A generic coordination approach applied to a manufacturing environment

This paper describes a generic coordination approach applied to the field of manufacturing engineering. The objective of the coordination mechanism with respect to this application is twofold. Firstly, it is shown that utilising the developed system can result in the efficient organisation of processes leading to a near optimum time taken to manufacture a number of artefacts. Secondly, successful operation of the system in this environment will demonstrate that the approach is generic in nature. The results already achieved using this system within a computational analysis environment supports this hypothesis

A methodology for design coordination in a distributed computing environment

At the conceptual stage of the design process it is increasingly common that analysis tools are involved in the evaluation of a large number of alternative designs. Designers use such analysis tools to assist with large scale concept evaluations and the prediction of good initial designs. Consequently there exists a need to coordinate these analysis tools to enable the early stage of design to be performed in a timely and efficient manner. This paper describes a generic methodology that allows the management and coordination of design analysis tools. A Computer Aided Design tool, namely the Design Coordination System (DCS), has been developed to assist the designer in performing computational analysis in a distributed computing environment. Within the DCS, a collection of design agents act as members of a multi-functional team operating in a cooperative and coordinated manner in order to satisfy the objective of efficiently performing the design analysis

Real-time co-ordinated resource management in a computational enviroment

Design co-ordination is an emerging engineering design management philosophy with its emphasis on timeliness and appropriateness. Furthermore, a key element of design coordination has been identified as resource management, the aim of which is to facilitate the optimised use of resources throughout a dynamic and changeable process. An approach to operational design co-ordination has been developed, which incorporates the appropriate techniques to ensure that the aim of co-ordinated resource management can be fulfilled. This approach has been realised within an agent-based software system, called the Design Coordination System (DCS), such that a computational design analysis can be managed in a coherent and co-ordinated manner. The DCS is applied to a computational analysis for turbine blade design provided by industry. The application of the DCS involves resources, i.e. workstations within a computer network, being utilised to perform the computational analysis involving the use of a suite of software tools to calculate stress and vibration characteristics of turbine blades. Furthermore, the application of the system shows that the utilisation of resources can be optimised throughout the computational design analysis despite the variable nature of the computer network

A methodology for prospective operational design co-ordination

Engineering companies are continually faced with the challenge of how best to utilise their design team given some design project. Decisions regarding how to distribute the project workload amongst the members of the design team are the responsibility of a project manager who, in order to do this, often relies upon previous experience and/or the support of some planning tool. Furthermore, a project manager rarely has the opportunity to assess the capability of the design team against the current work load in order to determine what, if any, alterations couldbe made to the team to facilitate appropriate reductions in project time and cost.This paper proposes a mathematical-based methodology aimed at identifying shortfalls in design teams, which if remedied would result in a more efficient project in terms of time and cost. The methodology provides a means of identifying those skills within the design team,with respect to the outstanding work load, in which improvements would have the greatest influence on reducing time and cost. In addition, the methodology employs a genetic algorithm for the purpose of scheduling tasks to be undertaken by potential design teams. The methodology is applied to two practical case studies provided by engineering industry.The first case study involves the assessment of a multi-disciplined design team consisting of single-skilled engineers. In contrast, the second case study entails the assessment of multiskilled engineers within a multi-disciplined design team. As a result of applying the methodology to the case studies, potential improvement to the design teams are identified and, subsequently, evaluated by observing their effects

Real-time co-ordinated scheduling using a genetic algorithm

Real-time co-ordination is an emerging approach to operational engineering management aimed at being more comprehensive and widely applicable than existing approaches. Schedule management is a key characteristic of operational co-ordination related to managing the planning and dynamic assignment of tasks to resources, and the enactment of the resulting schedules, throughout a changeable process. This paper presents the application of an agent-oriented system, called the Design Co-ordination System, to an industrial case study in order to demonstrate the appropriate use of a genetic algorithm for the purpose of real-time scheduling. The application demonstrates that real-time co-ordinated scheduling can provide significant reductions in time to complete the computational design process

A preliminary approach for modelling and planning the composition of engineering project teams

Managing engineering projects is a complex activity involving multiskilled engineers, who have varying levels of capability in these skills. This paper outlines a preliminary approach to modelling and planning the composition of engineering project teams, taking into consideration the skills and capabilities of engineers and the nature of the project work to be undertaken. The approach includes a simple means of identifying engineers' skills and then quantifying their level of capability in these skills. Subsequently, the approach uses a genetic algorithm along with a task-to-engineer allocation strategy to establish how best to utilize the mix of skills and capabilities of the team of engineers assigned to the project under consideration. The approach also provides a means of identifying imbalances or shortfalls in skill and capability within a team, and the formulation of an appropriate development strategy to redress/overcome them. An application of the approach to an industrial case study is presented, which led to significant potential reductions in expected project duration and labour cost. These potential reductions could be achieved by appropriately modelling engineers' skills and capabilities, and redressing the imbalance within the team through proposed changes to its composition

Molecular systematics of Malpighiaceae: evidence from plastid rbcL and matK sequences

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141234/1/ajb21847.pd

Adaptive Lévy processes and area-restricted search in human foraging

A considerable amount of research has claimed that animals’ foraging behaviors display movement lengths with power-law distributed tails, characteristic of Lévy flights and Lévy walks. Though these claims have recently come into question, the proposal that many animals forage using Lévy processes nonetheless remains. A Lévy process does not consider when or where resources are encountered, and samples movement lengths independently of past experience. However, Lévy processes too have come into question based on the observation that in patchy resource environments resource-sensitive foraging strategies, like area-restricted search, perform better than Lévy flights yet can still generate heavy-tailed distributions of movement lengths. To investigate these questions further, we tracked humans as they searched for hidden resources in an open-field virtual environment, with either patchy or dispersed resource distributions. Supporting previous research, for both conditions logarithmic binning methods were consistent with Lévy flights and rank-frequency methods–comparing alternative distributions using maximum likelihood methods–showed the strongest support for bounded power-law distributions (truncated Lévy flights). However, goodness-of-fit tests found that even bounded power-law distributions only accurately characterized movement behavior for 4 (out of 32) participants. Moreover, paths in the patchy environment (but not the dispersed environment) showed a transition to intensive search following resource encounters, characteristic of area-restricted search. Transferring paths between environments revealed that paths generated in the patchy environment were adapted to that environment. Our results suggest that though power-law distributions do not accurately reflect human search, Lévy processes may still describe movement in dispersed environments, but not in patchy environments–where search was area-restricted. Furthermore, our results indicate that search strategies cannot be inferred without knowing how organisms respond to resources–as both patched and dispersed conditions led to similar Lévy-like movement distributions

Transforming Growth Factor Beta 1 drives a switch in connexin mediated cell-to-cell communication in tubular cells of the diabetic kidney

Aims/Hypothesis: Changes in cell-to-cell communication have been linked to several secondary complications of diabetes, but the mechanism by which connexins affect disease progression in the kidney is poorly understood. This study examines a role for glucose-evoked changes in the beta1 isoform of transforming growth factor (TGFβ1), on connexin expression, gap-junction mediated intercellular communication (GJIC) and hemi-channel ATP release from tubular epithelial cells of the proximal renal nephron. Methods: Biopsy material from patients with and without diabetic nephropathy was stained for connexin-26 (CX26) and connexin-43 (CX43). Changes in expression were corroborated by immunoblot analysis in human primary proximal tubule epithelial cells (hPTECs) and model epithelial cells from human renal proximal tubules (HK2) cultured in either low glucose (5mmol/L) ± TGFβ1 (2-10ng/ml) or high glucose (25mmol/L) for 48h or 7days. Secretion of the cytokine was determined by ELISA. Paired whole cell patch clamp recordings were used to measure junctional conductance in control versus TGFβ1 treated (10ng/ml) HK2 cells, with carboxyfluorescein uptake and ATP-biosensing assessing hemi-channel function. A downstream role for ATP in mediating the effects of TGF-1 on connexin mediated cell communication was assessed by incubating cells with ATPS (1-100M) or TGF-1 +/- apyrase (5 Units/ml). Implications of ATP release were measured through immunoblot analysis of interleukin 6 (IL-6) and fibronectin expression. Results: Biopsy material from patients with diabetic nephropathy exhibited increased tubular expression of CX26 and CX43 (P<0.01, n=10), data corroborated in HK2 and hPTEC cells cultured in TGFβ1 (10ng/ml) for 7days (P<0.001, n=3). High glucose significantly increased TGFβ1 secretion from tubular epithelial cells (P<0.001, n=3). The cytokine (10ng/ml) reduced junctional conductance between HK2 cells from 4.5±1.3nS in control to 1.15±0.9nS following 48h TGFβ1 and to 0.42±0.2nS after 7days TGFβ1 incubation (P<0.05, n=5). Acute (48h) and chronic (7day) challenge with TGFβ1 produced a carbenoxolone (200M)-sensitive increase in carboxyfluorescein loading, matched by an increase in ATP release from 0.29±0.06μM in control to 1.99±0.47μM after 48hr incubation with TGFβ1 (10ng/ml; P<0.05, n=3). TGF-1 (2-10ng/ml) and ATPs (1-100M) increased expression of IL-6 (P<0.001 n=3) and fibronectin (P<0.01 n=3). The effect of TGF-1 on IL-6 and fibronectin expression was partially blunted when preincubated with apyrase (n=3). Conclusion: These data suggest that chronic exposure to glucose-evoked TGFβ1 induce an increase in CX26 and CX43 expression, consistent with changes observed in tubular epithelia from patients with diabetic nephropathy. Despite increased connexin expression, direct GJIC communication decreases, whilst hemichannel expression/function and paracrine release of ATP increases, changes that trigger increased levels of expression of interleukin 6 and fibronectin. Linked to inflammation and fibrosis, local increases in purinergic signals may exacerbate disease progression and highlight connexin mediated cell communication as a future therapeutic target for diabetic nephropath

Another Non-segregated Blue Straggler Population in a Globular Cluster: the Case of NGC 2419

We have used a combination of ACS-HST high-resolution and wide-field SUBARU data in order to study the Blue Straggler Star (BSS) population over the entire extension of the remote Galactic globular cluster NGC 2419. The BSS population presented here is among the largest ever observed in any stellar system, with more than 230 BSS in the brightest portion of the sequence. The radial distribution of the selected BSS is essentially the same as that of the other cluster stars. In this sense the BSS radial distribution is similar to that of omega Centauri and unlike that of all Galactic globular clusters studied to date, which have highly centrally segregated distributions and, in most cases, a pronounced upturn in the external regions. As in the case of omega Centauri, this evidence indicates that NGC 2419 is not yet relaxed even in the central regions. This observational fact is in agreement with estimated half-mass relaxation time, which is of the order of the cluster age.Comment: in press in the Ap