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A coordenação híbrida e a percepção dos fornecedores de manufatura contratada sobre a complementariedade contratual na produção de bens eletrônicos de consumo no estado de São Paulo
(Universidade Federal de São Carlos, 2014-05-26) Cruz, Valcir de Jesus Sousa da; Paulillo, Luiz Fernando de Oriani e; https://lattes.cnpq.br/9919942357089937; https://lattes.cnpq.br/8104600618605089
In the electronics industry the companies owners of brands ( OEM ) are hiring outside manufacturing service providers ( EMS ) , and transfer to them major portions of their production. The EMSs have contributed to the OEMs in activities such as supply of components, engineering, manufacturing and distribution services. With the growth of this practice, the EMSs accumulate ever more capacity as providers of highly specialized commoditized electronic products, reducing costs and sharing risks across the electronic industry.The objective of this research was to scale the perception among EMSs, about the attributes of trust, mutuality and leadership, governance mechanisms as complementary to contract manufacturing in the consumer electronics industry considering the contributions of Ménard (2004) for the development of hybrid modes of governance. A field survey was carried out, being interviewed companies providing contract manufacturing headquartered in São Paulo. The analyzes show that allowed transactions providing electronic manufacturing are coordinated by complementary mechanisms to contracts through a governance model multiple hybrid formed by trust, mutuality and leadership.
Optical and transport properties of p-i-n GaAs/AlAs resonant tunneling diode
(Universidade Federal de São Carlos, 2014-05-26) Awan, Iram Taj; Gobato, Yara Galvão; https://lattes.cnpq.br/7558531056409406; https://lattes.cnpq.br/9790521790751945
In this thesis, we have investigated the optical and transport properties of a p-i-n GaAs-AlAs resonant tunneling diode (RTD). The possibility of controlling and significantly varying the density of carriers accumulated at different layers of this structure simply by applying an external bias makes it very useful to investigate various fundamental issues. Furthermore, the process of tunneling that critically depends on the alignment from confined energy levels and the injection of carriers that attain quasi - equilibrium distribution at distinct accumulation layers makes this structure very special for analyzing optical properties in general, and in special, spin-polarization effects when an external magnetic field is applied to the RTD. Particularly, two emission bands were observed for the quantum well (QW) of our structure and were associated to the recombination of electrons and holes that tunnel into the QW and may recombine either as an exciton involving the fundamental states of the QW or a transition involving an acceptor state in the QW. It was also observed that the relative intensity of these emission bands strongly depend on the applied bias voltage. The optical recombination involving acceptors states becomes relatively more efficient as compared to the excitonic recombination for higher densities of electrons in the QW. This effect was discussed considering how the electron carrier density depends on the applied voltage and other effects such the capture rate of holes by the acceptors and electron and hole differences concerning mobility, effective mass and tunneling processes. We have also investigated spin properties of the tunneling carriers in our device by measuring the polarization-resolved electroluminescence from the quantum well (QW) and the contact layers under low temperatures and high magnetic fields, up to 15 T. Under these conditions, we have observed that the QW emission presents a large negative polarization degree which depends on the external applied bias voltage. The VII QW spin polarization shows oscillations and abrupt changes at the electron resonant peak. The results are mainly attributed to the abrupt changes of intensity of the two QW emission lines. Furthermore, the contact-layer emission have also shown voltage dependent emission lines that were attributed to the two-dimensional electron gas formed at the accumulation layer under an applied bias. The contact-layer emission presents a large negative polarization degree which is also voltage dependent. The QW spin polarization degree was discussed considering different effects such as the presence of neutral acceptors in the QW, the voltage control of carrier densities in the device, hole and electron tunneling processes and the spin injection of spin polarized two-dimensional gases formed at the accumulation layers.
Uma abordagem de otimização para a roteirização e programação de navios: um estudo de caso na indústria petrolífera
(Universidade Federal de São Carlos, 2014-05-26) Rodrigues, Vinícius Picanço; Morabito Neto, Reinaldo; https://lattes.cnpq.br/6693329429907988
This work studies the ship routing and scheduling problem in oil transportation from offshore platforms to inland terminals. It is motivated by a real situation in a Brazilian oil company. Brazil is one of the world's greatest oil producers and has around 80% of its oil explored in offshore mode. Thus, transportation costs play an important role in achieving operational excellence, and the recent growth trends for oil exploration in Brazil has transformed its operations and demanded agile and effective decision support systems for addressing the oil sector dynamism. This work's goal consists in developing and applying an optimization-based approach using a mixed integer linear programming model in real decision-making situations, along with a solution method based on mathematical programming (MIP-heuristics) in order to solve the model, such as relax-and-fix. The proposed model is inspired in a problem formulation for pickup and delivery with time windows (PDPTW) and heterogeneous fleet, where costs incurred for fuel consumption and fleet contracts is the objective function to be minimized. The pickup and delivery pairs are predetermined and the model's main decision refers to ship allocation to these pairs compounding a route. Furthermore, some additional constraints are modeled and proposed, such as terminal access and platform mooring limitation according to ship types, as well as product blend incompatibility. The model was implemented in a modeling language along with an optimizarion software. Computational experiments with the model and the heuristics are presented for different data sets supplied by the case study company. These experiments show the potential benefits of this approach for finding good solutions for the problem as well as the dificulty in finding solutions for realistic instances due to its NP-hard characteristics.
Ansatz de Bethe algébrico com fronteiras triangulares
(Universidade Federal de São Carlos, 2014-05-26) Pimenta, Rodrigo Alves; Santos, Antonio Lima; https://lattes.cnpq.br/8463237728503334
In this work we study vertex models with non-diagonal boundaries, characterized by reection matrices with an upper triangular form. By means of an extension of the algebraic Bethe ansatz, we construct generalized Bethe states as well as the respective eigenvalues for two classes of models: six and nineteen vertex models. As usual, in both cases the exact solution is given in terms of the Bethe equations.
Mecanismo em nuvem de monitoramento a dados sensíveis
(Universidade Federal de São Carlos, 2014-05-26) Souza, Rafael Tomé de; Zorzo, Sérgio Donizetti; https://lattes.cnpq.br/2523715806470871; https://lattes.cnpq.br/5732745431754357
The privacy guarantee of a person s data is understood as the capacity of this person to manage, store, change, restrict or disclose for groups of individual of his choice. The data shared can be sensitive, revealing private content that deserves protection in sharing, for example financial personal information. In many computing services a lot of sensitive data does not have any mechanism that guarantees the owner s privacy. This work shows a mechanism that guarantees the privacy of the person who has the data accessed, the data owner, and the privacy of the person who accesses the data. It was developed a cloud monitoring mechanism for data whose access needs to be monitored with intrusion detection scenario available for the data owner. The propose feasibility was evaluated by response time test of a monitored page access, server overload and the server resource consumption through the prism of an application using the mechanism. Such mechanism has been a viable solution due to its minimal impact in computational resources and a solution that assists in sensitive data access monitoring.