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Papers by hector L trujillo

Research paper thumbnail of Piezo-response of lateral bipolar transistors

Sensors and Actuators A: Physical, 1998

Abstract The influence of mechanical stresses upon the offset of merged lateral bipolar magnetotr... more Abstract The influence of mechanical stresses upon the offset of merged lateral bipolar magnetotransistors (LMTs) is studied. The experimental setup for analyzing the response of such structures to torsional and flexural stresses is briefly described. It has been found that their sensitivity to torsional stresses is much higher than to flexural stresses, and this may be explained in terms of the piezojunction effect which gives rise to emitter injection modulation (EIM), a phenomenon analogous to the one previously reported to explain the magnetic response of some types of LMTs. Other analogies between the response to mechanical stresses and to a magnetic field are described. Two different modes of electrical connections of the four collectors of the device are analyzed: cross-coupled and parallel. The parallel connection allows some degree of compensation of the offset due to torsional stresses, whereas the cross-coupled one is more sensitive to flexural stresses. It is concluded that: (1) the response to a magnetic field and a mechanical stress have many common aspects; (2) the piezojunction effect is the fundamental mechanism behind the measured sensitivity; and (3) these devices are potentially excellent stress sensors.

Research paper thumbnail of Socio-ecological analisys of artisanal fisheries on Eastern Island

Latin American Journal of Aquatic Research, Oct 22, 2014

Research paper thumbnail of Step stress tests: Monte Carlo simulation and evaluation

Microelectronics Reliability, 1989

AMtract-In this technical note the historical development of step stress tests is briefly treated... more AMtract-In this technical note the historical development of step stress tests is briefly treated. Monte Carlo simulation of such tests has been applied to the case of simple tests (one ladder of stresses), wherein an Arrhenius reaction rate model is considered and semiconductor cumulative failure distribution vs. time is assumed to be lognormal at constant stress. Calculated results for activation energy are obtained by means of a computer program. It is concluded that the smaller the step height, the better the results and also that simple tests have an advantage over two ladder tests because they don't require a minimum step height nor previous knowledge of the activation energy.

Research paper thumbnail of Step stress tests: Monte Carlo simulation and evaluation

Microelectronics Reliability, 1989

AMtract-In this technical note the historical development of step stress tests is briefly treated... more AMtract-In this technical note the historical development of step stress tests is briefly treated. Monte Carlo simulation of such tests has been applied to the case of simple tests (one ladder of stresses), wherein an Arrhenius reaction rate model is considered and semiconductor cumulative failure distribution vs. time is assumed to be lognormal at constant stress. Calculated results for activation energy are obtained by means of a computer program. It is concluded that the smaller the step height, the better the results and also that simple tests have an advantage over two ladder tests because they don't require a minimum step height nor previous knowledge of the activation energy.

Research paper thumbnail of Planificación ambiental : una visión de conjunto / editado por Marisol Aguilera,Héctor Trujillo P

ABSTRACT Incluye bibliografía e índice

Research paper thumbnail of Knowledge and Research on Chilean Fisheries Resources: diagnosis and propositions for a sustainable development

World …, 2011

Summary As part of their efforts to improve the national fisheries management system, Chilean fis... more Summary As part of their efforts to improve the national fisheries management system, Chilean fisheries authorities have identified the need to develop a fisheries research program based on state-of-the-art fisheries knowledge and information systems. To meet ...

Research paper thumbnail of Socio ecological analysis of the artisanal fishing system on Easter Island

Latin American Journal of Aquatic Research, 2014

This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Isl... more This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Island (27º07′S, 109º22′W) through the identification and interaction of stakeholders. It also comprises a structural analysis of the system aiming to identify any key issues and then propose research and development programs for multiple fisheries that will contribute to their sustainable development. The methodology is divided into four stages: i) identification of issues with stakeholder (fishers, government workers and expert scientists) participation, ii) analysis of a structural matrix consisting of a direct causality study of the symmetric, structural and binary matrix based on socio-ecological issues allowing the calculation of the level of influence and dependence of each issue, iii) identification of key issues with an influence/dependency diagram, and iv) proposal of research and development programs according to the needs and opportunities identified in the previous stages. The Easter Island artisanal fishing system is used as a case study for this methodological approach. Thus, the fishers identified 108 issues, which were then grouped by similarity, reducing the number to 27 global issues, of which seven were identified as key. Surveyed local and central government workers and expert scientists identified 7, 2 and 5 issues, respectively. Finally, research and development programs are proposed that will encourage a series of changes to the fisheries situation on the island, in order to resolve issues and promote their sustainable development.

Research paper thumbnail of Socio ecological analysis of the artisanal fishing system on Easter Island

Latin American Journal of Aquatic Research, 2014

This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Isl... more This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Island (27º07′S, 109º22′W) through the identification and interaction of stakeholders. It also comprises a structural analysis of the system aiming to identify any key issues and then propose research and development programs for multiple fisheries that will contribute to their sustainable development. The methodology is divided into four stages: i) identification of issues with stakeholder (fishers, government workers and expert scientists) participation, ii) analysis of a structural matrix consisting of a direct causality study of the symmetric, structural and binary matrix based on socio-ecological issues allowing the calculation of the level of influence and dependence of each issue, iii) identification of key issues with an influence/dependency diagram, and iv) proposal of research and development programs according to the needs and opportunities identified in the previous stages. The Easter Island artisanal fishing system is used as a case study for this methodological approach. Thus, the fishers identified 108 issues, which were then grouped by similarity, reducing the number to 27 global issues, of which seven were identified as key. Surveyed local and central government workers and expert scientists identified 7, 2 and 5 issues, respectively. Finally, research and development programs are proposed that will encourage a series of changes to the fisheries situation on the island, in order to resolve issues and promote their sustainable development.

Research paper thumbnail of Piezo-response of lateral bipolar transistors

Sensors and Actuators A: Physical, 1998

Abstract The influence of mechanical stresses upon the offset of merged lateral bipolar magnetotr... more Abstract The influence of mechanical stresses upon the offset of merged lateral bipolar magnetotransistors (LMTs) is studied. The experimental setup for analyzing the response of such structures to torsional and flexural stresses is briefly described. It has been found that their sensitivity to torsional stresses is much higher than to flexural stresses, and this may be explained in terms of the piezojunction effect which gives rise to emitter injection modulation (EIM), a phenomenon analogous to the one previously reported to explain the magnetic response of some types of LMTs. Other analogies between the response to mechanical stresses and to a magnetic field are described. Two different modes of electrical connections of the four collectors of the device are analyzed: cross-coupled and parallel. The parallel connection allows some degree of compensation of the offset due to torsional stresses, whereas the cross-coupled one is more sensitive to flexural stresses. It is concluded that: (1) the response to a magnetic field and a mechanical stress have many common aspects; (2) the piezojunction effect is the fundamental mechanism behind the measured sensitivity; and (3) these devices are potentially excellent stress sensors.

Research paper thumbnail of Socio-ecological analisys of artisanal fisheries on Eastern Island

Latin American Journal of Aquatic Research, Oct 22, 2014

Research paper thumbnail of Step stress tests: Monte Carlo simulation and evaluation

Microelectronics Reliability, 1989

AMtract-In this technical note the historical development of step stress tests is briefly treated... more AMtract-In this technical note the historical development of step stress tests is briefly treated. Monte Carlo simulation of such tests has been applied to the case of simple tests (one ladder of stresses), wherein an Arrhenius reaction rate model is considered and semiconductor cumulative failure distribution vs. time is assumed to be lognormal at constant stress. Calculated results for activation energy are obtained by means of a computer program. It is concluded that the smaller the step height, the better the results and also that simple tests have an advantage over two ladder tests because they don't require a minimum step height nor previous knowledge of the activation energy.

Research paper thumbnail of Step stress tests: Monte Carlo simulation and evaluation

Microelectronics Reliability, 1989

AMtract-In this technical note the historical development of step stress tests is briefly treated... more AMtract-In this technical note the historical development of step stress tests is briefly treated. Monte Carlo simulation of such tests has been applied to the case of simple tests (one ladder of stresses), wherein an Arrhenius reaction rate model is considered and semiconductor cumulative failure distribution vs. time is assumed to be lognormal at constant stress. Calculated results for activation energy are obtained by means of a computer program. It is concluded that the smaller the step height, the better the results and also that simple tests have an advantage over two ladder tests because they don't require a minimum step height nor previous knowledge of the activation energy.

Research paper thumbnail of Planificación ambiental : una visión de conjunto / editado por Marisol Aguilera,Héctor Trujillo P

ABSTRACT Incluye bibliografía e índice

Research paper thumbnail of Knowledge and Research on Chilean Fisheries Resources: diagnosis and propositions for a sustainable development

World …, 2011

Summary As part of their efforts to improve the national fisheries management system, Chilean fis... more Summary As part of their efforts to improve the national fisheries management system, Chilean fisheries authorities have identified the need to develop a fisheries research program based on state-of-the-art fisheries knowledge and information systems. To meet ...

Research paper thumbnail of Socio ecological analysis of the artisanal fishing system on Easter Island

Latin American Journal of Aquatic Research, 2014

This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Isl... more This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Island (27º07′S, 109º22′W) through the identification and interaction of stakeholders. It also comprises a structural analysis of the system aiming to identify any key issues and then propose research and development programs for multiple fisheries that will contribute to their sustainable development. The methodology is divided into four stages: i) identification of issues with stakeholder (fishers, government workers and expert scientists) participation, ii) analysis of a structural matrix consisting of a direct causality study of the symmetric, structural and binary matrix based on socio-ecological issues allowing the calculation of the level of influence and dependence of each issue, iii) identification of key issues with an influence/dependency diagram, and iv) proposal of research and development programs according to the needs and opportunities identified in the previous stages. The Easter Island artisanal fishing system is used as a case study for this methodological approach. Thus, the fishers identified 108 issues, which were then grouped by similarity, reducing the number to 27 global issues, of which seven were identified as key. Surveyed local and central government workers and expert scientists identified 7, 2 and 5 issues, respectively. Finally, research and development programs are proposed that will encourage a series of changes to the fisheries situation on the island, in order to resolve issues and promote their sustainable development.

Research paper thumbnail of Socio ecological analysis of the artisanal fishing system on Easter Island

Latin American Journal of Aquatic Research, 2014

This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Isl... more This paper introduces a socio-ecological analysis of the artisanal fisheries system on Easter Island (27º07′S, 109º22′W) through the identification and interaction of stakeholders. It also comprises a structural analysis of the system aiming to identify any key issues and then propose research and development programs for multiple fisheries that will contribute to their sustainable development. The methodology is divided into four stages: i) identification of issues with stakeholder (fishers, government workers and expert scientists) participation, ii) analysis of a structural matrix consisting of a direct causality study of the symmetric, structural and binary matrix based on socio-ecological issues allowing the calculation of the level of influence and dependence of each issue, iii) identification of key issues with an influence/dependency diagram, and iv) proposal of research and development programs according to the needs and opportunities identified in the previous stages. The Easter Island artisanal fishing system is used as a case study for this methodological approach. Thus, the fishers identified 108 issues, which were then grouped by similarity, reducing the number to 27 global issues, of which seven were identified as key. Surveyed local and central government workers and expert scientists identified 7, 2 and 5 issues, respectively. Finally, research and development programs are proposed that will encourage a series of changes to the fisheries situation on the island, in order to resolve issues and promote their sustainable development.