209 research outputs found

    On HRTF Notch Frequency Prediction Using Anthropometric Features and Neural Networks

    Full text link
    High fidelity spatial audio often performs better when produced using a personalized head-related transfer function (HRTF). However, the direct acquisition of HRTFs is cumbersome and requires specialized equipment. Thus, many personalization methods estimate HRTF features from easily obtained anthropometric features of the pinna, head, and torso. The first HRTF notch frequency (N1) is known to be a dominant feature in elevation localization, and thus a useful feature for HRTF personalization. This paper describes the prediction of N1 frequency from pinna anthropometry using a neural model. Prediction is performed separately on three databases, both simulated and measured, and then by domain mixing in-between the databases. The model successfully predicts N1 frequency for individual databases and by domain mixing between some databases. Prediction errors are better or comparable to those previously reported, showing significant improvement when acquired over a large database and with a larger output range

    Binaural Reproduction Based on Bilateral Ambisonics

    Get PDF
    Binaural reproduction of high-quality spatial sound has gained considerable interest with the recent technology developments in virtual and augmented reality. The reproduction of binaural signals in the Spherical-Harmonics (SH) domain using Ambisonics is now a well-established methodology, with flexible binaural processing realized using SH representations of the sound-field and the Head-Related Transfer Function (HRTF). However, in most practical cases, the binaural reproduction is order-limited, which introduces truncation errors that have a detrimental effect on the perception of the reproduced signals, mainly due to the truncation of the HRTF. Recently, it has been shown that manipulating the HRTF phase component, by ear-alignment, significantly reduces its effective SH order while preserving its phase information, which may be beneficial for alleviating the above detrimental effect. Incorporating the ear-aligned HRTF into the binaural reproduction process has been suggested by using Bilateral Ambisonics, which is an Ambisonics representation of the sound-field formulated at the two ears. While this method imposes challenges on acquiring the sound-field, and specifically, on applying head-rotations, it leads to a significant reduction in errors caused by the limited-order reproduction, which yields a substantial improvement in the perceived binaural reproduction quality even with first order SH

    New Upper Bounds for Evolving Secret Sharing via Infinite Branching Programs

    Get PDF
    Evolving secret-sharing schemes, defined by Komargodski, Naor, and Yogev [TCC 2016B, IEEE Trans. on Info. Theory 2018], are secret-sharing schemes in which there is no a-priory bound on the number of parties. In such schemes, parties arrive one by one; when a party arrives, the dealer gives it a share and cannot update this share in later stages. The requirement is that some predefined sets (called authorized sets) should be able to reconstruct the secret, while other sets should learn no information on the secret. The collection of authorized sets that can reconstruct the secret is called an evolving access structure. The challenge of the dealer is to be able to give short shares to the the current parties without knowing how many parties will arrive in the future. The requirement that the dealer cannot update shares is designed to prevent expensive updates. Komargodski et al. constructed an evolving secret-sharing scheme for every monotone evolving access structure; the share size of the ttht^{\text{th}} party in this scheme is 2t12^{t-1}. Recently, Mazor [ITC 2023] proved that evolving secret-sharing schemes require exponentially-long shares for some evolving access structure, namely shares of size 2to(t)2^{t-o(t)}.In light of these results, our goal is to construct evolving secret-sharing schemes with non-trivial share size for wide classes of evolving access structures; e.g., schemes with share size 2ct2^{ct} for c<1c<1 or even polynomial size. We provide several results achieving this goal: -We define layered infinite branching programs representing evolving access structures, show how to transform them into generalized infinite decision trees, and show how to construct evolving secret-sharing schemes for generalized infinite decision trees. Combining these steps, we get a secret-sharing scheme realizing the evolving access structure. As an application of this framework, we construct an evolving secret-sharing scheme with non-trivial share size for access structures that can be represented by layered infinite branching programs with width at layer tt of at most 20.15t2^{0.15t}. If the width is polynomial, then we get an evolving secret-sharing scheme with quasi-polynomial share size. -We construct efficient evolving secret-sharing schemes for dynamic-threshold access structures with high dynamic-threshold and for infinite 22 slice and 33-slice access structures. The share size of the ttht^{\text{th}} party in these schemes is 2O~((logt)1/2+ϵ)2^{\tilde{O}((\log t)^{1/\sqrt{2}+\epsilon})} for any constant ϵ>0\epsilon>0, which is comparable to the best-known share size of 2O~((logt)1/2))2^{\tilde{O}((\log t)^{1/2}))} for finite 22-slice and 3-slice access structures. -We prove lower bounds on the share size of evolving secret-sharing schemes for infinite kk-hypergraph access structures and for infinite directed st-connectivity access structures. As a by-product of the lower bounds, we provide the first non-trivial lower bound for finite directed st-connectivity access structures for general secret-sharing schemes

    A PHABULOSA/cytokinin feedback loop controls root growth in arabidopsis

    Get PDF
    The hormone cytokinin (CK) controls root length in Arabidopsis thaliana by defining where dividing cells, derived from stem cells of the root meristem, start to differentiate [ [1], [2], [3], [4], [5] and [6]]. However, the regulatory inputs directing CK to promote differentiation remain poorly understood. Here, we show that the HD-ZIPIII transcription factor PHABULOSA (PHB) directly activates the CK biosynthesis gene ISOPENTENYL TRANSFERASE 7 (IPT7), thus promoting cell differentiation and regulating root length. We further demonstrate that CK feeds back to repress both PHB and microRNA165, a negative regulator of PHB. These interactions comprise an incoherent regulatory loop in which CK represses both its activator and a repressor of its activator. We propose that this regulatory circuit determines the balance of cell division and differentiation during root development and may provide robustness against CK fluctuations

    Comparative effectiveness of intensity modulated radiation therapy to 3-dimensional conformal radiation in locally advanced lung cancer: pathological and clinical outcomes.

    Get PDF
    OBJECTIVE: Intensity-modulated radiotherapy (IMRT) has better normal-tissue sparing compared with 3-dimensional conformal radiation (3DCRT). We sought to assess the impact of radiation technique on pathological and clinical outcomes in locally advanced non-small cell lung cancer (LANSCLC) treated with a trimodality strategy. METHODS: Retrospective review of LANSCLC patients treated from August 2012 to August 2018 at Sheba Medical Center, Israel. The trimodality strategy consisted of concomitant chemoradiation to 60 Gray (Gy) followed by completion surgery. The planning target volume (PTV) was defined by co-registered PET/CT. Here we compare the pathological regression, surgical margin status, local control rates (LC), disease free (DFS) and overall survival (OS) between 3DCRT and IMRT. RESULTS: Our cohort consisted of 74 patients with mean age 62.9 years, male in 51/74 (69%), adenocarcinoma in 46/74 (62.1%), stage 3 in 59/74 (79.7%) and chemotherapy in 72/74 (97.3%). Radiation mean dose: 59.2 Gy (SD ± 3.8). Radiation technique : 3DCRT in 51/74 (68.9%), IMRT in 23/74 (31%). Other variables were similar between groups.Major pathological response (including pathological complete response or less than 10% residual tumor cells) was similar: 32/51 (62.7%) in 3DCRT and 15/23 (65.2%) in IMRT, p=0.83. Pathological complete response (pCR) rates were similar: 17/51 (33.3%) in 3DCRT and 8/23 (34.8%) in IMRT, p=0.9. Surgical margins were negative in 46/51 (90.1%) in 3DCRT vs. 17/19 (89.4%) in IMRT (p=1.0).The 2-year LC rates were 81.6% (95% CI 69-89.4%); DFS 58.3% (95% CI 45.5-69%) and 3-year OS 70% (95% CI57-80%). Comparing radiation techniques, there were no significant differences in LC (p=0.94), DFS (p=0.33) and OS (p=0.72). CONCLUSION: When used to treat LANSCLC in the neoadjuvant setting, both IMRT and 3DCRT produce comparable pathological and clinical outcomes. ADVANCES IN KNOWLEDGE: This study validates the real-world effectiveness of IMRT compared to 3DCRT

    Robustness and Generalization

    Full text link
    We derive generalization bounds for learning algorithms based on their robustness: the property that if a testing sample is "similar" to a training sample, then the testing error is close to the training error. This provides a novel approach, different from the complexity or stability arguments, to study generalization of learning algorithms. We further show that a weak notion of robustness is both sufficient and necessary for generalizability, which implies that robustness is a fundamental property for learning algorithms to work

    Medieval Emergencies and the Contemporary Debate

    Get PDF
    Abstract The contemporary debate on emergencies and the state of exception often relies on historical examples. Yet, the most recent discussions on the state of exception (a legal construct that deals with emergencies) also assume its modern inception. This article shows that medieval France formulated its own state of exception, meant to deal with emergencies, based on the legal principle of necessity. This article has two purposes. First, it challenges the historical narrative inherent in the contemporary debate, which assumes the modern inception of the state of exception. Second, it reinforces the trepidation with which many scholars today view the uses and abuses of the state of exception. This article does so by showing that the French crown used and abused the medieval principle of necessity in ways similar to current uses of the state of exception; it served similar purposes. Just as some scholars fear today, the French medieval state of exception often served as a pretext meant to change the legal order, turning the exception into the ordinary. The French crown used the state of exception to enhance its power, and it was central in the long process of building the early-modern French state

    Genetically Blocking the Zebrafish Pineal Clock Affects Circadian Behavior

    Get PDF
    The master circadian clock in fish has been considered to reside in the pineal gland. This dogma is challenged, however, by the finding that most zebrafish tissues contain molecular clocks that are directly reset by light. To further examine the role of the pineal gland oscillator in the zebrafish circadian system, we generated a transgenic line in which the molecular clock is selectively blocked in the melatonin-producing cells of the pineal gland by a dominant-negative strategy. As a result, clock-controlled rhythms of melatonin production in the adult pineal gland were disrupted. Moreover, transcriptome analysis revealed that the circadian expression pattern of the majority of clock-controlled genes in the adult pineal gland is abolished. Importantly, circadian rhythms of behavior in zebrafish larvae were affected: rhythms of place preference under constant darkness were eliminated, and rhythms of locomotor activity under constant dark and constant dim light conditions were markedly attenuated. On the other hand, global peripheral molecular oscillators, as measured in whole larvae, were unaffected in this model. In conclusion, characterization of this novel transgenic model provides evidence that the molecular clock in the melatonin-producing cells of the pineal gland plays a key role, possibly as part of a multiple pacemaker system, in modulating circadian rhythms of behavior
    corecore