Bayesian Aspects of Classification Procedures

We consider several statistical approaches to binary classification and multiple hypothesis testing problems. Situations in which a binary choice must be made are common in science. Usually, there is uncertainty involved in making the choice and a great number of statistical techniques have been put forth to help researchers deal with this uncertainty in separating signal from noise in reasonable ways. For example, in genetic studies, one may want to identify genes that affect a certain biological process from among a larger set of genes. In such examples, costs are attached to making incorrect choices and many choices must be made at the same time. Reasonable ways of modeling the cost structure and choosing the appropriate criteria for evaluating the performance of statistical techniques are needed. The following three chapters have proposals of some Bayesian methods for these issues. In the first chapter, we focus on an empirical Bayes approach to a popular binary classification problem formulation. In this framework, observations are treated as independent draws from a hierarchical model with a mixture prior distribution. The mixture prior combines prior distributions for the ``noise\u27\u27 and for the ``signal\u27\u27 observations. In the literature, parametric assumptions are usually made about the prior distribution from which the ``signal\u27\u27 observations come. We suggest a Bayes classification rule which minimizes the expectation of a flexible and easily interpretable mixture loss function which brings together constant penalties for false positive misclassifications and $L_2$ penalties for false negative misclassifications. Due in part to the form of the loss function, empirical Bayes techniques can then be used to construct the Bayes classification rule without specifying the ``signal\u27\u27 part of the mixture prior distribution. The proposed classification technique builds directly on the nonparametric mixture prior approach proposed by Raykar and Zhao (2010, 2011). Many different criteria can be used to judge the success of a classification procedure. A very useful criterion called the False Discovery Rate (FDR) was introduced by Benjamini and Hochberg in a 1995 paper. For many applications, the FDR, which is defined as the expected proportion of false positive results among the observations declared to be ``signal\u27\u27, is a reasonable criterion to target. Bayesian versions of the false discovery rate, the so-called positive false discovery rate (pFDR) and local false discovery rate, were proposed by Storey (2002, 2003) and Efron and coauthors (2001), respectively. There is an interesting connection between the local false discovery rate and the nonparametric mixture prior approach for binary classification problems. The second part of the dissertation is focused on this link and provides a comparison of various approaches for estimating Bayesian false discovery rates. The third chapter is an account of a connection between the celebrated Neyman-Pearson lemma and the area (AUC) under the receiver operating characteristic (ROC) curve when the observations that need to be classified come from a pair of normal distributions. Using this connection, it is possible to derive a classification rule which maximizes the AUC for binormal data

The World Bank and biopolitical governance: The ARMM Social Fund Project

This thesis analyzes the policies and practices of development as a biopolitical technology for managing culturally perceived `risky\u27 populations in the southern Philippines. Since post-9/11 and its reinforcement by the war on terrorism, the interrelations of security and development underscore the proliferation of securitized discourses that operate within and beyond transnational aid organizations. Within this security-development nexus, I focus on the World Bank\u27s ARMM Social Fund Project. I analyze its techniques of generalized descriptions, quantifications, and responsibilization that aim to shape individuals occupying the ARMM `borderland\u27 as a governed entity. I reveal how these biopolitical techniques guide the actions of the poor, shape ideas of poverty and poverty reduction, and legitimize development interventions that aim to manage the lives of the poor. The thesis concludes by examining new possibilities for social transformations that link local struggles with transnational actions

Basic helix-loop-helix transcription factors in evolution: Roles in development of mesoderm and neural tissues

Basic helix‐loop‐helix (bHLH) transcription factors have attracted the attention of developmental and evolutionary biologists for decades because of their conserved functions in mesodermal and neural tissue formation in both vertebrates and fruit flies. Their evolutionary history is of special interest because it will likely provide insights into developmental processes and refinement of metazoan‐specific traits. This review briefly considers advances in developmental biological studies on bHLHs/HLHs. I also discuss recent genome‐wide surveys and molecular phylogenetic analyses of these factors in a wide range of metazoans. I hypothesize that interactions between metazoan‐specific Group A, D, and E bHLH/HLH factors enabled a sophisticated transition system from cell proliferation to differentiation in multicellular development. This control mechanism probably emerged initially to organize a multicellular animal body and was subsequently recruited to form evolutionarily novel tissues, which differentiated during a later ontogenetic phase

The Role of Cultural Influences in Japanese Communication : A Literature Review on Social and Situational Factors and Japanese Indirectness

One of the distinguishing characteristics of Japanese communication is the use of what are often perceived to be ambiguous expressions, silence and/or lack of explanation, frequent use of hesitation and pauses, laughter and smiling (when they might seem inappropriate), and the use of honorific and humble forms. A review of the existing literature demonstrates the purpose, meaning, and significance of these features. These features constitute an important aspect of Japanese communication

GESI: Gammachirp Envelope Similarity Index for Predicting Intelligibility of Simulated Hearing Loss Sounds

We propose an objective intelligibility measure (OIM), called the Gammachirp Envelope Similarity Index (GESI), which can predict the speech intelligibility (SI) of simulated hearing loss (HL) sounds for normal hearing (NH) listeners. GESI is an intrusive method that computes the SI metric using the gammachirp filterbank (GCFB), the modulation filterbank, and the extended cosine similarity measure. The unique features of GESI are that i) it reflects the hearing impaired (HI) listener's HL that appears in the audiogram and is caused by active and passive cochlear dysfunction, ii) it provides a single goodness metric, as in the widely used STOI and ESTOI, that can be used immediately to evaluate SE algorithms, and iii) it provides a simple control parameter to accept the level asymmetry of the reference and test sounds and to deal with individual listening conditions and environments. We evaluated GESI and the conventional OIMs, STOI, ESTOI, MBSTOI, and HASPI versions 1 and 2 by using four SI experiments on words of male and female speech sounds in both laboratory and remote environments. GESI was shown to outperform the other OIMs in the evaluations. GESI could be used to improve SE algorithms in assistive listening devices for individual HI listeners.Comment: This paper was submitted to JASA on March 14, 202

音楽学校として機能する劇場 ―改良楽器とモンゴル国カザフ民俗楽器オーケストラの事例から―

本稿の目的は、モンゴル国バヤンウルギー県にあるバヤンウルギー県音楽ドラマ劇場（以降BMDT）における改良楽器奏者の育成状況を、当県の社会と関連づけて明らかにすることである。バヤンウルギー県はモンゴル国の最西部に位置し、人口の約9割をカザフ人が占めている。社会主義を経たバヤンウルギー県では、1950年代から音楽家の職業化が進み、BMDTは主にカザフ共和国（現カザフスタン）の影響を受けて、カザフの楽器を中心に演奏活動が行われてきた。BMDT内には1959年にカザフ民俗楽器オーケストラが設立されており、そこに所属する団員は主にBMDT入団時に「実習生」として入団し、改良楽器という入団時とは異なる楽器を演奏しはじめる。「実習生」とは、音楽大学卒以外の団員を対象に、「先生」から約6か月の期間、担当する楽器の演奏技術や楽典を学ぶ者のことである。現在のカザフ民俗楽器オーケストラでは団員の約半数が「実習生」を経験した後に、カザフの改良楽器に移行することで新たに改良楽器を学び始めている。こうした団員による改良楽器への移行と学びが生まれた社会的要因として、バヤンウルギー県とカザフスタン及びモンゴル国との歴史的かつ地理的な関係から、次の2点を指摘した。1点目に、現在のカザフ民俗楽器オーケストラの団員育成が「実習生」制度に依存している状況が見られる点である。1959年のカザフ民俗楽器オーケストラ設立時に、「実習生」が基礎となって設立されると同時に、カザフ共和国への留学によって専門的な音楽の指導者の育成がなされた。この「実習生」とカザフ共和国への留学は1990年代初頭まで続けられたが、1990年代以降、カザフスタンの独立による政治的かつ経済的な理由でカザフスタンへの留学が行われなくなり、「実習生」を経た団員が改良楽器を学ぶようになっている。2点目は、対照的に、モンゴル国の首都ウランバートルでカザフ人の音楽を学ぶ公的な教育機関が存在していない点である。同様に、バヤンウルギー県においても改良楽器がBMDTにしか存在しなかったため、改良楽器に関する専門的な教育が行われてこなかった。この2点から、BMDT内で改良楽器を演奏するために、独自に改良楽器を演奏できる人を用意する必要が生じた。そこで、BMDT内部でカザフの改良楽器の技術や楽典の教授といった音楽教育を行いながら、独自に改良楽器の演奏者を育成している状況が見られると結論づけた。Modified musical instruments are those altered to widen their range for orchestral music during the time of Socialism. This study focuses on modified Kazakh musical instruments as played in the Theater of Music and Drama in Bayan-Ölgii (BMDT), which functions as the only musical school teaching these musical instruments in Mongolia. Participant observations and semi-structured interviews revealed that the teaching system for modified Kazakh musical instruments in BMDT shifted to comply with the domestic education system after the collapse of the Soviet Union. Since the appearance of professional Kazakh musicians in the 1950s, BMDT has been performing Kazakh music in Mongolia, mainly influenced by the music of Kazakhstan. Therefore, most BMDT musicians played the same instruments as those used in Kazakhstan.In 1959, BMDT established the Orchestra of Kazakh Folk Musical Instruments (the Kazakh Orchestra). Since then, the Kazakh Orchestra has adopted the dagaldan (trainee) system for orchestra members who are not music college graduates. The dagaldan learn the techniques of musical instruments and the theory of music for six months. After finishing the training, they are recognized as jinkhen (real) musicians, and begin to learn the Kazakh modified musical instruments. Nowadays, half of the members of the Kazakh orchestra start out as dagaldan and then transfer to learn Kazakh’s modified musical instruments.This study focuses on the relationship between Bayan-Ölgii provinces, Kazakhstan, and Mongolia, and points out two historical and geographical factors standing in the background of the dagaldan’s study of the modified musical instruments. Firstly, since the Soviet era ended, the BMDT ‘dagaldan system’ has been the only means of educating the orchestra’s members. When the Kazakh orchestra was first established in 1959, dagaldan members were given a chance to study at music colleges in Kazakhstan. The purpose of this study program was to give professional musical leaders the skills to play Kazakh instruments, including modified musical instruments. This program for the musicians in the Kazakh orchestra continued until the early 1990s, but was drawn to a close due to political and economic issues following the independence of Kazakhstan. Secondly, it was found that Kazakh modified musical instruments exist only in BMDT, and there is no public educational institution for Kazakh music in Ulaanbaatar, the capital of Mongolia. These situations inside and outside of Mongolia after the Soviet era encouraged the development of a unique educational system within BMDT, where skills for playing Kazakh modified musical instruments were passed down

What Does mu-tau Symmetry Imply about Neutrino Mixings?

The requirement of the mu-tau symmetry in the neutrino sector that yields the maximal atmospheric neutrino mixing is shown to yield either sin(\theta_{13})=0 (referred to as C1)) or sin(\theta_{12})=0 (referred to as C2)), where \theta_{12(13)} stands for the solar (reactor) neutrino mixing angle. We study general properties possessed by approximately mu-tau symmetric textures. It is argued that the tiny mu-tau symmetry breaking generally leads to cos(2\theta_{23}) \simsin(\theta_{13}) for C1) and cos(2\theta_{23}) \sim \Delta m^2_\odot/\Delta m^2_{atm}(\equiv R) for C2), which indicates that the smallness of cos(2\theta_{23}) is a good measure of the mu-tau symmetry breaking, where \Delta m^2_{atm} (\Delta m^2_\odot) stands for the square mass differences of atmospheric (solar) neutrinos. We further find that the relation R \sim sin^2(\theta_{13}) arises from contributions of O(sin^2(\theta_{13})) in the estimation of the neutrino masses (m_{1,2,3}) for C1), and that possible forms of textures are strongly restricted to realize sin^2(2\theta_{12})=O(1) for C2). To satisfy R \sim sin^2(\theta_{13}) for C1), neutrinos exhibit the inverted mass hierarchy, or the quasi degenerate mass pattern with | m_{1,2,3}| \sim O(\sqrt{\Delta m^2_{atm}}), and, to realize sin^2(2\theta_{12})=O(1) for C2), there should be an additional small parameter \eta whose size is comparable to that of the mu-tau symmetry breaking parameter \epsilon, giving tan(2\theta_{12}) \sim \epsilon/\eta with \eta \sim \epsilon to be compatible with the observed large mixing.Comment: 10 pages, title slightly modified, comments added in the introdction, typos corrected, references updated, version to appear in Physical Reviews

Hunting for Significance: Bayesian Classifiers Under a Mixture Loss Function

Detecting significance in a high-dimensional sparse data structure has received a large amount of attention in modern statistics. In the current paper, we introduce a compound decision rule to simultaneously classify signals from noise. This procedure is a Bayes rule subject to a mixture loss function. The loss function minimizes the number of false discoveries while controlling the false nondiscoveries by incorporating the signal strength information. Based on our criterion, strong signals will be penalized more heavily for nondiscovery than weak signals. In constructing this classification rule, we assume a mixture prior for the parameter which adapts to the unknown sparsity. This Bayes rule can be viewed as thresholding the “local fdr” (Efron, 2007) by adaptive thresholds. Both parametric and nonparametric methods will be discussed. The nonparametric procedure adapts to the unknown data structure well and outperforms the parametric one. Performance of the procedure is illustrated by various simulation studies and a real data application