bluuebunny/crossref_metadata_2025 huggingface dataset:
Models in motion: Ethnography moves from complicatedness to complex systems
Authors: ANDERSON KEN , SALVADOR TONY , BARNETT BRANDON
Published: February 2014

Since the 90's, one of ethnography's values has been about the reduction in the risk of developing new products and services by providing contextual information about people's lives. This model is breaking down. Ethnography can continue to provide value in the new environment by enabling the corporation to be agile. We need to: (1) identify flux in social‐technological fabric; (2) engage in the characterization of the business ecosystems to understand order; and (3) be a catalyst with rapid deep dives. Together we call it a FOC approach (flux, order, catalyst).
Session 4: (Co)creation and (co)participation: multiple actors in the research
Authors: ORTLIEB MARTIN
Published: February 2014

The fourth session questions how ethnography is produced through multiple voices. Coming from different disciplinary backgrounds including Design, Business and Software Engineering, researchers report on co‐creating and co‐participating in the formation of ideas, practices and outcomes.

Once upon a time, ethnographic reports were stereotypically produced in the Malinowskian manner: a single outside researcher enters the location to subsequently reproduce and represent his vision of the reality in that place. In 2013, and probably for the majority of the attendees of EPIC, this is no longer the case. Ethnography no longer has just a single voice: There are multiple stakeholders, often directly involved in the research, even though they may hail from different disciplinary backgrounds ranging from Design, Business to Software Engineering. Moreover, these days we often have multiple researchers reporting several perspectives for the same project. Finally, often the ‘subjects’ of the research are becoming involved in data reporting, data analysis, and/or implementation of insights as well as consumers/recipients of and through ethnography. In this session we hear from 4 different groups on such co‐creative, and co‐participatory endeavours that cut across all the above developments in various situated projects, ranging from post‐disaster community rebuilding to intra‐company international employee relationships and from post‐operation cancer care to capturing the intangible of successful individuals in specific company roles.
Human API as a research source in health care
Authors: BAEK KNOWL , DUKE KYLE , LUO ROY , LEE MONICA , MATHEW ANIJO
Published: February 2014

This paper illustrates how the concept of “Human API” can help cancer post‐treatment cancer patients with challenges they face once they are released from the hospital. The results and implications of this semester long graduate project will help illuminate how the Human API through its various data collection methods could potentially play a larger role in extended cancer care. The research will also attempt to determine if hyper‐connected networks of individual patients could become effective sources of information for health institutions to engage and connect with patients after treatment or surgery.
Ethnography and the “Age Wave”: Knowledge capture for succession planning
Authors: GENTRY KRISTINE MCKENZIE
Published: February 2014

The “age wave,” or aging of the population and concurrent increase in retirees, is creating a loss of knowledge unlike that experienced in the American work force to date. Since many Baby Boomers are loyal employees who have worked for the same employer for several decades, the knowledge, both tacit and explicit, contained within this single generation is vast and integral to the continued success of many organizations and industries. While Knowledge Management (KM) has become a priority for many organizations, several studies have shown that current KM methods and technologies have not proven effective as a means of transferring knowledge between workers. Ethnography offers some advantages as a technique to capture, record, and transfer tacit and explicit knowledge. This paper uses two case studies to examine how ethnography and a co‐creative method can be utilized to assist with knowledge management and succession planning.
Co‐opetition as the new path to innovation? Negotiating strategic change through user‐centred design approaches:
Authors: Peinado Alice , Jarvin Magdalena , Jouanny Corinne
Published: February 2014

This essay analyses how consensus was reached in a co‐opetitive setting by looking at two, consecutive but related projects spanning from 14 to 18 months in length. The projects took place in Paris, France, between 2009 and 2013, and involved key players from the banking and insurance industry. FiDJi, short for Finance, Design et Joie d'Innover, was meant to test a new innovation method based on a design thinking approach. FAIR, short for Finance, Assurance & Innovation Responsable, was conceived as a sequel to FiDJi but had the more ambitious goal to develop a new methodology that, while using a design thinking approach as a starting mode, would provide an independent set of guidelines with respect to sustainable, responsible innovation. Consequently, the dynamic of each project varied, as did the end goals. Both projects took design thinking as a starting point but while FiDJi produced a new innovation methodology based on a user‐centred design approach, FAIR had the more ambitious goal to develop a set of guidelines and a method for responsible innovation specific to the banking and insurance industry.

The essay builds on a previous essay that analysed the dynamics proper to the FiDJi project in order to explore how anthropologists and designers are increasingly called upon to enable change (Peinado et al. 2011). It seeks to further expand on the role of anthropologists and designers as not merely enablers but enactors of change in multi‐disciplinary, team based, co‐opetitive contexts. Moving beyond an understanding of anthropologists and designers as providing discipline specific knowledge and skills to an understanding of their role as consultants, this essay will argue that as professionals anthropologists and designers need to be able to both contextualise their role and translate it so as to create value for their clients, users and themselves. This is consonant with repeated calls within the EPIC community to move beyond discipline specific definitions in order to understand the role we currently play and we could play in the future within industry‐based contexts. We will argue that both anthropologists and designers are particularly apt at this since they can understand organisational contexts and provide insights into the nature of transformation.
Serendipity and business development – Design anthropological investigations at The Post
Authors: Kjaersgaard Mette Gislev
Published: February 2014

This paper describes how ‘The Post’ (a postal service company in the northern part of Europe) sets out to design an online digital platform for involving their employees in developing new services for the company. It is a story of a design project that failed to accomplish this task, but through sensitivity to serendipity disclosed other and potentially more valuable business opportunities in the process. It is also a story about design anthropology as a particular way of engaging with ‘the field’; challenging assumptions and eliciting insight through design orientated investigations of actual and potential relations between people, things, practices and contexts.
Consumer fetish
Authors: ARNOULD ERIC , CAYLA JULIEN
Published: February 2014

Commercial ethnography has become an important activity for accessing the lived experiences of consumers that are constructed as “others” that firms have to discover and manage. In organizational contexts where the necessity to accumulate organizational knowledge about markets have become paramount, the figure of the “consumer” has become a quasi‐magical object bestowed with the aura of the real, a fetish that comes to stand for the market, and symbolizes the firm's effective orientation towards the market. In this paper we demonstrate how the anthropological concept of the fetish may be usefully employed in understanding the nature of this process, whereby the voices and images of consumers are endowed with power within organizational contexts. Consumer fetish is at once a quasi object and a manifestation of analogical knowledge.
ARTEFACTS
Authors: DORNADIC ALICIA , DRAZIN ADAM
Published: February 2014

When an idea is cast into the world, others are able to play with it, learn from it, expand, discuss, replicate or challenge it. The idea becomes shareable. EPIC Artefacts are a way to put ethnographic ideas out in the world. From research, design, and teaching tools, new methodologies, ways of thinking, and communicating, to finished products and films, the makers who created this year's artefacts push the boundaries of ethnographic production and interpretations of their work in current and future contexts. They come from corporations, consultancies, non‐profits, start‐ups, and academia to share their ideas with you.
SALONS
Authors: PULMAN‐JONES SIMON , JONES STOKES , BAXTER KATHY , RADKA RICH
Published: February 2014

EPIC Salons are not a seminar, not a presentation, nor workshops with a ‘leader’. In 2013, the first year this format was featured, the Salons achieved their sole goal of offering more space for ‘horizontal’ conversation between EPIC attendees – by offering a forum for shared in‐depth explorations of a single topic.
WORKSHOPS
Authors: MACAULAY CATRIONA , ROBERTS SIMON
Published: February 2014

EPIC 2013 features nine handpicked workshops that were designed to provide attendees with fresh skills and perspectives on the art and science of ethnographically informed work. A clutch of workshops will discuss how we train and mobilise as a professional community in‐ and outside of academia. An‐ other will discuss how we sell our work (and how it is bought). Other sessions were designed to introduce attendees to new tools that can be used to conduct fieldwork or how to create a digital ecosystem of ideas, information and conversations. Simple, human‐scale technologies and cognition came to the fore in workshops designed to teach people how to think with their hands, to command a room with a whiteboard and marker pen or unfold creative thinking processes.
Alcohol abuse in deceased liver donors: impact on post‐transplant outcomes
Authors: Mangus Richard S , Kubal Chandrashekhar A , Fridell Jonathan A , Pena Jose M , Frost Evan M , Joseph Tector A.
Published: February 2014

Background

Many deceased liver donors with a history of alcohol abuse are excluded based upon medical history alone. This paper summarizes the transplant outcomes for a large number of deceased liver donors with a documented history of alcohol abuse.

Methods

The records for 1478 consecutive deceased liver donors were reviewed (2001–2012). As per the United Network for Organ Sharing criteria, heavy alcohol use by an organ donor is defined as chronic intake of two or more drinks per day. Donors with a documented history of alcohol abuse were divided into three groups according to duration of abuse (<10 years, 10–24 years and 25 +  years). Reperfusion biopsies are reported. Outcomes include biopsy appearance, early graft function and early and late graft survival.

Results

There were 161 donors with alcohol abuse: <10 years (29%); 10–24 years (42%); and ≥25 years (29%). Risk of 90‐day graft loss for these three groups was: 0%, 3% and 2%, compared to 3% for all other donors (P = 0.62). Graft survival at 1 year for donor grafts with and without alcohol abuse was 89% and 87% (P = 0.52). There was no difference in early graft function. Cox proportional hazards modelling for graft survival demonstrates no statistically significant difference in survival up to 10 years post‐transplant.

Conclusions

This study demonstrates successful transplantation of a large number of deceased donor liver grafts from donors with a documented history of alcohol abuse (n = 161; 11% of all grafts). These extended criteria donor allografts may, therefore, be utilized successfully with similar outcomes.
From Movement to Mentality, from Paradigm to Perspective, from Action to Performance: Law and Society at Mid‐Life
Authors: Sarat Austin
Published: February 2014

Kitty Calavita's Invitation to Law & Society: An Introduction to the Study of Real Law (2010) offers a broad and useful overview of the intellectual accomplishments of law and society scholars and a self‐confident assertion that they perform an invaluable service by focusing on “real law,” that is, law in action rather than law on the books. This essay argues that the field is more fragmented than Calavita notes and that law and society research is neither engaged with a common set of questions nor organized around a single central insight or an agreed‐upon paradigm. Moreover, this essay raises questions about Calavita's claims about “real” law and suggests that we complement law and society's traditional focus by examining the varied performances of law, whether in texts or in the world beyond those texts.
Identification and characterization of the ‘missing’ terminal enzyme for siroheme biosynthesis in α‐proteobacteria
Authors: Bali Shilpa , Rollauer Sarah , Roversi Pietro , Raux‐Deery Evelyne , Lea Susan M. , Warren Martin J. , Ferguson Stuart J.
Published: February 2014

It has recently been shown that the biosynthetic route for both the d1‐haem cofactor of dissimilatory cd1 nitrite reductases and haem, via the novel alternative‐haem‐synthesis pathway, involves siroheme as an intermediate, which was previously thought to occur only as a cofactor in assimilatory sulphite/nitrite reductases. In many denitrifiers (which require d1‐haem), the pathway to make siroheme remained to be identified. Here we identify and characterize a sirohydrochlorin–ferrochelatase from Paracoccus pantotrophus that catalyses the last step of siroheme synthesis. It is encoded by a gene annotated as cbiX that was previously assumed to be encoding a cobaltochelatase, acting on sirohydrochlorin. Expressing this chelatase from a plasmid restored the wild‐type phenotype of an Escherichia coli mutant‐strain lacking sirohydrochlorin–ferrochelatase activity, showing that this chelatase can act in the in vivo siroheme synthesis. A ΔcbiX mutant in P. denitrificans was unable to respire anaerobically on nitrate, proving the role of siroheme as a precursor to another cofactor. We report the 1.9 Å crystal structure of this ferrochelatase. In vivo analysis of single amino acid variants of this chelatase suggests that two histidines, His127 and His187, are essential for siroheme synthesis. This CbiX can generally be identified in α‐proteobacteria as the terminal enzyme of siroheme biosynthesis.
Tacrolimus does not alter the production of several cytokines and antimicrobial peptide in Malassezia furfur‐infected‐keratinocytes
Authors: Balato Anna , Paoletti Iole , De Gregorio Vincenza , Cantelli Mariateresa , Ayala Fabio , Donnarumma Giovanna
Published: February 2014

Topical immunosuppressant therapy is widely used in the treatment of inflammatory skin diseases, such as atopic dermatitis and psoriasis. Besides its beneficial therapeutic effects, application of topical anti‐inflammatory drugs may render the epidermis more vulnerable to invading pathogens by suppressing innate immune responses in keratinocytes (KCs). Cytokines, chemokines and antimicrobial peptides (AMPs) produced by epithelial cells enable them to participate in innate and acquired immune responses. The aim of the present work was to study the influence of tacrolimus (FK506) on KCs infected with Malassezia furfur (M. furfur), evaluating the expression of pro‐inflammatory cytokines IL‐1α and IL‐6, chemokine IL‐8, anti‐inflammatory cytokines transforming growth factor beta1 (TGF‐β1) and IL‐10 and AMP β‐defensin‐2. Human KCs were obtained from surgical specimens of normal adult skin. The expression of mRNAs in KCs: FK506‐treated, FK506‐treated and M. furfur‐infected as well as only M. furfur‐infected was quantified by real‐time quantitative polymerase chain reaction. Next, the production of the AMP β‐defensin‐2 and of the above‐mentioned pro‐inflammatory and anti‐inflammatory cytokines was evaluated using enzyme‐linked immunosorbent assay. In this study, FK506 did not alter cytokine and AMP production by KCs; this led us to hypothesise that it may not enhance the risk of mycotic skin infections.
Physiological Arousal and Political Beliefs
Authors: Renshon Jonathan , Lee Jooa Julia , Tingley Dustin
Published: February 2014

It is by now well known that political attitudes can be affected by emotions. Most earlier studies have focused on emotions generated by some political event (e.g., terrorism or increased immigration). However, the methods used in previous efforts have made it difficult to untangle the various causal pathways that might link emotions to political beliefs. In contrast, we focus on emotions incidental (i.e., irrelevant) to the decision process, allowing us to cleanly trace and estimate the effect of experimentally induced anxiety on political beliefs. Further, we build upon innovative new work that links physiological reactivity (Hatemi, McDermott, Eaves, Kendler, & Neale, 2013; Oxley et al., 2008a) to attitudes by using skin conductance reactivity as a measure of emotional arousal. We found that anxiety—generated by a video stimulus—significantly affected physiological arousal as measured by tonic skin‐conductance levels, and that higher physiological reactivity predicted more anti‐immigration attitudes. We show that physiological reactivity mediated the relationship between anxiety and political attitudes.
Nitrogen isotope discrimination as an integrated measure of nitrogen fluxes, assimilation and allocation in plants
Authors: Kalcsits Lee A. , Buschhaus Hannah A. , Guy Robert D.
Published: February 2014

Fractionation of nitrogen isotopes between a plant and its environment occurs during uptake and assimilation of inorganic nitrogen. Fractionation can also occur between roots and the shoot. Under controlled nitrogen conditions, whole‐plant and organ‐level nitrogen isotope discrimination (Δ15N) is suggested to primarily be a function of three factors: nitrogen efflux back to the substrate relative to gross influx at the root (efflux/influx), the proportion of net influx assimilated in the roots and the export of remaining inorganic nitrogen for assimilation in the leaves. Here, an isotope discrimination model combining measurements of δ15N and nitrogen content is proposed to explain whole‐plant and organ‐level variation in δ15N under steady‐state conditions and prior to any significant retranslocation. We show evidence that nitrogen isotope discrimination varies in accordance with changes to nitrogen supply or demand. Increased whole‐plant discrimination (greater Δ15N or more negative δ15N relative to the source nitrogen δ15N) indicates increased turnover of the cytosolic inorganic nitrogen pool and a greater efflux/influx ratio. A greater difference between shoot and root δ15N indicates a greater proportion of inorganic nitrogen being assimilated in the leaves. In addition to calculations of integrated nitrogen‐use traits, knowledge of biomass partitioning and nitrogen concentrations in different plant organs provides a spatially and temporally integrated, whole‐plant phenotyping approach for measuring nitrogen‐use in plants. This approach can be used to complement instantaneous cell‐ and tissue‐specific measures of nitrogen use currently used in nitrogen uptake and assimilation studies.
130th Anniversary of Prof. Dr. Vladimir Markov
Authors: Mitov Ivan
Published: February 2014

This year marks 130 years since the birth of the founder and leader (untill 1958) of the Department of Microbiology at the Medical University Sofia in Bulgaria, the eminent and internationally recognized scholar Prof. Dr. VLADIMIR NESTOROV MARKOV, Full Member of the Bulgarian Academy of Sciences (Academician). ...
HCIB Based Control for Reducing Low Frequency Driveline Vibrations on Commercial Vehicles
Authors: Song Xubin , Liu Jason
Published: February 2014

HCIB, high-capacity inertia brake, is a frictional braking device used in Eaton’s transmission to slow down the engine speed during the gear shifting process. This paper develops a control strategy to apply HCIB for reducing torsional vibration on the driveline for a specific driving situation in which the driver uses the gas pedal to maintain a truck position on an upslope, known as the hill holding condition. Under this condition the truck is standing still on a hill while the engine is running to deliver torque to the wheels through the entire drivetrain system. It is a clutch-slipping drive with frictional torque to transmit power from engine to wheels. In this developed control algorithm, output-shaft speed and accelerator pedal signals are used to identify the pattern for this driving situation and at the same time the input-shaft speed and engine speed are used to determine vibration amplitudes at a certain interested frequency range. The estimated vibration amplitude is then used to derive the control signal of HCIB for vibration reduction. The torsional vibration control (TVC) algorithm has been successfully implemented and tested on a prototype MD (Medium Duty) truck.
Singularity Analysis of a Single-Loop Underactuated Wrist
Authors: Di Gregorio Raffaele
Published: February 2014

In a previous paper, this author proposed a novel type of underactuated parallel wrist (PW) with a single-loop architecture containing only one nonholonomic constraint. Moreover, he addressed its position analysis and path planning and showed that closed-form formulas can be used to solve all the finite-kinematics problems involved in the path planning of the novel PW. Here, the instantaneous kinematics and the singularity analysis of this PW are addressed. In particular, both the analytic and geometric conditions which identify the singular configurations are presented together with their static interpretation. The presented results are relevant for designing this type of PWs.
Influence of the Lubrication Model on the Dynamic Response of Mechanical Systems
Authors: Flores Paulo
Published: February 2014

The main objective of this work is to present a study on the use of different hydrodynamic force models on the dynamic response of mechanical systems with lubricated revolute joints. For this purpose, the fundamental issues related to the classical theory of lubrication for dynamically loaded journal-bearings are revised, which is used to evaluate the Reynolds’ equation for dynamic regime. The hydrodynamic forces that develop at the lubricated revolute joints are determined and included into the dynamic equations of motion.

In this study, three different approaches are considered to evaluate the hydrodynamic forces, namely the Pinkus and Sternlicht approach for long journal-bearings and the Frêne et al. models for both long and short journal-bearings. Results for a mechanical system with a lubricated revolute joint are presented and used to discuss the main assumptions and procedures adopted in this work. From the computational simulations performed, it can be observed that the hydrodynamic force model play a crucial role in predicting the dynamic behavior of mechanical systems and originate some uncertainties in their dynamic responses.
Utilizing Emergent Levels to Facilitate Complex Systems Design: Demonstrated in a Synthetic Biology Domain
Authors: Egan Paul F. , Cagan Jonathan , Schunn Christian , LeDuc Philip R.
Published: February 2014

Designing complex systems often requires consideration of many components interacting across vast scales of space and time, thus producing highly challenging design spaces to search. In particular, nano-based technologies may require considerations of how nanoscale (10−9) embodiments affect macroscale (∼100) systems and typically have multiple layers of emergent behavior. It is frequently cited that counter-intuitive properties of emergence complicates design tasks; however, we investigate whether some multiscale emergent systems have organizational levels that may inform more effective design methods and searches.

Investigations are conducted by extending an agent-based simulation that predicts the emergent interactions of myosin motors interacting with a motile actin filament. Both the behaviors of individual motors and an ensemble of motors are stochastic, therefore analytical methods are often unable to form accurate design evaluations and computationally intensive simulations are required for investigation. Our modification of the simulation enables the prediction of the duration of time that motors will carry an actin filament before system dissociation (termed its processive life-time), which is a vital performance metric for future nanotechnology designs such as molecular sorters.

Virtual experiments were conducted that determines how perturbations of synthetic myosin design configurations, and the number of myosins present, affects emergent ensemble performance with respect to run-length and energy usage. It is found that all systems have nearly identical average processive life-times for a given input energy regardless of how much energy individual myosins utilize. Such a finding reduces the total information that a designer must consider, since it is a fundamental relationship that holds regardless of lower level component configurations. Such relationships may occur in complex systems in additional domains, and knowledge of these emergent relationships could greatly facilitate the efficiencies of design methods and automated searches for future technologies.
Advanced Modeling for Miniaturized Potted Smart Munitions Development
Authors: Chao Nien-Hua , DeAngelis Mario E. , Lee Jyeching , Kleinbach K. S. , Cheng Ron-Bin
Published: February 2014

Miniaturized electronics and components are becoming more common in precision-guided artillery-launched munitions and missiles. Due to the highly dynamic nature of projectile launch, and the demands for increased structural robustness, many miniaturized smart munitions resort to a potted design in order to achieve functionality and reliability requirements. In most of these applications, the potted electronics are inactive for most of their lifetime and may be stored without environmental (temperature and humidity) controls for up to 20 years. The uncontrolled environment for smart munitions however makes the thermal management task especially difficult due to the coefficient of thermal expansion (CTE) mismatch between the potting material and the electronic components.

It has been previously observed that modeling a potted device, in support of its development through finite-element simulations, is a complex task due to the numerical-convergence issues, material properties and meshes, during simulations as well as resource limitations. In this paper, we will present a modeling/simulation methodology which can be used in the development of miniaturized potted smart munitions and the product qualification process. There are two basic tests that a potential new munition needs to satisfy: 1) a highly accelerated temperature-cycling life test (HALT), to emulate the un-controlled projectile storage environment and, 2) the extremely high-G acceleration during a projectile launch. In this paper, we will present, 1) the use of finite-element analysis to support design decisions to overcome the CTE differences between electronic components on the circuit board assembly and the potting material and, 2) the use of finite-element simulations to study and improve the survivability of the electronic components on the circuit board assembly during extremely high-G acceleration projectile launches.
A Smooth Contact Algorithm Using Cubic Spline Surface Interpolation for Rigid and Flexible Bodies
Authors: Choi Juhwan , Choi Jin Hwan
Published: February 2014

The contact analysis of multi-flexible-body dynamics (MFBD) has been an important issue in the area of computational dynamics because the realistic dynamic analysis of many mechanical systems includes the contacts among rigid and flexible bodies. But, until now, the contact analysis in the multi-flexible-body dynamics has still remained as a big, challenging area. Especially, the most of contact algorithms have been developed based on the facetted triangles. As a result, the contact force based on the facetted surface was not accurate and smooth because the geometrical error is already included in the contact surface representation stage. This kind of error can be very important in the precise mechanism such as gear contact or cam-valve contact problems. In order to resolve this problem, this study suggests a cubic spline surface representation method and related contact algorithms.

The proposed contact algorithms are using the compliant contact force model based on the Hertzian contact theory. In order to evaluate the smooth contact force, the penetration depth and contact normal directions are evaluated by using the cubic spline surface interpolation. Also, for the robust and efficient contact algorithm development, the contact algorithms are divided into four main parts which are a surface representation, a pre-search, a detailed search and a contact force generation. In the surface representation part, we propose a smooth surface representation method which can be used for smooth rigid and flexible bodies. In the pre-search, the algorithm performs collision detection and composes the expected contact pairs for the detailed search. In the detailed search, the penetration depth and contact reference frame are calculated with the cubic spline surface interpolation in order to generate the accurate and smooth contact force. Finally in the contact force generation part, we evaluate the contact force and Jacobian matrix for the implicit time integrator.
Design and Analysis of an Air/Electric Hybrid System
Authors: Hwang Yean-Ren , Huang Shih-Yao
Published: February 2014

This paper proposes a hybridization design and analysis of an air/electric power system in order to extend the service life of the batteries. During the analysis process, the dynamic model of air motor, electric motor and hybrid power mode will be constructed and used in the FPGA speed controller design. By the modular methodology of FPGA, the hybrid power system can successfully operate under ECE-40 driving cycle with PI speed controller. The testing results indicate that the total air consumption is about 256 liters under air motor mode and the electric energy consumption is about 530 coulombs under DC servo motor mode. However, in a hybrid mode, the current reduction of the battery is about 18.5%, and then the service life of the battery can be improved. In addition, the experimental data shows that the chattering ranges of the air motor and the electric motor are within ±1 km/h and ±0.2 km/h respectively under ECE-40 driving cycle testing.
The Magnus Expansion for Periodic Delay Differential Equations
Authors: Takács Árpád , Butcher Eric A. , Insperger Tamás
Published: February 2014

In this paper, the application of the Magnus expansion on periodic time-delayed differential equations is proposed, where an approximation technique of Chebyshev Spectral Continuous Time Approximation (CSCTA) is first used to convert a system of delayed differential equations (DDEs) into a system of ordinary differential equations (ODEs), whose solution are then obtained via the Magnus expansion. The stability and time response of this approach are investigated on two examples and compared with known results in the literature.
Correlation of Tooth Surface Wear Prediction With Experimental Results of Spur and Helical Gears in Commercial Vehicle Transmissions
Authors: Wink Carlos H.
Published: February 2014

Gear pair dynamic loads can increase significantly with involute profile changes caused by wear resulting in vibration and noise issues. Tooth stresses such as root stress and contact stress can also increase reducing gear life. Wear prediction is important during the design phase to minimize the effects of worn tooth surfaces on product performance. Some analytical models have been proposed to predict gear tooth wear; however published correlations of predictions with experimental results are still limited, especially from the gear industry. But they are vital to build confidence in analytical tools. This paper presents a correlation of wear predictions with experimental results of spur and helical gear pairs that are used in commercial vehicle transmissions. Four different gear lubricants were considered, and also three tooth finishes, grinding, honing, and shaving. A modified Archard’s wear model was used for wear predictions. The model combines a gear contact model and an iterative numerical procedure to account for tooth surface changes. Wear coefficients were determined from experiments. The correlation between predictions and dynamometer testing data was established.
Reliability and Functionality of Repairable Systems Using a Minimal Set of Metrics: Design and Maintenance of a Smart Charging Microgrid
Authors: Pandey Vijitashwa , Skowronska Annette G. , Mourelatos Zissimos P. , Gorsich David , Castanier Matthew
Published: February 2014

The definition of reliability may not be readily applicable for repairable systems. Our recent work has shown that multiple metrics are needed to fully account for the performance of a repairable system under uncertainty. Optimal tradeoffs among a minimal set of metrics can be used in the design and maintenance of these systems. A minimal set of metrics provides the most information about the system with the smallest number of metrics using a set of desirable properties. Critical installations such as a remote microgrid powering a military installation require a careful consideration of cost and repair strategies. This is because of logistical challenges in performing repairs and supplying necessary spare parts, particularly in unsafe locations. This paper shows how a minimal set of metrics enhances decision making in such a scenario. It enables optimal tradeoffs between critical attributes in decision making, while guaranteeing that all important performance measures are satisfied. As a result, cost targets and inventory planning can be achieved in an optimal way. We demonstrate the value of the proposed approach using a US Army smart-charging microgrid installation.
Process Capability — A Surrogate Measure of Process Robustness: A Case Study
Authors: Mondal S. C.
Published: February 2014

A robust process is insensitive to the effect of noise variables. Noise variables are the main source for producing variation. Noise variables are included in the outer array in robust design experiment for enhancing robustness. The approach of robust design is to make the process robust (insensitive) to variation due to noise variables. The effect of noise factors can be modelled in a response surface model which helps to determine the settings of the design factors that neutralize the effects of the noise factors and improve robustness. In experimental design the noise factors are assumed fixed value whereas in real world manufacturing noise factors vary randomly. Again for a large scale manufacturing, it is extremely difficult to study robustness using experimentation as there are chances of stoppage of production. In such a situation a simulation-based model can be developed using industrial data to study robustness of a real manufacturing process. This paper proposed a method (a combination of simulation, regression modelling and robust design technique) to study robustness of a hardening and tempering process producing component worm shaft used in the steam power plant. The process capability indices (both univariate and multivariate) are determined based on the model responses. The variation of process performance (process capability values) due to random noise variation is studied using a general purpose process control chart (R-chart). The results show that noise factors in hardening and tempering process are insensitive to manufacturing variation and process capability indices act as a surrogate measure of process robustness.
A New Theoretical and Numerical Approach to Finite Rigid Body Rotations Based on Lie Group Theory
Authors: Natsiavas Sotirios , Paraskevopoulos Elias , Potosakis Nikolaos
Published: February 2014

A systematic theoretical approach is presented first, in an effort to provide a complete and illuminating study on motion of a rigid body rotating about a fixed point. Since the configuration space of this motion is a differentiable manifold possessing group properties, this approach is based on some fundamental concepts of differential geometry. A key idea is the introduction of a canonical connection, matching the manifold and group properties of the configuration space. Next, following the selection of an appropriate metric, the dynamics is also carried over. The present approach is theoretically more demanding than the traditional treatments but brings substantial benefits. In particular, an elegant interpretation can be provided for all the quantities with fundamental importance in rigid body motion. It also leads to a correction of some misconceptions and geometrical inconsistencies in the field. Finally, it provides powerful insight and a strong basis for the development of efficient numerical techniques in problems involving large rotations. This is demonstrated by an example, including the basic characteristics of the class of systems examined.
Analyzing and Designing Serial Flexure Elements
Authors: Hopkins Jonathan B.
Published: February 2014

In this paper we introduce the principles necessary to analyze and design serial flexure elements, which may be used to synthesize advanced compliant mechanisms (CMs). The most commonly used flexure elements (e.g., wire, blade, or living hinge flexures) are often parallel and thus impose constraining forces directly through all parts of their geometry to the rigid bodies that they join within the CM. Serial flexure elements, on the other hand, constrain rigid bodies with a larger variety of forces and moments and thus enable CMs to achieve (i) more degrees of freedom (DOFs), (ii) larger dynamic and elastomechanic versatility, and (iii) greater ranges of motion than parallel elements. In this paper, we extend the principles of the Freedom and Constraint Topologies (FACT) synthesis approach such that it enables the synthesis of CMs that are not only constrained by parallel flexure elements, but also by serial elements. FACT utilizes geometric shapes to intuitively guide designers in visualizing compliant element geometries that achieve any desired set of DOFs. In this way, designers can rapidly generate a host of new serial flexure elements for various CM applications. Such elements are provided here as case studies.
Torsional Vibration of a Spur Gear System With Time-Varying and Square Nonlinearities
Authors: Ding Qian , Zhang Wei
Published: February 2014

This paper investigates the torsional vibration of a spur gear system with time-varying and square nonlinearities, by both the analytical method and numerical simulation. First, the equations of motion of a rotating spur gear system are established. Then a single-dof equivalent system is induced to describe the relative motion or torsional vibration of the gears. The harmonic balance method is used to obtain the steady-state response. Influence of the input torque on the response is discussed and a phenomenon, one resonant peak split up into two peaks when the input torque is high enough is revealed. Last, numerical simulations are carried out and bifurcation diagrams and amplitude-frequency curve is given by taking the excitation frequency as control parameter. Selected typical motions are also presented in detail by time-histories, phase portraits, Poincaré map and frequency spectra.
Open-Source Real-Time Robot Operation and Control System for Highly Dynamic, Modular Machines
Authors: Peekema Andrew , Renjewski Daniel , Hurst Jonathan
Published: February 2014

The control system of a highly dynamic robot requires the ability to respond quickly to changes in the robot’s state. This type of system is needed in varying fields such as dynamic locomotion, multicopter control, and human-robot interaction. Robots in these fields require software and hardware capable of hard real-time, high frequency control. In addition, the application outlined in this paper requires modular components, remote guidance, and mobile control. The described system integrates a computer on the robot for running a control algorithm, a bus for communicating with microcontrollers connected to sensors and actuators, and a remote user interface for interacting with the robot. Current commercial solutions can be expensive, and open source solutions are often time consuming. The key innovation described in this paper is the building of a control system from existing — mostly open source — components that can provide realtime, high frequency control of the robot. This paper covers the development of such a control system based on ROS, OROCOS, and EtherCAT, its implementation on a dynamic bipedal robot, and system performance test results.
Bio-Inspired, Low-Cost, Self-Regulating Valves for Drip Irrigation in Developing Countries
Authors: Zimoch Pawel J. , Tixier Eliott , Joshi Abhijit , Hosoi A. E. , Winter Amos G.
Published: February 2014

We use nonlinear behavior of thin-walled structures — an approach inspired by biological systems (the human airway, for example) — to address one of the most important problems facing subsistence farmers in developing countries: lack of access to inexpensive, water-efficient irrigation systems. An effective way of delivering water to crops is through a network of emitters, with up to 85% of the water delivered being absorbed by plants. However, of the 140 million hectares of cropped land in India alone, only 61 million are irrigated and just 5 million through drip irrigation. This is, in part, due to the relatively high cost of drip irrigation. The main cost comes from the requirement to pump the water at relatively high pressure (>1bar), to minimize the effect of uneven terrain and viscous losses in the network, and to ensure that each plant receives the same amount of water. Using a prototype, we demonstrate that the pressure required to drive the system can be reduced significantly by using thin-walled structures to design emitters with completely passive self-regulation that activates at approximately 0.1bar. This reduction in driving pressure could help bring the price of drip irrigation systems from several thousand dollars to approximately $300, which is within reach of small-scale farmers. Using order-of-magnitude calculations, we show that due to increased sensitivity of the proposed design to the applied pressure differential, a pressure compensating valve for drip irrigation could be built without using costly silicone membranes.
Design of Isotropic Accelerometer Strapdowns for Rigid-Body Pose-and-Twist Estimation
Authors: Zou Ting , Angeles Jorge
Published: February 2014

Coupling of tangential and centripetal acceleration components occurs in the estimation of rigid-body pose and twist with current accelerometer strapdowns. To address this shortcoming and its pernicious effects, a novel design of biaxial accelerometer strapdown is proposed. By virtue of its inherent isotropy, point tangential acceleration is decoupled from its centripetal counterpart, thereby realizing a straightforward and accurate acceleration estimation. The algorithm associated with the strapdown is validated by means of a numerical example, which shows the precision of the strapdown in estimating rigid-body pose and twist.
Stakeholder and Constraint-Driven Innovation of a Novel, Lever-Propelled, All-Terrain Wheelchair
Authors: Winter Amos G.
Published: February 2014

The Leveraged Freedom Chair (LFC) is a low-cost, all-terrain, lever-propelled wheelchair designed primarily for use in developing countries. LFC technology was conceived because 70 percent of wheelchair users in these markets live in rural areas and no currently available mobility aid enables them to travel long distances on rough terrain and maneuver in tight, indoor confines. Because developing world markets impose constraints on cost, durability, and performance, a novel solution was required to satisfy stakeholder requirements. The key innovation behind the LFC is its single speed, variable mechanical advantage lever drivetrain. The user effectively changes gear by shifting his hands along the levers; grasping near the ends increases torque, while grasping near the pivots enables a larger angular displacement with every stroke, which increases speed. The drivetrain is made from low-cost bicycle parts found throughout the developing world, which enables the LFC to be sold for $200 and be repairable anywhere.

During three user trials in East Africa, Guatemala, and India, stakeholder feedback was used to refine the chair between trials, resulting in a device 9.1 kg (20 lbs) lighter, 8.9 cm (3.5 in) narrower, and with a center of gravity 12.7 cm (5 in) lower than the first iteration. Survey data substantiated increases in performance after successive iterations. Quantitative biomechanical performance data were also measured during the Guatemala and India trials, which showed the LFC to be 76 percent faster and 41 percent more efficient during a common daily commute, and able to produce 53 percent higher peak propulsion force compared to conventional, pushrim-propelled wheelchairs. The LFC offers comparable performance at less than one-twentieth the cost of off road wheelchairs available in the rich world. Stakeholder feedback and the highly-constrained environment for which the LFC was created drove the technology towards a novel, innovative solution that offers a competitive advantage in both developing and developed markets. The paper concludes with a description of how the LFC is a “constraint-driven innovation.” This idea ties together the theories of “disruptive innovation” and “reverse innovation,” and may be used as a design tool for engineers striving to create technologies that have global impact.
Strategies for Non-Linear System Identification in Base Excited Structure
Authors: Doranga Sushil , Wu Christine
Published: February 2014

The traditional nonlinear parameter identification techniques described in the existing literature required force and response information at all degrees of freedom. For cases, where the excitation comes from base input, those methods cannot be applied directly unless the measurement is made in all degrees of freedom. The emphasis of this research is upon nonlinear identification of the large, multi-mode, lightly damped, continuous system, where the excitation comes from the moving base. The emphasis is to identify the nonlinear model in parametric forms, where the linear modal testing method is not sufficient to describe the dynamics of the structure. For this reason, a method suitable for the identification of a model based on improved hybrid modal space and modal space is considered. The proposed methodology shows the extraction process of pseudo force projected at the measured degrees of freedom. An experiment is performed to validate the proposed method in a cantilever beam. Nonlinear parameter selections are done through multilinear regression in a modal domain. A significant cubic stiffness nonlinearity is found in the first mode. The cross-coupling stiffness terms are found to be insignificant during regression analysis.