Hidden Markov Model for Automatic Transcription of MIDI Signals

This paper describes a Hidden Markov Model (HMM)-based method of automatic transcription of MIDI (Musical Instrument Digital Interface) signals of performed music. The problem is formulated as recognition of a given sequence of fluctuating note durations to find the most likely intended note sequence utilizing the modern continuous speech recognition technique. Combining a stochastic model of deviating note durations and a stochastic grammar representing possible sequences of notes, the maximum likelihood estimate of the note sequence is searched in terms of Viterbi algorithm. The same principle is successfully applied to a joint problem of bar line allocation, time measure recognition, and tempo estimation. Finally, durations of consecutive n notes are combined to form a "rhythm vector" representing tempo-free relative durations of the notes and treated in the same framework. Significant improvements compared with conventional "quantization" techniques are shown

Rhythm and tempo recognition of music performance from a probabilistic approach

This paper concerns both rhythm recognition and tempo analysis of expressive music performance based on a probabilistic approach. In rhythm recognition, the modern continuous speech recognition technique is applied to find the most likely intended note sequence from the given sequence of fluctuating note durations in the performance. Combining stochastic models of note durations deviating from the nominal lengths and a probabilistic grammar representing possible sequences of notes, the problem is formulated as a maximum a posteriori estimation that can be implemented using efficient search based on the Viterbi algorithm. With this, significant improvements compared with conventional “quantization ” techniques were found. Tempo analysis is performed by fitting the observed tempo with parametric tempo curves in order to extract tempo dynamics and characteristics of performance to use. Tempo-change timings and parameter values in tempo curve models are estimated through the segmental k-means algorithm. Experimental results of rhythm recognition and tempo analysis applied to classical and popular music performances are also demonstrated

Automatic Music Transcription from Multiphonic MIDI Signals

For automatically transcribing human-performed polyphonic music recorded in the MIDI format, rhythm and tempo are decomposed through probabilistic modeling using Viterbi search in HMM for recognizing the rhythm and EM algorithm for estimating the tempo. Experimental evaluation are also presented

Proceedings of the International Symposium on Musical Acoustics, March 31st to April 3rd 2004 (ISMA2004), Nara, Japan Maximum Likelihood Method for Estimating Rhythm and Tempo

This paper presents a rhythm recognition technique based on a probabilistic approach by utilizing generative model for timing information in expressive music performance. The problem of rhythm recognition including rhythm parsing and tempo tracking, is to retrieve information of rhythm and tempo from a sequence of observed note durations. Since performed note length deviates in real performance and decomposition of the duration into rhythm and tempo is not unique in general, this problem must be solved in a probabilistic approach. We formulate rhythm recognition as maximum a posteriori (MAP) state sequence estimation among a finite state network of Hidden Markov Models (HMMs). The structure of the proposed stochastic model is almost equivalent to a network model of HMMs used in continuous speech recognition technique. The most likely rhythm and tempo in this probabilistic model are obtained by use of an effective search algorithm, level building. Experimental evaluation using MIDI recordings of a classical music piece is also reported

Redox-dependent axial ligand replacement and its functional significance in heme-bound iron regulatory proteins

Iron regulatory proteins (IRPs), regulators of iron metabolism in mammalian cells, control the translation of proteins involved in iron uptake, storage and utilization by binding to specific iron-responsive element (IRE) sequences of mRNAs. Two homologs of IRPs (IRP1 and IRP2) have a typical heme regulatory motif (HRM), a consensus sequence found in "heme-regulated proteins". However, specific heme binding to HRM has been reported only for IRP2, which is essential for oxidative modification and loss of binding to target mRNAs. In this paper, we confirmed that IRP1 also specifically binds two molar equivalents of heme, and found that the absorption and resonance Raman spectra of heme-bound IRP1 were quite similar to those of heme-bound IRP2. This shows that the heme environmental structures in IRP1 are close to those of proteins using heme as a regulatory molecule. Pulse radiolysis experiments, however, dearly revealed an axial ligand exchange from Cys to His immediately after the reduction of the heme iron to form a 5-coordinate His-ligated heme in heme-bound IRP2, whereas the 5-coordinate His-ligated heme was not observed after the reduction of heme-bound IRP1. Considering that the oxidative modification is only observed in heme-bound IRP2, but not IRP1, probably owing to the structural flexibility of IRP2, we propose that the transient 5 -coordinate His-ligated heme is a prerequisite for oxidative modification of heme-bound IRP2, which functionally differentiates heme binding of IRP2 from that of IRP1

Processing of a single ribonucleotide embedded into DNA by human nucleotide excision repair and DNA polymerase η

DNA polymerases often incorporate non-canonical nucleotide, i.e., ribonucleoside triphosphates into the genomic DNA. Aberrant accumulation of ribonucleotides in the genome causes various cellular abnormalities. Here, we show the possible role of human nucleotide excision repair (NER) and DNA polymerase η(Pol η) in processing of a single ribonucleotide embedded into DNA. We found that the reconstituted NER system can excise the oxidized ribonucleotide on the plasmid DNA. Taken together with the evidence that Pol η accurately bypasses a ribonucleotide, i.e., riboguanosine (rG) or its oxidized derivative (8-oxo-rG) in vitro, we further assessed the mutagenic potential of the embedded ribonucleotide in human cells lacking NER or Pol η. A single rG on the supF reporter gene predominantly induced large deletion mutations. An embedded 8-oxo-rG caused base substitution mutations at the 3'-neighboring base rather than large deletions in wild-type cells. The disruption of XPA, an essential factor for NER, or Pol η leads to the increased mutant frequency of 8-oxo-rG. Furthermore, the frequency of 8-oxo-rG-mediated large deletions was increased by the loss of Pol η, but not XPA. Collectively, our results suggest that base oxidation of the embedded ribonucleotide enables processing of the ribonucleotide via alternative DNA repair and damage tolerance pathways