bluuebunny/crossref_metadata_2025 huggingface dataset:
Symbolic Singular Value Decomposition for Simple Redundant Manipulators and Its Application to Robot Control
Authors: Kirćanski Manja
Published: March 2007

Solving the inverse kinematic problem in the vicinity of singu larities by the use of the damped least squares method is one of the most efficient means to overcome numeric problems in singularities. The high numeric complexity of numeric algo rithms for the singular value decomposition (SVD) has so far prevented a broader application of this method. The use of the symbolic SVD in robot control for nonredundant manipulators was proposed in Kirćanski and Borić (1993). In this article symbolic expressions for singular values and singular vectors for a 7-DOF redundant manipulator are derived, together with the damped least squares joint velocities. Numeric complexity is reduced by about seven times. Simulation results show that the position error is reduced to a minimum, while joint rates are limited. Symbolic expressions are used to describe robot dex terity and isotropic configurations. Application to other simple redundant robot geometries with special Jacobian structures is discussed.
Robot Grasp Synthesis Algorithms: A Survey
Authors: Shimoga K.B.
Published: March 2007

This article presents a survey of the existing computational algorithms meant for achieving four important properties in autonomous multifingered robotic hands. The four properties are: dexterity, equilibrium, stability, and dynamic behavior The multifingered robotic hands must be controlled so as to possess these properties and hence be able to autonomously perform complex tasks in a way similar to human hands.

Existing algorithms to achieve dexterity primarily involve solving an unconstrained linear programming problem where an objective function can be chosen to represent one or more of the currently known dexterity measures. Algorithms to achieve equilibrium also constitute solving a linear program ming problem wherein the positivity, friction, and joint torque constraints of all fingers are accounted for while optimizing the internal grasping forces. Stability algorithms aim at achiev ing positive definite grasp impedance matrices by solving for the required fingertip impedances. This problem reduces to a nonlinear programming problem. Dynamic behavior algorithms determine fingertip impedances, which, when achieved, lead to a desired dynamic behavior. This problem, too, becomes a linear programming problem.

If a robotic hand has to acquire any or all of these proper ties, the corresponding algorithms should become integral parts of the hand control system. These algorithms are collectively referred to in this article as robot grasp synthesis algorithms.
An Autonomous Guided Vehicle for Cargo Handling Applications
Authors: Durrant-Whyte Hugh F.
Published: March 2007

This article describes an autonomous guided vehicle (AGV) system designed to transport ISO standard cargo containers in port environments. The AGV consists of a large 17.5-ton chassis, which is driven and steered through a diesel-hydraulic power set. The vehicle drives on pneumatic wheels over un prepared road surfaces at speeds up to 6 m/s. The navigation system is based on the use of millimeter-wave radar sensors detecting beacons placed at known locations in the environ ment. The navigation system reliably achieves accuracies of better than 3 cm. The planning and control systems allow the AGV to operate in the quay and yard area, to dock with gantry cranes, and to achieve a duty cycle comparable to that of a conventional manned vehicle. This article concentrates on describing three principal contributions of this work: the de sign of the overall vehicle and on-board systems architecture; the development of a navigation system appropriate for large, outdoor, high-speed vehicles; and the experimental program leading to validation of the vehicle system.
The Interpretation of Phase and Intensity Data from AMCW Light Detection Sensors for Reliable Ranging
Authors: Adams M.D. , Probert P.J.
Published: March 2007

The analysis of sensor range data and its application to mo bile robot navigation are of crucial importance in the field of mobile robotic research.

We analyze the range data produced by an amplitude- modulated continuous wave (AMCW) light detection and ranging sensor and show that by physically modeling such sensors, we not only can produce reliable range estimates, but can also quantify our certainty in each range data point. We discuss the noise in the sensor and show the importance of using both phase and intensity data for calibration and data interpretation.

We consider in detail the phenomenon of "mixed pixel points" whereby false range measurements occur when the light beam transmitted is split between two or more surfaces of differing range and/or reflectivity. We describe a new algorithm capable of detecting sudden changes in surface reflectance and/or range in order to identify these "spurious" data points. We quantify the regions over which the detection method will work, as we consider its sensitivity to changes in range and surface reflectance, while also quantifying the possibility of falsely predicting a discontinuity.
Scaling of Direct Drive Robot Arms
Authors: Hannaford Blake , Marbot Pierre-Henry , Buttolo Pietro , Moreyra Manuel , Venema Steven
Published: March 2007

This article studies the ways that the performance of direct drive (DD) serial robots changes as system size is changed. We are particularly interested in the physical laws for scaling down direct drive arms to small sizes. Using theoretical scaling analysis, we show that there is a net physical performance advantage to small direct drive arms. A key factor for direct drive robot performance is the torque-to-mass ratio of the actuators, U. We show how U varies with the scale of DD actuators, and we also calculate how the dynamic performance varies with scale and U. We compare our calculations with experimental measurements of actuators of various sizes taken from small hard disk drives and compare them with published data for larger motors. Finally, we describe a prototype, five- axis, direct drive serial arm having a reach of 10 cm and a work volume of about 136 cm3. Some potential applications are briefly discussed.
Comparative Study of Robust Saturation-Based Control of Robot Manipulators: Analysis and Experiments
Authors: Liu Guangjun , Goldenberg Andrew A.
Published: March 2007

This article presents two proposed saturation-based robust con trol methods for robot manipulators and a comparison with their counterpart published coritrol laws. Both analytical and experimental comparisons are conducted following a classifi cation of the control methods according to their basic model formulations. Experimental results have shown the outstand ing performance of the proposed control methods. The best tracking performance was achieved under the proposed control method based on dynamic model decomposition, which deals with different sources of uncertainty separately and possesses an enhanced fine-tuning ability. Discussions and insights gained from our experiments are also presented.
Directly Visualizing Spatial Freedom from Geometric Models
Authors: Sturges Robert H. , Sathirakul Korntham , Laowattana Schitt
Published: March 2007

When two parts are in contact, their relative freedom of motion is restricted according to the geometry of their contacts. Rela tive freedom tells us how one part is allowed to move relative to another. Although a determination of relative freedom was solved by Ohwovoriole in the last decade, a graphical tool to visualize and represent relative freedom remained to be devel oped. The relative freedom of a polyhedral object exhibiting different types of contacts has been derived based on screw theory. The contacts are modeled as a set of essential wrenches normal to a contact plane. An algorithm to identify essential wrenches is developed. A twist field of a contact contains all possible twists that are reciprocal or repelling to the essen tial wrenches representing the contact. The relative freedom is represented by a set of freedom twists in space, which are derived by intersecting all the twist fields. The result of our analysis is a means with which to graphically visualize and algorithmically determine relative freedom.
Stable Pushing: Mechanics, Controllability, and Planning
Authors: Lynch Kevin M. , Mason Matthew T.
Published: March 2007

We would like to give robots the ability to position and orient parts in the plane by pushing, particularly when the parts are too large or heavy to be grasped and lifted. Unfortunately, the motion of a pushed object is generally unpredictable due to unknown support friction forces. With multiple pushing contact points, however, it is possible to find pushing directions that cause the object to remain fixed to the manipulator. These are called stable pushing directions. In this article we consider the problem of planning pushing paths using stable pushes. Pushing imposes a set of nonholonomic velocity constraints on the motion of the object, and we study the issues of local and global controllability during pushing with point contact or stable line contact. We describe a planner for finding stable pushing paths among obstacles, and the planner is demon strated on several manipulation tasks.
An Analysis of Astrictive Prehension
Authors: Monkman G.J.
Published: March 2007

Astrictive robot grippers are one of the most common methods of prehension used in automation, which include vacuum suc tion, magnetoadhesion and electroadhesion. The most important parameters when considering the implementation of any grip per, including astrictive devices, are retention pressure, energy efficiency, and response time. The actual gripping techniques evaluated qualitatively and quantitatively in this article are not new. What is new is the comparative theoretical analysis and its applicability to the evaluation of response times and relative energy efficiencies of astrictive robot grippers. Coupled with the material- and surface geometry-dependent factors, this provides the basic essentials required in research, development, and design. It is the intention of this article to present the ba sic theory and examples of typical parameters in order to assist in the selection of appropriate gripping techniques and to aid in the design process.
On Computing Four-Finger Equilibrium and Force-Closure Grasps of Polyhedral Objects
Authors: Ponce Jean , Sullivan Steve , Sudsang Attawith , Boissonnat Jean-Daniel , Merlet Jean-Pierre
Published: March 2007

This article addresses the problem of computing stable grasps of three-dimensional polyhedral objects. We consider the case of a hand equipped with four hard fingers and assume point contact with friction. We prove new necessary and sufficient conditions for equilibrium and force closure, and present a geometric characterization of all possible types of four-finger equilibrium grasps. We then focus on concurrent grasps, for which the lines of action of the four contact forces all intersect in a point. In this case, the equilibrium conditions are linear in the unknown grasp parameters, which reduces the problem of computing the stable grasp regions in configuration space to the problem of constructing the eight-dimensional projec tion of an ll-dimensinnal polytope. We present two projection methods: the first one uses a simple Gaussian elimination ap proach, while the second one relies on a novel output-sensitive contour-tracking algorithm. Finally, we use linear optimization within the valid configuration space regions to compute the maximal object regions where fingers can be positioned inde pendently while ensuring force closure. We have implemented the proposed approach and present several examples.
Force Tracking in Impedance Control
Authors: Seraji Homayoun , Colbaugh Richard
Published: March 2007

This article presents two simple on-line schemes for force tracking within the impedance-control framework. The force- tracking capability of impedance control is particularly important for providing robustness in the presence of large uncertainties or variations in environmental parameters. The two proposed schemes generate the reference position trajec tory required to produce a desired contact force despite lack of knowledge of the environmental stiffness and location. The first scheme uses direct adaptive control to generate the refer ence position on-line as a function of the force-tracking error. Alternatively, the second scheme utilizes an indirect adaptive strategy in which the environmental parameters are estimated on-line, and the required reference position is computed based on these estimates. In both schemes, adaptation allows au tomatic gain adjustment to provide a uniform performance despite variations in the environmental parameters. Simula tion studies are presented for a 7-DOF Robotics Research arm using full arm dynamics, demonstrating that the adaptive schemes are able to compensate for uncertainties in both the environmental stiffness and location. The simulation studies also highlight the limitations of pure impedance control without the force-tracking capability for robust execution of realistic contact tasks. Experimental results are also presented for the Robotics Research arm to demonstrate that the end effector applies the desired contact force while exhibiting the specified impedance dynamics.
On-Line Manipulation Planning for Two Robot Arms in a Dynamic Environment
Authors: Li Tsai-Yen , Latombe Jean-Claude
Published: March 2007

In a constantly changing and partially unpredictable envi ronment, robot-motion planning must be on-line. The planner receives a continuous flow of information about occurring events and generates new plans while previously planned mo tions are being executed. This article describes an on-line planner for two cooperating arms whose task is to grab parts of various types on a conveyor belt and transfer them to their respective goals, while avoiding collisions with obstacles. Parts arrive on the belt in random order, at any time. Both goals and obstacles may be dynamically changed. This scenario is typi cal of manufacturing cells serving machine tools, assembling products, or packaging objects. The proposed approach breaks the overall planning problem into subproblems, each involving a low-dimensional configuration or configuration x time space, and orchestrates very fast primitives solving these subproblems. The resulting planner has been implemented and extensively tested in a simulated environment, as well as with a real dual- arm system. Its competitiveness has been evaluated against an oracle making (almost) the best decision at any one time; the results show that the planner compares extremely well.
An Experimental Study of Nonlinear Stiffness, Hysteresis, and Friction Effects in Robot Joints with Harmonic Drives and Torque Sensors
Authors: Kircanski Nenad M. , Goldenberg Andrew A.
Published: March 2007

Despite widespread industrial applicatzon of harmonic drives, the source of some elastokinetic phenomena and their impact on overall system behavior has not been fully addressed thus far. Some of these phenomena severely influence the behavior of robot arms, both in free and constrained motions, when the end effector is in contact with an environment. The primary goal of this study is to derive an effective, control-oriented model of a harmonic-drive-based robot joint. Systematic observations of an experimental robot with harmonic drives has revealed that the harmonic drive could not entirely transmit the input torque to the output shaft, due to a nonlinear meshing process between the flexible and circular spline teeth. The torque transmitted to the output shaft might saturate at a much lower value than expected (e.g., motor torque multiplied by the gear ratio). This phenomenon may severely influence the system behavior, par ticularly in force/impedance control tasks when full joint-torque capacity and wide bandwidth are needed. To understand the harmonic-drive behavior, as well as to derive a convenient form of its model, we have shown restrained motion experi ments to be much more useful than free-motion experiments.

In this article, we also introduce mathematical models and describe experiments related to other physical phenomena, such as nonlinear stiffness, hysteresis, and soft windup. The goal of our modeling strategy was not to develop a precise and possi bly complicated model, but to generate an appropriate model that could be easily used by control engineers to improve joint behavior To visualize the developed model, equivalent mechan ical and electrical schemes of the joint are introduced. Finally, a simple and reliable estimation procedure has been established for obtaining joint parameters, to ascertain the integrity of the proposed model.
Smooth Local-Path Planning for Autonomous Vehicles1
Authors: Kanayama Yutaka J. , Hartman Bruce I.
Published: March 2007

We propose a new method for generating smooth paths for vehicle path planning. The problem of finding the "smoothest path" joining two given configurations is solved (a configu ration is a position and a direction). Generally, we solve the problem using two "simple " path segments. The most important issue is how to define the smoothness cost of a path. We pro pose two distinct definitions: the first is the path curvature, and the second is the derivative of the path curvature. We use cir cular arcs with the first definition, and we use "cubic spirals" with the second for "simple curves" respectively. The set of cubic spirals has several advantages when used in smooth-path planning, one of which is curvature continuity. This theory also reveals other important concepts in robotics, such as "symmet ric configurations " and "symmetric means. " This algorithm has been successfully implemented on the autonomous mobile robot Yamabico-11 at the University of California at Santa Barbara and at the Naval Postgraduate School.
Human Prehension and Dexterous Robot Hands
Authors: Iberall Thea
Published: March 2007

The human hand is versatile in its interactions with the envi ronment, demonstrating skills that designers of dexterous robot hands would like to emulate. Various postures and features of the human hand combine to provide a great deal of functional ity. In this article, an analysis of human prehensile capability is presented, comparing a symbolic description of prehension to an opposition-space, parameterized framework. By pointing out features of the human hand in prehensile tasks, we hope to offer insights that designers can use for building more versatile robot and prosthetic hands.
Terrain-Adaptive Gait for Walking Machines
Authors: Jiménez Maria A. , González de Santos P.
Published: March 2007

One of the primary advantages of walking machines is their inherent capacity for moving over different terrains. However, it is important to provide algorithms that modify the gait ac cording to the terrain. Existing articles about terrain-adaptive locomotion are based on intelligent foothold selection, and use periodic and/or aperiodic gaits. This article proposes a strategy to adapt walking robot locomotion to an irregular terrain in real time that is based on the variations of parameters of a periodic gait affecting leg coordination. Its main feature is that it does not require knowledge of footholds. In addition, this adaptive gait control can be incorporated into a system with external stereoceptive sensors to select footholds. As a working example, a particular class of periodic gaits, called wave-crab gaits, are used in a quadruped robot. However, the proposed adaptive-gait method can be used for any other periodic gait and for robots with a greater number of legs. Adaptive-gait control has been implemented in a quadruped robot named RIMHO, demonstrating its ability to move over different ter rains. Static stability results from computer simulations and experimentally obtained velocity results are also presented.
Control of Contact Interactions with Acatastatic Nonholonomic Constraints
Authors: Sarkar Nilanjan , Xiaoping Yun  , Kumar Vijay
Published: March 2007

A robot arm performs many tasks by interacting with objects or other robots in the environment. It is important for the robot arm to be able to exhibit controlled interactions with the objects and other robots. The contact motion between the robot arm and an object can be rolling, sliding, or separation. In this article, we address the problem of maintaining rolling contact between the robot arm and an external moving object. We assume that a nominal model of the motion of the moving object is available. The dynamic system that characterizes the motion of the robot arm and the moving object in this case is acatastatic and nonholonomic. We have designed a nonlinear feedback for the control of such a system that successfully maintains rolling contact. Simulation results are presented to demonstrate the effectiveness of the system.
Let Them Fall Where They May: Capture Regions of Curved Objects and Polyhedra
Authors: Kriegman David J.
Published: March 2007

When a three-dimensional object is placed in contact with a supporting plane, gravitational forces move it to one of a finite set of stable poses. For each stable pose, there is a region in the part's configuration space called a capture region; for any initial configuration within the region, the object is guaranteed to converge to that pose. The problem of computing maximal capture regions from an object model is analyzed assuming only that the dynamics are dissipative; the precise equations governing the system are unnecessary. An algorithm, based on Morse theory, is first developed for objects with smooth, convex hulls. The formulation is then extended to objects with piecewise-smooth hulls using a catalog of critical points de rived from stratified Morse theory. Algorithms have been fully implemented for objects with smooth and polyhedral convex hulls. As examples from the implementation demonstrate, calcu lating these regions from a geometric model is computationally practical.
Communication
Authors: Rossi Mauro , Wang David , Kai Zuo
Published: March 2007

In this article, issues in the design of passive controllers for a class of multilink manipulators with the last link flexible are discussed. It is well known that for the single flexible-link manipulator, the mapping from the input torques to the joint ve locities is passive, whereas the mapping from the input torques to the derivative of net-tip movements (the usual output chosen) is not. However, if an appropriate output variable is selected, the transfer function can be made passive, provided that the hub inertia seen by a flexible link is sufficiently small. Then, by the Passivity theorem, using any strictly passive controller with finite gain will result in an L2-stable system. However, for a multilink industrial robot, the effective hub inertia seen by the flexible link is usually large. In addition, the dynamic equations are highly nonlinear. Approaches are examined for extending these passivity results to multilink manipulators. Experimental results are presented for a five-bar-linkage manipulator with the last link being flexible.
PD Control with Desired Gravity Compensation of Robotic Manipulators
Authors: Kelly Rafael
Published: March 2007

One of the simplest position controllers for robot manipula tors is the PD control with desired gravity compensation. The objective of this article is to review important aspects of this control scheme that are reported in the literature. We begin by showing the boundedness of solutions for the closed-loop system, and conditions for equilibrium uniqueness. The global asymptotic stability analysis provided by Takegaki and Arimoto (1981) is discussed in detail, as well as an alternative method that uses a strict Lyapunov function. The stability robustness of the control system against parametric uncertainties is also ad dressed. We show that interesting phenomena such as equilibria bifurcation can appear if the design procedure is violated. To overcome parametric uncertainties, we review an adaptive ver sion of the PD control with desired gravity compensation, and finally, we revise an extension of the controller to handle robots with elastic joints.
Information Invariants for Distributed Manipulation
Authors: Donald Bruce Randall , Jennings James , Rus Daniela
Published: March 2007

In Donald (1995), we described a manipulation task for coop erating mobile robots that can push large, heavy objects. There, we asked whether explicit local and global communication between the agents can be removed from a family of pushing protocols. In this article, we answer in the affirmative. We do so by using the general methods of Donald (1995), analyzing information invariants.

We discuss several measures for the information complexity of the task: (1) How much internal state should the robot retain? (2) How many cooperating agents are required, and how much communication between them is necessary? (3) How can the robot change (side effect) the environment to record state or sensory information for performing a task? (4) How much information is provided by sensors? and (5) How much computation is required by the robot? To answer these questions, we develop a notion of information invariants. We develop a technique whereby one sensor can be constructed from others by adding, deleting, and reallocating 1) through 5), among collaborating autonomous agents. We add a resource to measures 1) through 5) and ask: 6) How much information is provided by the task mechanics? By answering this question, we hope to develop information invariants that explicitly trade- off resource 6) with resources 1) through 5). The protocols

we describe here have been implemented in several different forms, and we report on experiments to measure and analyze information invariants using a pair of cooperating mobile robots for manipulation experiments in our laboratory.
Vision and Motion Planning for a Mobile Robot under Uncertainty
Authors: Miura Jun , Shirai Yoshiaki
Published: March 2007

This article describes a framework for vision and motion plan ning for a mobile robot. The robot's task is to reach the desti nation in the minimum time while detecting possible routes by vision. Since visual recognition is computationally expensive and the recognition result includes uncertainty, a trade-off must be considered between the cost of visual recognition and the effect of information to be obtained by recognition. Using a probabilistic model of the uncertainty of the recognition result, vision-motion planning is formulated as a recurrence formula. With this formulation, the optimal sequence of observation points is recursively determined. A generated plan is globally optimal, because the planner minimizes the total cost. An effi cient solution strategy is also described that employs a pruning method based on the lower bound of the total cost calculated by assuming perfect sensor information. Simulation results and experiments with an actual mobile robot demonstrate the feasibility of our approach.
Model-Based Planar Contour Following in the Presence of Pose and Model Errors
Authors: Demey Sabine , Bruyninckx Herman , De Schutter Joris
Published: March 2007

This article shows how the use of a geometric model during planar contour following with a force-controlled robot results in a higher quality (i.e., faster and/or more accurate) task execution, even in the presence of pose and model errors. Neither the pose (i.e., position and orientation) of the contour nor the starting point on the contour have to be known in advance.

The contour is described by curvature and/or orientation of the normal direction, as a function of arc length. The con tour is identified on-line from the sensor measurements, and matched on-line with its model. This yields an estimate of the point in the model that corresponds to the real contact point. The curvature from the model is then used to generate feed- forward velocity set points.

The article compares a nonrecursive deterministic least- squares matching strategy with recursive stochastic matching strategies, based on the extended Kalman filter and the Page- Hinkley hypothesis test. Matching is preferably based on cur vature profiles, since these are Euclidean invariant and hence reduce the search space of the matching. On contours with piecewise constant curvature, however, the extended Kalman- filter strategy uses the orientation of the normal direction. Extensive experimental evaluation of these strategies is given, including shape matching based on data during a deburring task.

1. The definition of this tangent frame is based on the Frenet frame; see Section 2.1.

2. Curvature, arc length, and orientation of the normal are defined in Section 2.1.
A Study of Socio-Demographic Characteristics of Individuals Evaluated for Insanity
Authors: Rogers Richard , Seman William , Stampley Jan , Rogers Richard
Published: March 2007

Social and demographic characteristics were com pared for 115 clinically evaluated and legally adjudicated on the issue of sanity. Prior history of schizophrenia, previous treat ment with psychoactive medication, absence of alcoholism, and completion of high school were all associated with individuals being clinically evaluated and legally adjudged insane. These and other findings were discussed with respect to the current research on insanity determinations.
Murder and Insanity: 19th Century Perspectives from the "American Journal of Insanity"
Authors: Pankratz Loren
Published: March 2007

Articles over 100 years old on murder and insanity were reviewed from the "American Journal of Insanity". Signs and patient behaviors that today would not be considered definitive of mental illness were then frequently cited by the alienist (psychiatrist) as evidence of insanity. Further, certain diagnostic labels were created and used in court because they "explained" reprehensible acts. However, courts were generally reluctant to accept labels and theories without the public history of severely disordered behavior. The review provided a sense of the enduring value of the judicial system.
A Descriptive and Comparative Cohort Analysis of High School Delinquency in a Small Town
Authors: Green Gary S.
Published: March 2007

Police contact with two small, male high school cohorts from a rural county is described and cautiously com pared with police contacts in the larger, urban male cohort study by Wolfgang, Figlio and Sellin. High school-aged males in both studies seem to have similar characteristics, particularly in regard to the amount of "harm" inflicted by officially recorded acts. In the present study, about one boy in four has at least one officially recorded police contact during high school. Some juvenile justice policy implications (involving desistance rates) are discussed. The problems associated with cohort research based on official records and comparisons between cohorts are addressed.
Group Therapy as a Means of Learning About the Sexually Assaultive Adolescent
Authors: Margolin Leslie
Published: March 2007

This paper attempts to show that traditional methods of gathering information are inadequate with regard to the adolescent sex offender. A new approach to learning about this type of individual is described which relies on self-disclosure in a group therapy context. Case illustrations are provided which suggest that group therapy generates information which is dramatically different from what is usually obtained by means of the individual interview, police report, or victim survey.
Jury To Judge Sentencing
Authors: Stevens Edward H.
Published: March 2007

This paper presents data and analysis concerning the effect of change in criminal sanctioning authority in the State of Alabama. The data indicate that judges impose longer sentences than juries, but they are less influenced by the race of the defendent. While the recent policy change has brought positive results, unanticipated consequences also occurred. It is suggested that further reform in Alabama sentencing procedure is required.
A Clinical Study of Male Adolescent Sexual Offenders
Authors: Saunders Elisabeth , Awad George A. , Levene Judy
Published: March 2007

A study comparing twenty-four male juvenile sex offenders and twenty-four other delinquents matched for age and social class showed few differences between the two groups. The differences indicate a higher prevalence of middle class boys, lower intellectual functioning and less incidence of truancy, alcohol abuse and temper tantrums among the sex offenders. The possible explanations of such findings are discussed.
Realism and Reification in the Ethnographic Genre
Authors: Webster Steven
Published: March 2007

This essay considers, from the vantage point of critical theory, some of the implications of an ethnographic genre of realism. Following Raymond Williams's discussion of the contemporary meanings of 'realism' in terms of attitudes towards the world and toward representations of it, I suggest that the current predicament of ethnography is to have purveyed a particular form of realism without awareness of the representational conventions with which it has done this, and foresee some reactions to any new awareness. To pursue this, I interpret Williams's discussion of the meanings of realism in the light of Benjamin's and Lukács's critiques of ideology in literary discourse. Then I discuss two recent analyses of ethnography as a genre, and suggest that ethnographic realism has developed in the specific sense of a reifying and critically impotent naturalism, and that as a scientific discourse this has paralleled literary realism rather as an inversion or a negation of it. The implicit concern of the two recent analyses with the historical development of the genre is pursued to suggest contradictions within and external to the formation of the ethnographic tradition, which further outline the general cultural hegemony of which it is a part.
Honour as a Red Herring
Authors: Lever Alison
Published: March 2007

Ideals relating to 'honour' and 'shame' have been presented by anthropologists as components of a shared value system which is typical of Mediterranean communities. Critics such as Herzfeld (1980) and Davis (1977) have noted respectively that concern with social standing linked to definitions of what constitutes socially desirable behaviour are not characteristics confined to the Mediterranean area, and that material considerations are inextricably linked to 'honour'

Research in the Castilian pueblo of San Santiago suggests that writers on honour/shame value systems in Spanish pueblos have tended to concentrate on the values of middle aged married men who are fathers and who carry economic weight in pueblos, with regard to each other. We have been told less of their views with regard to those in different age, family position, and gender categories, and in different classes. Furthermore, these others may merely pay lipservice to the values of dominant groups, while holding very different views themselves. The argument presented here is that the way values have been described by many anthropologists has been misleading, and that honour/shame has become a 'red herring', distracting attention from the values of non-dominant groups, as well as failing to account for the way values change.
The Underclass, 'Social Isolation' and 'Concentration Effects'
Authors: Maxwell Andrew H.
Published: March 2007

Increasing impoverishment in inner-city localities has prompted the development of new concepts such as William Julius Wilson's 'social isolation' and 'concentration effects'. It is said that these concepts refer to the community-level effects of economic restructuring in the United States. For this reason it is argued that such concepts differ from Oscar Lewis's 'culture of poverty' notion; they do not imply a self-perpetuating, autonomous cultural entity. Nevertheless, Wilson's work is being fiercely debated. In attempting to clarify this aspect of the discussion I will examine the conceptual foundations of Wilson's view of 'the underclass'.
The Localization of Anthropological Practice
Authors: Mintz Sidney W.
Published: March 2007

■ By examining the history of migration in the 19th century, the author finds grounds for contending that the view of transnationalism as a qualitatively different phenomenon is exaggerated, and the rejection of such terms as 'com munity', 'culture' and 'region' unnecessary or premature. The Caribbean region emerges as representative of an earlier transnational (or international) era, beginning with conquest, enslavement and the plantation economy.
Colonial Encounters in Postcolonial Contexts
Authors: Cunningham Hilary
Published: March 2007

■ The Human Genome Diversity Project (HGDP) has raised some sig nificant ethical and methodological issues for anthropologists, particularly in light of the recent patenting of a cell-line from a Papua New Guinea man. Through a discussion of the HGDP, this article explores the 'locatedness' of the anthropologist in light of two significant trends: the globalization of the economy (particularly in the areas of intellectual property rights and biotechnology patents) and the creation of a new global context for political activism. The article concludes by discussing the concept of 'collaboration' as a politically- embedded practice that has become critical to the pursuit of contemporary anthropological knowledge.
The Mexican Contribution to Restructuring US Capitalism
Authors: Gledhill John
Published: March 2007

■ This article analyzes the history of Mexico-US migration in relation to the contemporary social impacts of labor market restructuring, relocation of production, and global lifestyle and real estate investments in the transnational space defined by NAFTA. Mexico is not simply a supplier of cheap labor that enables US capital to confront globalization. Economics is entangled in politics and a specific history of racialized labor markets, neocolonialism and nation- state construction. The sectors of Mexican capital that benefit from NAFTA are as mobile as US capital and integrated with it, whilst segmentation of the migrant population has been exacerbated by the changes of the past two decades. Multiple contradictions are transforming economic, social and politi cal life throughout the NAFTA region, but although the social consequences of neoliberalism have diminished Mexico's governability, the key issue is whether local social movements and transnational coalitions can modify this regime of accumulation.
For Whom the Taco Bells Toll
Authors: Gutmann Matthew C.
Published: March 2007

■ This article explores recent forms of Mexican popular nationalism in the wake of the North American Free Trade Agreement. Drawing on ethno graphic research in a colonia popular of Mexico City, I maintain that analyses of nationalism and class, including within critical theory, should re-examine cul tural questions pertaining to national sovereignty within contemporary globaliz ation. Responses to the Free Trade Agreement among the urban poor in Mexico, for instance, indicate a growing disparity between elite and popular perceptions regarding issues such as democracy and nationalism. Although grassroots leftist politics in the last two decades have been successful in overcoming a previous neglect of daily needs and realities for the poor, the article also argues that recent popular social movements have too often ignored debate on questions of trans nationalism and nationalism.
The Story of Cain and Abel: a Narrative Study
Authors: van Wolde Ellen
Published: March 2007

The story of Cain and Abel is a concise short story marked by an elliptic use of language. A narrative study of the actions of the three protagonists YHWH, Cain and Abel demonstrates that the actions of (not) looking are the main ones. These actions are all concerned with the theme of brotherhood. YHWH is the only one in this story who is paying attention to Abel, the so-called worthless one. Even the narrator is not paying much attention to him. Both YHWH's actions and the narrative ellipses intend to persuade the readers to follow YHWH's preference for the weak brother.
Freedom or Knowledge? Perspective and Purpose in the Exodus Narrative (Exodus 1-15)
Authors: Eslinger Lyle
Published: March 2007

In this article I focus on a neglected aspect of the exodus story. The fact that the story dwells on absolute divine control over all aspects of these events, especially the minds and hearts of Israel's Egyptian captors, suggests that our reading of the well- known theme of liberation needs be tempered by the dominant theme of omnipotence and its revelation to humankind. The well-being of Israel and its Egyptian partner is clearly subordinate to Yahweh's overarching goal: 'that ye may know how that I am the LORD' (Exod. 10.2). Such a reading suggests that we take a little less heart from the story and come away with a little more fear and trembling.
The Redaction of Daniel
Authors: Miller James E.
Published: March 2007

The bilingual book of Daniel results from the redacting together of two books of Daniel, one in Hebrew and one in Aramaic. Dan. 7.1-2a is a late addition to the book, and once this text is removed the distinct character of the two source books becomes clear. The bilingual book of Ezra had the role of model and legitimator. The problem of the bilingual ch. 2 is solved by postulating two versions of this story, one in each book. Given two versions of ch. 2, a chiastic structure for the Hebrew book may be demonstrated to complement a similar structure in the Aramaic book.
Role Dedifferentiation in the Book of Ruth
Authors: Berquist Jon L.
Published: March 2007

Recent studies of Ruth have rightly emphasized the narrative nature of this short story, but sociological analysis also offers helpful tools for the interpretation of Ruth. The concept of role provides a locus of possible integration. Since the book of Ruth is literature, the figures within this book's story undergo characterization, depicting and developing their roles within the story. Within this narrative world, the characters appear as social actors and their behavior conforms to recognizable social processes within definable social roles. Thus, the gender roles of the characters exhibit a social function of dedifferentiation, as role segments typically considered male or female are interchanged.
No Prophets? Recent Developments in Biblical Prophetic Research and Ancient Near Eastern Prophecy
Authors: Barstad Hans M.
Published: March 2007

Recently, scholars like Auld and Carroll have advocated the view that we can learn little or nothing about ancient Israelite prophecy from the so-called prophetic books of the Hebrew Bible, and that the biblical prophets are not really 'prophets', but 'poets'. Taking its starting point from the recent discussion of biblical prophecy, the present article argues for the necessity of a phenomenological, rather than a narrowly historical, approach, and for the necessity of taking other ancient Near Eastern prophetic texts into consideration. Following this approach, the author seeks to demonstrate that we can actually learn a great deal about ancient Israelite prophecy from the biblical books.
Portraying Prophecy: of Doublets, Variants and Analogies in the Narrative Representation of Jeremiah's Oracles—Reconstructing the Hermeneutics of Prophecy
Authors: Diamond A.R. Pete
Published: March 2007

The search for consistency of theme in Jeremiah's message to the post-597 BCE community in Jerusalem has seemed almost impossible to discern. Current redaction- critical study resolves this problem by analyzing the extant narrative into discreet self- consistent editorial layers. This, however, raises the question of why the ancient editor(s) would have expected the narrative to be readable in its present form. Differences in the underlying hermeneutics of prophecy are suggested. Analyzing the narrative management of prophetic oracles in the tradition elucidates the way in which the editors' assumptions about the nature of prophecy shaped their portrayals. The existence in the tradition of inconsistent oracles is rationalized in a framework of moral contingencies. Moral contingency played out against the matrix of Deuteronomistic assumptions about prophecy enables the editor(s) to synthesize variant postures of the prophet into a coherent tableau that is subordinated to his/their rhetorical ends.
What If Dinah Is Not Raped? (Genesis 34)
Authors: Bechtel Lyn M.
Published: March 2007

From a modern, predominantly 'individual-oriented' perspective it is assumed that Shechem rapes Dinah. But is this what the story intends to portray? The conclusion, after a careful analysis of the story and its group-oriented dynamics, is that Dinah is not 'raped'. Instead, the story portrays Dinah and Jacob as folks who are interested in interacting with outsiders (Shechem, Hamor and the Shechemites) that show allegiance to their group values and customs. But Simeon, Levi and the sons of Jacob are militant folks who arc threatened by the impure outsiders and want to maintain strict group purity and absolute separation. The story challenges this isolationist attitude by showing its potential danger for the overall group.
Living in a Land of Epithets: Anonymity in Judges 19-21
Authors: Hudson Don Michael
Published: March 2007

Recently, scholars such as Cheryl Exum and Mieke Bal have utilized a literary method for understanding the peculiar narrative technique of the Judges corpus. Exum explains that the narrator is utilizing the disintegration of his own plot to exhibit the dissolution of Israel's society, and Mieke Bal emphasizes the 'incoherence' of chronology as a means rather than an obstacle to understanding Judges. Moreover, I am suggesting that the narrator is applying disintegrating characterization to reflect a macabre society in which individuals dehumanize. This dehumanizing propelled the entire nation toward internal, self-imposed exile. Furthermore and more importantly, the narrator employs the concept of anonymity as a major literary technique to display both the universality of 'every one doing right in his own eyes' and the annihilation of the identity of the powerless individual which leads to the dismemberment of familial, tribal and national wholeness. Anonymity in Judg. 19-21 as a literary technique symbolizes and epitomizes the gradual, downward spiraling disintegration that is occurring increasingly throughout the narrative until the community faces radical anarchy in chs. 17-21.
Who's Afraid of Feminist Criticism? Who's Afraid of Biblical Humour? the Case of the Obtuse Foreign Ruler in the Hebrew Bible
Authors: Brenner Athalya
Published: March 2007

Several foreign rulers (Egyptian, Moabite, Cannanite, Persian, 'Babylonian' and Israelite) are configured in the Hebrew Bible as obtuse. This paper explores the configuration from two perspectives: humour and feminist concerns. The foreign rulers are presented as ludicrous, with bitter humour bordering on malice and contempt for their (im)potence. Their reported inadequacy is satirized by scornful allusions to their maleness and male sexuality, at times also to their bodily functions. These rulers' ineptitude is negatively mirrored by their relations with women and the latter's smarter actions. The configuration discloses the political and gender ideologies it is grounded in. 'Foreign' means a threat; humour is an important weapon for the politically powerless. Females are inferior social agents, and their resourcefulness amplifies male (foreign) shortcomings.

The reading offered is corroborated by the exclusion of the offensive materials from Flavius Josephus's recounting of the relevant texts.