Mixed assembly line rebalancing: A binary integer approach applied to real world problems in the automotive industry

Industrial organizations have increasingly sought to optimize the resources needed for the manufacture of its products from the competition, in order to maintain their profit margins. The search for balance of resources and balanced distribution of tasks in various types of industrial environments is called balancing. When adjustments are made and adequacy of an assembly line that is already in operation, this process is called rebalancing. This paper presents a case study involving a problem of rebalancing of automotive assembly line in an environment of arbitrarily mixed models of products, also known as mix. The proposed procedure for solving the rebalancing in the company in question is based on Binary Integer Programming, in particular the branch and bound algorithm. For comparison, we used a heuristic method based on precedence diagrams for solving the rebalancing of lines. To evaluate the results obtained between the two procedures were used performance indicators such as number of workstations created, average load of work and level of unbalance. The proposed algorithm has resulted in significant improvements in the production line capacity.     

Evaluating goals and impacts of two metro alternatives by the AHP

The transport planning and its decision making involve a large number of goals and more than one alternative to be evaluated. This analysis comprises technical and financial features up to social and environmental impacts. We show how the AHP is a useful tool in this procedure, and evaluate several objectives and impacts of the implantation of the third metro line in the city of Sao Paulo, Brazil, where there were two alternative outlines and one of them to be selected.     

Driver recruitability for advanced traveler information system experiments

A number of Advanced Traveler Information System (ATIS) field experiments are being undertaken to study the effectiveness of the ATIS concept in ameliorating traffic congestion and reducing delays. Many of these experiments require the participation of private drivers willing to allow in-vehicle navigation units to be installed in their vehicles over an extended period of time. A critical part of any ATIS field experiment is the selection or recruitment of private drivers to fulfill the multi-purpose participation needs of the ATIS experiment. To provide an informed basis for designing such a driver recruitment effort, it is important to understand the factors affecting driver recruitability or “willingness to participate.” This research presents the results of a quantitative analysis of driver recruitability conducted to aid in the design of recruitment procedures for ADVANCE (Advanced Driver and Vehicle Advisory Navigation Concept), the largest ATIS field experiment of its kind. The approach used a telephone survey to assess driver willingness to participate in the ADVANCE field experiment and to explore variations in that willingness among different drivers and across characteristics of the ADVANCE system and experimental design. The results indicate that the willingness to participate in the ADVANCE field test is greater for men, persons who hold executive or managerial occupations, individuals who drive extensively, persons who use electronic devices such as personal computers and car phones regularly, and persons who have positive beliefs regarding the usefulness of the ADVANCE concept. The result also suggest that drivers' willingness to participate is not strongly affected by monitoring/reporting requirements such as responding to surveys, mailing electronically stored records of system operation, and periodic service requirements. However, the willingness decreases considerably if drivers have to bear the financial responsibility for damage of the navigation equipment and any equipment-caused electrical failures to the car. Finally, the incentive of a lottery prize raises the level of participation willingness. These results have important implications for the recruitment effort, both in terms of recruiting drivers for participation in the demonstration and specifying the operational details of the field test.     

在不同水质地区实地进行海洋生物膜对SS UNS S32760不锈钢腐蚀行为研究（英文）

In the presence of biofilms, stainless steels(SS) exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential(Ecorr) behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo,Southeastern Brazil. The biofilm at Forno Harbor(an anthropogenically disturbed area) was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms(especially Navicula sp.) on day 10 and dinoflagellates on day 18,whereas no clear trend was recorded at Cabo Frio Island(an undisturbed area). The ennoblement of Ecorr values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Ecorr values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in important gaps in this knowledge.     

Developing management guidelines for oil and gas activities: The louisiana experience

Abstract

Preliminary management guidelines have been derived for oil and gas activities in coastal Louisiana. Derivation of these guidelines was done in terms of the natural function of the coastal ecosystem; this means that all economic activities should be designed to complement natural function as much as possible. The guidelines range in scope from very specific, almost performance standards, to very general admonitions. For example, we have suggested that spoil banks, produced as a result of dredging, should not be higher than the height of the daily tide or roughly 15 cm in coastal Louisiana, and at the other extreme, we have suggested that all dredging should be done with great care during wildlife migrations, spawning, and nesting times.     

A review of freight modelling procedures

This paper reviews the current practice of modelling freight movements for highway planning purposes. It is noted that few, if any models are explanatory and there is normally a two stage process involving a Macro Forcasting Model that predicts overall changes in vehicle miles, tons lifted and vehicles operated and a Local Spatial Model that predicts changes of movement patterns constrained to the totals provided by the Macro Model. Alternative forms of Spatial Models are described with examples how they have been used and suggestions are made of where improvements could be undertaken.

     

Time use,mobility and expenditure: an innovative survey design for understanding individuals’ trade-off processes

A large amount of information is required to model the complex trade-off processes between travel activities, non-travel activities and budget assignment at the individual level. This paper describes the development of a new survey design, which incorporates components of travel surveys, time use surveys and consumer expenditure surveys in an integrated format, which is expected to deliver a richer data set allowing deeper insights into individuals’ activity and consumption patterns. The survey procedure and the incentives paid, which were necessary to obtain acceptable response rates, are also described. Results from two pilot studies using a trip-based and an activity-based diary format are presented. The paper examines to which extent the diaries have been capable of collecting the required data with high quality and response rates. The innovative “Mobility–Activity–Expenditure-Diary” is introduced and results of the main survey using this design are presented. Travel behaviour and non-travel activities were reported at high quality. Expenditures would require longer observation periods (and preferably not only telephone but also personal support in the survey process) to reduce unsystematic variations and to better capture individuals’ long term equilibrium.