Tam Chi Sang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 73-76). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.p.1 / Chapter 1.1 --- Review of Literature --- p.p.4 / Chapter 1.2 --- Relationships to the existing works --- p.p.11 / Chapter 2 --- Demand Functions --- p.p.20 / Chapter 3 --- Exogenous Timing Duopoly --- p.p.24 / Chapter 3.1 --- Description of the game --- p.p.24 / Chapter 3.2 --- Equilibrium Analysis --- p.p.27 / Chapter 4 --- Endogenous Timing Duopoly --- p.p.38 / Chapter 4.1 --- Description of the game --- p.p.38 / Chapter 4.2 --- Equilibrium Analysis --- p.p.41 / Chapter 5 --- Concluding Remarks --- p.p.52 / Chapter 6 --- Appendix --- p.p.56 / Chapter 6.1 --- Reaction functions in the Exogenous Timing Model --- p.p.56 / Chapter 6.2 --- Reaction functions in the Endogenous Timing Model --- p.p.62 / Chapter 6.3 --- Proofs for Inequalities (10)，(13)，and Proposition 1 --- p.p.66 / Chapter 6.4 --- "Proofs for Inequalities (22), (23), (26), (27), and Proposition 2" --- p.p.67 / Chapter 6.4.1 --- Proofs for Inequalities (22) and (23) with γ >0 --- p.p.67 / Chapter 6.4.2 --- Proofs for Inequalities (26) and (27) with γ <0 --- p.p.70 / Chapter 6.4.3 --- Proof for Proposition 2 --- p.p.72 / References --- p.p.73

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Alfred P. Sloan School of Management. / Microfiche copy available in Archives and Dewey. / Bibliography: leaves 123-129. / M.S.

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A major challenge in designing and controlling flow lines is to achieve high customer service level while stay lean. Just-In-Time (JIT) manufacturing approach has triggered various 'pull production system', such as CONWIP or Kanban controls, which emphasizes on response to demand rather than forecasts. We identified and documented the anatomy of various pull type control policies. Based on the analysis, we designed a new class of control policy called Extended CONWIP Kanban control (ECK). We conducted comprehensive simulation comparison studies. Simulation results showed that the new control policy can achieve higher service levels with lower inventories than other policies including hybrid ones. We developed a state space comparison methodology to compare various policies with that of optimum solution. Our analysis reveals that our ECK policy provides the most adjustment flexibility toward the optimum. We also proposed a parameter design procedure and an adaptive parameter adjusting system. A case study verifies the advantages and utilities of the ECK policy. Beside the cost savings, another major advantage of the ECK policy is its robustness. That is, the total cost of the ECK policy is less sensitive to demand or system variations.

There are many business in Taiwan that their production type are indistinct between make-to-stock and make-to-order. This kind of production type can shorten the lead time of order and decrease the fluxion of customer¡¦s demand, on it¡¦s technology of predicting customer¡¦s demand for pre-production and inventory. Thus, the efficacy of production must depend on it¡¦s precision of predicting customer¡¦s demand. Recognition that traditional work order dispatching made to some specific standardization. Therefore, it is leaded to customization product and less flexible. And the decision-maker must choose one goal between minizing inventory cost, WIP¡¦s level and lead time. The production type, work order dispatching must have flexibility,and it must accomplish the customer¡¦s order on time considering inventory cost and customer service. This thesis hopes that it would be to develop a work order dispatching method to improve the efficiency of WIP administering, the flexibility for work order dispatching and decreasing lead time of customer¡¦s order. According to production¡¦s characteristic of different manufacturing stage, it can create one applicable dispatching rules to increase the production efficiency. Finally, using simulation software, applying to case study comparing the performance of the real case and new work order dispatching

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 135-138). Also available in electronic version. Access restricted to campus users.

During production from gas condensate reservoirs, significant productivity loss occurs after the pressure near the production wells drops below the dew point of the hydrocarbon fluid. Several methods such as gas recycling, hydraulic fracturing and solvent injection have been tried to restore gas production rates after a decline in well productivity owing to condensate and/or water blocking. These methods of well stimulation offer only temporary productivity restoration and cannot always be used for a variety of reasons. Significant advances have been made during this study to develop and extend a chemical treatment to reduce the damage caused by liquid (condensate + water) blocking in gas condensate reservoirs. The chemical treatment alters the wettability of water-wet sandstone rocks to neutral wet, and thus reduces the residual liquid saturations and increases gas relative permeability. The treatment also increases the mobility and recovery of condensate from the reservoir. A nonionic polymeric fluoro-surfactant in a glycol-alcohol solvent mixture improved the gas and condensate relative permeabilities by a factor of about 2 on various outcrop and reservoir sandstone rocks. The improvement in relative permeability after chemical treatment was quantified by performing high pressure and high temperature coreflood experiments on outcrop and reservoir cores using synthetic gas mixtures at reservoir conditions. The durability of the chemical treatment has been tested by flowing a large volume of gas-condensate fluids for a long period of time. Solvents used to dissolve and deliver the surfactant play an important part in the treatment, especially in the presence of high water saturation or high salinity brine. A screening test based on phase behavior studies of treatment solutions and brines has been used to select appropriate mixtures of solvents based on reservoir conditions. The adsorption of the surfactant on the rock surface has been measured by measuring the concentration of the surfactant in the effluent. Wettability of treated and untreated reservoir rocks has been analyzed by measuring the USBM and Amott-Harvey wettability indices to evaluate the effect of chemical treatment on wettability. For the first time, chemical treatments have also been shown to remove the damage caused by water blocking in gas wells and for increasing the fracture conductivity and thus productivity of fractured gas-condensate wells. Core flood experiments done on propped fractures show significant improvement in gas and condensate relative permeability due to surface modification of proppants by chemical reatment. Relative permeability measurements have been done on sandstone and limestone cores over a wide range of conditions including high velocities typical of high rate gas wells and corresponding to both high capillary numbers and non-Darcy flow. A new approach has been presented to express relative permeability as a function three non-dimensionless terms; capillary number, modified Reynolds Number and PVT ratio. Numerical simulations using a compositional simulator have been done to better understand and design well treatments as a function of treatment volume and other parameters. Injection of treatment solution and chase gas and the flow back of solvents were simulated. These simulations show that chemical treatments have the potential to greatly increase production with relatively small treatment volumes since only the near-well region blocked by condensate and/or water needs to be treated.

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