Western Michigan University

This paper provides an overview of the Internet of Things (IoT) with emphasis on enabling technologies, protocols, and application issues. The IoT is enabled by the latest developments in RFID, smart sensors, communication technologies, and Internet protocols. The basic premise is to have smart sensors collaborate directly without human involvement to deliver a new class of applications. The current revolution in Internet, mobile, and machine-to-machine (M2M) technologies can be seen as the first phase of the IoT. In the coming years, the IoT is expected to bridge diverse technologies to enable new applications by connecting physical objects together in support of intelligent decision making. This paper starts by providing a horizontal overview of the IoT. Then, we give an overview of some technical details that pertain to the IoT enabling technologies, protocols, and applications. Compared to other survey papers in the field, our objective is to provide a more thorough summary of the most relevant protocols and application issues to enable researchers and application developers to get up to speed quickly on how the different protocols fit together to deliver desired functionalities without having to go through RFCs and the standards specifications. We also provide an overview of some of the key IoT challenges presented in the recent literature and provide a summary of related research work. Moreover, we explore the relation between the IoT and other emerging technologies including big data analytics and cloud and fog computing. We also present the need for better horizontal integration among IoT services. Finally, we present detailed service use-cases to illustrate how the different protocols presented in the paper fit together to deliver desired IoT services.

The literature indicates that dysfunctional individual and organizational consequences result from the existence of role conflict and role ambiguity in complex organizations. Yet, systematic measurement and empirical testing of these role constructs is lacking. This study describes the development and testing of questionnaire measures of role conflict and ambiguity. Analyses of responses of managers show these two constructs to be factorially identifiable and independent. Derived measures of role conflict and ambiguity tend to correlate in two samples in expected directions with measures of organizational and managerial practices and leader behavior, and with member satisfaction, anxiety, and propensity to leave the organization.

Preface Special Features Audience Acknowledgments Chapter 1. Introduction Leadership Defined Ways of Conceptualizing Leadership Definition and Components Leadership Described Trait Versus Process Leadership Assigned Versus Emergent Leadership Leadership and Power Leadership and Coercion Leadership and Management Plan of the Book Summary Chapter 2. Trait Approach Description Intelligence Self-Confidence Determination Integrity Sociability Five-Factor Personality Model and Leadership Emotional Intelligence How Does the Trait Approach Work? Strengths Criticisms Application Case Studies Case 2.1: Choosing a New Director of Research Case 2.2: A Remarkable Turnaround Case 2.3: Recruiting for the Bank Leadership Instrument Leadership Trait Questionnaire (LTQ) Scoring Interpretation Summary Chapter 3. Skills Approach Description Three-Skill Approach Technical Skill Human Skill Conceptual Skill Summary of the Three-Skill Approach Skills Model Competencies Problem-Solving Skills Social Judgment Skills Knowledge Individual Attributes General Cognitive Ability Crystallized Cognitive Ability Motivation Personality Leadership Outcomes Effective Problem Solving Performance Career Experiences Environmental Influences Summary of the Skills Model How Does the Skills Approach Work? Strengths Criticisms Application Case Studies Case 3.1: A Strained Research Team Case 3.2: A Shift for Lieutenant Colonel Adams Case 3.3: Andy's Recipe Leadership Instrument Skills Inventory Scoring Scoring Interpretation Summary Chapter 4. Style Approach Description The Ohio State Studies The University of Michigan Studies Blake and Mouton's Managerial (Leadership) Grid Authority-Compliance (9,1) Country Club Management (1,9) Impoverished Management (1,1) Middle-of-the-Road Management (5,5) Team Management (9,9) Paternalism/Maternalism Opportunism How Does the Style Approach Work? Strengths Criticisms Application Case Studies Case 4.1: A Drill Sergeant at First Case 4.2: Eating Lunch Standing Up Case 4.3: Enhancing the Department's Culture Leadership Instrument Style Questionnaire Scoring Scoring Interpretation Summary Chapter 5. Situational Approach Description Leadership Styles Development Levels How Does the Situational Approach Work? Strengths Criticisms Application Case Studies Case 5.1: What Style Do I Use? Case 5.2: Why Aren't They Listening? Case 5.3: Getting the Message Across Leadership Instrument Situational Leadership: A Brief Questionnaire Scoring Interpretation Summary 6. Contingency Theory Description Leadership Styles Situational Variables How Does Contingency Theory Work? Strengths Criticisms Application Case Studies Case 6.1: No Control Over the Student Council Case 6.2: Giving Him a Hard Time Case 6.3: What's the Best Leader Match? Leadership Instrument Least Preferred Coworker (LPC) Measure Scoring Interpretation Summary Chapter 7. Path--Goal Theory Description Leader Behaviors Directive Leadership Supportive Leadership Participative Leadership Achievement-Oriented Leadership Subordinate Characteristics Task Characteristics How Does Path--Goal Theory Work? Strengths Criticisms Application Case Studies Case 7.1: Three Shifts, Three Supervisors Case 7.2: Direction for Some, Support for Others Case 7.3: Marathon Runners at Different Levels Leadership Instrument Path--Goal Leadership Questionnaire Scoring Scoring Interpretation Summary Chapter 8. Leader--Member Exchange Theory Description Early Studies Later Studies Leadership Making How Does LMX Theory Work? Strengths Criticisms Application Case Studies Case 8.1: His Team Gets the Best Assignments Case 8.2: Working Hard at Being Fair Case 8.3: Taking On Additional Responsibilities Leadership Instrument LMX 7 Questionnaire Scoring Interpretation Summary Chapter 9. Transformational Leadership Description Transformational Leadership Defined Transformational Leadership and Charisma A Model of Transformational Leadership Transformational Leadership Factors Idealized Influence Inspirational Motivation Intellectual Stimulation Individualized Consideration Transactional Leadership Factors Contingent Reward Management-by-Exception Nonleadership Factor Laissez-Faire Other Transformational Perspectives Bennis and Nanus Kouzes and Posner Model the Way Inspire a Shared Vision Challenge the Process Enable Others to Act Encourage the Heart How Does the Transformational Approach Work? Strengths Criticisms Application Case Studies Case 9.1: The Vision Failed Case 9.2: Students Dig It Case 9.3: Her Vision Was a Model Research Center Case 9.3: Her Vision Was a Model Research Center Leadership Instrument Sample Items From the Multifactor Leadership Questionnaire (MLQ) Form 5X-Short Summary Chapter 10. Authentic Leadership Description Authentic Leadership Defined Intapersonal Definition Developmental Definition Interpersonal Definition Approaches to Authentic Leadership Practical Approaches Robert Terry's Authentic Leadership Approach Bill George's Authentic Leadership Approach Theoretical Approach Background to the Theoretical Approach Components of Authentic Leadership Factors that Influence Authentic Leadership How Does Authentic Leadership Work? Strengths Criticisms Application Case Studies Case 10.1: Am I Really a Leader? Case 10.2: Moving Mountains for Education and Peace Case 10.3: The Reluctant First Lady Leadership Instrument Authentic Leadership Self Assessment Questionnaire Summary Chapter 11. Team Leadership - Susan E. Kogler Hill Description Team Leadership Model Leadership Decisions Leadership Decision 1: Should I Monitor the Team or Take Action? Leadership Decision 2: Should I Intervene to Meet Task or Relational Needs? Leadership Decision 3: Should I Intervene Internally or Externally? Leadership Actions Internal Task Leadership Actions Internal Relational Leadership Actions External Environmental Leadership Actions Team Effectiveness Clear, Elevating Goal Results-Driven Structure Competent Team Members Unified Commitment Collaborative Climate Standards of Excellence External Support and Recognition Principled Leadership How Does the Team Leadership Model Work? Strengths Criticisms Application Case Studies Case 11.1: Can This Virtual Team Work? Case 11.2: They Dominated the Conversation Case 11.3: Starts With a Bang, Ends With a Whimper Leadership Instrument Team Excellence and Collaborative Team Leader Questionnaire Scoring Interpretation Summary Chapter 12. Psychodynamic Approach - Ernest L. Stech Description Background Eric Berne and Transactional Analysis Sigmund Freud and Personality Types Carl Jung and Personality Types Functions and Preferences Types and Leadership Sixteen Types and Leadership Dealing With Followers How Does the Psychodynamic Approach Work? Strengths Criticisms Case Studies Case 12.1: Not the Type Who Sees the Big Picture Case 12.2: Staff Meeting Problems Case 12.3: Unexpected Reactions Leadership Instrument Psychodynamic Approach Survey Scoring Scoring Interpretation Summary Chapter 13. Women and Leadership - Crystal L. Hoyt Description Gender and Leadership Styles Gender and Leadership Effectiveness The Glass Ceiling Evidence of the Glass Ceiling Motives for Removing the Barriers Explaining the Glass Ceiling Human Capital Differences Gender Differences Prejudice Breaking the Glass Ceiling Strengths Criticisms Application Case Studies Case 13.1: The Glass Ceiling Case 13.2: Lack of Inclusion and Credibility Case 13.3: Pregnancy as a Barrier to Job Status Leadership Instrument The Gender--Leader Implicit Association Test Scoring Summary Chapter 14. Culture and Leadership Description Culture Defined Related Concepts Ethnocentrism Prejudice Dimensions of Culture Uncertainty Avoidance Power Distance Institutional Collectivism In-Group Collectivism Gender Egalitarianism Assertiveness Future Orientation Performance Orientation Humane Orientation Clusters of World Cultures Characteristics of Clusters Anglo Confucian Asia Eastern Europe Germanic Europe Latin America Latin Europe Middle East Nordic Europe Southern Asia Sub-Saharan Africa Leadership Behavior and Culture Clusters Eastern Europe Leadership Profile Latin America Leadership Profile Latin Europe Leadership Profile Confucian Asia Leadership Profile Nordic Europe Leadership Profile Anglo Leadership Profile Sub-Saharan Africa Leadership Profile Southern Asia Leadership Profile Germanic Europe Leadership Profile Middle East Leadership Profile Universally Desirable and Undesirable Leadership Attributes Strengths Criticisms Application Case Studies Case 14.1: A Challenging Workplace Case 14.2: A Special Kind of Financing Case 14.3: Whose Hispanic Center Is It? Leadership Instrument Dimensions of Culture Questionnaire Scoring Scoring Interpretation Summary Chapter 15. Leadership Ethics Description Ethics Defined Ethical Theories Centrality of Ethics to Leadership Heifetz's Perspective on Ethical Leadership Burns's Perspective on Ethical Leadership Greenleaf's Perspective on Ethical Leadership Principles of Ethical Leadership Ethical Leaders Respect Others Ethical Leaders Serve Others Ethical Leaders Are Just Ethical Leaders Are Honest Ethical Leaders Build Community Strengths Criticisms Application Case Studies Case 15.1: A Struggling Company With Not Enough Cash Case 15.2: How Safe Is Safe? Case 15.3: Reexamining a Proposal Leadership Instrument Perceived Leader Integrity Scale (PLIS) Scoring Scoring Interpretation Summary Name Index Subject Index About the Author About the Contributors

We review Phanerozoic sea-level changes [543 million years ago (Ma) to the present] on various time scales and present a new sea-level record for the past 100 million years (My). Long-term sea level peaked at 100 +/- 50 meters during the Cretaceous, implying that ocean-crust production rates were much lower than previously inferred. Sea level mirrors oxygen isotope variations, reflecting ice-volume change on the 10(4)- to 10(6)-year scale, but a link between oxygen isotope and sea level on the 10(7)-year scale must be due to temperature changes that we attribute to tectonically controlled carbon dioxide variations. Sea-level change has influenced phytoplankton evolution, ocean chemistry, and the loci of carbonate, organic carbon, and siliciclastic sediment burial. Over the past 100 My, sea-level changes reflect global climate evolution from a time of ephemeral Antarctic ice sheets (100 to 33 Ma), through a time of large ice sheets primarily in Antarctica (33 to 2.5 Ma), to a world with large Antarctic and large, variable Northern Hemisphere ice sheets (2.5 Ma to the present).

The use of unmanned aerial vehicles (UAVs) is growing rapidly across many civil application domains, including real-time monitoring, providing wireless coverage, remote sensing, search and rescue, delivery of goods, security and surveillance, precision agriculture, and civil infrastructure inspection. Smart UAVs are the next big revolution in the UAV technology promising to provide new opportunities in different applications, especially in civil infrastructure in terms of reduced risks and lower cost. Civil infrastructure is expected to dominate more than $45 Billion market value of UAV usage. In this paper, we present UAV civil applications and their challenges. We also discuss the current research trends and provide future insights for potential UAV uses. Furthermore, we present the key challenges for UAV civil applications, including charging challenges, collision avoidance and swarming challenges, and networking and security-related challenges. Based on our review of the recent literature, we discuss open research challenges and draw high-level insights on how these challenges might be approached.

Latent class analysis (LCA) is a statistical procedure used to identify qualitatively different subgroups within populations who often share certain outward characteristics. The assumption underlying LCA is that membership in unobserved groups (or classes) can be explained by patterns of scores across survey questions, assessment indicators, or scales. The application of LCA is an active area of research and continues to evolve. As more researchers begin to apply the approach, detailed information on key considerations in conducting LCA is needed. In the present article, we describe LCA, review key elements to consider when conducting LCA, and provide an example of its application.

The purpose of this study was to replicate and extend the classic study of vowel acoustics by Peterson and Barney (PB) [J. Acoust. Soc. Am. 24, 175-184 (1952)]. Recordings were made of 45 men, 48 women, and 46 children producing the vowels /i,I,e, epsilon,ae,a, [symbol: see text],O,U,u, lambda,3 iota/ in h-V-d syllables. Formant contours for F1-F4 were measured from LPC spectra using a custom interactive editing tool. For comparison with the PB data, formant patterns were sampled at a time that was judged by visual inspection to be maximally steady. Analysis of the formant data shows numerous differences between the present data and those of PB, both in terms of average frequencies of F1 and F2, and the degree of overlap among adjacent vowels. As with the original study, listening tests showed that the signals were nearly always identified as the vowel intended by the talker. Discriminant analysis showed that the vowels were more poorly separated than the PB data based on a static sample of the formant pattern. However, the vowels can be separated with a high degree of accuracy if duration and spectral change information is included.

The contemporary quality management (QM) literature prescribes various quality improvement strategies. However, it lacks scientifically developed and tested constructs that represent an integrative QM philosophy. Moreover, an impact of the prescribed QM strategies on a firm's product quality has not been analyzed. Through a detailed analysis of the literature, this research identifies 12 constructs of integrated QM strategies. Using a survey of 371 manufacturing firms, the constructs are then empirically tested and validated. LISREL 7 is used for this purpose. Finally, a framework to examine the effects of integrated QM strategies on a firm's product quality is suggested. Comparisons between this and two other comprehensive scales of TQM are made.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and the presence of restricted interests and repetitive behaviors. There have been recent concerns about increased prevalence, and this article seeks to elaborate on factors that may influence prevalence rates, including recent changes to the diagnostic criteria. The authors review evidence that ASD is a neurobiological disorder influenced by both genetic and environmental factors affecting the developing brain, and enumerate factors that correlate with ASD risk. Finally, the article describes how clinical evaluation begins with developmental screening, followed by referral for a definitive diagnosis, and provides guidance on screening for comorbid conditions.

Abstract This article reviews current scholarship about how to promote change in instructional practices used in undergraduate science, technology, engineering, and mathematics (STEM) courses. The review is based on 191 conceptual and empirical journal articles published between 1995 and 2008. Four broad categories of change strategies were developed to capture core differences within this body of literature: disseminating curriculum and pedagogy, developing reflective teachers, enacting policy, and developing shared vision. STEM education researchers largely write about change in terms of disseminating curriculum and pedagogy. Faculty development researchers largely write about change in terms of developing reflective teachers. Higher education researchers largely write about change in terms of enacting policy. New work often does not build on prior empirical or theoretical work. Although most articles claim success of the change strategy studied, evidence presented to support these claims is typically not strong. For example, only 21% of articles that studied implementation of a change strategy were categorized as presenting strong evidence to support claims of success or failure of the strategy. These analyses suggest that the state of change strategies and the study of change strategies are weak, and that research communities that study and enact change are largely isolated from one‐another. In spite of the weak state of the literature, some conclusions related to the design of change strategies can be drawn from this review. Two commonly used change strategies are clearly not effective: developing and testing “best practice” curricular materials and then making these materials available to other faculty and “top‐down” policy‐making meant to influence instructional practices. Effective change strategies: are aligned with or seek to change the beliefs of the individuals involved; involve long‐term interventions, lasting at least one semester; require understanding a college or university as a complex system and designing a strategy that is compatible with this system. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 952–984, 2011

Recently, artificial intelligence (AI) and blockchain have become two of the most trending and disruptive technologies. Blockchain technology has the ability to automate payment in cryptocurrency and to provide access to a shared ledger of data, transactions, and logs in a decentralized, secure, and trusted manner. Also with smart contracts, blockchain has the ability to govern interactions among participants with no intermediary or a trusted third party. AI, on the other hand, offers intelligence and decision-making capabilities for machines similar to humans. In this paper, we present a detailed survey on blockchain applications for AI. We review the literature, tabulate, and summarize the emerging blockchain applications, platforms, and protocols specifically targeting AI area. We also identify and discuss open research challenges of utilizing blockchain technologies for AI.

This article builds on job characteristics and optimal flow theory to describe the experience of individuals using computers in the workplace. A model was developed and tested with linear structural relationship modeling (LISREL) with data from 149 professionals employed in a variety of organizations. Flow, which is characterized by intense concentration and enjoyment, was found to be significantly linked with exploratory use behavior, which in turn was linked to extent of computer use. Flow was itself determined by the individual's sense of being in control and the level of challenge perceived in using computers. Perceived control was more important for individuals with high task-scope jobs, that is, jobs with high variety, identity, autonomy, and feedback. Challenge played a greater role for low task-scope individuals. Practical and theoretical implications of the model are discussed, and suggestions for further research are offered.

An extensive set of volatile organic compounds (VOCs) and particulate organic matter (POM) was measured in polluted air during the New England Air Quality Study in 2002. Using VOC ratios, the photochemical age of the sampled air masses was estimated. This approach was validated (1) by comparing the observed rates at which VOCs were removed from the atmosphere with the rates expected from OH oxidation, (2) by comparing the VOC emission ratios inferred from the data with the average composition of urban air, and (3) by the ability to describe the increase of an alkyl nitrate with time in terms of the chemical kinetics. A large part of the variability observed for oxygenated VOCs (OVOCs) and POM could be explained by a description that includes the removal of the primary anthropogenic emissions, the formation and removal of secondary anthropogenic species, and a biogenic contribution parameterized by the emissions of isoprene. The OVOC sources determined from the data are compared with the available literature, and a satisfactory agreement is obtained. The observed sub‐μm POM was highly correlated with secondary anthropogenic gas‐phase species, strongly suggesting that the POM was from secondary anthropogenic sources. The results are used to describe the speciation and total mass of gas‐ and particle‐phase organic carbon as a function of the photochemical age of an urban air mass. Shortly after emission the organic carbon mass is dominated by primary VOCs, while after two days the dominant contribution is from OVOCs and sub‐μm POM. The total measured organic carbon mass decreased by about 40% over the course of two days. The increase in sub‐μm POM could not be explained by the removal of aromatic precursors alone, suggesting that other species must have contributed and/or that the mechanism for POM formation is more efficient than previously assumed.

A discriminative stimulus is a stimulus condition which, (1) given the momentary effectiveness of some particular type of reinforcement (2) increases the frequency of a particular type of response (3) because that stimulus condition has been correlated with an increase in the frequency with which that type of response has been followed by that type of reinforcement. Operations such as deprivation have two different effects on behavior. One is to increase the effectiveness of some object or event as reinforcement, and the other is to evoke the behavior that has in the past been followed by that object or event. "Establishing operation" is suggested as a general term for operations having these two effects. A number of situations involve what is generally assumed to be a discriminative stimulus relation, but with the third defining characteristic of the discriminative stimulus absent. Here the stimulus change functions more like an establishing operation than a discriminative stimulus, and the new term, "establishing stimulus," is suggested. There are three other possible approaches to this terminological problem, but none are entirely satisfactory.

This research offers a new theory predicting the effects of three exchange variables, job satisfaction, investment size, and quality of alternatives, on four general responses to dissatisfaction—exit, voice, loyalty, and neglect. Three studies designed to test model predictions' received good support. High satisfaction and investment encouraged voice and loyalty and discouraged exit and neglect. Satisfaction and investment interacted, with variations in investment most strongly promoting voice given high satisfaction. Better alternatives encouraged exit and voice and discouraged loyalty. However, there was no link between alternatives and neglect.

To examine the role of neutrophils, their presence and the degree of infiltration, as important determinants of ischemia and reperfusion injury of the liver, male Sprague-Dawley rats were subjected to 60 and 90 min of total-liver ischemia. The presence of neutrophils, assessed by the measurement of liver tissue myeloperoxidase (MPO), and the degree of neutrophil liver infiltration, determined by the naphthol AS-D chloroacetate esterase technique, correlated well with animal survival and response to FK506 and cyclosporine administration. Lipid peroxidation, measured by the malondialdehyde (MDA) test in liver tissue, was another factor closely linked with liver function and survival. Pretreatment with FK506 (0.3 mg/kg) and CsA (5 mg/kg) was given at 4 hr and 1 hr before ischemia and at the time of reperfusion. Control ischemic animals showed increased neutrophil liver infiltration, high MPO and MDA liver levels, and diminished overall survival. FK506 and CsA-treated animals had better survival and diminished neutrophil liver infiltration, as well as MPO and MDA levels. The mechanism by which FK506 and CsA protected the animals from severe liver ischemic injury is unknown. Our data indicated that the presence and the degree of infiltration of neutrophils were important components of liver ischemia/reperfusion injury in the rat. So it is possible that one of the fundamental effects of the FK506 and CsA might be through the inhibition of the presence and infiltration of neutrophils in liver tissue.

Bridge monitoring and maintenance is an expensive yet essential task in maintaining a safe national transportation infrastructure. Traditional monitoring methods use visual inspection of bridges on a regular basis and often require inspectors to travel to the bridge of concern and determine the deterioration level of the bridge. Automation of this process may result in great monetary savings and can lead to more frequent inspection cycles. One aspect of this automation is the detection of cracks and deterioration of a bridge. This paper provides a comparison of the effectiveness of four crack-detection techniques: fast Haar transform (FHT), fast Fourier transform, Sobel, and Canny. These imaging edge-detection algorithms were implemented in MatLab and simulated using a sample of 50 concrete bridge images (25 with cracks and 25 without). The results show that the FHT was significantly more reliable than the other three edge-detection techniques in identifying cracks.

The purpose of this study was to conduct a systematic review of the secondary transition correlational literature to identify in-school predictors of improved postschool outcomes in the areas of education, employment, and/or independent living for students with disabilities. Based on results of this review, 16 evidence-based, in-school predictors of postschool outcomes were identified. Of the 16 predictors, 4 (25%) predicted improved outcomes in all three postschool outcome areas, 7 (43.8%) predicted improved outcomes for only postschool education and employment, and 5 (31.3%) predicted improved outcomes for employment only. Limitations and implications for future research and practice are discussed.

Abstract Reform efforts emphasize teaching science to promote contemporary views of the nature of science (NOS) and scientific inquiry. Within the framework of situated cognition, the assertion is that engagement in inquiry activities similar to those of scientists provides a learning context conducive to developing knowledge about the methods and activities through which science progresses, and, in turn, to developing desired views of NOS. The inclusion of a scientific inquiry context to teach about NOS has intuitive appeal. Yet, whether the learners are students, teachers, or scientists, the empirical research does not generally support the claim that engaging in scientific inquiry alone enhances conceptions of NOS. We studied developments in NOS conceptions during a science research internship course for preservice secondary science teachers. In addition to the research component, the course included seminars and journal assignments. Interns' NOS views were assessed in a pre/post format using the Views of Nature of Science questionnaire, [VNOS‐C] and interviews. Results indicate most interns showed substantial developments in NOS knowledge. Three factors were identified as important for NOS developments during the internship: (1) reflection, (2) context, and (3) perspective. Reflective journal writing and seminars had the greatest impact on NOS views. The science research component provided a context for reflection. The interns' role perspective appeared to impact their abilities to effectively reflect. Interns who assumed a reflective stance were more successful in deepening their NOS conceptions. Those who maintained a scientist's identity were less successful in advancing their NOS views through reflection. In light of these results, we discuss the significance and challenges to teaching about NOS within inquiry contexts. © 2004 Wiley Periodicals, Inc. Sci Ed 88: 610–645, 2004

The purpose of this study was to evaluate the effectiveness of several acoustic measures in predicting breathiness ratings. Recordings were made of eight normal men and seven normal women producing normally phonated, moderately breathy, and very breathy sustained vowels. Twenty listeners rated the degree of breathiness using a direct magnitude estimation procedure. Acoustic measures were made of: (a) signal periodicity, (b) first harmonic amplitude, and (c) spectral tilt. Periodicity measures provided the most accurate predictions of perceived breathiness, accounting for approximately 80% of the variance in breathiness ratings. The relative amplitude of the first harmonic correlated moderately with breathiness ratings, and two measures of spectral tilt correlated weakly with perceived breathiness.