The 1991 3rd NASA Symposium on VLSI Design

Papers from the symposium are presented from the following sessions: (1) featured presentations 1; (2) very large scale integration (VLSI) circuit design; (3) VLSI architecture 1; (4) featured presentations 2; (5) neural networks; (6) VLSI architectures 2; (7) featured presentations 3; (8) verification 1; (9) analog design; (10) verification 2; (11) design innovations 1; (12) asynchronous design; and (13) design innovations 2

An optimal nephelometric model design method for particle characterisation

Scattering nephelometry is a particle characterisation method applicable to fluid suspensions containing impurities. Solutions derived by the method feature particle classification by size (diameter), volume or texture as well as continuous on-line and in-situ monitoring, The replacement of turbidimeters with nephelometers in many existing turbidity applications could result in suppression of side effects caused by limitations and uncontrolled parameter drifts and satisfaction of problem-defined constraints at virtually no change in implementation cost. A major issue of nephelometric model design is the selection of a mathematical tool suitable for the modelling of the data analysis system. [Continues.

Hardware/software architectures for iris biometrics

Nowadays, the necessity of identifying users of facilities and services has become quite important not only to determine who accesses a system and/or service, but also to determine which privileges should be provided to each user. For achieving such identification, Biometrics is emerging as a technology that provides a high level of security, as well as being convenient and comfortable for the citizen. Most biometric systems are based on computer solutions, where the identification process is performed by servers or workstations, whose cost and processing time make them not feasible for some situations. However, Microelectronics can provide a suitable solution without the need of complex and expensive computer systems. Microelectronics is a subfield of Electronics and as the name suggests, is related to the study, development and/or manufacturing of electronic components, i.e. integrated circuits (ICs). We have focused our research in a concrete field of Microelectronics: hardware/software co-design. This technique is widely used for developing specific and high computational cost devices. Its basis relies on using both hardware and software solutions in an effective way, thus, obtaining a device faster than just a software solution, or smaller devices that use dedicated hardware developed for all the processes. The questions on how we can obtain an effective solution for Biometrics will be solved considering all the different aspects of these systems. In this Thesis, we have made two important contributions: the first one for a verification system based on ID token and secondly, a search engine used for massive recognition systems, both of them related to Iris Biometrics. The first relevant contribution is a biometric system architecture proposal based on ID tokens in a distributed system. In this contribution, we have specified some considerations to be done in the system and describe the different functionalities of the elements which form it, such as the central servers and/or the terminals. The main functionality of the terminal is just left to acquiring the initial biometric raw data, which will be transmitted under security cryptographic methods to the token, where all the biometric process will be performed. The ID token architecture is based on Hardware/software co-design. The architecture proposed, independent of the modality, divides the biometric process into hardware and software in order to achieve further performance functions, more than in the existing tokens. This partition considers not only the decrease of computational time hardware can provide, but also the reduction of area and power consumption, the increase in security levels and the effects on performance in all the design. To prove the proposal made, we have implemented an ID token based on Iris Biometrics following our premises. We have developed different modules for an iris algorithm both in hardware and software platforms to obtain results necessary for an effective combination of same. We have also studied different alternatives for solving the partition problem in the Hardware/software co-design issue, leading to results which point out tabu search as the fastest algorithm for this purpose. Finally, with all the data obtained, we have been able to obtain different architectures according to different constraints. We have presented architectures where the time is a major requirement, and we have obtained 30% less processing time than in all software solutions. Likewise, another solution has been proposed which provides less area and power consumption. When considering the performance as the most important constraint, two architectures have been presented, one which also tries to minimize the processing time and another which reduces hardware area and power consumption. In regard the security we have also shown two architectures considering time and hardware area as secondary requirements. Finally, we have presented an ultimate architecture where all these factors were considered. These architectures have allowed us to study how hardware improves the security against authentication attacks, how the performance is influenced by the lack of floating point operations in hardware modules, how hardware reduces time with software reducing the hardware area and the power consumption. The other singular contribution made is the development of a search engine for massive identification schemes, where time is a major constraint as the comparison should be performed over millions of users. We have initially proposed two implementations: following a centralized architecture, where memories are connected to the microprocessor, although the comparison is performed by a dedicated hardware co-processor, and a second approach, where we have connected the memory driver directly in the hardware coprocessor. This last architecture has showed us the importance of a correct connection between the elements used when time is a major requirement. A graphical representation of the different aspects covered in this Thesis is presented in Fig.1, where the relation between the different topics studied can be seen. The main topics, Biometrics and Hardware/Software Co-design have been studied, where several aspects of them have been described, such as the different Biometric modalities, where we have focussed on Iris Biometrics and the security related to these systems. Hardware/Software Co-design has been studied by presenting different design alternatives and by identifying the most suitable configuration for ID Tokens. All the data obtained from this analysis has allowed us to offer two main proposals: The first focuses on the development of a fast search engine device, and the second combines all the factors related to both sciences with regards ID tokens, where different aspects have been combined in its Hardware/Software Design. Both approaches have been implemented to show the feasibility of our proposal. Finally, as a result of the investigation performed and presented in this thesis, further work and conclusions can be presented as a consequence of the work developed.-----------------------------------------------------------------------------------------Actualmente la identificación usuarios para el acceso a recintos o servicios está cobrando importancia no sólo para poder permitir el acceso, sino además para asignar los correspondientes privilegios según el usuario del que se trate. La Biometría es una tecnología emergente que además de realizar estas funciones de identificación, aporta mayores niveles de seguridad que otros métodos empleados, además de resultar más cómodo para el usuario. La mayoría de los sistemas biométricos están basados en ordenadores personales o servidores, sin embargo, la Microelectrónica puede aportar soluciones adecuadas para estos sistemas, con un menor coste y complejidad. La Microelectrónica es un campo de la Electrónica, que como su nombre sugiere, se basa en el estudio, desarrollo y/o fabricación de componentes electrónicos, también denominados circuitos integrados. Hemos centrado nuestra investigación en un campo específico de la Microelectrónica llamado co-diseño hardware/software. Esta técnica se emplea en el desarrollo de dispositivos específicos que requieren un alto gasto computacional. Se basa en la división de tareas a realizar entre hardware y software, consiguiendo dispositivos más rápidos que aquellos únicamente basados en una de las dos plataformas, y más pequeños que aquellos que se basan únicamente en hardware. Las cuestiones sobre como podemos crear soluciones aplicables a la Biometría son las que intentan ser cubiertas en esta tesis. En esta tesis, hemos propuesto dos importantes contribuciones: una para aquellos sistemas de verificación que se apoyan en dispositivos de identificación y una segunda que propone el desarrollo de un sistema de búsqueda masiva. La primera aportación es la metodología para el desarrollo de un sistema distribuido basado en dispositivos de identificación. En nuestra propuesta, el sistema de identificación está formado por un proveedor central de servicios, terminales y dichos dispositivos. Los terminales propuestos únicamente tienen la función de adquirir la muestra necesaria para la identificación, ya que son los propios dispositivos quienes realizan este proceso. Los dispositivos se apoyan en una arquitectura basada en codiseño hardware/software, donde los procesos biométricos se realizan en una de las dos plataformas, independientemente de la modalidad biométrica que se trate. El reparto de tareas se realiza de tal manera que el diseñador pueda elegir que parámetros le interesa más enfatizar, y por tanto se puedan obtener distintas arquitecturas según se quiera optimizar el tiempo de procesado, el área o consumo, minimizar los errores de identificación o incluso aumentar la seguridad del sistema por medio de la implementación en hardware de aquellos módulos que sean más susceptibles a ser atacados por intrusos. Para demostrar esta propuesta, hemos implementado uno de estos dispositivos basándonos en un algoritmo de reconocimiento por iris. Hemos desarrollado todos los módulos de dicho algoritmo tanto en hardware como en software, para posteriormente realizar combinaciones de ellos, en busca de arquitecturas que cumplan ciertos requisitos. Hemos estudiado igualmente distintas alternativas para la solucionar el problema propuesto, basándonos en algoritmos genéticos, enfriamiento simulado y búsqueda tabú. Con los datos obtenidos del estudio previo y los procedentes de los módulos implementados, hemos obtenido una arquitectura que minimiza el tiempo de ejecución en un 30%, otra que reduce el área y el consumo del dispositivo, dos arquitecturas distintas que evitan la pérdida de precisión y por tanto minimizan los errores en la identificación: una que busca reducir el área al máximo posible y otra que pretende que el tiempo de procesado sea mínimo; dos arquitecturas que buscan aumentar la seguridad, minimizando ya sea el tiempo o el área y por último, una arquitectura donde todos los factores antes nombrados son considerados por igual. La segunda contribución de la tesis se refiere al desarrollo de un motor de búsqueda para identificación masiva. La premisa seguida en esta propuesta es la de minimizar el tiempo lo más posible para que los usuarios no deban esperar mucho tiempo para ser identificados. Para ello hemos propuesto dos alternativas: una arquitectura clásica donde las memorias están conectadas a un microprocesador central, el cual a su vez se comunica con un coprocesador que realiza las funciones de comparación. Una segunda alternativa, donde las memorias se conectan directamente a dicho co-procesador, evitándose el uso del microprocesador en el proceso de comparación. Ambas propuestas son comparadas y analizadas, mostrando la importancia de una correcta y apropiada conexión de los distintos elementos que forman un sistema. La Fig. 2 muestra los distintos temas tratados en esta tesis, señalando la relación existente entre ellos. Los principales temas estudiados son la Biometría y el co-diseño hardware/software, describiendo distintos aspectos de ellos, como las diferentes modalidades biométricas, centrándonos en la Biometría por iris o la seguridad relativa a estos sistemas. En el caso del co-diseño hardware/software se presenta un estado de la técnica donde se comentan diversas alternativas para el desarrollo de sistemas empotrados, el trabajo propuesto por otros autores en el ¶ambito del co-diseño y por último qué características deben cumplir los dispositivos de identificación como sistemas empotrados. Con toda esta información pasamos al desarrollo de las propuestas antes descritas y los desarrollos realizados. Finalmente, conclusiones y trabajo futuro son propuestos a raíz de la investigación realizada

A strategy for the visual recognition of objects in an industrial environment.

This thesis is concerned with the problem of recognizing industrial objects rapidly and flexibly. The system design is based on a general strategy that consists of a generalized local feature detector, an extended learning algorithm and the use of unique structure of the objects. Thus, the system is not designed to be limited to the industrial environment. The generalized local feature detector uses the gradient image of the scene to provide a feature description that is insensitive to a range of imaging conditions such as object position, and overall light intensity. The feature detector is based on a representative point algorithm which is able to reduce the data content of the image without restricting the allowed object geometry. Thus, a major advantage of the local feature detector is its ability to describe and represent complex object structure. The reliance on local features also allows the system to recognize partially visible objects. The task of the learning algorithm is to observe the feature description generated by the feature detector in order to select features that are reliable over the range of imaging conditions of interest. Once a set of reliable features is found for each object, the system finds unique relational structure which is later used to recognize the objects. Unique structure is a set of descriptions of unique subparts of the objects of interest. The present implementation is limited to the use of unique local structure. The recognition routine uses these unique descriptions to recognize objects in new images. An important feature of this strategy is the transference of a large amount of processing required for graph matching from the recognition stage to the learning stage, which allows the recognition routine to execute rapidly. The test results show that the system is able to function with a significant level of insensitivity to operating conditions; The system shows insensitivity to its 3 main assumptions -constant scale, constant lighting, and 2D images- displaying a degree of graceful degradation when the operating conditions degrade. For example, for one set of test objects, the recognition threshold was reached when the absolute light level was reduced by 70%-80%, or the object scale was reduced by 30%-40%, or the object was tilted away from the learned 2D plane by 300-400. This demonstrates a very important feature of the learning strategy: It shows that the generalizations made by the system are not only valid within the domain of the sampled set of images, but extend outside this domain. The test results also show that the recognition routine is able to execute rapidly, requiring 10ms-500ms (on a PDP11/24 minicomputer) in the special case when ideal operating conditions are guaranteed. (Note: This does not include pre-processing time). This thesis describes the strategy, the architecture and the implementation of the vision system in detail, and gives detailed test results. A proposal for extending the system to scale independent 3D object recognition is also given

Mixed-Cell Methods for Diffusion Problems in Multiphase Systems.

We simulate diffusion in multimaterial systems with a cell-centered Eulerian mesh in two dimensions. A system with immiscible fluids contains sharp interfaces. An Eulerian mesh is fixed in space and does not move with the material. Therefore, cells with an interface contain multiple fluids; these are known as mixed cells. The treatment of mixed cells can vary in computational cost and accuracy. In some cases, the primary source of inaccuracy can be attributed to approximations made in modeling the mixed cells. This thesis focuses on the treatment of mixed cells based on the diffusion approximation of the transport equation. We introduce five subgrid, mixed-cell models. Two models have a single temperature for each cell, while the other three allow a separate temperature for each phase. The single-temperature models are implemented using the Support-Operators Method, which is derived herein. The first single-temperature model utilizes an effective tensor diffusivity that distinguishes diffusion tangent and normal to the interface. The second single-temperature model specifies a unique diffusivity in each corner of a mixed cell, which is effectively a mesh refinement of the mixed cell. The three multi-temperature models have increasingly accurate levels of approximation of the flux: (i) flux is calculated between cell-centers for each phase, (ii) flux is calculated between the centroid of each phase, and (iii) flux normal to an interface is calculated between centroids of each phase. The physical interpretations of these models are: (i) each phase occupies the entire cell, (ii) oblique flux is continuous, (iii) only normal flux is continuous. The standard approximation, using the harmonic mean of the diffusivities present in a mixed cell as an effective diffusivity, is also tested for comparison. We also derive two time-dependent analytical solutions for diffusion in a two-phase system, in both one and two dimensions. With the standard model as a reference point, the accuracy of the new models is quantified, and the convergence rates of the error are determined between pairs of spatial resolutions for the two problems with analytical solutions. Simulations of multiphysics and multimaterial phenomenon may benefit from increased mixed-cell fidelity achieved in this dissertation.PHDApplied PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/107150/1/leftynm_1.pd

Second Annual Workshop on Space Operations Automation and Robotics (SOAR 1988)

Papers presented at the Second Annual Workshop on Space Operation Automation and Robotics (SOAR '88), hosted by Wright State University at Dayton, Ohio, on July 20, 21, 22, and 23, 1988, are documented herein. During the 4 days, approximately 100 technical papers were presented by experts from NASA, the USAF, universities, and technical companies. Panel discussions on Human Factors, Artificial Intelligence, Robotics, and Space Systems were held but are not documented herein. Technical topics addressed included knowledge-based systems, human factors, and robotics

1993-1994 Louisiana Tech University Catalog

The Louisiana Tech University Catalog includes announcements and course descriptions for courses offered at Louisiana Tech University for the academic year of 1993-1994.https://digitalcommons.latech.edu/university-catalogs/1021/thumbnail.jp