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201.
Disruptions in automated manufacturing systems for machining automotive parts caused by system changes and disturbances reduce the productivity, and increase the downtime as well as the cost of products. To cope with these challenges, the paper presents a biology inspired manufacturing system (Bio-MS). The model of Bio-MS is inherited from the organization of the living systems in biology and nature such as ant colony, school of fish, bee’s foraging behaviors, and so on. In which, the resources of the manufacturing system are considered as biological organisms, which are autonomous entities so that the manufacturing system has the advanced characteristics inspired from biology such as self-adaptation, self-diagnosis, and self-healing. To realize the Bio-MS, the cognitive agent and swarm intelligence were proposed. The disturbances happening when machining the transmission cases at an automotive company in Korea were analyzed to classify them and to find out the corresponding management methods. Currently, the system utilization was too low due to the manual recovery, only 70–76 percent of total production time is used for manufacturing and the rest of the time is wasted in different disturbances. The Bio-MS with autonomous behaviors adapts efficiently to the changes of the manufacturing environment. It enables to increase the system utilization more than 80 percent. 相似文献
202.
N. Oppenchaim 《Recherche - Transports - Sécurité》2011,27(2):93-103
Do the working-class teenagers have a specific and homogeneous use of the space outside their neighbourhood? Do they have different practices of mobility when they live in “Zones Urbaines Sensibles” (ZUS)? These questions have hardly been investigated in contrast to these teenagers’ use of the space inside their neighbourhood. Yet, in spite of a mobility potential lower than that of other teenagers, they spend a lot of time outside their neighbourhood. Among these teenagers, those residing in the ZUS experiment personal autonomy at a younger age in taking public transportation. Also, one notes a greater immobility of girls. Beyond these gender disparities, a closer look at the daily mobility reveals five predominant ways of using the space outside the neighbourhood — public transportation being part of this space. These ways are tightly linked to the nature of the relationship with that neighbourhood. These five predominant ways, influenced by social and territorial variables, depict the heterogeneity of the inhabitants of the ZUS and of the current working class. 相似文献
203.
N. G. Park J. H. Ryu H. W. Lee Y. H. Jeon N. Zhang 《International Journal of Automotive Technology》2009,10(3):341-346
An Inner Spherical CVT (ISCVT) transfers engine power by utilizing the traction force of the lubricant fluid film on the contact
point between concave and convex spherical rolling bodies. Since the concave and the convex contact surfaces of the ISCVT
are exactly spherical parts, they have a large circular (not elliptic) contact area, and the ISCVT mechanism has a larger
torque capacity, less spin loss, and better stability than other traction drive mechanisms. The IVT (Infinitely Variable Transmission)
performances also can easily be embodied in the ISCVT. In this work, we developed a prototype of the ISCVT for a motorcycle
with a 125cc single cylinder engine having a maximum torque of 13.73 Nm at 8,000 rpm. The design parameters were determined,
and the transmission performances were evaluated by optimal design procedure. The transmission efficiency, the life time,
the maximum severe stresses on each part of the ISCVT, and the work needed for varying speed ratio were theoretically investigated,
and the efficiency performances were experimentally measured. The manufactured prototype was installed in an actual motorcycle,
which was fixed on the test-bench equipped with a dynamometer. The parasitic loss of the prototype and the cross-sectional
road load performance were tested. The power efficiency of the simulated prototype was between 87∼92%, and the life span was
more than 50,000 hours. The tested overall power efficiency was around 70∼92% under frequent driving conditions, which is
an impressive performance in a motorcycle transmission despite the small difference from the simulation. 相似文献
204.
目的 研究抑癌基因 p1 6及Rb的表达与胆囊癌预后的关系。方法 用SP免疫组化法同步检测 41例胆囊癌患者抑癌基因 p1 6及Rb的蛋白表达。 结果 p1 6与Rb蛋白表达阳性组生存率明显优于阴性组。结论 p1 6及Rb在胆囊癌的预后判定中具有重要价值 ,同步检测两者的预后价值优于单一检测。 相似文献
205.
Options-Based Multi-Objective Evaluation of Product Platforms 总被引:1,自引:0,他引:1
JAVIER P. GONZALEZ-ZUGASTI KEVIN N. OTTO CLIFFORD A. WHITCOMB 《Naval Engineers Journal》2007,119(3):89-106
A platform is the set of elements and interfaces that are common to a family of products. Design teams must choose among feasible platform concepts upon which a product family could be based, often involving new technologies. Multiple performance objectives need to be considered. A standard approach is to convert the performance outcomes into financial figures, which can then be weighed against the required investments. However, it is not always possible to transform performance outcomes (benefits) into monetary terms, such as in defense or highly technical projects. A multi-objective form of real-options-based platform selection is developed. Systems are compared based on multiple technical and economic goals, incorporating uncertainty by representing the unknown factors during the subsequent development process with probability distributions. The range of uncertain outcomes is integrated into single expected measures of effectiveness, which can then be applied to select the most appropriate platform and set of support product variants. An application to the design of platform-based families of naval high-speed ships is shown. 相似文献
206.
Large-scale physical controls on phytoplankton growth in the Irminger Sea Part I: Hydrographic zones, mixing and stratification 总被引:3,自引:1,他引:2
N.P. Holliday J.J. Waniek R. Davidson D. Wilson L. Brown R. Sanders R.T. Pollard J.T. Allen 《Journal of Marine Systems》2006,59(3-4):201-218
Hydrographic surveys in three consecutive seasons in the Irminger Sea in 2001/2002 have revealed six physical regimes (zones) in which different surface mixing and spring re-stratification processes dominate. They are the South Irminger Current, the North Irminger Current, the Central Irminger Sea, the Polar-origin East Greenland Current, the Atlantic-origin East Greenland Current and the Reykjanes Ridge. The variations in restratification processes in particular have significant implications for the timing of shallow spring mixed layer development and therefore the timing and strength of the spring bloom. The relative roles of heat and freshwater in controlling re-stratification are examined for each hydrographic zone, and it is shown that the simplest concept of solar warming generating spring stratification is appropriate for the Irminger Current and the central Irminger Sea. However in the East Greenland Current and the Reykjanes Ridge zones, the springtime arrival of fresh or saline water at the surface dominates re-stratification and generates the earliest and strongest spring blooms of the region. In the cool fresh centre of the Irminger Sea the relatively low chlorophyll-a throughout the year cannot be wholly explained by stratification or nutrient concentrations. Details of the annual cycle in temperature, salinity, chlorophyll-a and nutrients are presented for each hydrographic zone. 相似文献
207.
J. Gao N.J. Leighton C. Morgan 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1998,29(4):261-273
An alternative technique for identifying the transfer function of automotive suspension systems is presented in this paper. The method establishes a frequency response from which the transfer function can be determined by using a low cost test rig developed for the purpose. This results in a transfer function matrix which can include asymmetry in the suspension, tyre stiffness and damping. The technique is validated by comparing results for a two-wheeled trailer with those obtained on a conventional hydraulic test rig. Results from this procedure may be used to evaluate passive or active suspension systems or to feed into a suspension modelling process for such purposes as active suspension control strategy development. 相似文献
208.
D. V. Lyridis T. Fyrvik G. N. Kapetanis N. Ventikos P. Anaxagorou E. Uthaug H. N. Psaraftis 《Maritime Policy and Management》2005,32(4):403-420
In order to identify the elements constituting quality in services, a business process modelling methodology has been applied in the case of a Greek liner shipping company. The company operations have been identified and analysed in order to assess the complete performance of service elements and thereafter identify how to match the service performance against the user requirements. A liner container service within Europe has to compete with the road transport which, in many cases, is an alternative to the sea transportation and not complementary to it. Thus, not only the ship has to be envisaged when aiming to improve quality in services but also the whole chain, namely port authorities, land transportation enterprises, subcontractors, agents, charterers and others. A set of potential improvements within this framework are thus suggested and time and cost (examined in a specific voyage scenario) are measured before and after the implementation of these measures. Very large time and cost savings are observed after the application of the technology improvements, allowing, in fact, the shipping company to even increase the number of round trips per year in the examined route. This indicates that very large benefits can be drawn by analysing and critically adjusting business processes in modern shipping companies. 相似文献
209.
The state of the art in airport terminal design has essentially remained unchanged since the 1970s, relying on the use of detailed simulation together with empirical and statistical formulae for sizing the terminal. Air transport has altered considerably since then, with increased use of air travel for both business and leisure, together with the increased use of ‘hub’ terminals in which the terminal acts as an interchange stop on a journey involving several flights. The use of simulation involves a detailed analysis of the terminal design under one set of conditions. To change the design or operating conditions involves a complete resimulation using the new design parameters which is time consuming and computationally expensive. By using a knowledge based approach, a system can be provided which has the flexibility and speed required to explore the consequences of implementing design decisions in a variety of conditions, together with the ability to use and alter facility sizing methodologies to reflect current and future design guidelines. 相似文献
210.
Despite decades of research, it is unclear under which circumstances travel is most onerous. While studies have found that some individuals derive positive utility from aspects of commuting, others have shown that traffic congestion can entail important time, monetary, and mental stress costs. Moreover, responses to traffic congestion-related stressors differs by individual characteristics. In response, this research captures how exposure to traffic congestion events, the duration of this exposure, and individual trait susceptibility to congestion affect the utility of commuting. Working through the lens of individual satisfaction with the duration of their commute, we show that not every minute of travel is valued the same by car commuters in Canadian cities. Results suggest a complex relationship between travel time, congestion, and individual predisposition to congestion-related stress. While improvements in travel time matter for increasing commute satisfaction, it is reductions in travel in congested conditions that matter most, particularly among those susceptible to congestion-related stressors. 相似文献