Modeling and analysis of passive dynamic bipedal walking with segmented feet and compliant joints

Passive dynamic walking has been developed as a possible explanation for the efficiency of the human gait. This paper presents a passive dynamic walking model with segmented feet, which makes the bipedal walking gait more close to natural human-like gait. The proposed model extends the simplest walking model with the addition of fiat feet and torsional spring based compliance on ankle joints and toe joints, to achieve stable walking on a slope driven by gravity. The push-off phase includes foot rotations around the toe joint and around the toe tip, which shows a great resemblance to human normal walking. This paper investigates the effects of the segmented foot structure on bipedal walking in simulations. The model achieves satisfactory walking results on even or uneven slopes.

RELAXATION IN DOMAINS:STRUCTURE AND SEGMENTAL DYNAMICS OF LC/I DIBLOCK COPOLYMERS

A series of block copolymers consisting of an isotropic (polystyrene) block and a side-chain liquid crystallineblock (LC) have been studied using small-angle X-ray scattering and dielectric spectroscopy. The triblock copolymer (PS-LC-PS) displays an order-to-order transition (OOT) together with the isotropic/nematic transition of the LC phase. The seriesof diblock copolymers show no clear OOT but the phase diagram differs from that of non-LC block copolymers. Thesegmental dynamics as measured with dielectric spectroscopy is dominated by the α and δ relaxation of the LC block. Bothdisplay a WLF like temperature dependence. The relaxation times are influenced by the constraints of the nanoscale domains.They are decreased for the LC confined in the domain as compared to the LC in the continuous matrix.

Discrete-Time Dynamic Image Segmentation Using Oscillators with Adaptive Coupling

In this study, we propose a novel discrete-time coupled model to generate oscillatory responses via periodic points with a high periodic order. Our coupled system comprises one-dimensional oscillators based on the Rulkov map and a single globally coupled oscillator. Because the waveform of a one-dimensional oscillator has sharply defined peaks, the coupled system can be applied to dynamic image segmentation. Our proposed system iteratively transforms the coupling of each oscillator based on an input value that corresponds to the pixel value of an input image. This approach enables our system to segment image regions in which pixel values gradually change with respect to a connected region. We conducted a bifurcation analysis of a single oscillator and a three-coupled model. Through simulations, we demonstrated that our system works well for gray-level images with three isolated image regions.

Preface

Micromechanics aims mainly at establishing the quantitative relation between the macroscopic mechanical behavior and the microstructure of heterogeneous materials.

An Efficient Approach for Historical Storage and Retrieval of Segmented Road Data in Geographic Information System for Transportation

One of the most powerful functions of Geographic Information System for Transportation (GIS-T) is Dynamic Segmentation (DS), which is used to increase the efficiency and precision of road management by generating segments based on attributes. The road segments describing transportation data are both spatially and temporally referenced. For a variety of transportation applications, historical road segments must be preserved. This study presents an appropriate approach to preserve and retrieve the historical road segments efficiently. In the proposed method, only the portions of segments of a time stamp that have been changed into new segments rather than storing the entire segments for every old time stamp are recorded .The storage of these portions is based on the type of changes. A recursive algorithm is developed to retrieve all segments for every old time stamp. Experimental results using real data of Tehran City, Iran justify the strength of the proposed approach in many aspects. An important achievement of the results is that database volume for 2006, 2007 and 2008 within the Historical Line Event Table (HLET) is reduced by 70%, 80% and 78%, respectively. The proposed method has the potential to prevent from vast data redundancy and the unnecessary storage of entire segments for each time stamp. Since the present technique is performed on ordinary plain tables that are readable by all GIS software, special software platforms to manage the storage and retrieval of historical segments are not needed. In addition, this method simplifies spatio-temporal queries.

Spatial Modeling Using High Resolution Image for Future Shoreline Prediction Along Junput Coast, West Bengal, India

National policies and legal decisions are very much dependent on the position of the shoreline. Shoreline change rates are frequently employed to summarize historical shoreline movements. This also helps to predict the future position of the shoreline based on the perceived historical trends. In this regard, the future shoreline positions at both the long-term, that is 2050, and short-term, that is 2015, time interval was predicted using the End Point Rate （EPR） model along the Junput Coast of West Bengal, India. The whole project work was divided into five parts. The first part showed the detection of shoreline from satellite data like IRS LISS IV and Landsat 7 ETM＋ and from the Survey of India Toposheet. The second part gave the glimpse of the dynamic segmentation of the shoreline to get the dynamically segmented nodal points along the shoreline. Shoreline prediction for the years 2015 and 2050 using End Point Rate （EPR） model was done in the third part. In the fourth part, Coastal Terrain Model （CTM） was prepared, and the digital shoreline estimated. The model result was validated and accuracy assessed with respect to the GPS data collected from the field at the fifth stage. Finally at the end of the present work, limitations of the project and the future scope of the work was sited.

Effects of Chain Entanglement on Liquid-Liquid Phase Separation Behavior of LCST-type Polymer Blends: Cloud Point and Decomposition Rate

By preparing homogenous blend samples with different degrees of chain entanglement, we report an anomalous contribution of chain entanglement to phase separation temperature and rate of poly（methyl methacrylate）/poly（styrene-co- maleic anhydride） （PMMA/SMA） blends presenting a typical lower critical solution temperature （LCST） behavior. The melt- mixed PMMA/SMA blends with a higher chain entanglement density present a lower cloud point （To） and shorter delay time, but lower phase separation rate at the given temperature than solution-cast ones, suggesting that for the polymer blends with different condensed state structure, thermodynamically more facilitation to phase separation （lower Tc） is not necessarily equivalent to faster kinetics （decomposition rate）. The experimental results indicate that the lower Tc of melt-mixed sample is ascribed to smaller concentration fluctuation wavelength （Am） induced by higher entanglement degree, while higher entanglement degree in melt-mixed sample leads to a confined segmental dynamics and consequently a slower kinetics （decomposition rate） dominated by macromolecular diffusion at a comparable quench depth. These results reveal that the chain packing in polymer blends can remarkably influence the liquid-liquid phase separation behavior, which is a significant difference from decomposition of small molecular mixtures.

Network level pavement evaluation with 1 mm 3D survey system

The latest iteration of PaveVision3D Ultra can obtain true 1 mm resolution 3D data at full- lane coverage in all 3 directions at highway speed up to 60 mph. This paper introduces the PaveVision3D Ultra technology for rapid network level pavement survey on approximately 1280 center miles of Oklahoma interstate highways. With sophisticated automated distress analyzer （ADA） software interface, the collected 1 mm 3D data provide Oklahoma Department of Transportation （ODOT） with comprehensive solutions for automated eval- uation of pavement surface including longitudinal profile for roughness, transverse profile for rutting, predicted hydroplaning speed for safety analysis, and cracking and various surface defects for distresses. The pruned exact linear time （PELT） method, an optimal partitioning algorithm, is implemented to identify change points and dynamically deter- mine homogeneous segments so as to assist ODOT effectively using the available 1 mm 3D pavement surface condition data for decision-making. The application of 1 mm 3D laser imaging technology for network survey is unprecedented. This innovative technology allows highway agencies to access its options in using the 1 mm 3D system for its design and management purposes, particularly to meet the data needs for pavement management system （PMS）, pavement ME design and highway performance monitoring system （HPMS）.