bluuebunny/crossref_metadata_2025 huggingface dataset:
Saints, Sluts and Sexual Assault: Rethinking the Relationship between Sex, Race and Gender
Authors: Cossins Anne
Published: April 2009

This article considers how legal cultures construct different female subjectivities, using an Australian case study that documented the differential treatment of Aboriginal and non-Aboriginal complainants within sexual assault trials. In particular, the article analyses the cultural significance of the concepts of sex and race within the sexual assault trial by comparing and contrasting the analytic utility of the sexed bodies approach and the concept of gender for understanding different women’s experiences. It argues that neither of these approaches adequately describes the experiences of black and indigenous women and, instead, presents the concept of convergence for explaining the interactions of sex and race and revealing the unique vulnerabilities of black and indigenous women within legal cultures.
The Liberal State Vs The National Soul: Mapping Civil Society Transplants
Authors: Mertus Julie
Published: April 2009

The story of the liberal agenda in the former Yugoslavia and other ‘societies in transition’ is a process involving a unity of opposites - of particularism and universalism; local nationalism and global liberalism. This essay suggests a set of tools with which to re-examine the work of foreign actors engaged in ‘rule of law’ and ‘civil society’ projects in countries such as the former Yugoslavia. The essay examines three orientations of the dominant paradigm informing the work of foreign intervenors and asserts counter-orientations. The author argues that there has not been a convergence to a liberal ideal; the liberal agenda cannot be transplanted wholesale to ‘societies in transition’ as localisms, including nationalisms, challenge claims to universalisms. Both liberalism and nationalism have the potential to be either liberatory or oppressive forces; however, no solution can be viable without an accommodation of both. To better examine the liberal campaign, the essay charts the actors at play, the rhetoric they use and the stakes at hand. The goal of such a mapping is to provoke the kind of inquiry that could change the plot, or at least give some of the minor characters a more major role in the production.
Building Theory, Building Community
Authors: Harris Angela P.
Published: April 2009

Critical race theory in the United States is at a crossroads. As a jurisprudence it seems to be a success story: the number of legal scholars affiliating themselves with the movement seems to be steadily expanding; works of critical race theory are widely cited; and the literature is slowly but steadily moving out from the legal academy to reach a wider public. On the other hand, critical race theory as a community seems in danger of fragmentation, implosion, or simple abandonment. This article argues that the ill health of critical race theory as a community stems from a lack of critical attention to the politics of community building itself. This lack of critical attention created a vacuum filled by a patriarchal conception of race as ‘family’, a conception that ignores the lessons of queer activism and theory as well as feminism. The article argues that treating community building and community maintenance with the same critical energies that critical race theorists give to their intellectual constructions is important not just to the project of saving critical race theory as a community, but to the world-wide project of how to situate ‘identity politics’ within a strong commitment to justice and human flourishing.
Queer Property, Queer Persons: Self-Ownership and Beyond
Authors: Davies Margaret
Published: April 2009

The primary focus of this article is the relationship between property and personality with reference to the specific form of transgression offered by queer theory, that is, transgression of the conventional boundaries of sexual identity and desire. Feminists have strongly challenged the gendered nature of personal relations expressed through property - the association of masculinity with the position of proprietor and femininity with the position of object of property, which in its turn relies upon a fixed opposition between subject and object. It is argued here that attention to certain aspects of queer theory and praxis offers a further ground of critique and the potential for reconfiguration of these fundamental relationships.
In Citing Chaos
Authors: Paul Danette
Published: April 2009

Research on citations has generally examined citations as part of a system of rewards or as a rhetorical tool for strengthening arguments. This study examines the role of citations both as reward and as rhetoric. The reward system was examined by tracing over time the citation patterns of 13 research articles by two groups of scientists in chaos theory. The rhetorical practices were examined by determining how these articles were cited, by reviewing 609 citations of the 13 research articles. The analysis revealed that scientists consistently used five rhetorical practices: (1) using citations in the introduction, (2) using authors' names in the citation, (3) using the citation in a statement that asserts a high level of certainty, (4) using citations to create a research space, and (5) combining the use of the authors' names with placement in the introduction. These features indicated the articles' centrality in scientific discourse.
Taking Cues from the Culture
Authors: Carliner Saul
Published: April 2009

This article explores the design choices for Network Earth, a museum exhibit that introduced the general public to computer networks and related issues. The exhibit was one of three studied in a larger research project to develop a grounded model of design for learn-ing in museums. Network Earth was developed by a team that had neither formal train-ing nor academic credentials usually associated with museum exhibits. Although the design process and some of the general goals were similar to those at other sites studied and in the literature, certain practices differed. The team excluded historical objects, let donors influence content, and used different terminology. These differences appear to be cultural. With a limited affiliation with the occupational culture of museum exhibit design, the Network Earth team made choices that were more consistent with the culture of high technology—the subject of the museum and the industry that provided most of its financial support.
Learning to Do Knowledge Work in Systems of Distributed Cognition
Authors: Winsor Dorothy A.
Published: April 2009

Within work sites that engage in knowledge work, newcomers have particular difficulty acquiring knowledge because knowledge keeps changing. Newcomers have to assimilate currently accepted knowledge while remaining open to learning and even generating new knowledge. Such acquisition and generation of communal knowledge are examples of distributed cognition. In workplaces engaging in knowledge work (where knowledge is the primary product), distributed cognition aims at a less stable goal than the one that Hutchins describes for ship navigation. A study of six summer interns in an engineering development center shows that, for them and their more experienced colleagues, learning did not precede activity but rather was the means by which they remained attuned to activity and able to function. Cognition was distributed not only among people but also among people and their tools. Communication tools were particularly important because communication was the means by which the system functioned as a unified whole.
The Lessons of Survivor Literature in Communicating Decisions to Downsize
Authors: Guiniven John E.
Published: April 2009

Many companies have entered a new era of human resources management—one based on transaction cost economics and one in which downsizing has become a permanent part of the corporate landscape. But their insistence on communicating decisions to downsize solely in economic terms is creating serious problems among employees who survive the layoffs. Disloyalty, disaffection, increased absenteeism, and even acts of sabotage are growing among workers who view downsizing as a social, not economic, issue. This article discusses the new era of human resources management and reviews survivor literature in an effort to provide guidance to companies about how to communicate downsizing, specifically, and how to communicate with the postdownsized workforce, generally.
Technical Communication and Late Capitalism
Authors: Wilson Greg
Published: April 2009

This article proposes a postmodern reconceptualization of technical communication pedagogy to make student and professional agency a major concern, especially because technical communicators must compete in a global economy that rewards flexibility and penalizes inflexibility. Postmodern mapping metaphors and Robert Reich's methodology for training “symbolic-analytic” workers are used to suggest ways in which a postmodern approach to technical communication could be taught.
Research Opportunities in the US Patent Record
Authors: Durack Katherine T.
Published: April 2009

Although scarcely explored to date, US patent records provide numerous opportunities for research in technical and scientific communication. This article reviews disciplinary research that taps this rich archive of information, describes ways in which patents act as moral and social barometers to technological change, and provides readers with a brief guide to basic information needed to initiate research using patent records.
Beyond Internationalization
Authors: Grobman Laurie
Published: April 2009

To bridge the gap between composition and professional communication studies, we should add multiculturalism to the widely accepted international perspective in professional communication instruction, thus transforming the classroom into a contact zone (Pratt). The practical necessity of intercultural communication in a global marketplace necessitates internationalization. The international perspective, accounting for the heterogeneity of the technical communication audience, focuses on audience analysis and leads us to encourage students to learn about the multiple, cultural layers of audience. A multicultural perspective, however, can teach students of professional communication about the complex relationship between language and ideology and the underlying forces that shape and reflect the ways we use language. Multiculturalism's critical component provides insights into the structures and ideologies of domination/subordination and provides students with the linguistic, intellectual, and moral tools for resisting fear and prejudices. Likewise, the international perspective in professional communication can inform issues of audience analysis in composition.
Teaching Business Communication in Singapore
Authors: Goby Valerie Priscilla
Published: April 2009

What is the primary focus of business communication teachers in classrooms in which English is not the native language of students? Do they concentrate on strategies for improved professional and interpersonal communication skills, or do they direct most attention to purely language issues? These questions have become more important because the number of nonnative English students in business communication classrooms in the United States, the United Kingdom, Australia, and so forth is increasing and because English is becoming more important for business and education in many Asian and African countries. This article outlines some of the language-related problems that occur when teaching nonnative speakers business communication and calls for a drive to address the issue of acceptable language usage in this context.
Nursing Support during Labor
Authors: Corbett Cheryl A. , Callister Lynn Clark
Published: April 2009

This descriptive study replicates and extends the previous work on nursing support during labor. Within 72 hours of giving birth, 88 participants rated 25 selected nursing behaviors on a Likert scale as to their perceived helpfulness, with two open-ended questions for additional comments on helpful nursing behaviors. Nursing behaviors were categorized as emotional, informational, or tangible support. The majority of behaviors considered most helpful were in the emotional support category. Sixteen of the 25 behaviors were considered helpful, with the most helpful behaviors being making the woman feel cared about as an individual, appearing calm and confident, and treating the woman with respect. Findings were consistent with those of a previous study and suggest that, regardless of the pain management used, nurses supporting childbearing women must not only be competent but also use a high degree of interpersonal skills in providing nursing care.
Faith, Prayer, and Health Outcomes in Elderly Native Americans
Authors: Meisenhelder Janice Bell , Chandler Emily N.
Published: April 2009

This survey questioned 71 Native Americans over age 65 living in the general community on their frequency of prayer, importance of faith, and their health status. The researchers hypothesized that people with higher scores in faith and prayer would experience a more positive health status. Self-reports of health indicated a high level of functioning overall. Older people and those living alone had poorer physical and emotional health outcomes than younger elders and those living with one or more persons, although neither age nor living situation was related to mental health. People who prayed more often and those who indicated a high importance of their faith scored higher in the mental health subscale, confirming the hypothesis for this dimension of health.
The Minimum Data Set
Authors: Crogan Neva L. , Corbett Cynthia F. , Short Robert A.
Published: April 2009

The purpose of this study was to describe the prevalence of protein-calorie malnutrition (PCM) among newly admitted elderly nursing home residents and identify the most significant predictors of PCM using Minimum Data Set (MDS) variables. Using a cross-sectional design, the authors studied 306 nursing home residents. Malnutrition risk factors found on the MDS were measured for each resident. Overall, 118 (38.6%) residents met the Nutrition Screening Initiative Guidelines for PCM.MDS variables found to be significant predictors were weight loss, leaves 25% or more of food uneaten at most meals, psychiatric/mood diagnoses, deteriorated ability to participate in activities of daily living, and older age. Three additional variables (antidepressant use, diuretic use, ther apeutic diet) were found to be protective—residents with these variables were more likely to have a normal body mass index. MDS data provide an opportunity for early identification of residents who are at risk for PCM and accompanying morbidity.
A Coupled Damage-plasticity Model for Energy Absorption in Composite
Authors: Xinran Xiao
Published: April 2009

Predicting the energy absorption of composite structures requires a constitutive model that is capable of representing post-peak softening and irreversible strains, i.e., a coupled damage-plasticity model. The development of such models requires a general damage-plasticity framework. This article examines the merits and limitations of the continuum damage mechanics (CDM) framework and the plasticity framework. Based on the physical evidence of damage accumulation process in composites and the fundamentals of the two theories, a simple coupling method was proposed. This method employs a perfect plastic flow rule within a CDM framework. The capability of this method was examined by incorporating plasticity into the Matzenmiller-Lubliner-Taylor (MLT) model, a classic CDM model for composites. The coupled MLT-plasticity model was implemented as a user defined material law in explicit finite element code LS-DYNA®, and subsequently numerical tests were conducted. It was demonstrated that the proposed method can extend an existing composite CDM model into a coupled damage-plasticity model seamlessly with only a few extra parameters, while retaining its computational efficiency. The capability of the coupled CDM-plasticity model in energy absorption prediction was validated in axial impact simulations of a composite tube reinforced with 1-ply carbon fiber tri-axial braid.
Anisotropic Deformation and Damage in Aluminium 2198 T8 Sheets
Authors: Steglich D. , Wafai H. , Brocks W.
Published: April 2009

The deformation and damage mechanisms of sheets aluminium alloy 2198 are investigated experimentally and numerically. Mechanical tests in three different orientations are carried out on smooth and U-notched flat specimens. The material’s microstructure is characterized to obtain the second phase area content, the morphology of particles and the void volume fraction. The fracture surfaces of the different specimens are examined using scanning electron microscopy. Smooth specimens loaded in the longitudinal and transversal orientation exhibit a slanted fracture surface, which has an angle of about 45° with respect to the loading direction. Samples loaded in 45°-orientation fail in a flat manner. Notched specimens show a V-shaped fracture surface. Failure initiates here at the notch root. It is shown that primary voids are first initiated at intermetallic particles. Void growth is promoted and rupture is caused by shear failure between regions of cavities. Finite element calculations are performed to simulate the orientation-dependent deformation and damage behavior. A phenomenological yield criterion combined with a porosity-based isotropic damage model allows for the quantitative prediction of specimen’s failure for different triaxialities. An interaction of deformation and damage evolution can be demonstrated. The deficit of the von Mises yield criterion for this kind of metallic materials becomes evident.
Aggression Among Children in Four Cultures
Authors: Munroe Robert L. , Hulefeld Robert , Rodgers James M. , Tomeo Damon L. , Yamazaki Steven K.
Published: April 2009

Behavioral aggression was observed among 192 3- to 9-year-old children in naturalistic settings in Belize, Kenya, Nepal, and American Samoa. Results showed that (a) boys exhibited aggression in approximately 10% of their social behaviors, girls in 6%, and in all four cultures the aggression of boys was more frequent than that of girls at a marginally significant level or better; (b) the aggression of boys occurred in the presence of large numbers (and proportions) of same-sex peers; (c) aggression declined with age; (d) only 5% of children’s aggressive interaction was directed toward adults (individuals aged 17 years or older), whereas 30% of their other, nonaggressive interaction was directed toward adults; (e) the presence of either parent tended to be associated with less aggression; and (f) aggression was displayed more frequently in the two patrilineal cultures (Kenya and Nepal) and less frequently in the other two cultures.
Independent and Interdependent Conceptions of Self: An Investigation of Age, Gender, and Culture Differences in Importance and Satisfaction Ratings
Authors: Watkins David , Mortazavi Shahrenaz , Trofimova Irina
Published: April 2009

Measures of the importance of and self-satisfaction with the independent and interdependent self were used to test age, gender, and culture differences in the nature of self-conception. The participants were 903 first or second-year college undergraduates and 936 middle-class adults from four countries differing markedly in religious, political, and cultural dimensions: Hong Kong, Iran, Russia, and the United States. In both college and adult samples from all four countries, the Interdependent self was rated more important and a greater source of satisfaction than the Independent self. Analyses of variance indicated substantial main effects for age Cross-Cultural Research, Vol. 34 No. 2, May 2000 113-134 and country but a very modest gender effect. However, the interaction effects were also substantial. The data were interpreted as casting doubt on explanations of the nature of self-conception in terms of a single cultural dimension, such as Individualism-Collectivism or gender. The danger of generalizing about a country from a single group, such as college students, was also evident, as within-country differences were consistently found for the adult and student samples.
A Social Psychology Perspective on the Study of Culture: An Eye on the Road to Interdisciplinarianism
Authors: Pepitone Albert
Published: April 2009

This article deals with segregation among the social sciences, an especially dysfunctional state of affairs for those disciplines committed to understanding culture and social behavior through comparative research. A necessary condition to reduce barriers is a dialogue in which disciplines define their identities and perspectives on theory and research. The article initiates such a self-analysis in social psychology. First, a historical overview of major theoretical systems and schools maps the territory of social psychology, its mission and method. Then, an examination of the strategy, design of experiments, and the interpretation of findings reveals specific sources of resistance to theorizing about cultural influences and conducting theory-driven cross-cultural research. Finally noted are barriers in ethnographic research, including restrictive definitions of culture that inhibit inquiry into mass cultures, a body of phenomena that defines a common meeting ground for fruitful exchange.
Child Care in India: An Examination of the “Household Size/Infant Indulgence” Hypothesis
Authors: Seymour Susan C.
Published: April 2009

This article provides an intracultural examination of John Whiting’s “household size and infant indulgence” hypothesis. Inspired by Ruth H. Munroe and Robert L. Munroe’s effort to replicate Whiting’s holocultural study with an intracultural study among the Logoli of East Africa, the author uses similar measures of infant indulgence and household density to examine child care data from India. Explanations are offered for the largely negative results for this sample of Indian households. Finally, an important implication of the Whiting hypothesis—the multiple caretaking of infants and young children—is explored.
Gender Concepts: Convergence in Cross-Cultural Research and Methodologies
Authors: Best Deborah L.
Published: April 2009

Gender concepts are salient aspects of sociocultural experience. Gender concepts have been examined by trained researchers who collect data in their cultures as part of a larger cross-cultural comparative project. Such studies use easily administered procedures with large numbers of participants acting as “cultural reporters.” Using this methodology, the author and her colleague studied gender stereotypes in 30 countries and masculinity-femininity and gender role ideology in 14 countries. Gender concepts have also been studied through naturalistic observations in specific cultures of interest. Face-to-face interviews and observations with small numbers of participants characterize these studies. Ruth and Robert Munroe’s studies of gender concepts with children and adults in Belize, Kenya, Nepal, and Samoa reflect this orientation. This article highlights the convergence of findings and methodologies of these different types of studies. Research exploring socialization experiences and cultural expectations that may be linked to gender differences and concepts are also discussed.
Is Mary Douglas's Grid/Group Analysis Useful for Cross-Cultural Research?
Authors: Caulkins D. Douglas
Published: April 2009

During the 1970s, anthropologist Mary Douglas developed a twodimensional framework for cultural comparisons: (a) grid or constraint by rules, and (b) group or incorporation into a bounded social unit. According to Douglas and her colleagues, the four grid/ group types constitute stable social configurations that are associated with distinctive values or ideologies: individualism, fatalism, hierarchy, and egalitarianism. The theory has inspired a great deal of elaboration, numerous intrasocietal studies, some controlled comparisons between social units in different societies, and some limited cross-national studies. Although plausible, the framework has not been subjected to extensive cross-cultural testing. This article addresses a preliminary question in the more rigorous crosscultural testing of the framework: Are grid, group, and ideology empirically separate dimensions as Douglas contends? A pilot study employing factor analysis of precoded variables from the 60-culture Human Relations Area Files (HRAF) probability sample file suggests that they may be. Further steps in testing this theoretical framework are proposed.
Exploring Cultural Issues in Puerto Rican Homelessness
Authors: Juliá María , Hartnett Helen P.
Published: April 2009

Research suggests that culture is one of the variables that significantly affects the construction and meaning of any social phenomenon. However, few studies have been devoted to homelessness—a particularly powerful social phenomenon—among ethnic groups. The rather limited data and literature about homelessness and ethnicity suggest marked differences between Puerto Rican homeless people and those from other ethnic groups, but specific analysis of the relevance of culture on homelessness within the Puerto Rican context has received minimal attention. The authors use existing data about homeless single adults who use shelter in Puerto Rico’s capital city, San Juan, and in the capital city of Columbus, Ohio, to explore and compare the incidences, causes, and demographic characteristics of homeless people in the two cities. Cultural issues that potentially underlie definitions, attitudes, and responses toward social phenomena are discussed. These cultural domains are offered to explain the differences between the two groups.
Resources for Security and Stability? The Politics of Regional Cooperation on the Mekong, 1957-2001
Authors: Makim Abigail
Published: April 2009

This article tells about the relationship between resource politics and security in international relations. Using the Mekong River Basin as its case study, the article examines the place of resource and development issues in attempts to develop regional institutions. The question of whether a resource development regime with apparently low productivity in terms of technical output, but high levels of resilience and longevity, should be considered a failure or not, is considered. This question is examined within the broader context of Southeast Asian politics during the First, Second, and Third Indochina conflicts as well as the post–cold war era. The article argues that survival and a capacity to change to meet the challenges of extreme broader events are clear evidence of regime success. From this standpoint, the article explores ways in which the Mekong resource regime is linked to more general concerns for political security and stability and may in fact reflect political concerns for subregional neighborhood maintenance.
Drowning in the Magic Well: Shaman Pharmaceuticals and the Elusive Value of Traditional Knowledge
Authors: Clapp Roger Alex , Crook Carolyn
Published: April 2009

Biodiversity prospecting, and ethnobotanical search methods that draw on the medicinal knowledge of traditional societies, are mechanisms of drug discovery with the potential to reward the conservers of biological resources. Shaman Pharmaceuticals aspired to be a model of ethnobotanical bioprospecting, discovering new medicines while sharing benefits with indigenous people. Shaman's failure to market any new pharmaceutical products and its ultimate bankruptcy were heralded as marking the failure, and future abandonment, of ethnobotanical bioprospecting. This analysis of Shaman's history suggests that risks inherent in drug development, company risk associated with Shaman's drug development strategy, and technological change in the industry all contributed to its failure. The authors examine the opportunities and constraints encountered in bioprospecting and ethnobotanical searches and argue that natural products will remain important to drug development. Technological change, however, means that new models and new institutional structures are required for drug development based on natural products.
Water and Conflict in the Middle East and South Asia: Are Environmental Issues and Security Issues Linked?
Authors: Lowi Miriam R.
Published: April 2009

Focusing on transboundary water issues in conflict settings, the linkages between environmental variables and security conditions are explored. The article is organized around a set of questions that has dominated debates about the notion of environmental security. The need for studies that are historically-informed and context-specific is stressed. A plea is made for a less narrowly focused research agenda and greater attention to the importance of political and institutional reform in the attenuation of environmental constraints.
Feedforward Control Law For A Shipboard Crane With Maryland Rigging System
Authors: Kimiaghalam Bahram , Homaifar Abdollah , Bikdash Marwan , Hunt Brian R.
Published: April 2009

A state-space model of the Maryland Rigging shipboard crane is derived from Newton's law under the assumptions of boom stiffness, fully controllable boom motion, no cable elasticity, no damping, and full control authority for changing the length of the rope. A chaotic rolling moment, with a dominant frequency of the same order as the resonance frequency of the shipboard crane, is applied to the ship as an external disturbance. The effect of this disturbance is studied. Since designing a controller by means of analytical methods for this system is too complex, we use a novel approach to this problem that focuses on the equilibrium point. By deriving the equations for calculating the position of the equilibrium point of the load in space, we change the problem to minimizing the change in the position of this point. A feedforward type controller is then designed as to keep the load closest to the “equilibrium point” for the actual roll angle. The controller seeks to suppress the load sway caused by the ship's rolling motion by changing the luffing angle while the friction in the pulley is assumed to be negligible. Changing the luffing angle seems to be the most effective control action in shipboard cranes. The feedforward gain is then optimized by numerical methods. The simulation results for this controller show a huge decrease in the sway magnitude as compared to the cases with no control. The roll angle, luffing angle of the boom, and the length of the rope are changed individually and then the related optimum feedforward gains are numerically obtained. Using these data, the mapping of the optimum gain based on these variables is derived. Scheduling the gain based on this mapping greatly improves the performance of the feedforward controller. This procedure can be repeated for similar applications.
Design Robust Nonlinear Controllers for Autonomous Underwater Vehicles with Comparison of Simulated and At-sea Test Data
Authors: Song Feijun , An Edgar , Smith Samuel M.
Published: April 2009

Successful controller development involves three distinct stages, namely, control law design, code debugging and field test. For Autonomous Underwater Vehicle (AUV) applications, the first two stages require special strategies. Since the dynamics of an AUV is highly nonlinear, and the environment that an AUV operates in is noisy with external disturbance that cannot be neglected, a robust control law must be considered in the first stage. The control law design is even more difficult when optimal criteria are also involved. In the second stage, since the software architecture on an AUV is very complicated, debugging the controllers alone without all the software routines running together often can not reveal subtle faults in the controller code. Thorough debugging needs at-sea test, which is costly. Therefore, a platform that can help designers debug and evaluate controller performance before any at-sea experiment is highly desirable. Recently, a 6 Degree of Freedom (DOF) AUV simulation toolbox was developed for the Ocean Explorer (OEX) series AUVs developed at Florida Atlantic University. The simulation toolbox is an ideal platform for controller in-lab debugging and evaluation. This paper first presents a novel robust controller design methodology, named the Sliding Mode Fuzzy Controller (SMFC). It combines sliding mode control and fuzzy logic control to create a robust, easy on-line tunable controller structure. A formal proof of the robustness of the proposed nonlinear sliding mode control is also given. A pitch and a heading controller have been designed with the presented structure and the controller code was tested on the simulation software package as well as at sea. The simulated and at-sea test data are compared. The whole controller design procedure described in this paper clearly demonstrates the advantage of using the simulation toolbox to debug and test the controller in-lab. Moreover, the pitch and heading controller have been used in the real system for more than 2 years, and have also been successfully ported to other types of vehicles without any major modification on the controller parameters. The similarity of the controller performances on different vehicles further demonstrates the robustness of the proposed Sliding Mode Fuzzy Controller. The main contribution of this paper is to provide useful insights into the design and implementation of the proposed control architecture, and its application in AUV control.
Dynamics Analysis of Parallel Three-Phase Converters
Authors: Ye Zhihong , Boroyevich Dushan , Lee Fred C.
Published: April 2009

In a distributed power system based on power electronics building blocks (PEBBs), it is desirable to use a parallel structure with standardized PEBB modules in order to increase power level, provide redundancy and improve system performance. Nonlinear couplings and interactions, however, may occur among the parallel modules. Compared with their counterpart DC/DC converters, three-phase AC/DC or DC/AC converters exhibit stronger dynamics when they operate in parallel. The objective of this paper is to comprehensively analyze the nonlinear dynamics among two parallel three-phase converters. The paper firstly develops a nonlinear average model in rotating coordinates. Based on the model, the nonlinear dynamics, such as small-signal interaction, zero-sequence circulating current and high frequency noise, are analyzed. To improve the system performance and minimize the interactions, some feedback control strategies are proposed. To deal with high-frequency noise, a feedforward control scheme is proposed. The scheme can significantly reduce both common-mode and differential-mode noise. Simulations and preliminary experimental results are presented.
Method of Reducing the Number of DOF in the Machine Tool-Cutting Process System from the Point of View of Vibrostability Analysis
Authors: Pajor M. , Marchelek K. , Powałka B.
Published: April 2009

The model of the mass-damping-spring (MDS) system of a machine tool is multi-degree of freedom model. The model of the cutting process (CP) has to correspond structurally to the MDS system model constituting the machine tool-cutting process (MT-CP) system model. This is often a model of time-variant parameters. Therefore, forecasting the vibrostability, i.e. resistance to the occurrence of self-excited vibrations, in the MT-CP system is a complicated task. To simplify analysis it is justified to reduce the number of degrees of freedom. The method presented simplifies significantly the computational model while the interpretation of the results applies to the whole construction. The reduced model carries information concerning vibration modes that determine vibrostability loss. The paper presents the mathematical fundamentals of the reduction of the machine tool MDS system model, analysis and selection of vibration modes considered in the reduced model and analysis of reduction errors.
Feature Extraction From Energy Distribution of Stamping Processes Using Wavelet Transform
Authors: Ge M. , Zhang G. C. , Du R. , Xu Y.
Published: April 2009

As one of the most commonly used manufacturing processes, stamping operations are applied to an extended range from centimeter-class parts to meter-class parts. The demand for the quality and productivity of stamping products is ever increasing. Hence, the extraction of the appropriate feature to implement on-line monitoring has been attempted. The vibration signals provide rich information for finding the dynamic behavior at high frequency vibration of the press. In this paper, an accelerometer has been employed in place of tonnage sensors or strain gauges to monitor the stamping process. In order to characterize the transient signal of the process, this work extracts the energy densities and frequency band energy (FBE) from the vibration signal. Owing to its inherent properties, the wavelet packet transformation decomposes the original signal into basis functions, with different energy distributions dominating in different time-frequency bands. Based on the experimental results, this suggests that extracting FBE from a vibration signal using a wavelet packet as a feature for fault diagnosis can, in practice be an effective approach for stamping process monitoring.
Double Panel Partition (AVNC) by Means of Optimized Piezoceramic Structural Boundary Control
Authors: Jemai B. , Ichchou M. N. , Jezequel L.
Published: April 2009

Towards low frequencies, the sound reduction of a double panel partition has an efficiency loss. A feasibility study is investigated to improve the sound reduction of a realistic double panel partition by means of piezoelectric elements as structural control actuators between the panel boundary. Finite element modeling of the double glazing window permits an understanding of the physical phenomenon governing the vibroacoustic behavior. In particular, the incidence of the fluid cavity and the boundary conditions effects on the insertion loss factor are analyzed. Hence, an original structural control experiment has been conducted using optimized piezoceramic actuators at the double glazing window boundaries. The performances of the proposed control strategy are evaluated and it is shown that an improvement has been achieved with a simple velocity or a pressure feedback control.
Aeromechanical Stability Analysis and Control of Smart Composite Rotor Blades
Authors: Chattopadhyay Aditi , Kim Jong-Sun , Liu Qiang
Published: April 2009

The use of segmented constrained layer damping treatment and closed loop control is investigated for improved rotor aeromechanical stability. The rotor blade load-carrying member is modeled using a composite box beam with arbitrary wall thickness. The ACLs are bonded to the upper and lower surfaces of the box beam to provide active and passive damping in the aeromechanical stability analysis. A finite element model based on a hybrid displacement theory is used to accurately capture the transverse shear effects in the composite primary structure, the viscoelastic and the piezoelectric layers within the ACL. The Pitt-Peters dynamic inflow model is used in the air resonance analysis under hover conditions. Rigid body pitch and roll degrees of freedom and fundamental flap and lead-lag modes are considered in this analysis. A transformation matrix is introduced to transform the time-variant system to a time-invariant system. A LQG controller is designed for the transformed system based on the available measurement output. The control performance is compared with the results of the open loop and the passive control systems. Numerical results indicate that the proposed control system with surface bonded ACL damping treatment significantly increases rotor lead-lag regressive modal damping in the coupled rotor-body system.
Modelling of a Beam with a Breathing Edge Crack and Some Observations for Crack Detection
Authors: Nandi A. , Neogy S.
Published: April 2009

The breathing behaviour of closing cracks has been adequately simulated as a small-displacement, frictionless contact problem. The problem of a beam with an edge crack subjected to harmonic loading has been considered as a plane problem and an attempt is made to solve it by using finite elements employing eight-node plane isoparametric elements. The proposed model allows the crack size and position to be varied. Another physically important problem of a cantilever beam held between two heavy jaws at the top and bottom, which are not equally flushed, is considered. This beam is also excited by a harmonic load at the tip. The contact model and a simple single degree of freedom model are used to solve the problem. Both the above problems (cracked beam and beam in offset jaws) show presence of integral multiples of the forcing frequency in their frequency spectra.

An important observation regarding cracked beams and beams with imperfect support is made. If the forcing frequency is such that it coincides or is close to any one of the integral sub-multiples (1/ n) of the first natural frequency of the system, then the nth harmonic of the forcing frequency will considerably shoot up. This effect is highly pronounced for the case n = 2 and this observation may be used to detect cracks in beams as small as 2.5% of the depth.

For cracked beams, the even harmonics are considerably stronger than the odd ones. As the crack size decreases, the odd harmonics become weaker. For a 2.5% crack only the second and fourth harmonics are visible in an 80 dB scale, with the former being the stronger.

However, it is important to note that cracked beams and beams with imperfect support have closely similar spectral characteristics and so due caution must be exercised during crack detection.
Analysis of Proportional—Derivative and Nonlinear Control of Mechanical Systems with Dynamic Backlash
Authors: Mata-Jiménez M. T. , Brogliato B.
Published: April 2009

In this paper, we focus on the analysis and control of a simple rigid-body mechanical system with clearance. Contrary to most of the existing works in the literature concerning control, we explicitly treat all the nonlinear non-smooth characteristics of this system considered as a rigid-body mechanical system with unilateral constraints and impacts (dynamic backlash). The model is therefore a hybrid dynamical system, mixing discrete events as well as continuous states. The regulation and tracking capabilities of the proportional—derivative (PD) scheme are investigated. In particular, a complete proof of the existence of a limit cycle for non-collocated PD control is provided, including viability constraints. It is concluded that tracking requires the development of specific control schemes. Consequently, we propose a hybrid control that may be used to track some desired trajectories in conjunction with a PD input. Throughout the paper, the particular features of unilaterally constrained mechanical systems are taken into account, such as the fundamental viability property of closed-loop solutions and controls. This work is a new approach to be considered for application in several areas including the control of kinematic chains with joint clearance and vibro-impact systems, as well as liquid slosh control. Numerical results are presented to illustrate the possible performance of the proposed control scheme and its robustness properties.
Snake-Like Locomotions of Multilink Mechanisms
Authors: Chernousko F. L.
Published: April 2009

Snake-like locomotions of a three-member linkage equipped with actuators are modeled and investigated. Longitudinal, lateral, and rotational motions of the mechanism along a horizontal plane in the presence of the dry friction are analyzed. The desired motions are presented as a combination of more simple elementary motions. Sufficient conditions are deduced under which these motions are possible. The dependence of the average speed of motions on various geometrical and mechanical parameters is investigated. The optimal values of the parameters which maximize the speed are obtained. The numerical results are presented and discussed.
Delayed Position-Feedback Controller for the Reduction of Payload Pendulations of Rotary Cranes
Authors: Masoud Ziyad N. , Nayfeh Ali H. , Al-Mousa Amjed
Published: April 2009

In this paper, we show that, in rotary cranes, it is possible to reduce payload pendulations significantly by controlling the crane's translational and rotational degrees of freedom. Such a control can be achieved with the heavy equipment that is already part of the crane, so that retrofitting existing cranes with such a controller would require little effort. Moreover, the control is superimposed transparently on the commands of the operator. The successful control strategy is based on delayed position feedback of the payload's in-plane and out-of-plane motions. Its effectiveness is demonstrated with a fully nonlinear three-dimensional computer simulation and with an experiment on a scaled model of a rotary crane. The results demonstrate that the pendulations can be significantly reduced, and therefore the rate of operation can be greatly increased. The effectiveness of the controller is demonstrated for both rotary and gantry modes of operation.
A Parametric Identification Technique for Single-Degree-of-Freedom Weakly Nonlinear Systems with Cubic Nonlinearities
Authors: Malatkar Pramod , Nayfeh Ali H.
Published: April 2009

We present a procedure for the identification of parameters describing a single-mode response of a structure possessing cubic geometric and inertia nonlinearities and linear (viscous) and quadratic damping (air drag). We use this procedure to identify the parameters describing the third mode of a cantilever beam. The beam is externally excited by a harmonic force having a frequency close to the beam's third natural frequency. We use the method of multiple scales to determine a first-order uniform expansion of the model equation and hence the beam response to such an excitation. We estimate the parameters based on the experimental frequency-response results and later use these values in the theoretical model. We then compare the model results with the experimental results. For the fourth mode, a comparison is also made between the results obtained using the proposed estimation technique with those obtained by the frequency-response curve-fitting method. We report on deviations and agreements between model and experimental results.
Vibration Control on a Pulse and Ramp Driven System with Friction
Authors: Shyu Kuo-Kai , Lee Yun-Yao , Wu Ruh-Hua
Published: April 2009

This paper investigates the sufficient stability condition of a three-phase proportional gain, pulse, and ramp (PPR) controller for pointing systems under the influence of friction. With the ramp and pulse schemes integrated, the PPR controller has been demonstrated to be an effective control strategy for fast and precise pointing applications. In this paper the LuGre model is used to derive the upper bounds of the ramp slope Sr for the sufficient stability condition to suppress vibrations around the [—0.5, +0.5] μm target region. Our study reveals that the frictional stiffness σ0 and the micro viscous damping coefficient σ1 in the LuGre model are required for the bounds of Sr . With the derived bounds of Sr , the Lyapunov direct method is applied to prove the stability of the PPR controller.