Describing intelligent agent behaviors

The development of new intelligent agents requires an interdisciplinary approach to programming. The initial challenge is to describe the desired agent behaviors and abilities without necessarily committing the agent development project to one particular programming language. What are the appropriate linguistic and logical tools for creating a top level, unambiguous, program-independent, and consistent description of the functions and behaviors of the agent? And how can that description then be translated easily into one of a number of program languages? This article provides a case study of the application of a simple Belief, Desire, and Intention (EDI) first order logic to a complex set of agent functions of a theoretical community of intelligent nano-spacecraft. The basic research was conducted at NASA-GSFC (Greenbelt), Advanced Architecture Branch, during the summer of 2001. The simple examples of applied BDI logic presented here suggest broad application in agent software development

Video analysis of the deformation and effective mass of gymnastics landing mats

Introduction: Landing mats that undergo a large amount of area deformation are now essential for the safe completion of landings from dismounts and vaults in gymnastics. The aim of this paper is to determine the effective mass, shock transmission time and deformation characteristics of a mat during impacts using high-speed video and hence improve the accuracy of measuring foot / mat contact forces during landing. To this end the same variables need to be accurately assessed using accelerometer and force plate data so that the high-speed video method can be validated. Methods: A 24 kg impactor with an attached accelerometer was dropped onto the sample mat from various heights. The surface deformation of the mat was recorded using high-speed video and force data were obtained from a force plate beneath the mat. Results: Impact velocities ranged from 4.3 ms-1 to 6.5 ms-1 resulting in maximum vertical deformations between 0.088 m and 0.118 m with corresponding volume deformation estimates ranging from 0.030 m3 to 0.044 m3. The delay between accelerometer and force plate readings at initial contact was approximately 7 ms whereas the delay between peak acceleration and peak force was 3 ms. The peak acceleration calculated from the video data was within 2.5 % of that recorded via the accelerometer. The effective mass of the mat being accelerated corresponded to a force that ranged from 481 N to 930 N and this cannot be ignored as it accounts for up to 12 % of the peak force. Conclusions: The acceleration estimates obtained from the high-speed video were combined with the effective mass estimates from the volume calculation to give peak calculated forces at the bottom of the mat to within -1.1% to +3.7% of the force recorded via the force plate. The use of high-speed video can be used to give data of sufficient accuracy for measuring foot / mat contact forces in gymnastics landings

Modelling a viscoelastic gymnastics landing mat during impact

Landing mats that undergo a large amount of area deformation are now essential for the safe completion of landings in gymnastics. The objective of this study was to develop an analytical model of a landing mat that reproduces the key characteristics of the mat-ground force during impact with minimal simulation runtime. A force plate and two high-speed video cameras were used to record the mat deformation during vertical drop testing of a 24 kg impactor. Four increasingly complex point mass spring-damper models, from a single mass-spring-damper system, Model 1, through to a 3 layer mass-spring-damper system, Model 4, were constructed using Matlab to model the mat’s behaviour during impact. A fifth model compromised of a 3 layer mass-spring-damper system was developed using visual Nastran 4D. The results showed that Models 4 and 5 were able to match the loading phase of the impact with simulation times of less than one second for Model 4 and 28 seconds for Model 5. Both Models 4 and 5 successfully reproduced the key force time characteristics of the mat-ground interface, such as peak forces, time of peak forces, inter-peak minima and initial rates of loading and could be incorporated into a gymnast-mat model

The influence of simulation model complexity on the estimation of internal loading in gymnastics landings

Evaluating landing technique using a computer simulation model of a gymnast and landing mat could be a useful tool when attempting to assess injury risk. The aims of this study were: (1) to investigate whether a subject-specific torque-driven or a subject-specific muscle-driven model of a gymnast is better at matching experimental ground reaction forces and kinematics during gymnastics landings, (2) to calculate their respective simulation run times and (3) to determine what level of model complexity is required to assess injury risk. A subject-specific planar seven-link wobbling mass model of a gymnast and a multi-layer model of a landing mat were developed for this study. Subject-specific strength parameters were determined which defined the maximum voluntary torque/angle/angular velocity relationship about each joint. This relationship was also used to produce subject-specific ‘lumped’ muscle models for each joint. Kinetic and kinematic data were obtained during landings from backward and forward rotating gymnastics vaults. Both torque-driven and muscle-driven models were capable of producing simulated landings that matched the actual performances (with overall percentage differences between 10.1% and 18.2%). The torque-driven model underestimated the internal loading on joints and bones, resulting in joint reaction forces that were less than 50% of those calculated using the muscle-driven model. Simulation time increased from approximately 3 min (torque driven) to more than 10 min (muscle driven) as model complexity increased. The selection of a simulation model for assessing injury risk must consider the need for determining realistic internal forces as the priority despite increases in simulation run time

Reducing ground reaction forces in gymnastics’ landings may increase internal loading

The aim of this study was to use a subject-specific seven-link wobbling mass model of a gymnast, and a multi-layer model of a landing mat, to determine landing strategies that minimise ground reaction forces (GRF) and internal forces. Subject-specific strength parameters were determined that defined the maximum voluntary torque/angle/angular velocity relationship at each joint. These relationships were used to produce subject-specific ‘lumped’ linear muscle models for each joint. Muscle activation histories were optimised using a Simplex algorithm to minimise GRF or bone bending moments for forward and backward rotating vault landings. Optimising the landing strategy to minimise each of the GRF reduced the peak vertical and horizontal GRF by 9% for the backward rotating vault and by 8% and 48% for the forward rotating vault, compared to a matching simulation. However, most internal loading measures (bone bending moments, joint reaction forces and muscle forces) increased compared to the matching simulation. Optimising the landing strategy to minimise the peak bone bending moments resulted in reduced internal loading measures, and in most cases reduced GRF. Bone bending moments were reduced by 27% during the forward rotating vault and by 2% during the backward rotating vault landings when compared to the matching simulations. It is possible for a gymnast to modify their landing strategy in order to minimise internal forces and lower GRF. However, using a reduction in GRF, due to a change in landing strategy, as a basis for a reduction in injury potential in vaulting movements may not be appropriate since internal loading can increase

Alabama Barbecue / music by J. Fred Coots; words by Benny Davis

Cover: collage drawing of African Americans engaged in various activities; text reads Cotton Club Parade; Publisher: Mills Music Inc. (New York)https://egrove.olemiss.edu/sharris_e/1039/thumbnail.jp

Sweet Mamma (Papa\u27s Getting Mad) / words by Fred Rose, George A. Little, and Peter L. Frost

Cover: photo of Sophie Tucker and Her Kings of Syncopation; Publisher: Jack Mills Inc. (New York)https://egrove.olemiss.edu/sharris_d/1007/thumbnail.jp

Nanocuration workflows: Establishing best practices for identifying, inputting, and sharing data to inform decisions on nanomaterials

There is a critical opportunity in the field of nanoscience to compare and integrate information across diverse fields of study through informatics (i.e., nanoinformatics). This paper is one in a series of articles on the data curation process in nanoinformatics (nanocuration). Other articles in this series discuss key aspects of nanocuration (temporal metadata, data completeness, database integration), while the focus of this article is on the nanocuration workflow, or the process of identifying, inputting, and reviewing nanomaterial data in a data repository. In particular, the article discusses: 1) the rationale and importance of a defined workflow in nanocuration, 2) the influence of organizational goals or purpose on the workflow, 3) established workflow practices in other fields, 4) current workflow practices in nanocuration, 5) key challenges for workflows in emerging fields like nanomaterials, 6) examples to make these challenges more tangible, and 7) recommendations to address the identified challenges. Throughout the article, there is an emphasis on illustrating key concepts and current practices in the field. Data on current practices in the field are from a group of stakeholders active in nanocuration. In general, the development of workflows for nanocuration is nascent, with few individuals formally trained in data curation or utilizing available nanocuration resources (e.g., ISA-TAB-Nano). Additional emphasis on the potential benefits of cultivating nanomaterial data via nanocuration processes (e.g., capability to analyze data from across research groups) and providing nanocuration resources (e.g., training) will likely prove crucial for the wider application of nanocuration workflows in the scientific community