Operational Redistribution Model for a Large-Scale Bicycle-Sharing System

2015 ◽  
Vol 2512 (1) ◽  
pp. 90-100 ◽  
Author(s):  
Mingzhu Song ◽  
Meng Li ◽  
Mingqiao Zou

In recent years, bicycle-sharing systems (BSSs) have been getting more and more popular in many cities all over the world, particularly in developing countries. However, a significant operating problem was the imbalance that occurred in the distribution of bicycles, especially in large-scale BSSs during peak hours. This problem could significantly reduce the level of service and number of potential users. To improve the level of service of BSSs, the necessity of redistribution was analyzed, and an operational redistribution model (ORM) that could deal with large-scale redistribution was developed. The objective of the ORM was to minimize the generalized operation costs of BSSs, which were the penalty cost of unserved user demand and the cost of redistribution of bicycles. The overall system performance was analyzed under several scenarios. The results demonstrated that an ORM could effectively improve the level of service of a BSS and could provide a detailed work plan for each redistribution truck to implement. For redistribution in a large-scale BSS, the partition of subzones was important to achieve a high level of service with relatively low generalized costs. In addition, an optimal number of subzones could be found through the scenario-based optimization process.

Aerospace ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 104 ◽  
Author(s):  
Ilias Lappas ◽  
Michail Bozoudis

The development of a parametric model for the variable portion of the Cost Per Flying Hour (CPFH) of an ‘unknown’ aircraft platform and its application to diverse types of fixed and rotary wing aircraft development programs (F-35A, Su-57, Dassault Rafale, T-X candidates, AW189, Airbus RACER among others) is presented. The novelty of this paper lies in the utilization of a diverse sample of aircraft types, aiming to obtain a ‘universal’ Cost Estimating Relationship (CER) applicable to a wide range of platforms. Moreover, the model does not produce absolute cost figures but rather analogy ratios versus the F-16’s CPFH, broadening the model’s applicability. The model will enable an analyst to carry out timely and reliable Operational and Support (O&S) cost estimates for a wide range of ‘unknown’ aircraft platforms at their early stages of conceptual design, despite the lack of actual data from the utilization and support life cycle stages. The statistical analysis is based on Ordinary Least Squares (OLS) regression, conducted with R software (v5.3.1, released on 2 July 2018). The model’s output is validated against officially published CPFH data of several existing ‘mature’ aircraft platforms, including one of the most prolific fighter jet types all over the world, the F-16C/D, which is also used as a reference to compare CPFH estimates of various next generation aircraft platforms. Actual CPFH data of the Hellenic Air Force (HAF) have been used to develop the parametric model, the application of which is expected to significantly inform high level decision making regarding aircraft procurement, budgeting and future force structure planning, including decisions related to large scale aircraft modifications and upgrades.


2020 ◽  
Author(s):  
Noah J. Goodall ◽  
Brian L. Smith

High-occupancy toll (HOT) lanes are in operation, under construction, and planned for in several major metropolitan areas. The premise behind HOT lanes is to allow single occupant vehicles (SOVs) to access high occupancy vehicle (HOV) lanes (and, a higher level of service) if they are willing to pay a toll. To maintain a high level of service in the HOT lanes, the toll rate is set dynamically to restrict the number of SOVs which access the facility as it nears capacity. Thus, HOT facilities provide operators of transportation systems with a new operations tool: pricing. In order to effectively use pricing, it is critical to understand driver behavior when faced with a set of traffic conditions and toll levels. This paper presents the results of an empirical investigation into the relationship between toll rate, traffic conditions, and SOV driver behavior, based on data from the dynamically-tolled I-394 HOT facility in Minneapolis, Minnesota. Analysis of the empirical data indicated that a large percentage of SOV drivers use the HOT lanes at different, yet predictable rates throughout the AM peak period, even when there is no clear travel time advantage. After accounting for these “regular” users, the remaining SOV drivers utilize the HOT lanes at greater rates when the cost per hour of commute time saved is lowest. A model was developed that incorporates both of these findings, predicting HOT lane usage rates based on time savings, time of day, and toll rates with an R2 value of 0.684.


2018 ◽  
Author(s):  
Berline Fopa Fomeju ◽  
Dominique Brunel ◽  
Aurélie Bérard ◽  
Jean-Baptiste Rivoal ◽  
Philippe Gallois ◽  
...  

AbstractNext-Generation Sequencing (NGS) technologies, by reducing the cost and increasing the throughput of sequencing, have opened doors of research efforts to generate genomic data to a range of previously poorly studied species. In this study, we proposed a method for the rapid development of a large scale molecular resources for orphan species. We studied as an example Lavandula angustifolia, a perennial sub-shrub plant native from the Mediterranean region and whose essential oil have numerous applications in cosmetics, pharmaceuticals, and alternative medicines.We first built a ‘Maillette’ reference Unigene, compound of coding sequences, thanks to de novo RNA-seq assembly. Then, we reconstructed the complete genes sequences (with exons and introns) using a transcriptome-guided DNA-seq assembly approach in order to maximize the possibilities of finding polymorphism between genetically close individuals. Finally, we used these resources for SNP mining within a collection of 16 lavender clones and tested the SNP within the scope of a phylogeny analysis. We obtained a cleaned reference of 8, 030 functionally annotated ‘genes’ (in silico annotation). We found up to 400K polymorphic sites, depending on the genotype analyzed, and observed a high SNP frequency (mean of 1 SNP per 90 bp) and a high level of heterozygosity (more than 60% of heterozygous SNP per genotype). We found similar genetic distances between pairs of clones, related to the out-crossing nature of the species, the restricted area of cultivation and the clonal propagation of the varieties.The method propose is transferable to other orphan species, requires little bioinformatics resources and can be realized within a year. This is the first reported large-scale SNP development on Lavandula angustifolia. All this data provides a rich pool of molecular resource to explore and exploit biodiversity in breeding programs.


2003 ◽  
Vol 14 (2) ◽  
pp. 35-45
Author(s):  
Kay Dobie ◽  
Jerry Wilson

The emphasis in the press, trade publications, and even academic publications is increasingly on supply chain operations, collaboration, and software. There is no argument that these are important considerations as companies struggle to compete in highly competitive markets and an economically difficult environment. This emphasis on “lean” or “JIT” operations presupposes the ability of the firm to operate on a minimum level of inventory and deliver a high level of service. Too often, the basic and vital interdependency between transportation and inventory, necessary to support this objective, is forgotten in the emphasis on the total picture as embodied by the supply chain. It has been said that “the devil is in the details.” It may be time for many firms to take another look at inventory, transportation and the cost of service.


Author(s):  
Georgi Derluguian

The author develops ideas about the origin of social inequality during the evolution of human societies and reflects on the possibilities of its overcoming. What makes human beings different from other primates is a high level of egalitarianism and altruism, which contributed to more successful adaptability of human collectives at early stages of the development of society. The transition to agriculture, coupled with substantially increasing population density, was marked by the emergence and institutionalisation of social inequality based on the inequality of tangible assets and symbolic wealth. Then, new institutions of warfare came into existence, and they were aimed at conquering and enslaving the neighbours engaged in productive labour. While exercising control over nature, people also established and strengthened their power over other people. Chiefdom as a new type of polity came into being. Elementary forms of power (political, economic and ideological) served as a basis for the formation of early states. The societies in those states were characterised by social inequality and cruelties, including slavery, mass violence and numerous victims. Nowadays, the old elementary forms of power that are inherent in personalistic chiefdom are still functioning along with modern institutions of public and private bureaucracy. This constitutes the key contradiction of our time, which is the juxtaposition of individual despotic power and public infrastructural one. However, society is evolving towards an ever more efficient combination of social initiatives with the sustainability and viability of large-scale organisations.


2000 ◽  
Vol 151 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Stephan Wild-Eck ◽  
Willi Zimmermann

Two large-scale surveys looking at attitudes towards forests, forestry and forest policy in the second half ofthe nineties have been carried out. This work was done on behalf of the Swiss Confederation by the Chair of Forest Policy and Forest Economics of the Federal Institute of Technology (ETH) in Zurich. Not only did the two studies use very different methods, but the results also varied greatly as far as infrastructure and basic conditions were concerned. One of the main differences between the two studies was the fact that the first dealt only with mountainous areas, whereas the second was carried out on the whole Swiss population. The results of the studies reflect these differences:each produced its own specific findings. Where the same (or similar) questions were asked, the answers highlight not only how the attitudes of those questioned differ, but also views that they hold in common. Both surveys showed positive attitudes towards forests in general, as well as a deep-seated appreciation ofthe forest as a recreational area, and a positive approach to tending. Detailed results of the two surveys will be available in the near future.


The productivity of land has been often discussed and deliberated by the academia and policymakers to understand agriculture, however, very few studies have focused on the agriculture worker productivity to analyze this sector. This study concentrates on the productivity of agricultural workers from across the states taking two-time points into consideration. The agriculture worker productivity needs to be dealt with seriously and on a time series basis so that the marginal productivity of worker can be ascertained but also the dependency of worker on agriculture gets revealed. There is still disguised unemployment in all the states and high level of labour migration, yet most of the states showed the dependency has gone down. Although a state like Madhya Pradesh is doing very well in terms of income earned but that is at the cost of increased worker power in agriculture as a result of which, the productivity of worker has gone down. States like Mizoram, Meghalaya, Nagaland and Tripura, though small in size showed remarkable growth in productivity and all these states showed a positive trend in terms of worker shifting away from agriculture. The traditional states which gained the most from Green Revolution of the sixties are performing decently well, but they need to have the next major policy push so that they move to the next orbit of growth.


1999 ◽  
Vol 39 (10-11) ◽  
pp. 289-295
Author(s):  
Saleh Al-Muzaini

The Shuaiba Industrial Area (SIA) is located about 50 km south of Kuwait City. It accommodates most of the large-scale industries in Kuwait. The total area of the SIA (both eastern and western sectors) is about 22.98 million m2. Fifteen plants are located in the eastern sector and 23 in the western sector, including two petrochemical companies, three refineries, two power plants, a melamine company, an industrial gas corporation, a paper products company and, two steam electricity generating stations, in addition to several other industries. Therefore, only 30 percent of the land in the SIA's eastern sector and 70 percent of land in the SIA's western sector is available for future expansion. Presently, industries in the SIA generate approximately 204,000 t of solid waste. With future development in the industries in the SIA, the estimated quantities will reach 240,000 t. The Shuaiba Area Authority (SAA), a governmental regulatory body responsible for planning and development in the SIA, has recognized the problem of solid waste and has developed an industrial waste minimization program. This program would help to reduce the quantity of waste generated within the SIA and thereby reduce the cost of waste management. This paper presents a description of the waste minimization program and how it is to be implemented by major petroleum companies. The protocols employed in the waste minimization program are detailed.


Author(s):  
Zheng Zhou ◽  
Erik Saule ◽  
Hasan Metin Aktulga ◽  
Chao Yang ◽  
Esmond G. Ng ◽  
...  

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