bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining Genetic Algorithms and Extended Kalman Filter to Estimate Ankle’s Muscle-Tendon Parameters
Authors: Coronado Luis Enrique , Chavez-Romero Raul , Maya Mauro , Cardenas Antonio , Piovesan Davide
Published: January 2016

This work proposes a set of simulation and experimental measurements to estimate muscle biomechanical parameter during human quiet standing. Understanding the mechanisms involved in postural stability is indispensable to improve the knowledge of how humans can regain balance against possible disturbances. Postural stability requires the ability to compensate the movement of the body’s center of gravity caused by external or internal perturbations. This paper describes the implementation of a hybrid parameter-estimation approach to infer the features of the human neuro-mechanical system during quiet standing and the recovery from a fall. The estimation techniques combines a genetic algorithm with the State-Augmented Extended Kalman Filter. These two algorithms running sequentially are utilized to estimate the musculo-skeletal parameters. This paper shows results of the approach when representing human standing as either a second-order or third order mechanical model. Experimental validation on a human subject is also presented.
Understanding Wind Turbine Interactions Using Spatiotemporal Pattern Network
Authors: Jiang Zhanhong , Sarkar Soumik
Published: January 2016

This paper presents a data-driven modeling framework to understand spatiotemporal interactions among wind turbines in a large scale wind energy farm. A recently developed probabilistic graphical modeling scheme, namely the spatiotemporal pattern network (STPN) is used to capture individual turbine characteristics as well as pair-wise causal dependencies. The causal dependency is quantified by a mutual information based metric and it has been shown that it efficiently and correctly captures both temporal and spatial characteristics of wind turbines. The causal interaction models are also used for predicting wind power production by one wind turbine using observations from another turbine. The proposed tools are validated using the Western Wind Integration data set from the National Renewable Energy Laboratory (NREL).
Active Sensing of Distributed Parameter Structures Enhanced by Robust Consensus Observer
Authors: Omidi Ehsan , Mahmoodi S. Nima
Published: January 2016

A robust consensus observer is described in this paper for state estimation in active distributed parameter structures. To this end, a distributed parameter flexible structure is enhanced by piezoelectric layers to acquire position data in a sensor network with certain directed topology. A decentralized observer dynamics is designed to enforce consensus between the estimated states by each sensor agent. The designed consensus estimator is then optimized using an Algebraic Riccati Equation. The robustness problem is addressed using H∞ performance constraints. The consensus state estimator is then numerically investigated to further support the theoretical expectations, where a sensor network of four agents is used over a flexible clamped-clamped beam. The optimal and robust systems are simulated and the results are illustrated and discussed. The robust consensus observer successfully estimates the states of the system in existence of measurement disturbances and in finite time, which makes the robust designed scheme practical for numerous applications.
Remote Lead Through Teaching by Human Demonstration Device
Authors: Lin Hsien-Chung , Tang Te , Tomizuka Masayoshi , Chen Wenjie
Published: January 2016

Industrial robots are playing increasingly important roles in production lines. The traditional pendant programming method, however, is unintuitive and time-consuming. Its complicated operation also sets a high requirement on users. To simplify the robot programming process, many new methods have been proposed, such as lead through teaching, teleoperation, and human direct demonstration. Each of these methods, however, suffers from its own drawbacks. To overcome the drawbacks, a novel robot programming method, remote lead through teaching (RLTT), is introduced in this paper. In RLTT, the operator uses a device to train the robot remotely, allowing the demonstrators to use the mature lead through teaching techniques in a safe environment. In order to implement RLTT, the human demonstration device (HDD) is also designed to transfer the demonstration information from the human to the robot.
Model Predictive Control-Based Probabilistic Search Method for Autonomous Ground Robot in a Dynamic Environment
Authors: Liu Chang , Li Shengbo Eben , Hedrick J. Karl
Published: January 2016

Target search using autonomous robots is an important application for both civil and military scenarios. In this paper, a model predictive control (MPC)-based probabilistic search method is presented for a ground robot to localize a stationary target in a dynamic environment. The robot is equipped with a binary sensor for target detection, of which the uncertainties of binary observation are modeled as a Gaussian function. Under the model predictive control framework, the probability map of the target is updated via the recursive Bayesian estimation and the collision avoidance with obstacles is enforced using barrier functions. By approximating the updated probability map using a Gaussian Mixture Model, an analytical form of the objective function in the prediction horizon is derived, which is promising to reduce the computation complexity compared to numerical integration methods. The effectiveness of the proposed method is demonstrated by performing simulations in dynamic scenarios with both static and moving obstacles.
Complete Coverage Path Planning for Flexible Parent-Child Unit Robots
Authors: Olaonipekun Dare , Vaughan Joshua
Published: January 2016

This paper presents a complete coverage algorithm for a flexible parent child unit robot by combining input shaping with the wavefront algorithm. Input shaping was used to control the command-induced vibration in the system, while the wavefront algorithm planned the complete coverage path for a given workspace. A model of the flexible robot was developed by treating the child units as inputs, replacing the link wire by springs and dampers, and treating the parent unit as a point mass. Results showed significant improvement in the coverage process for the shaped coverage in comparison to the unshaped coverage.
Optimal Slip Control of a Torque Converter Clutch
Authors: Wang Yaoying , Sun Zongxuan
Published: January 2016

Slip control of a torque converter clutch (TCC) has been developed for years but most approaches are focused on time-based methods without offering a systematic approach for dealing with the time-varying signals associated with the engine torque pulsation. As one of the major vibration sources of a vehicle, engine torque is periodic in the crankshaft rotational angle but aperiodic in time as the engine speed changes in real-time. This paper first presents a powertrain vibration analysis based on the transient engine torque input and the conventional TCC slip control. Simulation results show that the conventional time-based TCC slip control does not settle the periodic nature of the engine torque vibration with respect to crankshaft angle. However, a time-varying angle-based control method can solve this issue. The paper then proposes an optimal TCC torque trajectory by using dynamic programming for this time-varying angle-based control method. Simulation results demonstrate the energy saving potential of the optimal trajectory over the conventional method.
A Control-Oriented Model of Blood Volume Response to Hemorrhage and Fluid Resuscitation
Authors: Bighamian Ramin , Reisner Andrew T. , Hahn Jin-Oh
Published: January 2016

This paper presents a control-oriented model of blood volume response to hemorrhage and fluid resuscitation that can be potentially utilized in closed-loop control of fluid resuscitation. A unique characteristic of the proposed model is that it is built to ensure structural parsimony while retaining physiological transparency. To accomplish this characteristic, blood volume regulation in the body to external perturbations of hemorrhage and fluid resuscitation was modeled as a low-order control system in which the fluid transfer between blood and interstitial fluid is governed by a proportional-integral controller. This in essence resulted in a minimal model with four parameters to be adapted to each individual. The validity of the proposed model was tested using data available in the literature. The results indicated that the proposed model was able to reproduce the blood volume response to hemorrhage and fluid resuscitation with high fidelity: on the average, the prediction error was only 1.53 ± 11.5 %, thus strongly supporting our claim that it can be used as viable basis for the design of closed-loop fluid resuscitation controllers.
Online Identification of System Uncertainties Using Coprime Factorizations With Application to Hard Disk Drives
Authors: Bagherieh Omid , Shahsavari Behrooz , Horowitz Roberto
Published: January 2016

In hard disk drive (HDD) magnetic recording bit patterned media (BPM), data are written in predetermined paths. The deviation of these paths from the perfect circle is categorized as repeatable run-out (RRO) which needs to be tracked. An adaptive RRO following algorithm was developed in [1,2] in order to track the RRO. This algorithm uses models of the closed-loop sensitivity transfer functions, from the feedforward injection points to position error signal (PES), to estimate the feedforward control actions that are needed to track the RRO. The phase difference between these models and the actual transfer functions must be less than 90 degrees, in order to guarantee the convergence of the adaptive RRO following algorithm. The dual-stage actuators’ gains and resonance modes are affected by temperature variations, which in turn affect all closed loop sensitivity transfer functions. As a consequence, the 90-degree criteria may be violated unless these transfer functions are periodically updated. In this paper, the coprime factorizations method has been used to factorize and identify the uncertain part of the model instead of identifying the entire transfer function of the model. Experimental results conducted on a hard disk drive equipped with dual-stage actuation, confirm the effectiveness of the proposed estimation algorithm.
Experimental Investigation of a Time Scales-Based Stability Criterion Over Finite Time Horizons
Authors: Mosley Matthew , Gravagne Ian , Poulsen Dylan , Davis John
Published: January 2016

Feedback control systems that employ large area networks or other unpredictable or unreliable communications protocols between sensors, actuators, and controllers may experience nonuniform sampling characteristics. Previous work by Poulsen, et. al. gives a criterion for exponential stability of non-uniformly discretized feedback control systems, assuming sample periods drawn from a known statistical distribution. However, the given stability theorem assumes an infinite time horizon. This work therefore examines the exponential stability criterion experimentally, over a finite time horizon, on a 2nd-order servo mechanism. This paper is the first to experimentally investigate the validity of this time scales stability criterion.
Mathematical Model for Coordinated Motion of Modular Mechatronic Devices (MechaCells)
Authors: Ristevski Stefan , Çakmakcı Melih
Published: January 2016

Manufacturing techniques have advanced exponentially in recent years, providing means for micro even nano scale manufacturing of different structures. Mechanical and electrical components are being manufactured at micro/nano scale, producing amazing opportunities in micro/nano modular robot development, for modules that are smaller and more powerful. Development of mathematical models for such modular devices is an important step in the design and development of control strategies for coordinated movement. A mathematical model for modular mechatronic device, MechaCell was developed, in which the interaction forces between module–workpiece are modeled as the disturbance to be compensated by the closed loop position controller for each device. Experiments with an actual workpiece are conducted and our mathematical model was validated. Our future work will include development of better control strategies for coordinated motion and object transportation and caging stratifies.
Probability-Based Optimal Path Planning for Two-Wheeled Mobile Robots
Authors: Lee Jaeyeon , Park Wooram
Published: January 2016

Most dynamic systems show uncertainty in their behavior. Therefore, a deterministic model is not sufficient to predict the stochastic behavior of such systems. Alternatively, a stochastic model can be used for better analysis and simulation. By numerically integrating the stochastic differential equation or solving the Fokker-Planck equation, we can obtain a probability density function of the motion of the system. Based on this probability density function, the path-of-probability (POP) method for path planning has been developed and verified in simulation. However, there are rooms for more improvements and its practical implementation has not been performed yet. This paper concerns formulation, simulation and practical implementation of the path-of-probability for two-wheeled mobile robots. In this framework, we define a new cost function which measures the averaged targeting error using root-mean-square (RMS), and iteratively minimize it to find an optimal path with the lowest targeting error. The proposed algorithm is implemented and tested with a two-wheeled mobile robot for performance verification.
Investigation of Energy Efficiency in Force Control of Pneumatic Actuators
Authors: Taheri Behzad , Case David , Richer Edmond
Published: January 2016

Pneumatic actuators, due to their unique features, have numerous industrial applications. However, when compared to electrical actuators, one of the major problems of the overall pneumatic system is low-efficiency. Thus it is important to develop control algorithms for force tracking of pneumatic actuators while minimizing the consumed energy. This paper presents three different approaches for force tracking of pneumatic cylinders. A dual-action pneumatic cylinder along with a real-time control platform were used to compare the energy efficiency and force tracking performance of these methods. Experiments with sinusoidal forces reveled that minimizing the chamber pressure gives the best tracking performance and energy efficiency in higher frequencies.
Efficient Spatial Dynamics for Continuum Arms
Authors: Godage Isuru S. , Wirz Raul , Walker Ian D. , Webster Robert J.
Published: January 2016

Continuum robot dynamic models have previously involved a choice between high accuracy, numerically intensive models, and low accuracy, computationally efficient models. The objective of this paper is to provide an accurate dynamic model with low computational overhead. Our approach is to place point masses at the center of gravity of the continuum section, rather than along the robot’s backbone or centerline. This enables the model to match the robot’s energetic characteristics with many fewer point masses. We experimentally validate the model using a pneumatic muscle actuated continuum arm. We find that the proposed model successfully captures both the transient and steady state dynamics of the arm.
Robust Bayesian Sequential Input Shaping for Optimal Li-Ion Battery Model Parameter Identifiability
Authors: Rothenberger Michael J. , Fathy Hosam K.
Published: January 2016

This paper examines the challenge of shaping a battery’s input trajectory to (i) maximize its Fisher parameter identifiability while (ii) achieving robustness to parameter uncertainties. The paper is motivated by earlier research showing that the speed and accuracy with which battery parameters can be estimated both improve significantly when battery inputs are optimized for Fisher identifiability. Previous research performs this trajectory optimization for a known nominal parameter set. This creates a tautology where accurate parameter identification is a prerequisite for Fisher identifiability optimization. In contrast, this paper presents an iterative scheme that: (i) uses prior parameter probability distributions to create a weighted Fisher metric; (ii) optimizes the battery input trajectory for this metric using a genetic algorithm; (iii) applies the resulting input trajectory to the battery; (iv) estimates battery parameters using a Bayesian particle filter; (v) re-computes the weighted Fisher information metric using the resulting posterior parameter distribution; and (vi) repeats this process until convergence. This approach builds on well-established ideas from the estimation literature, and applies them to the battery domain for the first time. Simulation studies highlight the ability of this iterative algorithm to converge quickly towards the correct battery parameter values, despite large initial parameter uncertainties.
Experimental verification of gain drop due to general ion recombination for a carbon‐ion pencil beam
Authors: Tansho Ryohei , Furukawa Takuji , Hara Yousuke , Mizushima Kota , Saotome Naoya , Saraya Yuichi , Shirai Toshiyuki , Noda Koji
Published: January 2016

Purpose:

Accurate dose measurement in radiotherapy is critically dependent on correction for gain drop, which is the difference of the measured current from the ideal saturation current due to general ion recombination. Although a correction method based on the Boag theory has been employed, the theory assumes that ionized charge density in an ionization chamber (IC) is spatially uniform throughout the irradiation volume. For particle pencil beam scanning, however, the charge density is not uniform, because the fluence distribution of a pencil beam is not uniform. The aim of this study was to verify the effect of the nonuniformity of ionized charge density on the gain drop due to general ion recombination.

Methods:

The authors measured the saturation curve, namely, the applied voltage versus measured current, using a large plane‐parallel IC and 24‐channel parallel‐plate IC with concentric electrodes. To verify the effect of the nonuniform ionized charge density on the measured saturation curve, the authors calculated the saturation curve using a method which takes into account the nonuniform ionized charge density and compared it with the measured saturation curves.

Results:

Measurement values of the different saturation curves in the different channels of the concentric electrodes differed and were consistent with the calculated values. The saturation curves measured by the large plane‐parallel IC were also consistent with the calculation results, including the estimation error of beam size and of setup misalignment. Although the impact of the nonuniform ionized charge density on the gain drop was clinically negligible with the conventional beam intensity, it was expected that the impact would increase with higher ionized charge density.

Conclusions:

For pencil beam scanning, the assumption of the conventional Boag theory is not valid. Furthermore, the nonuniform ionized charge density affects the prediction accuracy of gain drop when the ionized charge density is increased by a higher dose rate and/or lower beam size.
Behavioral Interventions and Physical Activity in Older Adults: Gains and Gaps
Authors: Wilcox Sara
Published: January 2016

There is strong evidence that older adults greatly benefit from regular physical activity. Yet, older age is consistently associated with lower levels of aerobic physical activity and strength training and higher levels of sedentary behavior, underscoring the need to better understand physical activity behavior in this population. Reviews of interventions to increase physical activity have overall yielded promising results. Interventions based on behavior theory appear to be more effective than non-theory-based interventions, yet strategies from these theories are underutilized in both research and practice. This paper discusses the importance of behavioral interventions, cites findings from the Active for Life initiative to illustrate several key concepts, and provides recommendations to address significant gaps in the literature, including the use of theory, mediation analyses, physical activity maintenance, diversity of participants, and dissemination and translational research.
Influence of pre-existing inflammation on the outcome of acute coronary syndrome: a cross-sectional study
Authors: Odeberg Jacob , Freitag Michael , Forssell Henrik , Vaara Ivar , Persson Marie-Louise , Odeberg Håkan , Halling Anders , Råstam Lennart , Lindblad Ulf
Published: January 2016

Objectives

Inflammation is a well-established risk factor for the development of coronary artery disease (CAD) and acute coronary syndrome (ACS). However, less is known about its influence on the outcome of ACS. The aim of this study was to determine if blood biomarkers of inflammation were associated specifically with acute myocardial infarction (MI) or unstable angina (UA) in patients with ACS.

Design

Cross-sectional study.

Setting

Patients admitted to the coronary care unit, via the emergency room, at a central county hospital over a 4-year period (1992–1996).

Participants

In a substudy of Carlscrona Heart Attack Prognosis Study (CHAPS) of 5292 patients admitted to the coronary care unit, we identified 908 patients aged 30–74 years, who at discharge had received the diagnosis of either MI (527) or UA (381).

Main outcome measures

MI or UA, based on the diagnosis set at discharge from hospital.

Results

When adjusted for smoking, age, sex and duration of chest pain, concentrations of plasma biomarkers of inflammation (high-sensitivity C reactive protein>2 mg/L (OR=1.40 (1.00 to 1.96) and fibrinogen (p for trend=0.035)) analysed at admission were found to be associated with MI over UA, in an event of ACS. A strong significant association with MI over UA was found for blood cell markers of inflammation, that is, counts of neutrophils (p for trend<0.001), monocytes (p for trend<0.001) and thrombocytes (p for trend=0.021), while lymphocyte count showed no association. Interestingly, eosinophil count (p for trend=0.003) was found to be significantly lower in patients with MI compared to those with UA.

Conclusions

Our results show that, in patients with ACS, the blood cell profile and degree of inflammation at admission was associated with the outcome. Furthermore, our data suggest that a pre-existing low-grade inflammation may dispose towards MI over UA.
Comparative study of linear and curvilinear ultrasound probes to assess quadriceps rectus femoris muscle mass in healthy subjects and in patients with chronic respiratory disease
Authors: Mandal S , Suh E , Thompson A , Connolly B , Ramsay M , Harding R , Puthucheary Z , Moxham J , Hart N
Published: January 2016

Introduction

Ultrasound measurements of rectus femoris cross-sectional area (RFCSA) are clinically useful measurements in chronic obstructive pulmonary disease (COPD) and critically ill patients. Technical considerations as to the type of probe used, which affects image resolution, have limited widespread clinical application. We hypothesised that measurement of RFCSAwould be similar with linear and curvilinear probes.

Methods

Four studies were performed to compare the use of the curvilinear probe in measuring RFCSA.Study 1investigated agreement of RFCSAmeasurements using linear and curvilinear probes in healthy subjects, and in patients with chronic respiratory disease.Study 2investigated the intra-rater and inter-rater agreement using the curvilinear probe.Study 3investigated the agreement of RFCSAmeasured from whole and spliced images using the linear probe.Study 4investigated the applicability of ultrasound in measuring RFCSAduring the acute and recovery phases of an exacerbation of COPD.

Results

Study 1showed demonstrated no difference in the measurement of RFCSAusing the curvilinear and linear probes (308±104 mm2vs 320±117 mm2, p=0.80; intraclass correlation coefficient (ICC)>0.97).Study 2demonstrated high intra-rater and inter-rater reliability of RFCSAmeasurement with ICC>0.95 for both.Study 3showed that the spliced image from the linear probe was similar to the whole image RFCSA(308±103.5 vs 263±147 mm2, p=0.34; ICC>0.98).Study 4confirmed the clinical acceptability of using the curvilinear probe during an exacerbation of COPD. There were relationships observed between admission RFCSAand body mass index (r=+0.65, p=0.018), and between RFCSAat admission and physical activity levels at 4 weeks post-hospital discharge (r=+0.75, p=0.006).

Conclusions

These studies have demonstrated that clinicians can employ whole and spliced images from the linear probe or use images from the curvilinear probe, to measure RFCSA. This will extend the clinical applicability of ultrasound in the measurement of muscle mass in all patient groups.
Should we add smells in simulation training? A systematic review of smells in healthcare-related simulation training
Authors: Kent Samuel John Wilfrid , Kent Frances Helen , Brown Craig William , Morrison Ian Gordon , Morse Jerry Charles
Published: January 2016

Olfactory stimuli are rarely used in healthcare-related simulation training. Their addition may improve simulator validity, biographical memory formation and coping mechanisms for exposure to strong malodours. Some military simulators already employ smells in simulation training, and the technology and principles may be used to cross over into medical simulation training. We set out to determine if there is evidence to suggest that smell should be routinely incorporated into medical simulation training. We carried out a systematic review of the literature relating to use of olfactory stimuli in medical simulation training, and identified 5 relevant papers. 3 were experimental studies and 2 were observational studies. The results of the experimental studies were mixed, though there were some indications that the use of a clinically relevant smell instead of a congruent background smell may be more effective. We discuss the benefits of the inclusion of smell in simulation training and identify that there are currently few high-quality studies addressing the use of smell in medical simulation training.
Focusing on geriatric pets
Authors: Davies Mike
Published: January 2016

An in‐depth consultation to screen geriatric patients can identify otherwise unrecognised problems and occasionally life‐threatening conditions that need to be managed properly. Mike Davies explains how a geriatric screening programme can improve patient care and reinforce the client‐practice bond, while also providing opportunities to enhance business activity.
Comments on the dilemma in the November/December issue: ‘Delivering profit?’
Authors: McCulloch Steven
Published: January 2016

In the dilemma discussed in the November/December issue of In Practice, a client had asked you to accompany him to see a tup that he considered to be an excellent buy in terms of its potential production value. However, you were aware that the client's farm had a history of caesarians and vet‐assisted lambings and were concerned that this tup might add to the problem (IP, November/December 2015, vol 37, pp 550‐551). Richard Brown suggested that it was not a lost cause to try and reduce the amount of vet‐assisted lambings. However, simply telling the client that the purchase was not a good idea could create a problem for the farmer and you should take time to find alternative solutions. It would be advisable to check with the farmer on his estimate of income, as he might have overestimated this. If you decided to go to the vendor's farm to see the tup, biosecurity should be a priority. You should also make it clear that your focus would be on animal health and welfare, not on the conformation or genetic merits of the animal.
JNIS podcasts: the early part of our journey
Authors: Hirsch Joshua A , Fargen Kyle , Ducruet Andrew F , Tarr Robert W
Published: January 2016

Podcasts are an area of innovation in the neurointerventional space that has the potential to convey information in ways that traditional journal articles in peer-reviewed journals do not. BMJ maintains an archive of all of its podcasts on theJournal of NeuroInterventional Surgery(JNIS) website. We sought to analyze this earlyJNISpodcast experience and assess the impact of content elements and an increased presence in social media.
Successful diagnosis and treatment of Orthohalarachne attenuata nasal mites utilising voluntary rhinoscopy in three Pacific walrus (Odobenus rosmarus divergens)
Authors: Fravel Vanessa , Procter Diana
Published: January 2016

A 17‐year‐old adult female walrus presented with copious nasal discharge for one week duration despite a normal appetite and attitude. Antibiotic treatment was initiated based on culture results from the nasal discharge. The amount of nasal discharge decreased dramatically during antibiotic treatment but returned soon after the treatment ended. The walrus had a mild leucocytosis, normal thoracic ultrasound and normal skull radiographs. After four weeks of training, voluntary endoscopy of the anterior nasal cavity was performed revealing mucus surrounding nasal mites, which were collected. The nasal mites were examined microscopically and determined to be Orthohalarachne attenuata nasal mites. The patient was successfully treated with ivermectin 0.2 mg/kg by mouth two weeks apart. This report highlights the importance of medical husbandry training to perform diagnostic procedures without the risk of anaesthesia.
Attracting and retaining farm vets
Authors: Allcock James
Published: January 2016

James Allcock, of Lambert, Leonard & May, a farm‐only vet practice in Shropshire, describes the steps the practice has taken to help with recruitment and retention of farm vets
Laboratory thermal calibration of contact pressure cells installed on integral bridge abutments
Authors: Huntley Shelley A. , Valsangkar Arun J.
Published: January 2016

Hydraulic contact pressure cells were installed on the abutments of an integral abutment bridge to monitor changes in earth pressure over an extended period of time. The accuracy of field data from such instruments is affected by a number of factors. In particular, temperature changes are one of the key factors that can influence earth pressure measurements. Thermal calibration factors supplied by manufacturers of such cells tend to only account for the effect of temperature on the pressure transducer, rather than on the instrument as a whole. Therefore, in an effort to quantify the effect of temperature on data collected from the contact pressure cells installed on the integral abutment bridge, laboratory thermal calibration of these sensors was undertaken. Construction-related time constraints precluded extensive testing of the instruments installed in the field; however, extensive tests were conducted on an identical contact and earth pressure cell. Laboratory thermal calibration tests were conducted on the sensors for an unloaded, unconfined condition and with sensors confined in soil and loaded with uniform pressure. All tests were conducted in a cold room where temperatures could be controlled over a wide range. Results indicate that both temperature and applied pressure affect the performance of hydraulic pressure cells. Thermal correction factors were developed from linear-regression analysis of the unloaded, unconfined test data; however, application of these factors to the loaded, confined test data was found to account for only a portion of the pressure variation, with the remaining variation still being significant. Similar correction factors by linear regression analysis could not be developed from the loaded, confined pressure test data. However, when considering the range of temperatures experienced by the pressure cells installed on the integral abutment bridge, it was concluded in a 2013 study by the authors that the thermal pressure variations present in the field data should not exceed ±10 kPa. The results of this research demonstrate the need for extensive laboratory calibration of these types of pressure cells for proper interpretation of field data.
A fuzzy logic approach to posture-based ergonomic analysis for field observation and assessment of construction manual operations
Authors: Golabchi Alireza , Han SangUk , Fayek Aminah Robinson
Published: January 2016

In construction, workers are frequently exposed to ergonomic risks that can lead to musculoskeletal disorders. To prevent ergonomic injuries, proper assessment of ergonomic risk is a key to identifying risk factors and modifying work practice in a timely manner. In field observation, however, difficulties in visually estimating human postures (e.g., body joint angles) required for ergonomic analysis have led to inconsistent results due to the subjectiveness of observers. This study thus proposes a fuzzy logic approach to posture-based ergonomic evaluation tools. Rapid Upper Limb Assessment (RULA) is selected as a case study to describe the fuzzy logic modelling of RULA scoring systems and discuss the application to modular construction shops. The results of validation comparing correlations with biomechanical analysis — used as a ground truth — reveal that the proposed system produces more accurate results than traditional methods and hence helps minimize human errors in observation for reliable on-site ergonomic assessment.
Automatic Handwriting Feature Extraction, Analysis and Visualization in the Context of Digital Palaeography
Authors: Liang Y. , Fairhurst M. C. , Guest R. M. , Erbilek M.
Published: January 2016

Digital palaeography is an emerging research area which aims to introduce digital image processing techniques into palaeographic analysis for the purpose of providing objective quantitative measurements. This paper explores the use of a fully automated handwriting feature extraction, visualization, and analysis system for digital palaeography which bridges the gap between traditional and digital palaeography in terms of the deployment of feature extraction techniques and handwriting metrics. We propose the application of a set of features, more closely related to conventional palaeographic assesment metrics than those commonly adopted in automatic writer identification. These features are emprically tested on two datasets in order to assess their effectiveness for automatic writer identification and aid attribution of individual handwriting characteristics in historical manuscripts. Finally, we introduce tools to support visualization of the extracted features in a comparative way, showing how they can best be exploited in the implementation of a content-based image retrieval (CBIR) system for digital archiving.
Multidimensional Scaling Visualization Using Parametric Entropy
Authors: Lopes António M. , Tenreiro Machado J. A. , Galhano Alexandra M.
Published: January 2016

This paper studies complex systems using a generalized multidimensional scaling (MDS) technique. Complex systems are characterized by time-series responses, interpreted as a manifestation of their dynamics. Two types of time-series are analyzed, namely 18 stock markets and the gross domestic product per capita of 18 countries. For constructing the MDS charts, indices based on parametric entropies are adopted. Multiparameter entropies allow the variation of the parameters leading to alternative sets of charts. The final MDS maps are then assembled by means of Procrustes’ method that maximizes the fit between the individual charts. Therefore, the proposed method can be interpreted as a generalization to higher dimensions of the standard technique that represents (and discretizes) items by means of single “points” (i.e. zero-dimensional “objects”). The MDS plots, involving one-, two- and three-dimensional “objects”, reveal a good performance in capturing the correlations between data.
Li–Yorke Chaos in Hybrid Systems on a Time Scale
Authors: Akhmet Marat , Fen Mehmet Onur
Published: January 2016

By using the reduction technique to impulsive differential equations [Akhmet & Turan, 2006], we rigorously prove the presence of chaos in dynamic equations on time scales (DETS). The results of the present study are based on the Li–Yorke definition of chaos. This is the first time in the literature that chaos is obtained for DETS. An illustrative example is presented by means of a Duffing equation on a time scale.
Joint Channel Estimation and Signal Detection for the OFDM System Without Cyclic Prefix Over Doubly-Selective Channels
Authors: Song Lijun , Lei Xia , Jin Maozhu , Lv Zhihan
Published: January 2016

In the high-speed railway wireless communication, a joint channel estimation and signal detection algorithm is proposed for the orthogonal frequency division multiplexing (OFDM) system without cyclic prefix in the doubly-selective fading channels. Our proposed method first combines the basis expansion model (BEM) and the inter symbol interference (ISI) cancellation to overcome the situation that exists with the fast time-varying channel and the normalized maximum multipath channel exceeding the length of the cyclic prefix (CP). At first, the channel estimation and signal detection can be approximated without considering the ISI. Then, the channel parameters and signal detection are updated through ISI cancellation and circular convolution reconstruction from the frequency domain. The simulations show the algorithm can improve the performance of channel estimation and signal detection.
Design of Radio Frequency Link in Automatic Test System for Multimode Mobile Communication Base Station
Authors: Zhang Weipeng
Published: January 2016

A modularized design for the radio frequency (RF) link in automatic test system of multimode mobile communication base station is presented, considering also the characteristics of wireless communication indices and composition of signals of base stations. The test link is divided into general module, time division duplex (TDD) module, module of spurious noise filter, module of downlink intermodulation, module of uplink intermodulation and uplink block module. The composition of modules and link functions are defined, and the interfaces of the general module and the module of spurious noise filter are described. Finally, the estimated gain budget of the test link is presented. It is verified by experiments that the system is reliable and the test efficiency is improved.
A Novel Discrete Differential Evolution Algorithm for the Vehicle Routing Problem in B2C E-Commerce
Authors: Xia Chao , Sheng Ying , Jiang Zhong-Zhong , Tan Chunqiao , Huang Min , He Yuanjian
Published: January 2016

In this paper, a novel discrete differential evolution (DDE) algorithm is proposed to solve the vehicle routing problems (VRP) in B2C e-commerce, in which VRP is modeled by the incomplete graph based on the actual urban road system. First, a variant of classical VRP is described and a mathematical programming model for the variant is given. Second, the DDE is presented, where individuals are represented as the sequential encoding scheme, and a novel reparation operator is employed to repair the infeasible solutions. Furthermore, a FLOYD operator for dealing with the shortest route is embedded in the proposed DDE. Finally, an extensive computational study is carried out in comparison with the predatory search algorithm and genetic algorithm, and the results show that the proposed DDE is an effective algorithm for VRP in B2C e-commerce.
A Traffic Motion Object Extraction Algorithm
Authors: Wu Shaofei
Published: January 2016

A motion object extraction algorithm based on the active contour model is proposed. Firstly, moving areas involving shadows are segmented with the classical background difference algorithm. Secondly, performing shadow detection and coarse removal, then a grid method is used to extract initial contours. Finally, the active contour model approach is adopted to compute the contour of the real object by iteratively tuning the parameter of the model. Experiments show the algorithm can remove the shadow and keep the integrity of a moving object.
A regime-switching model with jumps and its application to bond pricing and insurance
Authors: Dong Yinghui , Wang Guojing , Yuen Kam Chuen
Published: January 2016

In this paper, we consider a Markovian, regime-switching model with jumps and its application to bond pricing and insurance. The jumps in the model are described by a compound Cox process, where the arrival intensity of the counting number-process follows a regime-switching shot noise process. Using a martingale method, we derive exponential-affine form expressions for the price of a zero-coupon bond and the joint Laplace transform of the aggregate accumulated claims and the arrival intensity.
Detection of homologous recombination in closely related strains
Authors: Kalinina Anastasia S. , Suvorikova Alexandra L. , Spokoiny Vladimir G. , Gelfand Mikhail S.
Published: January 2016

Detection of recombination events in a bacterial genome is both important from the evolutionary point of view, and of practical interest. Indeed, homologous recombination (HR) plays a major role in the exchange of antigenic determinants between strains. There exist statistical methods to detect recently recombined segments in whole-genome sequences that use a high local density of substitutions as a signal of HR events with a source outside considered strains. However, it is difficult to detect the HR events within a set of strains, which represent whole species diversity, due to a low number of substitutions in recombined segments and high level of diversity of strains. Here, we analyzed HR in 20 Escherichia coli (E. coli) strains to define what fraction of segments with a high substitution rate were introduced in a genome by HR. For detection of HR, we used the segmentation, performed by the adaptive weights smoothing (AWS) algorithm. It detects sharp changes in the structure of observed data analyzing only qualitative structural information. We validated the approach on simulated data, applied it to the analysis of E. coli strains, and determined the recombination rates between phylogroups.
Issues in performance evaluation for host–pathogen protein interaction prediction
Authors: Abbasi Wajid Arshad , Minhas Fayyaz Ul Amir Afsar
Published: January 2016

The study of interactions between host and pathogen proteins is important for understanding the underlying mechanisms of infectious diseases and for developing novel therapeutic solutions. Wet-lab techniques for detecting protein–protein interactions (PPIs) can benefit from computational predictions. Machine learning is one of the computational approaches that can assist biologists by predicting promising PPIs. A number of machine learning based methods for predicting host–pathogen interactions (HPI) have been proposed in the literature. The techniques used for assessing the accuracy of such predictors are of critical importance in this domain. In this paper, we question the effectiveness of K-fold cross-validation for estimating the generalization ability of HPI prediction for proteins with no known interactions. K-fold cross-validation does not model this scenario, and we demonstrate a sizable difference between its performance and the performance of an alternative evaluation scheme called leave one pathogen protein out (LOPO) cross-validation. LOPO is more effective in modeling the real world use of HPI predictors, specifically for cases in which no information about the interacting partners of a pathogen protein is available during training. We also point out that currently used metrics such as areas under the precision-recall or receiver operating characteristic curves are not intuitive to biologists and propose simpler and more directly interpretable metrics for this purpose.
Free Vibration of Cross-Ply Laminated Plates with Variable Thickness Based on Shear Deformation Theory
Authors: Viswanathan K. K. , Aziz Z. A. , Javed Saira , Salleh Shaharuddin , Tumiran Siti Aisyah Binti , Sivakumar Bellie
Published: January 2016

Free vibration of laminated cross-ply plates of variable thickness including transverse problem is solved numerically to obtain eigenvalues as frequency parameter and associated eigenvectors which are spline coefficients. The variation of frequency parameters with respect to the aspect ratio, side-to-thickness ratio, ply-angle, number of layer and thickness variations for two different materials under simply supported boundary conditions are analyzed.
Active versus passive transformations in the presence of a magnetic field
Authors: Torres del Castillo G. F. , Rosete-Álvarez D. A.
Published: January 2016

It is shown that, when there is a magnetic field present, in the framework of classical or quantum mechanics, the active translations differ from the passive ones and that the canonical momentum is not the generator of them. It is also shown that an infinitesimal generator of passive translations or rotations exists only if the magnetic field is invariant under these transformations.
Killing symmetries as Hamiltonian constraints
Authors: lusanna Luca
Published: January 2016

The existence of a Killing symmetry in a gauge theory is equivalent to the addition of extra Hamiltonian constraints in its phase space formulation, which imply restrictions both on the Dirac observables (the gauge invariant physical degrees of freedom) and on the gauge freedom. When there is a time-like Killing vector field only pure gauge electromagnetic fields survive in Maxwell theory in Minkowski space-time, while in ADM canonical gravity in asymptotically Minkowskian space-times only inertial effects without gravitational waves survive.
Analogues of the binomial coefficient theorems of Gauss and Jacobi
Authors: Al-Shaghay Abdullah , Dilcher Karl
Published: January 2016

The theorems of Gauss and Jacobi that give modulo [Formula: see text] evaluations of certain central binomial coefficients have been extended, since the 1980s, to more classes of binomial coefficients and to congruences modulo [Formula: see text]. In this paper, we further extend these results to congruences modulo [Formula: see text]. In the process, we prove congruences to arbitrarily high powers of [Formula: see text] for certain quotients of Gauss factorials that resemble binomial coefficients and are related to Morita's [Formula: see text]-adic gamma function. These congruences are of a simple form and involve Catalan numbers as coefficients.
The average multiplicative order of a finitely generated subgroup of the rationals modulo primes
Authors: Pehlivan Cihan
Published: January 2016

Let [Formula: see text] be a finitely generated subgroup of [Formula: see text]. Let [Formula: see text] be a prime number for which the reduction group [Formula: see text] is a well-defined subgroup of the multiplicative group [Formula: see text], and denote the order of [Formula: see text] by [Formula: see text]. Assuming the Generalized Riemann Hypothesis, we study the average of [Formula: see text] and the average of the powers of [Formula: see text] as [Formula: see text] ranges over prime numbers. The problem was considered in the case of rank 1 by Pomerance and Kurlberg. In the case when [Formula: see text] contains only positive numbers, we give an explicit expression for the involved density in terms of an Euler product. We conclude with some numerical computations.