Model-driven engineering for mobile robotic systems: a systematic mapping study

Software and Systems Modeling - Mobile robots operate in various environments (e.g. aquatic, aerial, or terrestrial), they come in many diverse shapes and they are increasingly becoming parts of...     

Fullerene-based ruthenium catalysts: a novel approach for anchoring metal to carbonaceous supports. I. Structure

The influence of fullerenes and related support materials on the structural and catalytic properties of ruthenium was investigated. Catalysts based on C₆₀, raw fullerene black, extracted fullerene black, cathode deposit and graphite were prepared by an impregnation/activation procedure with Ru₃CO₁₂. The local co-ordination sphere of the resulting highly dispersed X-ray amorphous ruthenium was investigated by means of EXAFS. The dominating role of the presence of non-six-membered carbon rings on the structure and the stability of the Ru particles will be illustrated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Discovery and analysis of e-mail-driven business processes

E-mail is used as the primary tool for business communication and collaboration. This paper presents a novel e-mail interaction mining method to discover and analyze e-mail-driven business processes. An e-mail-driven business process is perceived as a human collaboration process that consists of interactions between people who may each play different roles. The notion of message threads (i.e. sets of e-mail messages that are replies to each other) is used as the fundamental building block to construct the interactions in the e-mail-driven business process. The proposed method adopts an interaction-centric business process modeling language to visualize the discovered e-mail-driven business process. The method identifies message threads from an e-mail archive, and constructs an interaction-centric process model based on the temporal order and similarity of the threads. Process-related information is extracted from e-mail header fields. A software tool, named E-mail Interaction Miner, implements the proposed method. A case study is used to apply and evaluate the method on a set of e-mails collected from a Dutch gas transport company. The evaluation results are discussed. These results comprise business process improvement opportunities for the case organization, and contributions to theory and language development.     

Maize and pigeon pea sole crop and intercrop nutrient response functions for Tanzania

The development of ecological circular agriculture has been highly encouraged by the Chinese government to recycle agricultural wastes, reduce mineral fertilizer input, and protect the environment. Biogas slurry, a byproduct of biogas engineering developed in rural areas of China, could be used as N fertilizer for crop growth. The field experiments were conducted in 2014 and 2015 to study the plant growth responses and environmental impacts of applying biogas slurry to two-season Zizania aquatica Turcz. growth. The potential factors that restrict the rational use of biogas slurry were also clarified. Mineral N fertilizer can be completely or partly substituted by N fertilizer from biogas slurry to satisfy Z. aquatica plant growth. It was not at the cost of sacrificing yield, dry matter accumulation, N accumulation and physiological N use efficiency in the above-ground parts. However, the growth inhibition occurs when the N quantity in biogas slurry was 2 or 2.7 times higher than that of mineral N fertilizer. Vitamin C in non-shell swollen culms (as edible part) of Z. aquatica significantly increased after biogas slurry application. Biogas slurry application substantially increased the N concentrations, i.e., total N, NH₄ ⁺–N, and NO₃ ^?–N in floodwater and delayed the time to reach national discharge standards. However, biogas slurry application did not affect the N concentrations in percolating water compared with the treatment with mineral N fertilizer only. Applying biogass slurry did not generate potential pollution risks by trace elements (Cu, Zn, Pb, Cr, Cd, As, and Hg) in the non-shell swollen culm and soil, and did not increase the nitrate content in non-shell swollen culm. We found the NH₄ ⁺–N concentration in biogas slurry can account for 77–93% of total N and reflects the N level in biogas slurry to a great degree. Semi-quantitative color-based colorimetric methods possessing simple and fast characteristics should be developed to determine the NH₄ ⁺–N concentration with the purpose of promoting reasonable use of biogas slurry in area of crop cultivation. Otherwise, excessive use of biogas slurry can adversely affect crops and increase environmental risks.     

The influence of condition-based maintenance on workforce planning and maintenance scheduling

Condition-based maintenance (CBM) is generally considered an attractive maintenance policy for a single component: it uses the operating condition of the component to predict a failure event and therefore tries to avoid any unplanned downtime and unnecessary maintenance activities. However, operations managers tend to be much more interested in optimising the performance of the entire asset-system, where the grouping of maintenance activities and the availability of maintenance workers may play a role. Therefore, this paper focuses on the impact of using either CBM or age-based replacement (ABR) in serial and parallel multi-component systems (1) without worker constraints, (2) with a single internal maintenance worker, and (3) with external maintenance workers with a significant response time. With an internal maintenance worker, the sequential execution of maintenance activities prevents efficiency gains in the serial configuration and here CBM performs better. Also in the parallel configurations, the efficiency under CBM is generally better than under ABR. However, with external maintenance workers, CBM is not able to group maintenance activities as well as ABR, which results in a lower efficiency in the serial configuration. CBM performs better than ABR with respect to total maintenance costs, while ABR results in a smoother maintenance plan.     

Examination of Interpenetrating Polymer Networks of Polyurea in Silicone Molds Arising during Vacuum Casting Processes

We present an in-depth investigation of the aging effects in silicone molds for vacuum casting processes. Their lifetime is limited to a few production cycles due to contamination with the diisocyanate component of polyurethane casting materials. Using thermogravimetric analysis measurements, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and helium-ion-microscopy the chemical and physical mechanisms of the aging process have been identified. It has been shown that a diffusion process of diisocyanate into the cavity surface leads to the formation of interpenetrating polymer networks of polyurea derivatives in silicone rubber. This has been proven by extracting and analyzing polyurea of low molecular weights from the silicone.     

Mössbauer studies of Gd-doped bismuth-based ceramic superconductors

The results of¹⁵⁵Gd Mössbauer studies (above 1·5K) of the oxides, Bi_3·5Gd_0·5Ca₃Sr₃Cu₄O _y and Bi₂Sr₂Ca_1?x Gd _x Cu₂O _y (x=0·25 and 0·5) are reported. The observed electric quadrupolar split resonance patterns suggest that Gd ions prefer to occupy Ca site in both series. The spectral features give evidence for paramagnetic relaxation of isolated Gd ions at low temperatures.     

Incidental discovery of emphysematous cystitis

The routine use of imaging studies for the evaluation of abdominal pain occasionally yields unexpected and unusual findings. We report a case of emphysematous cystitis that was incidentally discovered on a computed tomography scan originally ordered as part of an evaluation of pancreatitis.     

Hindsight bias among physicians weighing the likelihood of diagnoses.

Examines findings showing that (1) those who know an event has occurred tend to claim that, if they had been asked to predict the event in advance, they would have been likely to do so; and (2) such Ss demonstrate hindsight bias to the extent that their "prediction" accuracy exceeds the accuracy of others who actually make the prediction without knowledge of the outcome. 75 practicing physicians were divided into 5 equal groups and given the same medical case history. The foresight group was asked to assign a probability estimate to each of 4 possible diagnoses. The 4 hindsight groups were asked to do the same, but each was told that a different 1 of the 4 possible diagnoses was correct. The hindsight groups, who were told that the least likely diagnoses were correct, assigned far greater probability estimates to these "correct" diagnoses than did the foresight group. Implications for physicians are discussed with respect to overconfident 2nd opinions, overconfidence in diagnostic accuracy, and inadequate appreciation of the original difficulty of diagnoses. (6 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)