Coupling mechanisms between the contralateral legs of a walking insect (Carausius morosus)

Cruse H, Knauth A. Coupling mechanisms between the contralateral legs of a walking insect (Carausius morosus). The journal of experimental biology. 1989;144(1):199-213.Interactions between contralateral legs of stick insects during walking were examined in the absence of mechanical coupling between the legs by studying animals walking on a horizontal plane covered with a thin film of silicone oil. Investigations of undisturbed walks showed that contralateral coupling is weaker han ipsilateral coupling. Two types of influence were found, (i) For each pair of front, middle and rear legs, when one leg started a retraction movement, the probability for the contralateral leg to start a protraction was increased, (ii) For front- and hind-leg pairs, it was found that the probability of starting a protraction in one leg was also increased, the farther the other leg was moved backwards during retraction. Whether such influences exist between middle legs could not be determined. Both ‘excitatory’ mechanisms very much resemble those influences which have been found to exist between ipsilateral legs. However, in contrast to ipsilateral legs, the interaction between two contralateral legs was found to act in both directions

The direct potential method in three dimensional elastostatics

Direct potential method applied to solution of three dimensional elastostatics problem

TALOS: A distributed architecture for intelligent monitoring and anomaly diagnosis of the Hubble Space Telescope

Lockheed, the Hubble Space Telescope Mission Operations Contractor, is currently engaged in a project to develop a distributed architecture of communicating expert systems to support vehicle operations. This architecture, named Telemetry Analysis Logic for Operating Spacecraft (TALOS), has the potential for wide applicability in spacecraft operations. The architecture mirrors the organization of the human experts within an operations control center

SRB frustrum 'smiley' cracking phenomenon study

The thermal protection system installed on the SRB frustrums incurs the formation of debonds between the MSA-2 TPS material and the substrate. The debonds can lead to surface penetrating cracks, called 'smileys' near sealed fasteners and other surface discontinuities. The study concluded that the 'smileys' were caused as the result of stress risers caused by excess fastener sealant (PR-1422) and weakly bonded surfaces. Once the debond occurs, 'smileys' form when the debond area is sufficiently large. The loading for the debond and 'smiley' formation is seen to be depressurization at the vacuum conditions near the end of powered boost. The porous nature of the MSA-2 material covered by a vapor barrier paint provides internal pressure loading of the MSA-2 material. Recommendations for eliminating the problem include elimination of excess PR-1422 sealant and improved attention to bonding surface preparation

Expert system support for HST operations

An expert system is being developed to support vehicle anomaly diagnosis for the Hubble Space Telescope (HST). Following a study of safemode entry analyses, a prototype system was developed which reads engineering telemetry formats, and when a safemode event is detected, extracts telemetry from the downlink and writes it into a knowledge base for more detailed analyses. The prototype then summarizes vehicle events (limits exceeded, specific failures). This prototype, the Telemetry Analysis Logic for Operations Support (TALOS) uses the Lockheed Expert System (LES) shell, and includes over 1600 facts, 230 rules, and 27 goals. Although considered a prototype, it is already an operationally useful system. The history leading into the TALOS prototype will be discussed, an overview of the present TALOS system will be presented, and the role of the TALOS system in contingency planning will be delineated

Permanent Objects, Disposable Systems

4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PresentationsDate: 2009-05-19 01:00 PM – 02:30 PMThe California Digital Library (CDL) preservation program is re-envisioning its curation infrastructure as a set of loosely-coupled, distributed micro-services. There are many monolithic systems that support a range of preservation activities but also require the user and the hosting institution to buy-in to a particular system culture. The result is an institution that becomes, say, a DSpace, Fedora, or LOCKSS "shop", with a specific worldview and set of object flows and structures that will eventually need to be abandoned when it comes time to transition to the next system. Experience shows that these transitions are unavoidable, despite claims that once an object is in the system, it will be safe forever. In view of this it is safer and more cost-effective to acknowledge from the outset the inevitable transient nature of systems and to plan on managing, rather than resisting change. The disruption caused by change can be mitigated by basing curation services on simple universal structures and protocols (e.g., filesystems, HTTP) and micro-services that operate on them. We promote a "mix and match" approach in which appropriate content- and context-specific curation workflows can be nimbly constructed by combining necessary functions drawn from a granular set of independent micro-services. Micro-services, whether deployed in isolation or in combination, are especially suited to exploitation upstream towards content creators who normally don't want to think about preservation, especially if it's costly; compared to buying into an entire curation culture, it is easy to adopt a small, inexpensive tool that requires very little commitment. We see digital curation as an ongoing process of enrichment at all stages in the lifecycle of a digital object. Because the early developmental stages are so critical to an object's health and longevity, it is desirable to push curation "best practices" as far upstream towards the object creators as possible. If preservation is considered only when objects are close to retirement, it is often too late to correct the structural and semantic deficiencies that can impair object usability. The later the intervention, the more expensive the correction process, and it is always difficult to fund interventions for "has been" objects. In contrast, early stage curation challenges traditional practices. Traditionally, preservation actions are often based on end-stage processing, where objects are deposited "as is" and kept out of harm's way by limiting access (i.e., dark archives). While some systems are designed to be dark or "dim", with limited access and little regard for versioning or object enrichment, enrichment and access are now seen as necessary curation actions, that is, interventions for the sake of preservation. In particular, the darkness of an entire collection can change in the blink of an eye, for example, as the result of a court ruling or access rights purchase; turning the lights on for a collection should be as simple as throwing a switch, and not require transferring the collection from a "preservation repository" to an "access repository". Effective curation services must be flexible and easily configurable in order to respond appropriately to the wide diversity of content and content uses. To be most effective, not only should curation practices be pushed upstream but also they should be pushed out to many different contexts. The micro-services approach promotes the idea that curation is an outcome, not a place. Curation actions should be applied to content where it most usefully exists for the convenience of its creators or users. For example, high value digital assets in access repositories, or even scholars' desktops, would certainly benefit from such things as persistent identification or regular audits to discover and repair bit-level damage, functions usually available only in the context of a "preservation system" but now easily applied to content where it most usefully resides without requiring transfer to a central location

Boundary elements in potential and elasticity theory

A general theory that describes the B.I.E. linear approximation in potential and elasticity problems, is developed. A method to tread the Dirichlet condition in sharp vertex is presented. Though the study is developed for linear elements, its extension to higher order interpolation is straightforward. A new direct assembling procedure of the global of equations to be solved, is finally showed

System reliability and risk assessment task goals and status

The major focus for continued development of the Numerical Evaluation of Stochastic Structures Under Stress (NESSUS) codes is in support of system testing and certification of advanced propulsion systems. Propulsion system testing has evolved over the years from tests designed to show success, to tests designed to reveal reliability issues before service use. Such test conditions as performance envelope corners, high rotor imbalance, power dwells, and overspeed tests are designed to shake out problems that can be associated with low and high cycle fatigue, creep, and stress rupture, bearing durability, and the like. Subsystem testing supports system certification by standing as an early evaluation of the same durability and reliability concerns as for the entire system. The NESSUS software system is being further developed to support the definition of rigorous subsystem and system test definition and reliability certification. The principal technical issues are outlined which are related to system reliability, including key technology issues such as failure mode synergism, sequential failure mechanisms, and fault tree definition

Probabilistic structural analysis methods for select space propulsion system components

The Probabilistic Structural Analysis Methods (PSAM) project developed at the Southwest Research Institute integrates state-of-the-art structural analysis techniques with probability theory for the design and analysis of complex large-scale engineering structures. An advanced efficient software system (NESSUS) capable of performing complex probabilistic analysis has been developed. NESSUS contains a number of software components to perform probabilistic analysis of structures. These components include: an expert system, a probabilistic finite element code, a probabilistic boundary element code and a fast probability integrator. The NESSUS software system is shown. An expert system is included to capture and utilize PSAM knowledge and experience. NESSUS/EXPERT is an interactive menu-driven expert system that provides information to assist in the use of the probabilistic finite element code NESSUS/FEM and the fast probability integrator (FPI). The expert system menu structure is summarized. The NESSUS system contains a state-of-the-art nonlinear probabilistic finite element code, NESSUS/FEM, to determine the structural response and sensitivities. A broad range of analysis capabilities and an extensive element library is present

Cognitive Metaphors of the Mind in the Canterbury Tales

The paper presents an analysis of a number of cognitive metaphors pertaining to the concept of mind (e.g. sanity and insanity), heart, and fire. The study has been based on the text of Canterbury Tales by Geoffrey Chaucer. The paper contains a short theoretical introduction and a discussion of different linguistic and psychological approaches to issues related to figurative and literal, conventional language use. The analytical part focuses on the detailed contextual study of the cognitive metaphorical concepts. It is argued that many apparently similar concepts can evoke semantically conflicting metaphors, while concepts that appear to be mutually exclusive can sometimes evoke common associations and thereby similar metaphors