Bio-inspired swing leg control for spring-mass robots running on ground with unexpected height disturbance

We proposed three swing leg control policies for spring-mass running robots, inspired by experimental data from our recent collaborative work on ground running birds. Previous investigations suggest that animals may prioritize injury avoidance and/or efficiency as their objective function during running rather than maintaining limit-cycle stability. Therefore, in this study we targeted structural capacity (maximum leg force to avoid damage) and efficiency as the main goals for our control policies, since these objective functions are crucial to reduce motor size and structure weight. Each proposed policy controls the leg angle as a function of time during flight phase such that its objective function during the subsequent stance phase is regulated. The three objective functions that are regulated in the control policies are (i) the leg peak force, (ii) the axial impulse, and (iii) the leg actuator work. It should be noted that each control policy regulates one single objective function. Surprisingly, all three swing leg control policies result in nearly identical subsequent stance phase dynamics. This implies that the implementation of any of the proposed control policies would satisfy both goals (damage avoidance and efficiency) at once. Furthermore, all three control policies require a surprisingly simple leg angle adjustment: leg retraction with constant angular acceleration

Revisiting logistical friendliness: perspectives of international freight forwarders

Logistical friendliness (unfriendliness) refers to the ease (difficulty) of arranging international freight operations to/from a particular country. The present paper builds upon previous research by 1) examininglogistical friendliness and unfriendliness as two different constructs (rather than as opposite ends of the same continuum), and 2) linking the delineation of logistically friendly and unfriendly countries with the reasons for friendliness (unfriendliness). The study results could be quite valuable with corporate decisions as to which countries to do business in, as well as with the appropriate organizational strategies for entering the chosen countries

Examining international freight forwarder services: the perspectives of current providers and users

The service quality literature indicates a variety of gaps between expected and perceived quality, and that service quality is a key determinant of customer satisfaction. As such, the present paper examines international freight forwarders (IFFs) and IFF customers with respect to various services which might be provided by IFFs; the paper also reports on user satisfaction with their IFFs. The study results identified several mismatches between what the forwarders are currently providing and what services the users view as important. In addition, the satisfaction ratings suggest that forwarders’ performance has room for improvement

Some propositions regarding rail-truck intermodal: an empirical analysis

Using data compiled from a recent of businesses located in a major metropolitan area, the present paper evaluates a series of propositions concerning rail-truck intermodal. In general, the study results tend to support the various propositions, and key findings suggest that users and nonusers of intermodal transportation have different perceptions about the quality of, and barriers to, intermodal service

Dynamics of Rumor Spreading in Complex Networks

We derive the mean-field equations characterizing the dynamics of a rumor process that takes place on top of complex heterogeneous networks. These equations are solved numerically by means of a stochastic approach. First, we present analytical and Monte Carlo calculations for homogeneous networks and compare the results with those obtained by the numerical method. Then, we study the spreading process in detail for random scale-free networks. The time profiles for several quantities are numerically computed, which allow us to distinguish among different variants of rumor spreading algorithms. Our conclusions are directed to possible applications in replicated database maintenance, peer to peer communication networks and social spreading phenomena.Comment: Final version to appear in PR

Snapshot Observation for 2D Classical Lattice Models by Corner Transfer Matrix Renormalization Group

We report a way of obtaining a spin configuration snapshot, which is one of the representative spin configurations in canonical ensemble, in a finite area of infinite size two-dimensional (2D) classical lattice models. The corner transfer matrix renormalization group (CTMRG), a variant of the density matrix renormalization group (DMRG), is used for the numerical calculation. The matrix product structure of the variational state in CTMRG makes it possible to stochastically fix spins each by each according to the conditional probability with respect to its environment.Comment: 4 pages, 8figure

Large Area Crop Inventory Experiment (LACIE). Intensive test site assessment report

There are no author-identified significant results in this report

Characterization of Milk Constituents of \u3ci\u3eBos Taurus\u3c/i\u3e and \u3ci\u3eBos Indicus\u3c/i\u3e × \u3ci\u3eBos Taurus\u3c/i\u3e Breed Types

Milk from eight Bos Taurus and Bos indicus × Bos Taurus breed types (n=128) was evaluated for percentage butterfat, protein, lactose and solids- non-fat. Milk samples were collected at approximately 60, 105, and 150 d after the onset of lactation by hand-milking the left front quarter following a 30-IU injection of oxytocin. Breed type variation was significant for some milk component traits at each stage of lactation. Brahman × Angus dams increased in component yields (kg) as lactation progressed; production levels of other breed types remained approximately the same or declined. Sex of calf influenced (P\u3c.05) yield (kg) of protein, butterfat and solids-non-fat at 105 d only. Mastitis effects caused a reduction (P\u3c.01) in percentage of lactose. Residual correlations between yield (kg) of milk components and weaning weight were all positive and significant

Finite Temperature Density Matrix Renormalization using an enlarged Hilbert space

We apply a generalization of the time-dependent DMRG to study finite temperature properties of several quantum spin chains, including the frustrated $J_1-J_2$ model. We discuss several practical issues with the method, including use of quantum numbers and finite size effects. We compare with transfer-matrix DMRG, finding that both methods produce excellent results.Comment: 4 pages and 4 figure