61 research outputs found
Fuori Standard. "4 casas" a Città del Messico. Gaeta Springall Arquitectos
No full textLo studio di progettazione fondato nel 2001 da Julio Gaeta e Luby Springall è sicuramente uno dei più interessanti del panorama messicano.
Entrambi docenti universitari, Gaeta e Springall sono stati invitati a partecipare a numerosi concorsi nazionali e internazionali e negli ultimi anni sono risultati vincitori in ben sette di queste competizioni.
Lo studio sta al momento lavorando su oltre venti differenti progetti che testimoniano la sua riconosciuta abilità e l’alto grado di appeal sulla committenza messicana
On Removing Randomness from a Parallel Algorithm for Minimum Cuts (Extended Abstract)
No full text) Michael Luby Joseph Naor y Moni Naor z TR-93-007 February 1993 Abstract The weighted minimum cut problem in a graph is a fundamental problem in combinatorial optimization. Recently, Karger suggested a randomized parallel algorithm for this problem. We show that a similar algorithm can be implemented using only O(log 2 n) random bits. We also show that our result holds for computing minimum weight k-cuts, where k is fixed. ICSI, UC Berkeley. E-mail: [email protected]. Research supported in part by NSF Grant CCR9016468 and grant No. 89-00312 from the United States-Israel Binational Science Foundation (BSF), Jerusalem, Israel y Computer Science Department, Technion University. E-mail: [email protected]. Part of this work was done while the author was visiting the International Computer Science Institute at Berkeley, CA. z Department of Applied Mathematics, Weizmann Institute of Science. E-mail: [email protected]. This work was done while the author was..
A method for quantifying individual decision thresholds of latent print examiners
No full textIn recent years, ‘black box’ studies in forensic science have emerged as the preferred way to provide information about the overall validity of forensic disciplines in practice. These studies provide aggregated error rates over many examiners and comparisons, but errors are not equally likely on all comparisons. Furthermore, inconclusive responses are common and vary across examiners and comparisons, but do not fit neatly into the error rate framework. This work introduces Item Response Theory (IRT) and variants for the forensic setting to account for these two issues. In the IRT framework, participant proficiency and item difficulty are estimated directly from the responses, which accounts for the different subsets of items that participants often answer. By incorporating a decision-tree framework into the model, inconclusive responses are treated as a distinct cognitive process, which allows inter-examiner differences to be estimated directly. The IRT-based model achieves superior predictive performance over standard logistic regression techniques, produces item effects that are consistent with common sense and prior work, and demonstrates that most of the variability among fingerprint examiner decisions occurs at the latent print evaluation stage and as a result of differing tendencies to make inconclusive decisions.This article is published as Luby, Amanda. "A method for quantifying individual decision thresholds of latent print examiners." Forensic Science International: Synergy 7 (2023): 100340. doi:10.1016/j.fsisyn.2023.100340. Posted with permission of CSAFE.© 2023 The Author. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Optimization of the Belief Propagation algorithm for Luby Transform decoding over the Binary Erasure Channel.
No full textLive-streaming media applications over the Internet are characterized by time deadlines and bandwidth constraints. Reliability over the Internet has been provided traditionally by the Transmission Control Protocol (TCP) based on retransmissions. However, resending the missed information leads to a waste in time and bandwidth. Erasure correcting codes can be used as an alternative to TCP. In this thesis, we consider the use of Luby Transform (LT) codes, which are part of the Digital Fountain (DF) codes. LT codes show a low encoding and decoding time as opposite to other erasure codes as Reed-Solomon (RS) and Low-Density Parity-Check (LDPC) codes. They are also the first realization of rateless codes, where the number of encoded symbols is potentially limitless. Therefore, they are suitable for Internet applications, where the channel conditions can change very fast or be unknown. The accepted efficient decoding algorithm for LT codes is the Belief Propagation (BP) algorithm, unfortunaly it shows a rather poor performance when used with small sizes of message symbols. This turns out to be a limitation in live-streaming applications, as they should wait until that number of source symbols have been received for attempting decoding. In our project, we explore optimisations of the BP decoding process for LT codes when the number of information symbols is small. We present two new decoding algorithms that improve the performance of BP while keeping a low complexity. We show simulation results of the new LT decoding algorithms success rate and complexity versus overhead when used with small sizes, proving the gain in performance compare with BP.Circuits and SystemsMicroelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc
Analyzing Spatial Responses: A Comparison of IRT-Based Approaches
No full textWe investigate two approaches for analyzing spatial coordinate responses using models inspired by Item Response Theory (IRT). In the first, we use a two-stage approach to first construct a pseudoresponse matrix using the spatial information and then apply standard IRT techniques to estimate proficiency and item parameters. In the second approach, we introduce the Spatial Error Model and use the spatial coordinates directly to infer information about the true locations and participant precision. As a motivating example, we use a study from forensic science designed to measure how fingerprint examiners use minutiae (small details in the fingerprint that form the basis for uniqueness) to come to an identification decision. The study found substantial participant variability, as different participants tend to focus on different areas of the image and some participants mark more minutiae than others. Using simulated data, we illustrate the relative strengths and weaknesses of each modeling approach, and demonstrate the advantages of modeling the spatial coordinates directly in the Spatial Error Model.This is the manuscript of a proceeding published as Luby, A., Daillak, T., Huang, S. (2023). Analyzing Spatial Responses: A Comparison of IRT-Based Approaches. In: Wiberg, M., Molenaar, D., González, J., Kim, JS., Hwang, H. (eds) Quantitative Psychology. IMPS 2022. Springer Proceedings in Mathematics & Statistics, vol 422. Springer, Cham. https://doi.org/10.1007/978-3-031-27781-8_31. Posted with permission of CSAFE
Modeling Covarying Responses in Complex Tasks
No full textIn testing situations, participants are often asked for supplementary responses in addition to the primary response of interest, which may include quantities like confidence or reported difficulty. These additional responses can be incorporated into a psychometric model either as a predictor of the main response or as a secondary response. In this paper we explore both of these approaches for incorporating participant’s reported difficulty into a psychometric model using an error rate study of fingerprint examiners. Participants were asked to analyze print pairs and make determinations about the source, which can be scored as correct or incorrect decisions. Additionally, participants were asked to report the difficulty of
the print pair on a five point scale. In this paper, we model (a) the responses of individual examiners without incorporating reported difficulty using a Rasch model, (b) the responses using their reported difficulty as a predictor, and (c) the responses and their reported difficulty as a multivariate response variable. We find that approach (c) results in more balanced classification errors, but incorporating reported difficulty using either approach does not lead to substantive changes in proficiency or difficulty estimates. These results suggest that, while there are individual differences in reported difficulty, these differences appear to be unrelated to examiners’ proficiency in correctly distinguishing matched from non-matched fingerprints.This is a manuscript of a conference proceeding published as Luby, A., Thompson, R.E. (2022). Modeling Covarying Responses in Complex Tasks. In: Wiberg, M., Molenaar, D., González, J., Kim, JS., Hwang, H. (eds) Quantitative Psychology. IMPS 2021. Springer Proceedings in Mathematics & Statistics, vol 393. Springer, Cham. https://doi.org/10.1007/978-3-031-04572-1_6. Posted with permission of CSAFE
Modeling covarying responses of forensic decision-makers within an IRT framework
No full textThe following was presentated at JSM 2020. Posted with permission of CSAFE
Analyzing spatial responses: A comparison of IRT-based approaches
No full textWe investigate two approaches for analyzing spatial coordinate responses using models inspired by Item Response Theory (IRT). In the first, we use a two-stage approach to first construct a pseudoresponse matrix using the spatial information and then apply standard IRT techniques to estimate proficiency and item parameters. In the second approach, we introduce the Spatial Error Model and use the spatial coordinates directly to infer information about the true locations and participant precision. As a motivating example, we use a study from forensic science designed to measure how fingerprint examiners use minutiae (small details in the fingerprint that form the basis for uniqueness) to come to an identification decision. The study found substantial participant variability, as different participants tend to focus on different areas of the image and some participants mark more minutiae than others. Using simulated data, we illustrate the relative strengths and weaknesses of each modeling approach, and demonstrate the advantages of modeling the spatial coordinates directly in the Spatial Error Model.This presentation is from the International Meeting of the Psychometric Society (IMPS), Bologna, Italy, July 11-15, 2022. Posted with permission of CSAFE
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