Foundations and Extensions underscores the purpose of optimization: to solve practical problems on a computer. Accordingly, the book is coordinated with free efficient C programs that implement the major algorithms studied: -The two-phase simplex method; -The primal-dual simplex method; -The path-following interior-point method; -The homogeneous self-dual methods. In addition, there are online JAVA applets that illustrate various pivot rules and variants of the simplex m...
Metsch, Klaus
1991-01-01
A famous theorem in the theory of linear spaces states that every finite linear space has at least as many lines as points. This result of De Bruijn and Erd|s led to the conjecture that every linear space with "few lines" canbe obtained from a projective plane by changing only a small part of itsstructure. Many results related to this conjecture have been proved in the last twenty years. This monograph surveys the subject and presents several new results, such as the recent proof of the Dowling-Wilsonconjecture. Typical methods used in combinatorics are developed so that the text can be understood without too much background. Thus the book will be of interest to anybody doing combinatorics and can also help other readers to learn the techniques used in this particular field.
Quantization via Linear homotopy types
Schreiber, Urs
2014-01-01
In the foundational logical framework of homotopy-type theory we discuss a natural formalization of secondary integral transforms in stable geometric homotopy theory. We observe that this yields a process of non-perturbative cohomological quantization of local pre-quantum field theory; and show that quantum anomaly cancellation amounts to realizing this as the boundary of a field theory that is given by genuine (primary) integral transforms, hence by linear polynomial functors. Recalling that traditional linear logic has semantics in symmetric monoidal categories and serves to formalize quantum mechanics, what we consider is its refinement to linear homotopy-type theory with semantics in stable infinity-categories of bundles of stable homotopy types (generalized cohomology theories) formalizing Lagrangian quantum field theory, following Nuiten and closely related to recent work by Haugseng and Hopkins-Lurie. For the reader interested in technical problems of quantization we provide non-perturbative quantizati...
Uniqueness theorems in linear elasticity
Knops, Robin John
1971-01-01
The classical result for uniqueness in elasticity theory is due to Kirchhoff. It states that the standard mixed boundary value problem for a homogeneous isotropic linear elastic material in equilibrium and occupying a bounded three-dimensional region of space possesses at most one solution in the classical sense, provided the Lame and shear moduli, A and J1 respectively, obey the inequalities (3 A + 2 J1) > 0 and J1>O. In linear elastodynamics the analogous result, due to Neumann, is that the initial-mixed boundary value problem possesses at most one solution provided the elastic moduli satisfy the same set of inequalities as in Kirchhoffs theorem. Most standard textbooks on the linear theory of elasticity mention only these two classical criteria for uniqueness and neglect altogether the abundant literature which has appeared since the original publications of Kirchhoff. To remedy this deficiency it seems appropriate to attempt a coherent description ofthe various contributions made to the study of uniquenes...
The linear multiplet and ectoplasm
Butter, Daniel; Kuzenko, Sergei M.; Novak, Joseph
2012-09-01
In the framework of the superconformal tensor calculus for 4D {N} = {2} super-gravity, locally supersymmetric actions are often constructed using the linear multiplet. We provide a superform formulation for the linear multiplet and derive the corresponding action functional using the ectoplasm method (also known as the superform approach to the construction of supersymmetric invariants). We propose a new locally supersymmetric action which makes use of a deformed linear multiplet. The novel feature of this multiplet is that it corresponds to the case of a gauged central charge using a one-form potential not annihilated by the central charge (unlike the standard {N} = {2} vector multiplet). Such a gauge one-form can be chosen to describe a variant nonlinear vector-tensor multiplet. As a byproduct of our construction, we also find a variant realization of the tensor multiplet in supergravity where one of the auxiliaries is replaced by the field strength of a gauge three-form.
QUANTUM OPTICS. Universal linear optics.
Carolan, Jacques; Harrold, Christopher; Sparrow, Chris; Martín-López, Enrique; Russell, Nicholas J; Silverstone, Joshua W; Shadbolt, Peter J; Matsuda, Nobuyuki; Oguma, Manabu; Itoh, Mikitaka; Marshall, Graham D; Thompson, Mark G; Matthews, Jonathan C F; Hashimoto, Toshikazu; O'Brien, Jeremy L; Laing, Anthony
2015-08-14
Linear optics underpins fundamental tests of quantum mechanics and quantum technologies. We demonstrate a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters integrated into a single photonic chip that is electrically and optically interfaced for arbitrary setting of all phase shifters, input of up to six photons, and their measurement with a 12-single-photon detector system. We programmed this system to implement heralded quantum logic and entangling gates, boson sampling with verification tests, and six-dimensional complex Hadamards. We implemented 100 Haar random unitaries with an average fidelity of 0.999 ± 0.001. Our system can be rapidly reprogrammed to implement these and any other linear optical protocol, pointing the way to applications across fundamental science and quantum technologies. PMID:26160375
The Smoothed Approximate Linear Program
Desai, V V; Moallemi, C C
2009-01-01
We present a novel linear program for the approximation of the dynamic programming cost-to-go function in high-dimensional stochastic control problems. LP approaches to approximate DP have typically relied on a natural `projection' of a well studied linear program for exact dynamic programming. Such programs restrict attention to approximations that are lower bounds to the optimal cost-to-go function. Our program--the `smoothed approximate linear program'--is distinct from such approaches and relaxes the restriction to lower bounding approximations in an appropriate fashion while remaining computationally tractable. Doing so appears to have several advantages: First, we demonstrate substantially superior bounds on the quality of approximation to the optimal cost-to-go function afforded by our approach. Second, experiments with our approach on a challenging problem (the game of Tetris) show that the approach outperforms the existing LP approach (which has previously been shown to be competitive with several AD...
Window observers for linear systems
Utkin Vadim
2000-01-01
Full Text Available Given a linear system x ˙ = A x + B u with output y = C x and a window function ω ( t , i.e., ∀ t , ω ( t ∈ {0,1 }, and assuming that the window function is Lebesgue measurable, we refer to the following observer, x ˆ = A x + B u + ω ( t L C ( x − x ˆ as a window observer. The stability issue is treated in this paper. It is proven that for linear time-invariant systems, the window observer can be stabilized by an appropriate design under a very mild condition on the window functions, albeit for linear time-varying system, some regularity of the window functions is required to achieve observer designs with the asymptotic stability. The corresponding design methods are developed. An example is included to illustrate the possible applications
Femtosecond fibre laser with a hybrid linear-ring cavity
A new type of a femtosecond self-mode-locked erbium fibre laser is proposed and fabricated. The original hybrid design of the laser cavity taking advantage of ring and linear cavity lasers allows continuous tuning of the pulse repetition rate in a broad range (more that 30 kHz) and provides a high reliability of the self-mode-locking regime. (letters)
TRANSFORMASI KANONIKAL LINEAR QUATERNION QUATERNION LINEAR CANONICAL TRANSFORM
Resnawati; Bahri, Mawardi; Kusuma, Jeffry
2013-01-01
Transformasi kanonikal linear quaternion (TKLQ) merupakan generalisasi Transformasi Fourier quaternion (TFQ). Penelitian ini bertujuan merumuskan definisi TKLQ satu sisi, konvolusi dan sifat-sifat yang berkaitan dengannya. Metode penelitian dilakukan dengan mengumpulkan dan mengkaji materi-materi yang berkaitan dengan TKLQ. Penelitian ini menghasilkan definisi TKLQ satu sisi dan rumusan sifat - sifat seperti linearitas, translasi, modulasi dan translasi frekuensi waktu. Penelitian...
Demo 89. Acelerador magnético o de Gauss
Ferrer Roca, Chantal; Cros Stotter, Ana
2013-01-01
Objetivo: Entender un fenómeno de aparente no conservación de la energía y momento lineal. Profundizar en el concepto de energía de ligadura y energía interna y su relación con la energía cinética.
Penyajian Integral dari Operator Non Linear
Budiman, Herdi; Sunusi, Nurtiti
2004-01-01
Fungsional linear kontinu pada suatu ruang fungsi dapat disajikan dengan suatu integral dan biasanya linear. Pada papaer ini akan diberikan penyajian integral dari suatu operator non linear, dengan cara mengkonstruksi integral non linear Henstock Kurzweil, fungsi f:[0,1] ---------> X, dengan X merupakan ruang Banach, dilanjutkan dengan penyajian integral dari operator non linear pada ruang C=C([0,1],X).
Why quantum dynamics is linear
A seed George planted 45 years ago is still producing fruit now. In 1961, George set out the fundamental proposition that quantum dynamics is described most generally by linear maps of density matrices. Since the first sprout from George's seed appeared in 1962, we have known that George's fundamental proposition can be used to derive the linear Schrodinger equation in cases where it can be expected to apply. Now we have a proof of George's proposition that density matrices are mapped linearly to density matrices, that there can be no nonlinear generalization of this. That completes the derivation of the linear Schrodinger equation. The proof of George's proposition replaces Wigner's theorem that a symmetry transformation is represented by a linear or antilinear operator. The assumption needed to prove George's proposition is just that the dynamics does not depend on anything outside the system but must allow the system to be described as part of a larger system. This replaces the physically less compelling assumption of Wigner's theorem that absolute values of inner products are preserved. The history of this question is reviewed. Nonlinear generalizations of quantum mechanics have been proposed. They predict small but clear nonlinear effects, which very accurate experiments have not seen. This begs the question. Is there a reason in principle why nonlinearity is not found? Is it impossible? Does quantum dynamics have to be linear? Attempts to prove this have not been decisive, because either their assumptions are not compelling or their arguments are not conclusive. The question has been left unsettled. The simple answer, based on a simple assumption, was found in two steps separated by 44 years.
Correct Linearization of Einstein's Equations
Rabounski D.
2006-06-01
Full Text Available Regularly Einstein's equations can be reduced to a wave form (linearly dependent from the second derivatives of the space metric in the absence of gravitation, the space rotation and Christoffel's symbols. As shown here, the origin of the problem is that one uses the general covariant theory of measurement. Here the wave form of Einstein's equations is obtained in the terms of Zelmanov's chronometric invariants (physically observable projections on the observer's time line and spatial section. The obtained equations depend on solely the second derivatives even if gravitation, the space rotation and Christoffel's symbols. The correct linearization proves: the Einstein equations are completely compatible with weak waves of the metric.
Matrix methods applied linear algebra
Bronson, Richard
2008-01-01
Matrix Methods: Applied Linear Algebra, 3e, as a textbook, provides a unique and comprehensive balance between the theory and computation of matrices. The application of matrices is not just for mathematicians. The use by other disciplines has grown dramatically over the years in response to the rapid changes in technology. Matrix methods is the essence of linear algebra and is what is used to help physical scientists; chemists, physicists, engineers, statisticians, and economists solve real world problems.* Applications like Markov chains, graph theory and Leontief Models are placed i
Introduction to computational linear algebra
Nassif, Nabil; Erhel, Jocelyne
2015-01-01
Introduction to Computational Linear Algebra introduces the reader with a background in basic mathematics and computer programming to the fundamentals of dense and sparse matrix computations with illustrating examples. The textbook is a synthesis of conceptual and practical topics in ""Matrix Computations."" The book's learning outcomes are twofold: to understand state-of-the-art computational tools to solve matrix computations problems (BLAS primitives, MATLAB® programming) as well as essential mathematical concepts needed to master the topics of numerical linear algebra. It is suitable for s
Generalized, Linear, and Mixed Models
McCulloch, Charles E; Neuhaus, John M
2011-01-01
An accessible and self-contained introduction to statistical models-now in a modernized new editionGeneralized, Linear, and Mixed Models, Second Edition provides an up-to-date treatment of the essential techniques for developing and applying a wide variety of statistical models. The book presents thorough and unified coverage of the theory behind generalized, linear, and mixed models and highlights their similarities and differences in various construction, application, and computational aspects.A clear introduction to the basic ideas of fixed effects models, random effects models, and mixed m
Linear feedback controls the essentials
Haidekker, Mark A
2013-01-01
The design of control systems is at the very core of engineering. Feedback controls are ubiquitous, ranging from simple room thermostats to airplane engine control. Helping to make sense of this wide-ranging field, this book provides a new approach by keeping a tight focus on the essentials with a limited, yet consistent set of examples. Analysis and design methods are explained in terms of theory and practice. The book covers classical, linear feedback controls, and linear approximations are used when needed. In parallel, the book covers time-discrete (digital) control systems and juxtapos