Papers by juan david castro gonzalez
Energies, 2021
The prescriptive path is the most widely used approach for commercial code compliance in the Unit... more The prescriptive path is the most widely used approach for commercial code compliance in the United States. Though easy to implement, prescriptive approaches do not typically discriminate between minimally compliant, high-performing and poorly performing HVAC system configurations. Hence, to meet aggressive energy and carbon reduction goals, it is clear that energy codes will need to transition from prescriptive to performance-based approaches, a transition that is riddled with several challenges. This paper discusses a new HVAC system-based performance approach (HVAC System Performance) which provides a simpler solution to HVAV system evaluation compared to whole building performance, while keeping tradeoffs limited to specific building systems. The Total System Performance Ratio (TSPR) is a metric for evaluation of overall system efficiency instead of individual component efficiency, a solution which could also eventually facilitate the transition to a 100% performance-based code ...
Good human drivers adjust radii, favor lanes and inherently set speeds while racing. They gracefu... more Good human drivers adjust radii, favor lanes and inherently set speeds while racing. They gracefully enter and exit turns, and "read the terrain" or use foreknowledge of the course to slow down for harsh terrain features. Robots do not yet do this without the benefit of preplanning. This paper describes technologies and methodologies for preplanning including: path detailing, speed setting, terrain knowledge, and verification. The result of preplanning is the generation of two high performance, successful routes for two autonomous robots in the 2005 Grand Challenge traverse of 132 miles in about 7 hours.
Soil maps are essential resources to soil scientists and researchers in any fields related to soi... more Soil maps are essential resources to soil scientists and researchers in any fields related to soils, land use, species conservation, hunger reduction, social development, etc. However, creating detailed soil maps is an expensive and time consuming task that most developing nations cannot afford. In recent years, there has been a significant shift towards digital representation of soil maps and environmental variables that has created the field of predictive soil mapping (PSM), where statistical analysis is used to create predictive models of soil properties. PSM requires less human intervention than traditional soil mapping techniques, and relies more on computers to create models and predict properties. However, because most of the research funds for soil research come from developed nations, the research in this field has mostly focused in temperate zones (where most developed nations are located). The areas of the world with more needs in terms of hunger and poverty are mostly lo...
This paper reports details of a versatile implementation of the TraderBots approach: A market-bas... more This paper reports details of a versatile implementation of the TraderBots approach: A market-based approach to multirobot coordination. The architectural layout, implementation details, and variety of features are described. Experimental results are presented using a team of Pioneer II DX robots engaged in exploration and distributed sensing tasks. Different features and strengths of the approach and the implementation are highlighted in the experimental results.
This paper argues for the use of multicultural literature in the classroom, and puts forth a unit... more This paper argues for the use of multicultural literature in the classroom, and puts forth a unit plan that uses critical literacy in an English 11 classroom, though it can be readapted to fit other grade levels. Bishop (1990) describes multicultural literature as a set of windows, that people use to view the experiences of others, and mirrors, that reflect and validate peoples’ experience, a core principal in this paper. Critical literacy is comprised of four dimensions (Lewison, Flint, & Van Sluys, 2002) that allows for analyzing literature in a different and meaningful way. The final part of this paper details a five phase unit plan that has students inquiring into different cultures using Jigsaw groups (Aronson, n.d.). Keywords: Multicultural Literature, Critical Literacy, Social Justice, Inquiry
DELVING INTO MULTICULTURAL LIT !3 Delving into Multicultural Literature using Inquiry Introduction Multicultural literature is something that I encountered much later in life. I did n...
2016 24th Euromicro International Conference on Parallel, Distributed, and Network-Based Processing (PDP), 2016
The correlation of performance bottlenecks and their associated source code has become a cornerst... more The correlation of performance bottlenecks and their associated source code has become a cornerstone of performance analysis. It allows understanding why the efficiency of an application falls behind the computer's peak performance and enabling optimizations on the code ultimately. To this end, performance analysis tools collect the processor call-stack and then combine this information with measurements to allow the analyst comprehend the application behavior. Some tools modify the call-stack during run-time to diminish the collection expense but at the cost of resulting in non-portable solutions. In this paper, we present a novel portable approach to associate performance issues with their source code counterpart. To address it, we capture a reduced segment of the call-stack (up to three levels) and then process the segments using an algorithm inspired by multi-sequence alignment techniques. The results of our approach are easily mapped to detailed performance views, enabling the analyst to unveil the application behavior and its corresponding region of code. To demonstrate the usefulness of our approach, we have applied the algorithm to several firsttime seen in-production applications to describe them finely, and optimize them by using tiny modifications based on the analyses.
Proceedings of the 10th Performance Metrics for Intelligent Systems Workshop on - PerMIS '10, 2010
ABSTRACT Most stand-alone planners have theoretical guarantees in terms of completeness, optimali... more ABSTRACT Most stand-alone planners have theoretical guarantees in terms of completeness, optimality and performance. However, no stand-alone planner is able to handle the complexity of real world systems accounting for kinematic and dynamic constraints while being able to operate over long ranges. This leads to hierarchical planning approaches that bring together different stand-alone planners for local and global navigation at the expense of weaker performance guarantees. This paper presents the results of using simulation combined with field testing in order to quantify the performance of integrated hierarchical planners. While these results don't provide performance guarantees, they show clear performance differences depending on the integrated hierarchical planner used. While in general the simulated results were a good predictor of performance in the field, in some scenarios the simulated experiments did not accurately reflect the performance in the field.
We have completed a high-resolution, high-signal-to-noise, spectroscopic survey of the northern m... more We have completed a high-resolution, high-signal-to-noise, spectroscopic survey of the northern members of the peculiar lambda Boo stars in order to investigate the frequency of the incidence of nonradial pulsation (NRP) in these metal-deficient stars. Of 18 objects observed, 9 show conclusive evidence of NRP, which suggests that pulsation instability is a common phenomenon in the lambda Boo class.
A fundamental part of many authentication protocols which authenticate a party to a human involve... more A fundamental part of many authentication protocols which authenticate a party to a human involves the human recognizing or otherwise processing a message received from the party. Examples include typical implementations of Verified by Visa in which a message, previously stored by the human at a bank, is sent by the bank to the human to authenticate the bank to the human; or the expectation that humans will recognize or verify an extended validation certificate in a HTTPS context. This paper presents general definitions and building blocks for the modelling and analysis of human recognition in authentication protocols, allowing the creation of proofs for protocols which include humans. We cover both generalized trawling and human-specific targeted attacks. As examples of the range of uses of our construction, we use the model presented in this paper to prove the security of a mutual authentication login protocol and a human-assisted device pairing protocol.
Tools for High Performance Computing 2013, 2014
Due to the increasing complexity of High Performance Computing (HPC) systems and applications it ... more Due to the increasing complexity of High Performance Computing (HPC) systems and applications it is necessary to maximize the insight of the performance data extracted from an application execution. This is the mission of the Performance Analytics field. In this chapter, we present three different contributions to this field. First, we demonstrate how it is possible to capture the computation structure of parallel applications at fine grain by using density-based clustering algorithms. Second, we introduce the use of multiple sequence alignment algorithms to asses the quality of a computation structure provided by the cluster analysis. Third, we propose a new clustering algorithm to maximize the quality of the computation structure detected minimizing the user intervention. To demonstrate the usefulness of the different techniques, we also present three use cases.
2012 IEEE International Conference on Robotics and Automation, 2012
Path planning in dynamic environments with moving obstacles is computationally complex since it r... more Path planning in dynamic environments with moving obstacles is computationally complex since it requires modeling time as an additional dimension. While in other domains there are state dominance relationships that can significantly reduce the complexity of the search, in dynamic environments such relationships do not exist. This paper presents a novel state dominance relationship tailored specifically for dynamic environments, and presents a planner that uses that property to plan paths over ten times faster than without using state dominance. Recent results in path planning with safe intervals[3], prove that when the cost function to be optimized is time, it is possible to substitute intervals for time in the state space without affecting the optimality of the result. A safe interval
ITSC2000. 2000 IEEE Intelligent Transportation Systems. Proceedings (Cat. No.00TH8493)
A vision system for Intelligent Vehicles is proposed here. The system exploits the characteristic... more A vision system for Intelligent Vehicles is proposed here. The system exploits the characteristics of the gray level histogram of the road to detect lane markers. Each lane marker is then analyzed using a decision tree, andJinally the relations between lane markers are analyzed to create structures defining the lane boundaries. The resulting system also generates images that can be used as preprocessing stages in lane detection, lane tracking or obstacle detection algorithms. The system runs in realtime at rates of about 30 Hz.
Digital Soil Mapping with Limited Data
Creating detailed soil maps is an expensive and time consuming task that most developing nations ... more Creating detailed soil maps is an expensive and time consuming task that most developing nations cannot afford. In recent years, there has been a significant shift towards digital representation of soil maps and environmental variables and the associated activity of predictive soil mapping, where statistical analysis is used to create predictive models of soil properties. Predictive soil mapping requires less human intervention than traditional soil mapping techniques, and relies more on computers to create models that can predict variation of soil properties. This paper reports on a multidisciplinary collaborative project applying advanced data-mining techniques to predictive soil modelling for Honduras. Gaussian process models are applied to map continous soil variables of texture and pH in Honduras at a spatial resolution of 1 km, using 2472 sites with soil sample data and 32 terrain, climate, vegetation and geology related variables. Using split sample validation, 45% of variability in soil pH was explained, 17% in clay content and 24% in sand content. The principle variables that the models selected were climate related. Gaussian process models are shown to be powerful approaches to digital soil mapping, especially when multiple explanatory variables are available. The reported work leverages the knowledge of the soil science and computer science communities, and creates a model that contributes to the state of the art for predictive soil mapping.
2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2005
We introduce a resolution-optimal path planner that considers uncertainty while optimizing any mo... more We introduce a resolution-optimal path planner that considers uncertainty while optimizing any monotonic objective function such as mobility cost, risk, or energy expended. The resulting path minimizes the expected cost of the objective function, while ensuring that the uncertainty in the position of the robot does not compromise the safety of the robot or the reachability of the goal. Although the problem domain is stochastic in nature, our algorithm takes advantage of deterministic path-planning techniques to achieve significant performance improvements.
2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2009
This paper presents two new approaches that enable the use of linear landmarks for planning paths... more This paper presents two new approaches that enable the use of linear landmarks for planning paths with uncertainty in position in outdoor environments. The first approach uses a combination of forward simulation and entropy to reduce the dimensionality of the search space, while still preserving most of the information required to propagate a full covariance matrix. The second approach adds incremental binning to improve the quality of the solution while still keeping the dimensionality of the search space relatively low. These approaches provide a better compromise of speed and quality of the solution than most existing approaches, and are able to successfully utilize linear landmarks in large outdoor environments. I. INTRODUCTION Planning with uncertainty in position deals with the problem of navigating autonomously when good prior maps are available but the position of the robot is not known precisely. Although the uncertainty in the position of the robot is often ignored because of the widespread availability of Global Positioning Systems (GPS), there are many scenarios where GPS is unavailable or its reliability is compromised. If GPS is not available, the position estimate of the robot depends on dead-reckoning alone, which drifts with time and can accrue very large errors. Most existing approaches to path planning and navigation for outdoor environments are unable to use prior maps if the position of the robot is not precisely known. Often these approaches end up performing the much harder task of navigating without prior information. An essential part of most approaches to planning with uncertainty in position is the use of landmarks. Because the dead-reckoning error is not bounded, landmarks are required to reduce the uncertainty in the position of the robot and to be able to travel long distances. However, most existing approaches are only able to use landmarks that reduce the uncertainty in the position of the robot in both x and y directions. Because these landmarks usually look like a point in a map, they are called point Manuscript received February 19, 2009. This work was sponsored by the U.S. Army Research Laboratory under contract "Robotics Collaborative Technology Alliance" (contract number DAAD19-01-2-0012). The views and conclusions contained in this document do not represent the official policies or endorsements of the U.S. Government.
2008 IEEE International Conference on Robotics and Automation, 2008
This paper presents two new approaches to planning with uncertainty in position that achieve bett... more This paper presents two new approaches to planning with uncertainty in position that achieve better performance than existing techniques and that are able to incorporate changes in the environment in near real-time. Both approaches reuse previous searches and replan when changes in the environment are detected. The first approach, called replanning with prior map updates, assumes that changes in the prior map originate from the same source as the original prior map. Therefore, the updates are registered with the existing map, but not with the position of the robot. The resulting path after applying the updates is the same as if the updates had been present in the original prior map. The second approach, called replanning with sensor updates, assumes that changes in the prior map originate from on-board sensors. Therefore, the updates are registered with the robot, but not with the existing map. The resulting path after applying the updates is not the same path that would be found if the updates had taken place in the original prior map. Replanning with prior map updates achieves a speed-up to one order of magnitude with respect to forward planning from scratch, while replanning with sensor updates achieves a speedup of almost two orders of magnitude.
Proceedings 2007 IEEE International Conference on Robotics and Automation, 2007
We present a novel approach to mobile robot navigation that enables navigation in outdoor environ... more We present a novel approach to mobile robot navigation that enables navigation in outdoor environments without GPS. The approach uses a path planner that calculates optimal paths while considering uncertainty in position, and that uses landmarks to localize the vehicle as part of the planning process. The landmarks are simple, possibly aliased, features that have been previously identified in a highresolution map. These landmarks are combined with an estimate of the position of the vehicle to create unique and robust features. This approach reduces or eliminates the need for GPS and enables the use of prior maps with imperfect map registration.
Unmanned Systems Technology XIV, 2012
ABSTRACT Creating robots that can help humans in a variety of tasks requires robust mobility and ... more ABSTRACT Creating robots that can help humans in a variety of tasks requires robust mobility and the ability to safely navigate among moving obstacles. This paper presents an overview of recent research in the Robotics Collaborative Technology Alliance (RCTA) that addresses many of the core requirements for robust mobility in human-populated environments. Safe Interval Path Planning (SIPP) allows for very fast planning in dynamic environments when planning timeminimal trajectories. Generalized Safe Interval Path Planning extends this concept to trajectories that minimize arbitrary cost functions. Finally, generalized PPCP algorithm is used to generate plans that reason about the uncertainty in the predicted trajectories of moving obstacles and try to actively disambiguate the intentions of humans whenever necessary. We show how these approaches consider moving obstacles and temporal constraints and produce high-fidelity paths. Experiments in simulated environments show the performance of the algorithms under different controlled conditions, and experiments on physical mobile robots interacting with humans show how the algorithms perform under the uncertainties of the real world.
Revista musical chilena, 2000
3000. CD digital. Composiciones de Eduardo Cáceres. Ensemble Bartók; Luis Orlandini (guitarra), Á... more 3000. CD digital. Composiciones de Eduardo Cáceres. Ensemble Bartók; Luis Orlandini (guitarra), Ángela Acuña (cello); Rarina Glasinovic (piano), Cecilia Plaza (piano), Quinteto de Vientos Pro Arte; Víctor Alarcón (tenor); Raimundo Garrido (percusión); Luis Hemán Ángel (tuba); Vima Osses (piano); Francesca Ancarola (voz acústica y electroacústica); Claudia Virgilio (voz procesada); Merly Donoso (tablas hindúes); Silvio Paredes (bajo eléctrico) y Eduardo Cáceres (dirección). SVR-ECR-3006-11.
IEEE Micro, 2011
Architecture simulation tools are extremely useful not only to predict the performance of future ... more Architecture simulation tools are extremely useful not only to predict the performance of future system designs, but also to analyze and improve the performance of software running on well know architectures. However, since power and complexity issues stopped the progress of singlethread performance, simulation speed no longer scales with technology: systems get larger and faster, but simulators do not get any faster. Detailed simulation of full-scale applications running on large clusters with hundreds or thousands of processors is not feasible. In this paper we present a methodology that allows detailed simulation of large-scale MPI applications running on systems with thousands of processors with low resource cost. Our methodology allows detailed processor simulation, from the memory and cache hierarchy down to the functional units and the pipeline structure. This feature enables software performance analysis beyond what performance counters would allow. In addition, it enables performance prediction targeting nonexistent architectures and systems, that is, systems for which no performance data can be used as a reference. For example, detailed analysis of the weather forecasting application WRF reveals that it is highly optimized for cache locality, and is strongly compute bound, with faster functional units having the greatest impact on its performance. Also, analysis of next-generation CMP clusters show that performance may start to decline beyond 8 processors per chip due to shared resource contention, regardless of the benefits of through-memory communication.
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Papers by juan david castro gonzalez