bluuebunny/crossref_metadata_2025 huggingface dataset:
Rao-Blackwellized Particle Filter Approach to Monocular vSLAM With a Modified Initialization Scheme
Authors: Farrokhsiar Morteza , Najjaran Homayoun
Published: July 2010

This paper presents a Rao-Blackwellized particle filter (RBPF) approach with a modified undelayed initialization scheme to solve the 3D visual SLAM problem (vSLAM) using a single camera. In the proposed method, landmarks are initialized using the inverse depth of the landmarks rather than the traditional use of their depths. In this scheme, there is no need to distinguish between partially and fully initialized landmarks. Once the landmarks are properly initialized, the RBPF enhances the estimation of the robot path and landmark location using bearing-only information obtained from a camera. The results of numerical simulations and experiments with a video clip have been included in this paper to verify the performance of the proposed approach.
A Secure Migration Protocol for Mobile Agent Systems
Authors: Malik Najmus Saqib , Ko David , Cheng Harry H.
Published: July 2010

This paper describes a secure migration process of mobile agents between agencies. Mobile-C is an IEEE Foundation for Intelligent Physical Agents (FIPA) standard compliant multi-agent platform for supporting C/C++ mobile and stationary agents. This secure migration process is inspired from Secure Shell (SSH). Before migration, both agencies authenticate each other using public key authentication. After successful authentication, an encrypted mobile agent is transferred and its integrity is verified. Mobile-C is specially designed for mechatronic and factory automation systems where, for correct system operations, agencies must accept mobile agents from trusted agencies. For this reason, the emphasis is on strong authentication of both agencies involved in migration process. Security aspects of other popular mobile agent systems are described briefly. A comparison study with SSH protocol is performed and future work is elaborated.
Concealed Weapon Detection Using Acoustic Spectral Characterisation
Authors: Vadakkel George A. , Oyadiji S. Olutunde
Published: July 2010

This paper focuses on showing how one could identify a component by using acoustic waves within the audible frequency range. The purpose of this study is to incorporate the findings from this paper in concealed weapon detection (CWD) where objects hidden behind a person’s clothing could be detected using acoustic or ultrasonic sound waves. Experimental trials are carried out using a directional speaker which generates a highly directional acoustic beam. This can then be pointed at any target and the sound reflected from it analyzed. Initially, a sound source is selected based on the maximum frequency range. The characteristic of the acoustic signal produced by the source is then recorded to be used as reference. Different objects are selected to be used as targets. The sound reflected from these objects is recorded. The spectrograms from these targets reveal that the incident sound waves have been modulated. By taking the ratio of the reflected and the incident sound signals one could obtain the natural frequencies of the object and the spectrogram of the reflected acoustic signal could give indication of the object’s shape.
The Initialization Response of Linear Fractional-Order Systems With Constant History Function
Authors: Hartley Tom T. , Lorenzo Carl F.
Published: July 2010

In this paper, the distinction between an operator’s historical initial condition function, the consequential initialization function of the operator, and the resulting initialization response of an entire system, is discussed. The paper then presents the initialization responses for fractional-order systems that have specifically had arbitrarily-long constant displacements in negative time.
An Object-Space Based Machining Simulation in Milling: Part 1 — By Natural Quadric and Flat Surfaces
Authors: Aras Eyyup
Published: July 2010

This two-part paper presents an efficient parametric approach to updating workpiece surfaces represented by the Z-map vectors. The methodology is developed for up to 3 1/2 1/2-axis machining in which a tool can be arbitrarily oriented. In calculations the Automatically Programmed Tool (APT)-type milling cutters represented by the natural quadrics, planar and the toroidal surfaces are used. The machining process is simulated through calculating the intersections between the Z-map vectors and the tool envelope surface which is modeled by using a tangency function. Part 1 of this two-part paper presents the methodology for the cutters with natural quadrics and planar surfaces. For those surfaces intersection calculations are performed analytically. The geometric complexity of a torus is higher than those of the natural quadric and planar surfaces. Furthermore if the torus has an arbitrary orientation then the intersection calculations for the torus present great difficulties. In NC machining typically a torus is considered as one of the constituent parts of a cutter. In this case only some parts of the torus envelopes, called contact-envelopes, can intersect with Z-map vectors. For this purpose in Part 2 of this two-part paper an analysis is developed for separating the contact-envelopes from the non-contact envelopes. Then a system of non-linear equations in several variables, obtained from intersecting Z-map vectors with contact envelopes, is transformed into a single variable non-linear function. Later using a nonlinear root finding analysis which guarantees the root(s) in the given interval, those intersections are addressed.
Hybrid Knowledge Representation and Reasoning With Ontology and Rules for Product Engineering
Authors: Noh Jung-Do , Suh Hyo-Won , Lee Heejung
Published: July 2010

This paper proposes a framework for building product information model (PIM) and product rule model (PRM), and integrated reasoning based on Description Frame Logic (DFL) [1] for collaborative product engineering environments. Most of the previous research has focused either on building ontology for PIM or on building a rule base for PRM respectively, not on both of them. Some research on product engineering has tried to build both ontology language and rule-language. But, the research is/has been limited to using both languages in a homogeneous approach under open world assumption (OWA) such as Web Ontology Language (OWL)/Semantic Web Rule Language (SWRL), which has some drawbacks to accommodate the requirements of enhanced expressivity for collaborative product engineering. We adopt Description Frame Logic (DFL) framework to integrate product semantics in PIM and engineering-specific knowledge in PRM based on description logic (DL) and logic programming (LP) under both open world assumption (OWA) and closed world assumption (CWA). This enables to secure seamless and interactive reasoning between PIM and PRM. We also include rule-expressions and constraint checking with DL for PIM while we include DL-expression in rules and LP’s non-logical features for PRM. This provides enhancement of expressiveness required for product engineering. Additionally, we show the benefits of the proposed framework with a case study.
Practical Stability Limits in Turning
Authors: Kalma´r-Nagy Tama´s
Published: July 2010

In this paper we establish a practical formula that could be used to augment existing linear stability charts for turning to include the occurrence of contact loss between tool and workpiece in turning. We show that the contact loss discontinuity in the global model is responsible for the creation of the experimentally observed coexistence of subcritical instability and hysteresis in the cutting process. Comparison of experimental data with extensive numerical simulations nicely support the theoretical findings.
Human Affective State Recognition and Classification During Human-Robot Interaction Scenarios
Authors: Zhang Zhe , Nejat Goldie
Published: July 2010

A new novel breed of robots known as socially assistive robots is emerging. These robots are capable of providing assistance to individuals through social and cognitive interaction. The development of socially assistive robots for health care applications can provide measurable improvements in patient safety, quality of care, and operational efficiencies by playing an increasingly important role in patient care in the fast pace of crowded clinics, hospitals and nursing/veterans homes. However, there are a number of research issues that need to be addressed in order to design such robots. In this paper, we address one main challenge in the development of intelligent socially assistive robots: The robot’s ability to identify, understand and react to human intent and human affective states during assistive interaction. In particular, we present a unique non-contact and non-restricting sensory-based approach for identification and categorization of human body language in determining the affective state of a person during natural real-time human-robot interaction. This classification allows the robot to effectively determine its taskdriven behavior during assistive interaction. Preliminary experiments show the potential of integrating the proposed gesture recognition and classification technique into intelligent socially assistive robotic systems for autonomous interactions with people.
Teamology: Case Study in Maruzen Industry
Authors: Mitani Tomoki , Funaki Yuta , Arakawa Masao
Published: July 2010

Teamology is a method to create creative project team established by Prof. Wilde. It is based on Questionnaire of Briggs & Myers identification of type (MBTI) called Personal Theory, whose base is on Jung’s Type Theory. From MBTI, Prof. Wilde makes formula to make balance project team both in Information Collection domain and Decision-Making domain. He has published his experiences in team construction and published a book as Teamology in 2008. In this case study, we investigate the effectiveness of balanced project teams and try to see how it works. We carried out questionnaire to more than 120 employees in Maruzen Industry, and make different types of teams and checked the difference of creativity. From the results, we have proven that balanced team showed the best performance. We also carried out the best way of questionnaire, and found out Prof. Wilde’s questionnaire shows the best identification of type.
Forward Displacement Analysis and Singularity Analysis of a 2-DOF 5R Spherical Parallel Manipulator
Authors: Kong Xianwen
Published: July 2010

This paper deals with the forward displacement analysis and singularity analysis of a 2-DOF 5R spherical parallel manipulator. An alternative formulation of the kinematic equations of the 2-DOF spherical parallel manipulator is proposed. A formula is then derived to produce directly the unique current solution to the FDA of the 2-DOF spherical parallel manipulator. It is proved that the formula is associated with the same assembly mode and working mode as the reference configuration of the spherical parallel manipulator. Unlike other parallel manipulators, the 2-DOF 5R spherical parallel manipulator always undergoes self-motion in a Type 2 singular configuration, and the 3R leg of the 2-DOF spherical parallel manipulator also always undergoes self-motion in a Type 1 singular configuration.
Review of Joost Kalker’s Wheel-Rail Contact Theories and Their Implementation in Multibody Codes
Authors: Zaazaa Khaled E. , Schwab A. L.
Published: July 2010

During the past decades Kalker developed a number of wheel-rail contact theories that can be used to determine the tangential forces and spin moment between the wheel and the rail [Kalker, 1990]. These theories are: Linear Theory, Strip Theory, Empirical Theory, Simplified Theory and Exact Three Dimensional Rolling Contact Theory. These theories assume that the contact between the two bodies is non-conformal. Recently, Li and Kalker [Li and Kalker 1998a, 1998b and Li, 2002] introduced an approach for numerical solution of the conformal contact between the wheel and the rail. In this paper, Kalker’s wheel-rail contact theories are presented. The paper provides an overview for each theory and its restriction or error as was reported by Kalker. In addition, a systematic procedure for implementing Kalkers’s wheel-rail contact theories in multibody codes is briefly presented.
Effect of Material Constants and Mechanical Damping on Piezoelectric Power Generation
Authors: Erturk Alper , Anton Steven R. , Bilgen Onur , Inman Daniel J.
Published: July 2010

Vibration-to-electricity conversion using piezoelectric transduction has been studied by several researchers over the last decade. PZT (lead zirconate titanate) - based piezoelectric ceramics such as PZT-5A and PZT-5H have been very frequently employed in design of piezoelectric energy harvester beams. Recently, the single-crystal piezoceramics PMN-PT (lead magnesium niobate – lead titanate) and PMN-PZT (lead magnesium niobate – lead zirconate titanate) have also been investigated for electrical power generation due to their large piezoelectric constants (particularly the d31 constant for the bending mode). Piezoelectric, elastic and dielectric properties of these piezoceramics differ from each other considerably. Even though the d31 constants of two piezoceramics might differ by an order of magnitude (e.g. PZT-5A and PMN-PZT), this large difference is not necessarily the case for their power outputs. It is theoretically discussed and experimentally demonstrated in this paper that the d31 piezoelectric constant alone is an insufficient parameter for selecting the best piezoelectric material to design a power generator for vibration-based energy harvesting. Elastic compliance of a piezoceramic has a strong effect on its electrical power output. In addition, since these devices are usually designed for resonance excitation, mechanical damping constitutes another parameter that might change the entire picture regarding the power generation performance. The last one is particularly critical considering the fact that it is difficult to control mechanical damping due to clamped interfaces and adhesive layers in practice. Theoretical comparisons are given for geometrically identical bimorphs with PZT-5A, PZT-5H, PMN-PT (with 30% PT), PMN-PT (with 33% PT) and PMN-PZT layers using an experimentally validated distributed-parameter electromechanical model. Two experimental demonstrations are presented. The first case compares two geometrically identical bimorphs (using PZT-5A and PZT-5H piezoceramics) and shows that the bimorph with PZT-5A can generate larger power than the one with PZT-5H in spite of the larger d31 constant of the latter. The second experimental case compares the power generation performances of a PZT-5H unimorph and a PMN-PZT unimorph. In agreement with the theory, considerably large damping identified for the PMN-PZT unimorph results in much lower power output compared to that of the PZT-5H unimorph.
A Three-Dimensional Lumped Parameter Model of Nanoscale Phononic Crystals
Authors: Davis Bruce L. , Hussein Mahmoud I.
Published: July 2010

This work focuses on modeling nanoscale phononic crystals by setting up the appropriate Lagrangian equations of motion. The atomic structure and force constants are accounted for by means of a lumped parameter mass-spring model. In particular we focus on a simple cubic lattice with one mass per primitive unit cell. We use the model to predict the wave propagation frequency spectrum. We then use the model to conduct a series of studies on the influence of defects intentionally introduced to the lattice at a supercell level. One area of interest is the effect of such alterations on the size and location of band gaps.
Dynamic Model of a Vertical Piano Action Mechanism
Authors: Masoudi Ramin , Birkett Stephen , McPhee John
Published: July 2010

The dynamic behavior of a vertical piano action mechanism is studied using a simulation model and compared qualitatively to observations obtained by high-speed imaging of a real action. The simulated response of all components is obtained for two different prescribed input force profiles applied at the key front. These inputs represent in simplified form the general shape of a typical force input by a pianist measured at the key surface for a strong (forte) strike, or two key strikes in rapid succession. The graph-theoretic multibody model constructed represents the components and their interactions. Explicit contact edges provide forces generated between two bodies as a function of their kinematic states, using a special contact model to represent the compression of felt lined interfaces that can separate during the key stroke. Masses and geometrical parameters of the action were measured by importing scanned images from a real action into CAD software. The highly nonlinear system of five ordinary differential equations of motion was derived symbolically and solved by a numerical stiff solver in Maple. The effects of two components not present in the horizontal grand piano action, the bridle strap and hammer butt spring, were examined using simulations. The butt spring is seen to serve an important function in assisting the return of the hammer to its rest position on key release. The model will be useful in future studies to compare vertical actions to horizontal grand piano actions, as these are known to exhibit quite different playing characteristics.
A Feedback Linearization Approach for Panel Flutter Suppression With Piezoelectric Actuation
Authors: Onawola Oluseyi O. , Sinha S. C.
Published: July 2010

Panel flutter suppression by exact state transformations and feedback control using piezoelectric actuation is presented. A nonlinear control system is formulated for the nonlinear partial differential equation governing the dynamics of a simply supported rectangular panel with bonded piezoelectric layers based on the von Ka´rman large-deflection plate theory. Distributed piezoelectric actuators and sensors connected to processing networks are used as modal actuators and sensors to actively control panel vibrations. The control inputs are given by the electric fields required to drive the actuators based on piezoelectric actuation. Nonlinear feedback control laws are formulated through a transformation of the nonlinear system into an equivalent controllable linear system. The simulated results show that the resulting closed-loop system based on feedback linearized controllers effectively suppress panel flutter limit-cycle motions.
Multi-Pulse Chaotic Dynamics of the Cantilevered Pipe Conveying Pulsating Fluid
Authors: Yao Ming-Hui , Zhang Wei , Cao Dong-Xing
Published: July 2010

The multi-pulse orbits and chaotic dynamics of the cantilevered pipe conveying pulsating fluid with harmonic external force are studied in detail. The nonlinear geometric deformation of the pipe and the Kelvin constitutive relation of the pipe material are considered. The nonlinear governing equations of motion for the cantilevered pipe conveying pulsating fluid are determined by using Hamilton principle. The four-dimensional averaged equation under the case of principle parameter resonance, 1/2 subharmonic resonance and 1:2 internal resonance and primary parametric resonance is obtained by directly using the method of multiple scales and Galerkin approach to the partial differential governing equation of motion for the cantilevered pipe. The system is transformed to the averaged equation. From the averaged equation, the theory of normal form is used to find the explicit formulas of normal form. Based on normal form obtained, the energy phase method is utilized to analyze the multi-pulse global bifurcations and chaotic dynamics for the cantilevered pipe conveying pulsating fluid. The analysis of global dynamics indicates that there exist the multi-pulse jumping orbits in the perturbed phase space of the averaged equation. From the averaged equations obtained, the chaotic motions and the Shilnikov type multi-pulse orbits of the cantilevered pipe are found by using numerical simulation. The results obtained above mean the existence of the chaos for the Smale horseshoe sense for the pulsating fluid conveying cantilevered pipe.
Reduced Order Controller Design for Nonlinear Systems With Periodic Coefficients
Authors: Gabale Amit P. , Sinha Subhash C.
Published: July 2010

This study provides a methodology for reduced order controller design for nonlinear dynamic systems with time-periodic coefficients. System equations are represented by quasi-linear differential equations in state space, containing a time-periodic linear part and nonlinear monomials of states with periodic coefficients. The Lyapunov-Floquet (L-F) transformation is used to transform the time-varying linear part of the system into a time-invariant form. Eigenvalue decomposition of the time-invariant linear part can then be used to identify the dominant/ non-dominant dynamics of the system. The non-dominant states of the system are expressed as a nonlinear, time-periodic, manifold relationship in terms of the dominant states. As a result, the original large system can be expressed as a lower order system represented only by the dominant states. A reducibility condition is derived to provide conditions under which a nonlinear order reduction is possible. Then a proper coordinate transformation and state feedback can be found under which the reduced order system is transformed into a linear, time-periodic, closed-loop system. This permits the design of a time-varying feedback controller in linear space to guarantee the stability of the system. The proposed methodology is illustrated by designing a reduced order controller for a 4-dof, inverted pendulum subjected to a periodic follower force. Treatment for the time-invariant case is also included as a subset of the problem.
A Method for Measuring Part Similarity Using Ontology and a Multi-Criteria Decision Making Method
Authors: Mun Duhwan , Cho Junmyon , Ramani Karthik
Published: July 2010

When existing parts are re-used for the development of a new product or business-to-business transactions, a method for searching parts from a part database that is similar to the user’s requirements is necessary. To this end, it is important to develop a part search method that can measure similarity between parts and the user’s input data with generality as well as robustness. In this paper, the authors suggest a method for measuring part similarity using ontology and a multi-criteria decision making method and address the technical details of the approach. The proposed method ensures interoperability with existing engineering information management systems, represents part specifications systematically, and has generality in the procedure for measuring part similarity in specifications. A case study for ejector pins conducted to demonstrate the proposed method is also discussed.
Elicitation and Development of Requirements Through Integrated Methods
Authors: Morkos Beshoy , Summers Joshua D.
Published: July 2010

This paper presents a case study of requirements elicitation for the development of computational support tools at an automotive OEM. The challenges presented in the requirements development necessitated the fusion of three distinct requirements elicitation approaches: traditional design, participatory design, and use case modeling through UML. The findings suggest that a single mode of operation is not sufficient and that to capture the requirements, it is preferred to borrow tools and methods from multiple domains. This case study serves as a broader motivation for a systematic development of engineering requirements modeling and analysis methods.
A Radio Frequency Sensor System for Prognostics and Health Management
Authors: Cheng Shunfeng , Thomas Larry , Cook Jason L. , Pecht Michael
Published: July 2010

This paper introduces a radio frequency identification sensor system and its application for prognostics and health management. In prognostics and health management applications, the radio frequency identification sensor system collects data and transfers the data wirelessly into computers. The data then is analyzed by failure detection and prediction algorithms. The performance of the sensor system for prognostics and health management is demonstrated by a field application.
Circuit Optimization and Vibration Analysis of Electromagnetic Energy Harvesting Systems
Authors: Zuo Lei , Tang Xiudong
Published: July 2010

In this paper we investigate an electrical circuit and its optimization for vibration energy harvesting using electromagnetic transducer. A step-up DC-DC converter regulated by Pulse-Width Modulation (PWM) is used to boost the voltage and control the power flow. An analytical expression for the optimal power flow from the rectified electromagnetic harvester is derived as a function of PWM duty cycle, vibration amplitude and frequency. Optimal duty cycles for both continuous and discontinuous modes are obtained analytically. The impedance of electromagnetic transducer and forward voltage drop of the diodes have been taken into account. It is also interesting to note that if a large inductor is adopted between the rectifier and step-up DC-DC converter, the energy harvesting system will exactly have the effect of Coulomb friction damper.
A Penalty Formulation for Dynamics Analysis of Redundant Mechanical Systems
Authors: Ruzzeh Bilal , Ko¨vecses Jo´zsef
Published: July 2010

Redundancy in constraining of mechanical systems achieves more stability and larger load capacity for the system, while in actuation it provides better robustness against singularities and higher maneuvrability. Few techniques have been developed to handle redundancy and singularities in dynamics analysis, yet difficulties and mathematical problems continue to manifest. This paper expands on the existing penalty techniques and incorporates the concept of actuating/passive constraints to present an elegant penalty formulation that is capable of efficiently handling singularities and redundancy in constraining and actuation and can carry out either forward or inverse dynamics analysis of mechanical systems. As such, the proposed approach is referred to as the actuating/passive constraints penalty approach, or the APCPA.
Torsion Angle Refinement and Dynamics as a Tool to Aid Crystallographic Structure Determination
Authors: Grosse-Kunstleve Ralf W. , Moriarty Nigel W. , Adams Paul D.
Published: July 2010

Crystallographic methods using experimental diffraction data have produced about 85% of the macromolecular structures in the Protein Data Bank. Before deposition, nearly all crystal structures are refined with gradient-driven optimization techniques. Refinement is typically performed with iterative local optimization methods. A common problem is convergence to local minima. Reparameterization of the model in torsion angle space reduces the number of parameters. This in itself can help to escape from local minima. Combination with rigid-body dynamics algorithms results in an important tool for sampling conformational space. This paper presents the torsion angle refinement and dynamics algorithms implemented for the phenix.refine program and the results of various tests.
Resonance Frequency Detection of Dental Implant Stability With Various Bone Defects: In-Vitro Experiments
Authors: Zhuang H.-B. , Chen Ch.-S. , Lee S.-Y. , Pan M.-Ch.
Published: July 2010

Resonance frequency analysis (RFA) has been applied to detect the stability and boundary condition of the dental implant osseointegration in several investigations. Its clinical relating application was generally accepted. Nevertheless, these studies only presented the overall phenomena of osseointegration around the implant and were unable to diagnose the location of the bone defect. Therefore, the aim of this study refers to an effective detection technique for locating the position of bone defect surrounding the dental implant. Various in-vitro bone defect models composed of a dental implant, a healing abutment and an artificial bone block were used to perform the experimental modal analysis (EMA). The bone defect model was excited by an impacted hammer; induced vibration response was acquired by an accelerometer and processed through a spectrum analyzer. The statistical analysis was used to generalize the relationship between the obtained RF values and various bone defects from experimental results. The finding of this study indicates that RF decreases remarkably when the range and depth of defects increase. Thus, the direction of the defect is decided first by RF variations of the sound and defective side, and the position of the defect is discriminated later by RF differences of various bone defect models. This conclusion assists doctors in diagnosis after surgery.
Mobile Agent Based Autonomic Dynamic Parallel Computing
Authors: Chou Yu-Cheng , Ko David , Cheng Harry H.
Published: July 2010

Parallel computing is widely adotped in scientific and engineering applications to enhance the efficiency. Moreover, there are increasing research interests focusing on utilizing distributed networked computers for parallel computing. The Message Passing Interface (MPI) standard was designed to support portability and platform independence of a developed parallel program. However, the procedure to start an MPI-based parallel computation among distributed computers lacks autonomicity and flexibility. This article presents an autonomic dynamic parallel computing framework that provides autonomicity and flexibility that are important and necessary to some parallel computing applications involving resource constrained and heterogeneous platforms. In this framework, an MPI parallel computing environment consisting of multiple computing entities is dynamically established through inter-agent communications using the IEEE Foundation for Intelligent Physical Agents (FIPA) compliant Agent Communication Language (ACL) messages. For each computing entity in the MPI parallel computing environment, a load-balanced MPI program C source code along with the MPI environment configuration statements are dynamically composed as a mobile agent code. A mobile agent wrapping the mobile agent code is created and sent to the computing entity where the mobile agent code is retrieved and interpretively executed. An example of autonomic parallel matrix multiplication is given to demonstrate the self-configuration and self-optimization properties of the presented framework.
An Estimation Method of a Constitutive-Law for the Rod Model of DNA Using Discrete-Structure Simulations
Authors: Hinkle Adam R. , Goyal Sachin , Palanthandalam-Madapusi Harish J.
Published: July 2010

The continuum-rod model has emerged as an efficient tool to describe the long-length-scale structural-deformations of DNA which are critical to understanding the nature of many biological processes such as gene expression. However, a significant challenge in continuum-mechanics-based modeling of DNA is to estimate its constitutive law, which follows from its interatomic bond-stiffness. Experiments and all-atom molecular dynamics (MD) simulations have suggested that the constitutive law is nonlinear and non-homogeneous (sequence-dependent) along the length of DNA. In this paper, we present an estimation method and a validation study using discrete-structure simulations. We consider a simple cantilever-rod with an artificially constructed, discrete lattice-structure which gives rise to a constitutive law. Large deformations are then simulated. An effective constitutive-law is estimated from these deformations using inverse methods. Finally, we test the estimated law by employing it in the continuum rod-model and comparing the simulation results with those of discrete-structure simulations under a different cantilever loading-conditions.
Design of a Tissue Resonator Indenter Device for Measurement of Soft Tissue Viscoelastic Properties Using Parametric Identification
Authors: Hariri Alireza , Zu Jean W.
Published: July 2010

The design of a new device called Tissue Resonator Indenter Device (TRID) for measuring soft tissue viscoelastic properties is presented. The two degrees-of-freedom device works based on mechanical vibration principles. When TRID comes into contact with a soft tissue, it can identify the tissue’s viscoelastic properties through the change of the device’s natural frequencies and damping ratios. In this paper, the deign of TRID is presented assuming Kelvin model for tissues. By working in the linear viscoelastic domain, TRID is designed to identify tissue properties in the range of 0–100 Hz. Assuming Kelvin model for tissues, the current paper develops a method for determining unknown tissue parameters using input-output data from TRID. Moreover, it is proved that the TRID’s parameters as well as the Kelvin tissue model parameters are globally identifiable. A parametric identification method using the prediction error approach is proposed for identifying the unknown tissue parameters in a grey-box state-space model. The reliability and effectiveness of the method for measuring soft tissue’s viscoelastic properties is demonstrated through simulation in the presence of considerable input and output noises.
A Comprehensive Project Risk Management Framework for Today’s Dynamic Environment
Authors: Abbasi Ghaleb Y.
Published: July 2010

A comprehensive risk management framework (RMF) was developed and introduced to help management deal with the project risks in today’s changing world using a well-defined process. Several projects were analyzed to determine their causes of failure and identify risk elements. The RMF consisted of six phases; project identification, risk identification, risk assessment, response development, contingency planning, and implementation and control. Each process must be tailored to the particular circumstances of the project and of the organization undertaking it. The RMF treated risks in a structured process starting by identifying the project and the potential risks, assessing these risks and responding to each risk. Using such an approach management can identify potential risks that may affect the project and respond proactively. The developed framework is comprehensive and applicable for any project type.
Photonic Control of Plates Laminated With Multi-DOF Photostrictive Actuators
Authors: Wang Xin-Jie , Yue Hong-Hao , Jiang Jing , Deng Zong-Quan , Tzou Horn-Sen
Published: July 2010

One dimensional (1D) single-layer and bimorph photostrictive actuators have been used in non-contact vibration control of flexible structures. These two types of photostrictive actuators showed control deficiencies in two-dimensional (2D) plate and shell structures. In this paper, a new multi-degree-of-freedom (DOF) photostrictive actuator configuration is introduced. Including the photodeformation induced forces and moments, the governing equation of a plate laminate with the new multi-DOF actuator is derived. The control effects of the square and rectangular plates with the new multi-DOF actuator and a single one-piece uni-axial actuator are evaluated. Studies suggest that the new multi-DOF actuator can control more natural modes of rectangular plates, as compared with the one-piece monoaxial actuator. However, multi-DOF actuator shows no control advantage in square plates (i.e., symmetrical structures). The control actions of the plate with various sizes of the new multi-DOF actuator are studied and analyzed. Analysis results reveal that increasing actuator size only enhances the control effects of specific plate modes and is ineffective to other modes. The optimal actuator size leading to the best control effect can be inferred from the modal actuation plots.
Complex Modal Decomposition Applied to Nematode Posturing
Authors: Feeny B. F. , Sternberg P. W. , Cronin C. J.
Published: July 2010

The complex orthogonal decomposition (COD), a process of extracting complex modes from complex ensemble data, is summarized, as is the use of complex modal coordinates. A brief assessment is made on how small levels of noise affect the decomposition. The decomposition is applied to the posturing of a wild Caenorhabditis elegans nematode. The decomposition indicates that the worm has a multi-modal posturing behavior, involving at least a dominant locomotion mode and a secondary, steering mode. The locomotion mode is closer to a pure traveling waveform than the steering mode. The characteristic wavelength of the primary mode was estimated in the complex plane. Frequency was obtained from the complex modal coordinate’s complex whirl rate of the complex modal coordinate, and from its fast Fourier transform.
Free and Forced Response of a Piecewise Linear 2-DOF System: Analysis and Experiments
Authors: Vestroni Fabrizio , Casini Paolo , Giannini Oliviero
Published: July 2010

The present paper analyzes the free and forced dynamics of a 2-DOF mechanical system with piecewise linear restoring force, by means of analytical/numerical and experimental investigations. This oscillator is roughly representative of an asymmetrically cracked cantilever beam vibrating in bending and hence exhibiting a bilinear stiffness, depending on whether the crack is open or closed. A parametric analysis of the NNMs has been performed for a wide range of the damage parameter: the influence of damage on the nonlinear frequencies has been investigated and bifurcations characterized by the onset of superabundant modes with or without internal resonance, have been revealed. The dynamic behavior of the system under harmonic base excitation has been numerically investigated assuming both low and high damping. It has been found that the NNMs of the free motion play a key role in the system forced response. Finally, a test set-up has then been built to investigate the validity of the proposed model for technical applications: the experimental measurements qualitatively and quantitatively capture the basic bifurcation scenarios anticipated by the model while a strong robustness of the phenomena pointed out by the theoretical analyses has been revealed in the experiments.
The Development and Performance Study of a Two-Level Wireless Sensor Network for Structural Health Monitoring
Authors: Wang Jinjiang , Chen Bo , Zang Chuanzhi
Published: July 2010

This paper presents the development and performance study of a two-level wireless sensor network (WSN) for structural health monitoring (SHM). The lower-level network adopts low-power ZigBee protocol whereas the higher-level network employs high speed WiFi communication for long distance data transmission. To promote distributed data processing and damage diagnosis, the higher-level sensor nodes are designed to possess high computational capabilities. A reliable data transmission mechanism is implemented in the lower-level ZigBee network. To reduce the power consumption and quickly respond to extreme events, an event-driven monitoring approach is proposed. The impact of the coexistence of ZigBee and WiFi on the system’s performance is also studied.
Towards Haptic Microrobotic Intracellular Injection
Authors: Horan Ben , Ghanbari Ali , Nahavandi Saeid , Chen XiaoQi , Wang Wenhui
Published: July 2010

This paper proposes a system providing the operator with an intuitive method for controlling a micromanipulator during intracellular injection. A low-cost haptic device is utilised and 3D position-to-position kinematic mapping allows the operator to control the micropipette using a similar method to handheld needle insertion. The workspaces of the haptic device and micromanipulator are analysed and the importance of appropriate scaling to positioning resolution and tracking performance is investigated. The control issues integral to achieving adequate control of the micromanipulator using the Phantom Omni haptic device are addressed. Aside from offering an intuitive method for controlling the micropipette, this work lays the foundation for real-time haptic assistance in the cell injection task.
Dynamical Analysis of Sawing Motion Tracks Muscle Fatigue Evolution
Authors: Segala David B. , Chelidze David , Gates Deanna , Dingwell Jonathan
Published: July 2010

Both for civilian and military applications, tracking and identifying muscle fatigue—usually caused by continuous, repetitive motion over a finite period of time—is of great importance. The muscle fatigue process is very difficult to track due to its hidden nature. Invasive procedures are often needed to measure fatigue. Here, easily obtainable noninvasive kinematic measurements are used to extract muscle fatigue related trends associated with a sawing motion. The methodology is derived from dynamical systems based fatigue identification in engineered systems. Ten right-handed subjects perform sawing motion until voluntary exhaustion. Three sets of joint kinematic angles are measured from the elbow, wrist, and shoulder. Fatigue is identified in two steps: (1) phase space warping based feature vectors are estimated from kinematic time series; and (2) smooth orthogonal decomposition (SOD) is used to extract fatigue related trends from these features. SOD-based trends are compared against independently obtained fatigue markers estimated from the mean and median frequencies of electrography (EMG) signals of individual muscles. SOD-based trends from elbow and shoulder kinematics adequately capature fatigue in the triceps muscle estimated from the EMG measurements. These same kinematic angles show little fatigue information in the flexor/extensor carpi radialis (not directly engaged in sawing motion). The methodology used here shows great potential in tracking individual muscle fatigue evolution using only motion kinematics data.
Feasibility of Wireless Sensors for Health Monitoring in Large Induction Motors
Authors: Garcilazo Rafael , Xue Xin , Sundararajan V.
Published: July 2010

Wired sensor systems are currently used to monitor the performance and health of electric motors. Since the sensors need to be wired, these systems can only use few sensor modalities which are generally insufficient to detect the wide range of faults in motors. Wireless sensors, on the other hand, allow access to sensors mounted in accessible locations and on rotating parts. They are easy to install and maintain. However, the reliability of the transmission due to electromagnetic interference and the fidelity of the data due to high winding temperatures inside the motor need to be examined. This paper studies the feasibility of wireless sensors inside a 200hp AC induction motor. Two wireless sensors are attached inside the motor — one on the stator frame and one on the rotating shaft. A wired sensor is attached on the outside of the stator frame to study the fidelity of data from the wireless sensor. The packet delivery performance as a function of spatial location in terms of direction and distance with respect to the base station and the fidelity of data received by the base station are studied. The results show that an average of 97% and 87.9% of the data from the wireless sensor attached on the stator frame and shaft respectively is received at the base station, thus showing that wireless sensors can be reliably used inside the motor.
A “Multisensor Guide System” to Assist Visually Impaired in Unfamiliar Environments
Authors: Ando` Bruno , Baglio Salvatore , La Malfa Salvatore , Marletta Vincenzo
Published: July 2010

In this paper an indoor aid to assist and to guide blind people exploring an unfamiliar structured environment is proposed. The system developed aims to lead the visual impaired to reach a specified destination suggesting him the path to walk avoiding obstacles and hazards and notifying the presence of services along the path. Main advantages of the system developed, as respect to the State of the Art, are the continuous monitoring of users position in the environment, the optimized redundancy of information to be provided to the user, the high reconfigurability, the poor demanding installation and the adaptive level of assistance to be provided to the user on the basis of his/her needs, ability and skills.
A Study on Vibration-Induced Fretting Degradation in Connector Systems
Authors: Chen Chen , Flowers George T. , Bozack Michael , Suhling Jeffrey
Published: July 2010

Vibration-induced fretting degradation is widely known as a major problem for electrical connectors. At present, much of the evaluation of fretting propensity for particular connector designs and the influence of variations in those designs on fretting performance is conducted through exhaustive experimental testing. Therefore, a simulation based method to predict the influence of various design factors would be beneficial to those responsible for connector design and application. In the authors’ previous work, a combined experimental and modeling study of vibration-induced fretting degradation was conducted for a single blade/receptacle connector pair. However, in actual application, multiple pin connector system are typically used. Thus, studying a complete connector system is an appropriate next step in investigating the relative influence of connector system characteristics on fretting degradation. In this study, a simplified 2-D model was developed using ABAQUS. A series of parallel simulation and corresponding experiments were performance. Good correlation between the experimentally observed results and those predicted by the models was observed.
Influence of Quantifiable Extrinsic Stresses on Tin Whisker Growth
Authors: Rodekohr Chad L. , Flowers George T. , Bozack Michael J. , Dean Robert N. , Jackson Robert L. , Lall Pradeep
Published: July 2010

Implementation of Restriction of Hazardous Substances (RoHS) directives regarding lead (Pb)-free electronics has resulted in the use of Pb-free and tin (Sn)-rich films as board finishes. These films pose serious reliability issues due to spontaneous Sn whisker growth formerly mitigated by the presence of Pb. Tangential compressive stress within thin films has long been cited as a principal cause of whisker growth, but there have been few direct stress measurements reported in the literature. In this study, we have manufactured two precision devices to impose eight known tangential (compressive and tensile) stress levels on Sn/Aluminum (Al) thin film/substrate systems. The results show that large numbers (∼ 103/cm2) of Sn whiskers are present on films subjected to both compressive and tensile extrinsic stresses and the lowest whisker risk occurs in films near the zero stress condition.
Dynamic Stiffness Matrix Method for the Free Vibration Analysis of Rotating Uniform Shear Beams
Authors: Jackson Dominic R. , Oyadiji S. Olutunde
Published: July 2010

The Dynamic Stiffness Method (DSM) is used to analyse the free vibration characteristics of a rotating uniform Shear beam. Starting from the kinetic and strain energy expressions, the Hamilton’s principle is used to obtain the governing differential equations of motion and the natural boundary conditions. The two equations are solved simultaneously and expressed each in terms of displacement and slope only. The Frobenius power series solution is applied to solve the equations and the resulting solutions are also expressed in terms of four independent solutions. Applying the appropriate boundary conditions, the Dynamic Stiffness Matrix is assembled. The natural frequencies of vibration using the DSM are computed by employing the in-built root finding algorithm in Mathematica as well as by implementing the Wittrick-Williams algorithm in a numerical routine in Mathematica. The results obtained using the DSM are presented in tabular and graphical forms and are compared with results obtained using the Timoshenko and the Bernoulli-Euler theories.