777 research outputs found

    A Prototype Method and Tool to Facilitate Knowledge Sharing in the New Product Development Process

    Get PDF
    New Product Development (NPD) plays a critical role in the success of manufacturing firms. Activities in the product development process are dependent on the exchange of knowledge among NPD project team members. Increasingly, many organisations consider effective knowledge sharing to be a source of competitive advantage. However, the sharing of knowledge is often inhibited in various ways. This doctoral research presents an exploratory case study conducted at a multinational physical goods manufacturer. This investigation uncovered three, empirically derived and theoretically informed, barriers to knowledge sharing. They have been articulated as the lack of an explicit definition of information about the knowledge used and generated in the product development process, and the absence of mechanisms to make this information accessible in a multilingual environment and to disseminate it to NPD project team members. Collectively, these barriers inhibit a shared understanding of product development process knowledge. Existing knowledge management methodologies have focused on the capture of knowledge, rather than providing information about the knowledge and have not explicitly addressed issues regarding knowledge sharing in a multilingual environment. This thesis reports a prototype method and tool to facilitate knowledge sharing that addresses all three knowledge sharing barriers. Initially the research set out to identify and classify new product development process knowledge and then sought to determine what information about specific knowledge items is required by project teams. Based on the exploratory case findings, an ontology has been developed that formally defines information about this knowledge and allows it to be captured in a knowledge acquisition tool, thereby creating a knowledge base. A mechanism is provided to permit language labels to be attached to concepts and relations in the ontology, making it accessible to speakers of different languages. A dissemination tool allows the ontology and knowledge base to be viewed via a Web browser client. Essentially, the ontology and mechanisms facilitate a knowledge sharing capability. Some initial validation was conducted to better understand implementation issues and future deployment of the prototype method and tool in practice

    Implementing QVT-R bidirectional model transformations using alloy

    Get PDF
    QVT Relations (QVT-R) is the standard language proposed by the OMG to specify bidirectional model transformations. Unfortunately, in part due to ambiguities and omissions in the original semantics, acceptance and development of effective tool support has been slow. Recently, the checking semantics of QVT-R has been clarified and formalized. In this paper we propose a QVT-R tool that complies to such semantics. Unlike any other existing tool, it also supports meta-models enriched with OCL constraints (thus avoiding returning ill-formed models), and proposes an alternative enforcement semantics that works according to the simple and predictable “principle of least change”. The implementation is based on an embedding of both QVT-R transformations and UML class diagrams (annotated with OCL) in Alloy, a lightweight formal specification language with support for automatic model finding via SAT solving.Fundação para a Ciência e a Tecnologi

    Toxicity and recovery in the pregnant mouse after gestational exposure to the cyanobacterial toxin, cylindrospermopsin

    Get PDF
    Cylindrospermopsin (CYN) is a tricyclic alkaloid toxin produced by fresh water cyanobacterial species worldwide. CYN has been responsible for both livestock and human poisoning after oral exposure. This study investigated the toxicity of CYN to pregnant mice exposed during different segments of gestation. The course of recovery and individual responses to the toxin were evaluated. Adverse effects of CYN were monitored up to 7 weeks post-dosing by clinical examination, histopathology, biochemistry and gene expression. Exposure on gestational days (GD) 8–12 induced significantly more lethality than GD13–17 exposure. Periorbital, gastrointestinal and distal tail hemorrhages were seen in both groups. Serum markers indicative of hepatic injury (alanine amino transferase, aspartate amino transferase and sorbitol dehydrogenase)were increased in both groups; markers of renal dysfunction (blood urea nitrogen and creatinine) were elevated in the GD8–12 animals. Histopathology was observed in the liver (centrilobular necrosis) and kidney (interstitial inflammation) in groups exhibiting abnormal serum markers. The expression profiles of genes involved in ribosomal biogenesis, xenobiotic and lipid metabolism, inflammatory response and oxidative stress were altered 24 h after the final dose. One week after dosing, gross, histological and serum parameters had returned to normal, although increased liver/body weight ratio and one instance of gastrointestinal bleeding was found in the GD13–17 group. Gene expression changes persisted up to 2 weeks post-dosing and returned to normal by 4 weeks. Responses of individual animals to CYN exposure indicated highly significant inter-animal variability within the treated groups

    Thalamic inputs to dorsomedial striatum are involved in inhibitory control: evidence from the five-choice serial reaction time task in rats

    Get PDF
    Rationale Corticostriatal circuits are widely implicated in the top-down control of attention including inhibitory control and behavioural flexibility. However, recent neurophysiological evidence also suggests a role for thalamic inputs to striatum in behaviours related to salient, reward-paired cues. Objectives Here, we used designer receptors exclusively activated by designer drugs (DREADDs) to investigate the role of parafascicular (Pf) thalamic inputs to the dorsomedial striatum (DMS) using the five-choice serial reaction time task (5CSRTT) in rats. Methods The 5CSRTT requires sustained attention in order to detect spatially and temporally distributed visual cues and provides measures of inhibitory control related to impulsivity (premature responses) and compulsivity (perseverative responses). Rats underwent bilateral Pf injections of the DREADD vector, AAV2-CaMKIIa-HA-hM4D(Gi)-IRES-mCitrine. The DREADD agonist, clozapine N-oxide (CNO; 1 ÎĽl bilateral; 3 ÎĽM) or vehicle, was injected into DMS 1 h before behavioural testing. Task parameters were manipulated to increase attention load or reduce stimulus predictability respectively. Results We found that inhibition of the Pf-DMS projection significantly increased perseverative responses when stimulus predictability was reduced but had no effect on premature responses or response accuracy, even under increased attentional load. Control experiments showed no effects on locomotor activity in an open field. Conclusions These results complement previous lesion work in which the DMS and orbitofrontal cortex were similarly implicated in perseverative responses and suggest a specific role for thalamostriatal inputs in inhibitory control

    Limits to Poisson's ratio in isotropic materials - general result for arbitrary deformation

    Full text link
    The lower bound usually cited for Poisson's ratio {\nu} is -1, derived from the relationship between {\nu} and the bulk and shear moduli. From consideration of the longitudinal and biaxial moduli, we recently determined that the lower bound on {\nu} for isotropic materials is actually 1/5, a value also consistent with experimental measurements on real materials. Herein we generalize this result, first by analyzing expressions for {\nu} in terms of six common elastic constants, and then by considering arbitrary strains. The results corroborate the prior finding that 1/5 <= {\nu} for linear elasticity to be applicable.Comment: 15 pages, 3 figures, 1 tabl
    • …
    corecore