Clandestinity and militant culture in Latin America, 1960s to the early 1980s: epistemological and historical reflections and an agenda for research

Clandestinity was a central aspect of the life and organisation of the militancies of the diverse cultures of the Cold War Latin America left. Yet the topic is scarcely considered central in testimonies or historical analyses of the period. In this article I approach both clandestinity as culture and the culture of clandestinity as lived experiences, ways of organising and modi operandi among militant organisations and individuals of the period. To do this, I resort to diverse types of literature, ranging from academic analyses to personal testimonies, including fictionalised accounts. I then elaborate on the possible historical, methodological and epistemological reasons why clandestinity has not been explored in the majority of the academic or testimonial corpuses presently available, stressing the possibility, as a hypothesis, that we may still be facing silence – a main tenet of clandestinity – as political doctrine. I also briefly discuss oral history as a main tool to access knowledge of clandestinity and question whether clandestinity may be an object of the historical record

Willingness-to-Pay for Attribute Level and Variability: The Case of Mexican Millers’ Demand for Hard Red Winter Wheat

In-person interviews were carried out with Mexican millers who were administered a conjoint-type survey designed to incorporate uncertainty in attribute levels. Two methods were used to model millers’ risk preferences: a modified mean-variance approach and an explicit expected utility approach. Controlling for variability, Mexican millers are willing to pay premiums for increases in quality factors such as test weight, protein content, falling number, and dough strength/extensibility. We find millers are not particularly sensitive to changes in the variability of quality characteristics. Out-of-sample forecasts suggest the mean-variance model provides an accurate depiction of actual Mexican imports.mean-variance, Mexican wheat market, moment generating function, preference elicitation, wheat quality, Agribusiness, Farm Management, Food Consumption/Nutrition/Food Safety, International Relations/Trade, Marketing, Production Economics, Risk and Uncertainty, C35, C42, Q13,

Polynomial-based surrogate modeling of RF and microwave circuits in frequency domain exploiting the multinomial theorem

A general formulation to develop EM-based polynomial surrogate models in frequency domain utilizing the multinomial theorem is presented in this paper. Our approach is especially suitable when the number of learning samples is very limited and no physics-based coarse model is available. We compare our methodology against other four surrogate modeling techniques: response surface modeling, support vector machines, generalized regression neural networks, and Kriging. Results confirm that our modeling approach has the best performance among these techniques when using a very small amount of learning base points on relatively small modeling regions. We illustrate our technique by developing a surrogate model for an SIW interconnect with transitions to microstrip lines, a dual band T-slot PIFA handset antenna, and a high-speed package interconnect. Examples are simulated on a commercially available 3D FEM simulator

Polynomial-based surrogate modeling of microwave structures in frequency domain exploiting the multinomial theorem

We propose a methodology for developing EM-based polynomial surrogate models exploiting the multinomial theorem. Our methodology is compared against four EM surrogate modeling techniques: response surface modeling, support vector machines, generalized regression neural networks, and Kriging. Results show that the proposed polynomial surrogate modeling approach has the best performance among these techniques when using a very small amount of learning base points. The proposed methodology is illustrated by developing a surrogate model for a T-slot PIFA antenna simulated on a commercially available 3D FEM simulator

Reliable full-wave EM simulation of a single-layer SIW interconnect with transitions to microstrip lines

We present a procedure to obtain reliable EM responses for a substrate integrated waveguide (SIW) interconnect with microstrip line transitions. The procedure focuses on two COMSOL configuration settings: meshing sizes and simulation bounding box. Once both are properly configured, the implemented structure is tested by perturbing the simulation bounding box to assure it has no effect on the EM responsesITESO, A.C

Design Optimization of Full-Wave EM Models by Low-Order Low-Dimension Polynomial Surrogate Functionals

A practical formulation for EM-based design optimization of high-frequency circuits using simple polynomial surrogate functionals is proposed in this paper. Our approach starts from a careful selection of design variables and is based on a closed-form formulation that yields global optimal values for the surrogate model weighting factors, avoiding a large set of expensive EM model data, and resulting in accurate low-order low-dimension polynomials interpolants that are used as vehicles for efficient design optimization. Our formulation is especially suitable for EM-based design problems with no equivalent circuital models available. The proposed technique is illustrated by the EM-based design optimization of a Ka-band substrate integrated waveguide (SIW) interconnect with conductor-backed coplanar waveguide (CBCPW) transitions, a low crosstalk PCB microstrip interconnect structure with guard traces, and a 10-40 GHz SIW interconnect with microstrip transitions on a standard FR4-based substrate. Three commercially available full-wave EM solvers are used in our examples: CST, Sonnet and COMSOL

Selecting Surrogate-Based Modeling Techniques for Power Integrity Analysis

In recent years, extensive usage of simulated power integrity (PI) models to predict the behavior of power delivery networks (PDN) on a chip has become more relevant. Predicting adequate performance against power consumption can yield to either cheap or costly design solutions. Since PI simulations including high-frequency effects are becoming more and more computationally complex and expensive, it is critical to develop reliable and fast models to understand system’s behavior to accelerate decision making during design stages. Hence, metamodeling techniques can help to overcome this challenge. In this work, a comparative study between different surrogate modeling techniques as applied to PI analysis is described. We model and analyze a PDN that includes two different power domains and a combination of remote sense resistors for communication and storage CPU applications. We aim at developing reliable and fast coarse models to make trade off decisions while complying with voltage levels and power consumption requirements

Surrogate-based Analysis and Design Optimization of Power Delivery Networks

As microprocessor architectures continue to increase computing performance under low-energy consumption, the combination of signal integrity, electromagnetic interference, and power delivery is becoming crucial in the computer industry. In this context, power delivery engineers make use of complex and computationally expensive models that impose time-consuming industrial practices to reach an adequate power delivery design. In this paper, we propose a general surrogate-based methodology for fast and reliable analysis and design optimization of power delivery networks (PDN). We first formulate a generic surrogate model methodology exploiting passive lumped models optimized by parameter extraction to fit PDN impedance profiles. This PDN modeling formulation is illustrated with industrial laboratory measurements of a 4th generation server CPU motherboard. We next propose a black box PDN surrogate modeling methodology for efficient and reliable power delivery design optimization. To build our black box PDN surrogate, we compare four metamodeling techniques: support vector machines, polynomial surrogate modeling, generalized regression neural networks, and Kriging. The resultant best metamodel is then used to enable fast and accurate optimization of the PDN performance. Two examples validate our surrogate-based optimization approach: a voltage regulator with dual power rail remote sensing intended for communications and storage applications, by finding optimal sensing resistors and loading conditions; and a multiphase voltage regulator from a 6th generation Intel® server motherboard, by finding optimal compensation settings to reduce the number of bulk capacitors without losing CPU performance.ITESO, A.C

Desarrollo de simulador de negocios en la industria de sensores: estrategia y toma de decisiones

El objetivo principal del presente trabajo de obtención de grado es documentar las experiencias vividas por el equipo Baldwin en el simulador de negocios CAPSIM. En la simulación, el equipo debe elegir e implementar una estrategia para una compañía de sensores y se deben tomar decisiones en las áreas de investigación y desarrollo, promociones, ventas, producción, recursos humanos y finanzas durante ocho años fiscales. Al finalizar cada año, se genera un reporte llamado Courier donde se presentan los resultados de la compañía y su competencia. De acuerdo con estos resultados, la empresa debe evaluar si va a seguir con la estrategia elegida o va a hacer modificaciones

Optimizing Phase Settings of High-Frequency Voltage Regulators for Power Delivery Applications

Every new computer server introduced to the market aims at delivering the best tradeoff between performance and power consumption. This goal is crucial in the case of servers for cloud computing hardware infrastructure. In this context, power delivery (PD) experts are adopting higher frequency switching voltage regulators (VR) to reduce platform’s cost as well as total cost of ownership (TCO). Because of this fact, the real estate of components, such as voltage regulators and output inductors, is shrinking as VR frequency increases. As a consequence, achieving the best performance of the VR implies looking into phase shedding schemes, as well as EM coupled inductor design, among other techniques, to mitigate power losses. This paper focuses on the study of the best angle arrangement possible for high frequency VR applications, by exploring angle settings under light load scenarios, aiming to minimize VR’s power loss and output’s voltage ripple