bluuebunny/crossref_metadata_2025 huggingface dataset:
An "Interesting" Strange Attractor in the Dynamics of a Hopping Robot
Authors: Vakakis A.F. , Burdick J.W. , Caughey T.K.
Published: March 2007

This article applies discrete dynamical systems theory to the dynamic analysis of a simplified vertical hopping robot model that is analogous to Raibert's hopping machines. A Poincaré return map is developed to capture the dynamic behavior, and two basic nondimensional parameters that influence the systems dynamics are iden tified. The hopping behavior of the system is investigated by constructing the bifurcation diagrams of the Poincaré return map. The bifurcation diagrams show a period-dou bling cascade leading to a regime of chaotic behavior, where a "strange attractor" is developed. An interesting feature of the dynamics is that the strange attractor can be controlled and eliminated by tuning an appropriate parameter corresponding to the duration of applied hop ping thrust. Physically, the collapse of the strange attrac tor leads to a globally stable period-1 orbit, which guar antees a stable uniform hopping motion.
Robot Motion Planning: A Distributed Representation Approach
Authors: Barraquand Jérôme , Latombe Jean-Claude
Published: March 2007

We propose a new approach to robot path planning that consists of building and searching a graph connecting the local minima of a potential function defined over the robot's configuration space. A planner based on this approach has been implemented. This planner is consider ably faster than previous path planners and solves prob lems for robots with many more degrees of freedom (DOFs). The power of the planner derives both from the "good" properties of the potential function and from the efficiency of the techniques used to escape the local min ima of this function. The most powerful of these tech niques is a Monte Carlo technique that escapes local min ima by executing Brownian motions. The overall approach is made possible by the systematic use of distributed rep resentations (bitmaps) for the robot's work space and configuration space. We have experimented with the plan ner using several computer-simulated robots, including rigid objects with 3 DOFs (in 2D work space) and 6 DOFs (in 3D work space) and manipulator arms with 8, 10, and 31 DOFs (in 2D and 3D work spaces). Some of the most significant experiments are reported in this article.
Manipulator Inverse Kinematics for Untimed End-Effector Trajectories With Ordinary Singularities
Authors: Kieffer Jon
Published: March 2007

This article addresses the following inverse kinematics problem: given an untimed spatial end-effector trajectory, determine joint trajectories that are consistent with its execution. An algorithm for the continuous iterative solution of this problem for six-degree-of-freedom manipulators of arbitrary structure is presented.

The main idea of this algorithm is that it converges with equal ease at both regular configurations and certain ( "or dinary ") singularities. Ordinary singularities (herein defined) depend on the given end-effector trajectory, as well as the ma nipulator configuration, and represent "dead points" where the end effector (but not the manipulator) must pause during trajectory execution.

The algorithm is based on the predictor-corrector method of path following using (1) a newly developed second-order predictor, (2) a first-order Newton method corrector, and (3) the idea of including the end effector's position (along its trajec tory) as a dependent (rather than independent) variable in the formulation. Both the predictor and the corrector are derived from Taylor series expansion of the 4 x 4 matrix equation of closure and require only the solution of linear systems of equations.

Examples are given that demonstrate the algorithm's ability to pass through ordinary singularities to determine alternate joint trajectories for the same end-effector trajectory. These examples also show how ordinary singularities can be included in manipulator motions that are similar to a boxer's jab or a runner's kick.
Gross Motion and Classification of Manipulators with Closed-Loop, Four-Bar Chains
Authors: Ting Kwun-Lon
Published: March 2007

This article presents an extensive study on the gross motion of 2-DOF manipulators with closed-loop, four-bar chains. The investigation is focused on (1) classification, (2) work space and sub-work space, (3) existence of singular circles, (4) number of postures and service angles, and (5) the effects of the orientation of the wrist on the floating link. One may find that closed-loop manipulators are not only lightweight, they can also provide better kinematic properties in view of work space, singularity, postures, and service angles.
Tracking Control of a Miniature Flexible Arm Using Piezoelectric Bimorph Cells
Authors: Jiang Z.W. , Chonan S. , Tani J.
Published: March 2007

A theoretical and experimental study is presented for the end- point control of a slender flexible arm driven by piezoelectric bimorph cells. A discrete-time formulation is presented for the arm-cell system and applied to the problem of moving the arm so that the tip closely tracks the fluctuation of target. The tip displacement (versus time) is compared with the target fluctuation, and the tip position error is used, together with other estimated system states, as the basis for applying control voltage to the cells. Both simulation and experimental results show that the PID control using the piezoelectric cells as the actuators is sufficient to make the arm tip follow the fluctuation of target precisely.
Self-Tuning Control of a Two-Link Manipulator With a Flexible Forearm
Authors: Koivo A.J. , Lee K.S.
Published: March 2007

The control of the motion of a two-link manipulator with a flex ible forearm is studied. The first link is rigid, and the second link has a flexible part as an extension of a rigid part. The motion of the manipulator takes place on a horizontal plane. The dynamics of the two-link manipulator with a flexible fore arm are determined in Lagrange's formulation. The positions of specified points on the flexible forearm are obtained from the strain gauge measurements and the positions of the joint vari ables. The inputs are applied to the actuators of the revolute first joint and the prismatic link.

For the controller design, a time series multivariate model of the autoregressive exogenous (ARX) type is used to describe the input/output relation. The discounted least squares method is used to estimate the parameters of the time series model. A self-tuning controller is so designed that the positions of the specified points on the flexible forearm track the given trajectory points. The controller operates on the Cartesian coordinates, which specify the positions of the chosen points on the flexible forearm.

Simulation results as well as laboratory experiments on a Stanford/JPL arm controlled by a self-tuning controller are presented to illustrate the approach.
Randomization in Robot Tasks
Authors: Erdmann Michael
Published: March 2007

This article explores the role of randomization in the solution of robot manipulation tasks. Randomization refers to the ran dom selection and execution of an action from a collection of possible actions. The intention is that this collection contains some actions that are useful for making progress toward ac complishing a task, but that the precise identity of these useful actions is unknown. Randomization offers one approach for ensuring progress in a probabilistic sense.

An example of randomization is given by the strategy of shaking a bin containing a part in order to orient the part in a desired stable state with some high probability. Another exam ple consists of using reliable sensory information to bring two parts close together, then relying on short random motions to actually mate the two parts once the part motions lie below the available sensing resolution. Further examples include tapping parts that are tightly wedged, twirling gears before trying to mesh them, and vibrating parts to facilitate a mating operation. Randomization is also useful for mobile robot navigation and as a means of guiding the design process.

Randomization is useful in three basic ways. First, random ization can increase the class of solvable tasks. This is because a randomized strategy need not guarantee task success with certainty in a specific number of steps, relying instead on re peated execution of the randomizing actions to accomplish the task in an expected sense. Second. randomization can reduce a strategy's knowledge requirements. This is because randomiza tion can tolerate and circumvent local failures, thereby making a strategy less sensitive to task details. Third, randomization can simplify the planning and execution process. This is be cause a randomized solution may be able to ignore precise prediction of special case scenarios, instead simply ensuring eventual accomplishment of the task independent of the actual scenarios encountered.
Kinematic Analysis of 7-DOF Manipulators
Authors: Kreutz-Delgado Kenneth , Long Mark , Seraji Homayoun
Published: March 2007

This article presents a kinematic analysis of seven-degree-of- freedom serial link spatial manipulators with revolute joints. To uniquely determine the joint angles for a given end-effector position and orientation, the redundancy is parameterized by a scalar variable that defines the angle between the arm plane and a reference plane. The forward kinematic mappings from joint space to end-effector coordinates and arm angle and the augmented Jacobian matrix that gives end-effector and arm angle rates as functions of joint rates are presented. Conditions under which the augmented Jacobian becomes singular are also given and are shown to correspond to the arm being either at a kinematically singular configuration or at a nonsingular configuration for which the arm angle ceases to parameterize the redundancy.
Passive Control of a Stiff Flexible Link
Authors: Wang David , Vidyasagar M.
Published: March 2007

It is demonstrated in the article that, for an appropriately chosen output variable, the transfer function for a sufficiently rigid single flexible link is passive. As such, by the passivity theorem, using any strictly passive controller with finite gain will result in an L2 -stable system. One approach to designing such a controller is outlined, and the experimental results are presented. The implications of this work are examined, and future research issues are discussed.
A Compact Inverse Velocity Solution for Redundant Robots
Authors: Kumar Vijay
Published: March 2007

A compact inverse rate kinematics solution for serial-chain, redundant, n-jointed robots is presented. The serial-chain inverse rate kinematics problem is dual to the inverse statics problem in in-parallel systems such as cooperating robots, in which the task of distributing the load wrench between multiple subsystems is typically underspecified. Therefore, methods for obtaining the wrench distribution in an in-parallel system can be applied to the underconstrained inverse kinematics problem for serial-chain manipulators. In particular, a solution that minimizes a weighted-norm of the joint rates vector is derived in this article. The advantages of this method are the ability to accommodate any type of joint and the availability of analytical, closed-form solutions for the joint rates. Finally, a geometric interpretation of the solution is provided using screw system theory.
Rigid Body Collisions of Planar Kinematic Chains With Multiple Contact Points
Authors: Hurmuzlu Yildirim , Marghitu Dan B.
Published: March 2007

This article deals with the rigid body collisions of planar kine matic chains with an external surface while in contact with other surfaces. Two solution procedures that cast the impact equations in differential and algebraic forms are developed to solve the general problem. The differential formulation can be used to obtain three sets of solutions based on the kinematic, kinetic, and energetic definitions of the coefficient of restitution, whereas the algebraic formulation can be used to obtain solu tions based on the approaches presented in Whittaker (1904) and Brach (1991). A specific example of a planar three-link chain with two contact points is studied to compare the out comes predicted by each approach. A particular emphasis is placed on the energy loss that results from the application of each solution scheme. The circumstances in which various methods lead to identical or distinct outcomes are investigated. Most importantly, the study elaborates on the rebounds at the noncolliding ends, a phenomenon that is observed only in multicontact collisions. The interaction of the chain with the contact surfaces at the noncolliding contact points is examined, and the differences in the prediction of rebounds that arise from using various methods are investigated.
Near-Minimum-Energy Paths on a Vertical-Axis Cone With Anisotropic Friction and Gravity Effects
Authors: Rowe Neil C. , Kanayama Yutaka
Published: March 2007

We determine near-optimal paths with respect to work against friction and gravity on the surface of a vertical-axis ideal cone, assuming a moving agent of negligible size, friction propor tional to the normal force, and power-maximum and stability limitations on the agent. This can provide good paths across hilly terrain for mobile robots. Our previous work required difficult-to-obtain polyhedral terrain models; cone surface patches permit easier and better models. We prove that our near-optimal paths on a vertical-axis cone surface are not much more complex than on polyhedra: There are qualitatively 22 kinds of path behavior (as opposed to four on a polyhedral face), and the area of the surface optimally reachable from a fixed start point by a given qualitative behavior has mathemat ically simple boundaries (only line segments, circle arcs, and arcs of logarithmic spirals in azimuth projection). We examine the possible cases based on agent characteristics and cone steepness and provide "behavior maps" for quickly finding near-optimal paths between any two points on the cone surface. Our models incorporate discontinuous effects with respect to traversal heading. Comparisons with a program using uniform- grid path planning show our methods run considerably, faster in less space, and our paths are much simpler to describe and easier to follow in the real world.
Path-tracking for a Tractor-Trailer-like Robot
Authors: DeSantis R.M.
Published: March 2007

Path-tracking controllers for tractor-trailer-like robots are de signed by generalizing the geometric path-tracking approach currently adopted for car-like robots. This is done by formaliz ing the concepts of speed and lateral and heading offsets and by assuming slippage-free motion. The main result is that for straight-line or circular-arc paths to be tracked with a con stant velocity, path-tracking may be ensured by means of a linear, time-invariant, and decoupled controller, the gains of which may be determined using familiar proportional-integral- derivative (PID) and state-feedback techniques.
On the Workspace of General 4R Manipulators
Authors: Ceccarelli Marco , Vinciguerra Adalberto
Published: March 2007

The workspace of a general 4R manipulator is analyzed by examining its cross-section evaluation to investigate its main characteristics and how they are affected by link parameters. An algebraic formulation is deduced for a workspace boundary of a general 4R manipulator from the geometry of an enve lope generation. This algebraic formulation is also useful for direct computation of the workspace volume and for detection of holes and voids. In addition, both analysis and synthesis cri teria are deduced from this algebraic formulation, taking into account the geometric nature of the 4R manipulator workspace as a volume of revolution. Several numerical examples show general geometries of 4R manipulator workspaces.
Two-Handed Assembly Sequencing
Authors: Wilson Randall H. , Kavraki Lydia , Latombe Jean-Claude , Lozano-Pérez Tomás
Published: March 2007

This article considers the computational complexity of automat ically determining assembly sequences for mechanical products. Specifically, we address the partitioning problem: given an assembly of rigid parts, identify a proper subassembly that can be removed as a rigid object without disturbing the rest of the assembly. We examine the complexity of the partition ing problem under various types of relative motions allowed for the subassemblies. We show that when arbitrary motions are allowed to separate the two subassemblies, partitioning is NP-complete.

We then describe a general framework for reasoning about assembly motions called the interference diagram. In its most general form the interference diagram yields an exponential- time algorithm to partition an assembly. However, two special cases of the interference diagram studied in this article yield polynomial-time sequencing algorithms. The first case occurs when assembly motions are restricted to single translations. The second case considers infinitesimal rigid motions in translation and rotation and yields a superset of all feasible partitionings. These two algorithms have important practical applications in assembly planning.
Feedback Control of a Nonholonomic Underwater Vehicle With a Constant Desired Configuration
Authors: Egeland O. , Dalsmo M. , Sørdalen O.J.
Published: March 2007

In this article we present a feedback control law that gives exponential convergence of a nonholonomic underwater vehicle to a constant desired configuration. This is achieved using a piecewise smooth feedback control law that is based on previous work on the control of nonholonomic mobile robots in the plane. The kinematic model of the underwater vehicle is given in SE(3) by homogeneous transformation matrices, and attitude deviations are given by Euler parameters. This gives a global description without singularities. It is also shown how controllability of the nonholonomic underwater vehicle can be analyzed in SE(3) without the use of local charts. The inputs of the system are the three angular velocity components and the forward velocity.
Liapunov Stability of Force-Controlled Grasps with a Multi-Fingered Hand
Authors: Jen Fuhua , Shoham Moshe , Longman Richard W.
Published: March 2007

Holding an object stably is a building block for dexterous ma nipulation with a multi-fingered hand. In recent years a rather large body of literature related to this topic has developed. These works isolate some desired property of a grasp and use this property as the definition of stable grasp. To varying degrees, these approaches ignore the system dynamics. The purpose of this article is to put grasp stability on a more basic and fundamental foundation by defining grasp stability in terms of the well-established stability theory of differential equations. This approach serves to unify the field and to bring a large body of knowledge to bear on the field. Some relationships be tween the stability concepts used here and the previously used grasp stability concepts are discussed. A hierarchy of three levels of approach to the problem is treated. We consider that the grasp force applied is a basic consideration, in terms of ensuring both that there is sufficient force to prevent dropping the object and that the forces are not too large to cause break age. As a result, we first investigate the use of constant force grasps. It is shown that with the proper combination of finger locations and grasp forces, such grasps can be Liapunov sta ble, and methods are presented that help find such grasps. It is also shown that such grasps cannot be asymptotically stable. To produce asymptotic stability, one must alter the forces ap plied to an object when the object deviates from equilibrium, and a linear feedback force law is given for this. It results in local asymptotic stability guaranteeing convergence to the desired grasp equilibrium from all states within a region of attraction in the state space. Some of the results are similar to results obtained previously, but this time they have a stronger meaning in terms of the dynamic response of the system. In the third level, a nonlinear force law is given that, to within certain limitations, produces global asymptotic grasp stability, so that all initial states are guaranteed to converge to the de sired grasp equilibrium. The method is robust to large classes of inaccuracies in the implementation.
Stabilization of Flexible One-Link Arm Position: Stability Domains in the Space of Feedback Gains
Authors: Formal'sky A.M. , Lavrovsky E.K.
Published: March 2007

A one-link flexible arm with a load at the end is considered. The arm can be rotated around its hub in a horizontal plane. This rotation is actuated by a DC motor. The dynamics of a controlled flexible arm are described by an infinite-dimensional mathematical model, which contains the Bernoulli-Euler beam equation, equations of the actuator motion and boundary con ditions. The control voltage fed to the motor is a linear com bination of arm angular position, integral, rotation speed, arm deformations, tip position, and velocity.

The principal goal of the article is to find linear feedback gains such that the desired arm position is asymptotically sta ble. This problem of stability arises when an elastic manipula tor is designed. We have analytically described the boundaries of the domains of asymptotic stability in the space of feedback gains and constructed these domains in different cases. It is shown that the stability domains for a flexible arm belong to and are less than the corresponding domains for a rigid arm. We have shown that under feedback on tip position and veloc ity, the one-link flexible manipulator is unstable if damping is small.
Designing Fault-Tolerant Manipulators: How Many Degrees of Freedom?
Authors: Paredis Christiaan J. J. , Khosla Pradeep K.
Published: March 2007

One of the most important parameters to consider when de signing a manipulator is the number of degrees of freedom (DOFs). This article focuses on the question: How many DOFs are necessary and sufficient for fault tolerance, and how should these DOFs be distributed along the length of the manipula tor ? A manipulator is fault tolerant if it can complete its task even when one of its joints fails and is immobilized. The num ber of DOFs needed for fault tolerance strongly depends on the knowledge available about the task. In this article, two approaches are explored. First, for the design of a general purpose fault-tolerant manipulator, it is assumed that neither the exact task trajectory nor the redundancy resolution algo rithm are known a priori and that the manipulator has no joint limits. In this case, two redundant DOFs are necessary and sufficient to sustain one joint failure, as is demonstrated in two design templates for spatial fault-tolerant manipulators. In a second approach, both the Cartesian task path and the redundancy resolution algorithm are assumed to be known. The design of such a task-specific fault-tolerant manipulator requires only one degree of redundancy.
On the Quantification of Penetration between General Objects
Authors: Ong Chong-Jin
Published: March 2007

In this article, we study the characterization, properties, and limitations of a variety of measures of penetration between two general object models. Measures of penetration between convex objects have appeared in the literature. We introduce new measures of penetration for general objects, which are generalizations of those for convex objects. We illustrate by example that these new measures are more accurate estimates of penetration in the case of nonconvex objects. Several proper ties of the new measures are derived. These include continuity of the measures with respect to rotational and translational parameters of the two objects, and invariance with respect to the choice of coordinate system. Since these measures are generalizations of the measures of penetration between convex objects, properties of the new measures are also properties of the traditional measures. An important property of these new penetration measures is established: the new penetration mea sures and the traditional penetration measures are the same in the case of convex objects.
Quantitative Evaluation of the Exploration Strategies of a Mobile Robot
Authors: Lee David , Recce Michael
Published: March 2007

This article describes an experimental investigation into the map-building and exploration capabilities of a mobile robot. Two types of map are used: a set of line and point features, and a grid-based free-space map. Potential features are ex tracted from sonar range readings and classed as "confirmed" if detected repeatedly. The free-space map is derived from the set of confirmed features. A distance-transform algorithm is then used to plan paths on this map. The confirmed features are used by a Kalman filter to estimate the robot's position relative to known objects.

This research places exceptional stress on the need for practical experimentation and quantitative, statistical evaluation of the results. For this to be possible, it is essential to have a clearly defined measure of map quality. A novel metric is defined that predicts the effectiveness of the robot if it were to use the map to execute a set of test tasks.

Exploration strategies are tested experimentally in a range of environments and starting positions. The results are eval uated and compared statistically. The tested strategies range from those that are totally reactive, such as wall-following, to those that use the developing map to focus attention on the un examined parts of the environment. The most promising results are observed from hybrid exploration strategies that combine the robustness of reactive navigation and the directive power of map-based strategies.
A Model-Based Approach to Cartesian Manipulation Contact Sensing
Authors: Eberman Brian
Published: March 2007

This article describes a new statistical, model-based approach to building a contact-state observer for time-invariant con straints for a point in three dimensions. Three-dimensional constraint estimation and selection, and the application of these procedures to a planar, two-dimensional maze is described in detail. The observer uses measurements of the contact force and position, and prior information about the task encoded in a network, to determine the current location of the robot in the task-configuration space. Each node represents what the measurements will look like in a small region of configuration space by storing a predictive, statistical, measurement model. Construction of the task network requires a model of both the grasped part and the environment. The model makes the system robust to alignment errors, however, gross errors can occur if the topology of the modeled configuration space differs from the true topology. Arcs in the task network represent possible transitions between models. Beam search is used to match the measurement history against possible paths through the model network to estimate the most likely path for the robot. The re sulting approach provides a new decision process that can be used as an observer for event-driven manipulation program ming.
Configuration- Dependent Vibration Controllability of Flexible-Link Manipulators
Authors: Konno Atsushi , Uchiyama Masaru , Murakami Mahito
Published: March 2007

In this article, the structural vibration controllability of flexible- link manipulators is discussed. For some spatial flexible- link manipulators, the structural vibration controllability is configuration-dependent. Therefore, the flexible-link manipulator may have some vibration-uncontrollable configurations. To un derstand the physical interpretation of vibration-uncontrollable configurations, we propose the modal accessibility concept, which indicates how well the actuators can affect the structural vibration modes. The configuration in which all of the actua tors cannot affect at least one of the manipulator's vibration modes is vibration uncontrollable. Main contributions of this article are the following two points: first, interesting structural vibration-uncontrollable configurations are found within the two-link, three-joint-type manipulator's workspace, and are verified experimentally; second, the modal accessibility index is introduced to indicate how well the corresponding vibration mode is controllable. Experimental results show that even in the controllable configurations, it becomes difficult to suppress vibration if the modal accessibility is small.
Display of the Operating Feel of Dynamic Virtual Objects with Frictional Surfaces
Authors: Yoshikawa Tsuneo , Zheng Xin-Zhi , Moriguchi Toshiki
Published: March 2007

An approach for displaying the feel of manipulating dynamic virtual objects with frictional surfaces using a haptic display device is introduced. A unified description of the dynamics of virtual objects based on the Lagrangian formulation is derived. The detection of the grasp states, and the friction effects at the grasp points on virtual object surfaces, which are important to help us recognize an object and handle it more dexterously, are treated explicitly. Display algorithms are provided that create and present to the operator the dynamic operating feel of an object as well as the friction feel on the object 's surface. Experimental verification on the proposed approaches is performed, and its results are outlined.
Forward Dynamics, Elimination Methods, and Formulation Stiffness in Robot Simulation
Authors: Ascher Uri M. , Pai Dinesh K. , Cloutier Benoit P.
Published: March 2007

The numerical simulation problem of tree-structured multi body systems, such as robot manipulators, is usually treated as two separate problems: 1) the forward dynamics problem for computing system accelerations, and 2) the numerical integra tion problem for advancing the state in time. The interaction of these two problems can be important, and has led to new conclusions about the overall efficiency of multibody simula tion algorithms (Cloutier, Pai, and Ascher 1995). In particular, the fastest forward dynamics methods are not necessarily the most numerically stable, and in ill-conditioned cases may slow down popular adaptive step-size integration methods. This phenomenon is called formulation stiffness.

In this article, we first unify the derivation of both the com posite rigid-body method (Walker and Orin 1982) and the articulated-body method (Featherstone 1983, 1987) as two elimination methods for solving the same linear system, with the articulated-body method taking advantage of sparsity. Then the numerical instability phenomenon for the composite rigid- body method is explained as a cancellation error that can be avoided, or at least minimized, when using an appropriate version of the articulated-body method. Specifically, we show that a variant of the articulated-body method is better suited to deal with certain types of ill-conditioning than the composite rigid-body method. The unified derivation also clarifies the un derlying linear algebra of forward dynamics algorithms, and is therefore of interest in its own right.
Inmates as Clinical Sociologists
Authors: Berg Bruce L.
Published: March 2007

In spite of considerable research in the area of adolescent delinquency, there continue to be few viable delinquency prevention programs operating within the criminal justice system which draw upon substantive social scientific theory. This article reports on a dynamic inmate run delinquency preventative program currently in operation at Auburn Correctional Facility. In addition to briefly describing several of the innovative clinical sociological techniques which have emerged in this program, this article suggests some of the weaknesses which this, and similarly geared delinquency preventative programs face.
Replacing the Mind
Authors: Nugent Stephen L.
Published: March 2007

While cognitive studies have historically been regarded as falling well within the anthropological brief, there is little evidence that contemporary versions of cognitive anthropology have much bearing in other fields of cognitive study. In this article I discuss the domination within anthropology of analyses which treate cognition as a residual category, and I discuss some of the ways in which cognitive studies which have bearing on anthropological inquiry are being carried out in other disciplines. The failure of anthropology to acknowledge the reemerging cognitive sciences, it is argued, is a result of the dominance of cultural relativism, the ignoring of developments in linquistics, and the resistance to theoretical departures which challenge the integrity of conventional anthropological objects of analysis.
Postcards of Palestine
Authors: Moors Annelies , Machlin Steven
Published: March 2007

'(The visitor) ... may find amoung the beduin of Beersheba precisely the conditions that prevailed in the time of Abraham; at Bethlehem he may see the women's costumes, and, in some respects, the mode of living of the period of the Crusades; the Arab villages are, for the most part, still under mediaeval conditions; the towns present many of the problems of the early nineteenth century; while the new arrivals from Eastern and Central Europe, and from America, bring with them the activities of the twentieth century, and sometimes, perhaps, the ideas of the twenty-first.' (Sir Herbert Samuel, the first High Commissioner of Palestine during the British Mandate; in: Luke and Keith-Roach 1922: xi).
Dispatch I. Amongst 'Our Selves'
Authors: Silverman Marilyn
Published: March 2007

Dispatches is a Critique forum where contributors can comment on issues which do not necessarily fall within the scope of a scholarly article. The first Dispatch in this issue concerns hiring practices; the second concerns ethnocidal practices. Both are awkward pieces, the first revealing the drab—if still compelling—politics of recruitment and reproduction of the anthropological workforce; it also shows distress ingly clearly the kind of manipulation of ethnic stereotypes which anthro pologists frequently claim as one of the main objects of their critical ire. The second dispatch reveals some of the realpolitik aspects of 'research in exotic places', in this case the State's alliance with private mining enterprise in convincing Indian groups that their interests are best represented by a cynical and criminal fraternity.

We encourage readers to avail themselves of the Dispatches section of Critique.
The exoticizing of magic from Durkheim to 'postmodern' anthropology
Authors: de Sardan Jean-Pierre Olivier
Published: March 2007

The projection of ethnocentric prejudices on non-western cultures is common practice not only in positivist or classical 'realist' anthropology. the recent fashion of the use of the ethnographic 'I'among so-called 'postmodern' anthropologists and others - the often over-dramatized story of the anthro pologist's own experiences in a faraway society - easily leads to 'ethno egocentnsm'. Magic and religion seem to be favoured domains in this respect. The fascination among certain anthropologists with the occult, the sacred, the esoteric and the 'supernatural' tends to hide the normality and the pragmatism of many magico- religious representations and practices in African societies- the fact that these representations are part of daily life and of people's 'natural attitude'. The inevitability of the fact that the anthropologist translates from one system of meanings to another requires a break with the exoticizing stereotypes which western common sense projects on non-western cultures.
Pushing Anthropology Past the Posts
Authors: Knauft Bruce M.
Published: March 2007

This article suggests that a critical analysis of postmodem and existentialist underpinnings reveals common political and ethical problems. These problems have an unsettling legacy in contemporary cultural anthro pology and cultural studies, especially for many of those who see themselves at the cutting edge of critically reflexive representations. Against this back ground, perspectives grounded in critical humanism are better at exposing and grappling with these problems, as well as facilitating better ethnographic documentation.
State Effects on Labor Exploitation
Authors: Heyman Josiah McC.
Published: March 2007

■ The power of enforcing labor control and exploitation is often attrib uted to states. However, such claims need careful empirical and analytical verifi cation. In order to do this, we should view states 'from below', involving state agencies, state workers, and the policed population, elements that are ignored in most state theories. In the case of undocumented immigrants who cross the United States-Mexico border to work, US state actions do add to exploitation. The smuggling, transportation and job arrangements required to overcome border and interior enforcement lead undocumented immigrants to enter con spiracies to avoid the law that are, in turn, used against them in workplaces. US undocumented immigration policy seen from below is not a deliberate system for labor control, but it follows a consistent pattern of stigmatizing immigrant labor, forcing it into an exploitative underworld. This analysis unites the current anti-immigration theme in US politics and the actual persistence of illegal, exploited labor in that nation.
The Academy as Marketplace
Authors: Pi-Sunyer Oriol
Published: March 2007

As the university becomes tied to the world of work, the professor - at least in the natural and some of the social sciences - takes on the characteristics of an entrepreneur. (Clark Kerr, quoted in Harrington 1969: 142)
Prophecy in History: the Social Reality of Intermediation
Authors: Overholt Thomas W.
Published: March 2007

This study examines and attempts to rebut four arguments—the history of terminology, the problem of definition, the conventional nature of the colophons, and the literary character of the texts—that have been marshaled in defense of an hypothesis that biblical figures like Amos and Jeremiah were prophets neither in their own eyes nor in the eyes of their contemporaries. The rebuttal stresses the social reality of prophetic activity (as revealed by cross-cultural studies) and the literary genre of prophetic books (they are anthologies).
In Search of Kir Hareseth: a Case Study in Site Identification
Authors: Jones Brian C.
Published: March 2007

The Moabite city Kir Hareseth has long been identified with Kerak, a site 18 miles south of the Wadi Mujib on the east side of the Dead Sea. This identification dates back to C. Vitringa's 1714 commentary on Isaiah, and is based primarily on the Targum rendering of Kir Moab in Isa. 15.1 as karakka demoab and the equation of Kir Moab and Kir Hareseth. A close examination of the Targum evidence, however, does not bear out this identification. Tne best evidence for locating the city is the implication of the Isaiah/Jeremiah poem that the city is located somewhere north of the Mujib in the area of Heshbon, Ele-alah, Sibmah and Jazer.
Isaiah 1.1-2.4 and 63-66, and the Composition of the Isaianic Corpus
Authors: Tomasino Anthony J.
Published: March 2007

Several scholars have noted that many verbal similarities exist between Isa. 1 and Isa. 66, or 65-66. This study expands upon these observations by demonstrating that chs. 63-66 have been deliberately patterned after the opening unit of Proto-Isaiah, 1.2-2.4. Furthermore, there are some specific correspondences between chs. 1 and ch. 66 that seem to indicate that ch. 66 has been reworked by yet another author who received the text after the insertion of the secondary introduction at 2.1, which breaks up the first unit of the text. Chapter 65 also is the product of this second author, designed to expand the cultic focus of the original text of chs. 63-66.
Paradise Lost Again: Violence and Obedience in the Flood Narrative
Authors: Forrest Robert W. E.
Published: March 2007

While the stories of the so-called Primeval History (Gen. 1-11) often appear repetitious, in fact they invariably advance the theme(s) significantly. Thus, while the Flood narrative might suggest a reiteration of the theme of human disobedience, it actually offers significant variations. The introductory and concluding episodes (6.1-4 and 9.20-27), which may function like a chiasmus, suggest that illicit relationships lead inevitably to that violence which destroys creation. Specifically, the activities of the 'sons of God' mirror those of Ham with the drunken Noah, or his wife. Even perfect human obedience (Noah), which it was carlier implied might have ensured humanity's tenure in Eden, provides insufficient protection against such disorder. Hence the necessity of first covenant and then Law/Torah as structures to ensure not only the survival of creation, but to channel human violence elsewhere, and to allow humanity full access to God.
To Question an End, to End a Question: Opening the Closure of the Book of Jonah
Authors: Crouch Walter B.
Published: March 2007

The narrative of Jonah's story lacks closure, a sense of completion, a sense that nothing necessary has been omitted from the work. The book ends without a resolution to the major conflict of the narrative's plot. The reader experiences the greatest sense of closure at the end of the third chapter, with the fourth chapter, containing the final scene, re-opening the closure experienced by the reader. The lack of closure at the end of the narrative is a literary device used to involve the reader in the ideological conflict that propels the plot. The final scene blurs the narrative frame, defocalizing the internal world of the text, to focalize on the external world of the reader.
Bytdwd and Swkt Dwyd: a Comparison
Authors: Davies Philip R.
Published: March 2007

A new proposal is made for understanding the enigmatic swkt dwyd in Amos 9.11, based on a similar construction in the recently discovered Tel Dan Stela.
The Anthropology of Clothing in the Joseph Narrative
Authors: Matthews Victor H.
Published: March 2007

One motif found throughout the Joseph narrative which has not received a great deal of attention is the garment motif. Garments are central to Joseph's position within his family and in the households he serves in Egypt. In each case he is given a distinctive garment and in the first three cases he leaves it behind, initiating a status change. In the final episode, when he has revealed himself to his family and is preparing to bring them to Egypt, Joseph reverses the pattern and gives garments to others (Gen. 45.22), marking the final status change in which he becomes the master.
The Deuteronomist and Voluntary Servitude To Foreign Powers
Authors: Na'aman Nadav
Published: March 2007

There is a remarkable critical approach on the part of the deuteronomistic authors of the books of Kings (Dtr1 and Dtr2) towards the rulers in whose time Israel/Judah voluntarily became vassal to foreign powers. These rulers are Menahem and Ahaz whose reigns marked the beginning of Israel's and Judah's servitude to Assyria, and Jehoiakim, whose reign marked the beginning of Judah's vassaldom to Egypt and Babylonia. The critical attitude toward the three kings is expressed by a combination of open and hidden polemic. In marked contrast to these kings stands Hezekiah, who rebelled against Assyria and is treated favourably by the historians. The stand of the deuteronomistic historians reflects a kind of 'national' ideology which deeply influenced their depiction of all four kings.
Asaph's History of Israel (Elohist Press, Bethel, 725 Bce)
Authors: Goulder Michael
Published: March 2007

The Psalms of Asaph (Pss. 50, 73-83) are a unity. They call God's people Joseph five times (once Ephraim, Benjamin and Manasseh); they usually call God Elohim, often El; they refer repeatedly to the covenant, and to God leading his flock; they presuppose a military crisis (a ring of enemies backed by Assyria, Ps. 83); they frequently appeal to history, especially the Exodus. After the Assyrian annexations of 732 BCE, 'Joseph' was what was left—Amos calls the people Joseph too; El and El Berith belong in Shechem/Bethel; and in the 720s Israel was facing extinction. So the many historical references, from the Egyptian oppression to Solomon's empire, constitute the 'elohist' history of Israel as known in Bethel in the 720s.
The Genealogical Relationships of Jehoram and Ahaziah, and of Ahaz and Hezekiah, Kings of Judah
Authors: Etz Donald V.
Published: March 2007

The chronology of the kingdoms of Judah and Israel has been highly controversial, and remains so today. The genealogy of the kings of Judah, on the other hand, has generally been accepted without demur. Only the parentage of Athaliah has been seriously debated. Nevertheless, serious issues are evident in the data. Notable are two relationships: that of Jehoram and Ahaziah, and that of Ahaz and Hezekiah. Their ages and lengths of reign, even considering alternatives suggested by many commentators, plus additional data given in Kings and Chronicles about their fami lies, strongly suggest that these are not father-son pairs but brothers or half-brothers.
The Immorality of God: Reflections On Some Passages in Genesis, Job, Exodus and Numbers
Authors: Whybray R.N.
Published: March 2007

A number of Old Testament texts—specifically Genesis 2-3, 18.22-33, Job 1-2, Exod. 32.7-14, Num. 11, 14.11—25—are discussed which depict God as a flawed deity behaving immorally or capriciously. Two of these—Genesis 2-3 and Job 1-2 may reflect the notion, found inter alia in the Ugaritic literature, of a pantheon in which conflict takes place among its members. Genesis 18.22-33 expresses a concern about the morality of God's standard of justice. The confrontations between Yahweh and Moses in Exodus and Numbers, which appear incongruous within their wider contexts, may preserve traces of an earlier saga about the life of Moses as the hero who defended his people against a vengeful deity.
Saul's Demise, David's Lament, and Custer's Last Stand
Authors: Barrick W. Boyd
Published: March 2007

Many readers, beginning with Josephus (Ant. 6.4.343-50), perceive the death of Saul as narrated in 1 Sam. 31 (1 Chron. 10).1-6 to be heroic or otherwise ennobling, a courageous but doomed 'last stand' in defense of his people. P.K. McCarter in par ticular finds this characterization also in the lament, translating 2 Sam. 1.19a 'Alas, prince of Israel [= Saul] slain standing erect', the pose evocative of bravery. This characterization, however, is a case of eisegesis spawned by the workings of the 'Martyred Hero' paradigm in the reader's mind and readerly imagination. This paradigm, identified by folklorist B.A. Rosenberg, is typified by the American popu lar legend of 'Custer's Last Stand' which envelops the death of Lt. Col. George Armstrong Custer at the Battle of the Little Bighorn (25 June 1876). Without this external and perhaps culturally anachronistic template, the ancient Hebrew narrative is seen to represent Saul's death as cowardly and disgraceful. McCarter's mgenious treatment of 'al bāmôteykâ hāllāl in 2 Sam. 1.19a (and 1.25b) is rejected on philolo gical and literary grounds in favor of 'slain upon thy back', originally proposed by D.N. Freedman in 1964. It is doubtful whether these materials yield anything sub stantive about the actual circumstances of Saul's death—assuming, of course, that Saul actually existed.
A Possible Mention of David in the Late Tenth Century Bce, and Deity Dod as Dead as the Dodo?
Authors: Kitchen K.A.
Published: March 2007

Following the recent controversies over the Tel Dan Stela, this paper presents a minimal interpretation of the main part of its text with resulting implications, and like wise of relevant passages on the Moabite Stone. A much earlier attestation of the name of David may very likely be found in a place name in the topographical list of Shoshenq I of Egypt, c. 925 BCE, carved only half a century after David's death. The supposed deity Dod appears to be a wholly specious modem invention.