<p> Integrating Techlog, Petrel, Eclipse, and COMSOL is a game changer and led to a better understanding of a very complex undercompacted and overpressurized sand in Block 276. Different reservoir simulation sensitivity runs on P1-sand indicated that putting a new well in block (2,34) under pure depletion will yield the highest incremental oil recovery of about 38%. The sensitivity runs included dumpfloods, waterfloods, and artificial lift. COMSOL has also shown that formation overlying the salt dome is hotter than other portions of the reservoir and that planning a new well on the western flank of the accumulation was the right decision. COMSOL has also shown that overpressurization is driven by undercompaction but that heat conduction from the dome and underlying diapirs affected pore pressure by 3 to 15%.</p><p>

<p> This dissertation introduce and empirically verify a structure of Energy Savings Performance Contracting (ESPC) perspective among clients, Energy Service Companies (ESCOs) and governments. The new approach ESPC structure model presented herein is built on the Motivation-Opportunity-Ability (MOA) theory where key influences are identified. An important component of performance contracting, the performance measurement, has been incorporated in the structure to monitor the effect on ESPC implementation success.</p><p> The proposed structure and hypothesis were verified as a current ESPC practice in the United States through an online survey. The proposed structure was analyzed to understand relationships between the stakeholders, key factors, barriers and/or practices among the constructs through the structural equation modeling (SEM) approach. Due to the complex relationship of non-normal data and small sample size compared to the number of variables, the Partial Least Square SEM (PLS-SEM) method was chosen. The survey statistical results were used to verify the ESPC-MOA structure, develop an implementation guide and identify the ESPC critical factors to help establish its implementation success.</p><p>

We have developed a systematic procedure for a limited class of chemical processes that includes control problems at the early stage of a flow sheet development. The procedure decomposes the control problem into a set of sub-problems. For the economic evaluations it is assumed that the raw-material and the recycle costs dominate the process economics, and therefore the variables which affect the input-output and the recycle material and energy flows are considered as the optimization variables (process-flow optimizations). The results obtained from this procedure will be helpful in the following areas: (1) Identifying potentially inoperable flow sheets due to the presence of trace component impurities in the feed streams or produced in the reactor, (2) Estimating the economically justified modifications (both in the flow sheet structure and the sizes of process units) to the optimum base-case design, (3) Generating alternative sets of process-flow, control structures (a set of controlled and manipulated variables, along with their pairing, that can drive the input-output and the recycle flows to their desired steady-states), (4) Estimating the magnitude of the overshoot of the manipulated variables during the transients, and changing the structure of the flow sheet, the equipment sizes, or the structure of the steady-state control structure to accommodate disturbances in an optimum way. Based on the process economics and the relative gain analysis, the optimum control structure is synthesized that would minimize the total operating cost in the face of disturbances. The optimum values of the sizes of the constrained unit designs (which restrict the process-flow optimization in the face of disturbances), and the optimum values of the process variables (i.e., the design variables and the process flows) are determined by solving a two-stage optimization problem. A method for developing approximate, dynamic models for the process flows for continuous chemical plants with recycle streams is described. (Abstract shortened with permission of author.)

A large scale interconnected system consists of several subsystems that interact dynamically with one another through an interconnection network. Because of the constraints on information flow, a decentralized control system usually provides a more practical control solution than a centralized control system. Previous studies on the control of large scale interconnected systems often ignore the important issue of modelling uncertainties in the subsystems and the interconnection dynamics, and thus result in control systems that are inadequate. This thesis develops a design procedure for designing decentralized control systems to achieve robust performance of large scale interconnected systems. Based on a set of subsystem interface specifications, the global design problem is first decomposed into a set of subsystem design problems. Each subsystem then attempts to solve the subsystem problems independently. The decomposition procedure has the property that if all the subsystem design problems are solved, then the original global system design problem is also solved. A number of issues arise from the decentralized design procedure: the problem of interface selection; the problem of robust performance characterization for systems with external signals which are modelled using independent bounds on subsets of the signals (component bounded signals); and the problem of selecting a single compensator to simultaneously satisfy the design objectives for each of several design models (multiple design models). The first issue arises from the problem decomposition procedure. In the context of this thesis, the latter two issues arise from the solution of the subsystem design problems. In addition, these problems can arise from other practical problem formulation and are of interest in their own right. These issues have been addressed in this thesis, and solution or algorithmic approaches have been provided.

Algorithmic and heuristic-based approaches are proposed for synthesizing integrated chemical systems. The former is used in the synthesis of reactor network and reactor-recycle-separator systems; the latter in the synthesis of integrated crystallization systems. In the algorithmic method, a network, or superstructure, which embeds all possible equipment to be used in the process and the potential interconnections among the equipment is generated. The procedure for generating the reactor network and the reactor-recycle-separator flow sheet structure is described. A nonlinear programming (NLP) problem is then formulated for the network. The optimal flow sheet and accompanying operational conditions are obtained by solving the NLP problem. For integrated crystallization process synthesis, a heuristic-based systematic procedure is developed. In a step-by-step manner, the procedure guides the user to generate alternative flow sheets for a given crystallization task. First, the required unit operations are determined by comparing the product specifications (production rate, product purity, and others) with the crystallizer effluent characteristics (occlusions, inclusions, crystal size, and others). Second, the destinations of the reaction solvent, mother liquor, wash liquid, recrystallization solvent, and drowning-out solvent are assigned. Then, the solvent recovery system is considered to recover the solvents and unconverted reactants, and to remove impurities from the system. Downstream system problems such as excessive filtration time and/or filter size are often caused by unfavorable crystal size. Various crystallizer designs to improve the crystal size distribution are discussed; short-cut equipment models are used to evaluate the alternatives for potential improvement. Issues related to minimization of inclusion impurities and heat integration are also examined. Guidelines are provided to help the user to add more details to the flow sheet at each level.

Process boundaries and difficult regions for separation units limit the feasible products and recovery of those products. When process boundaries are encountered, a separating agent and or combinations of different types of equipment are used. In this manner, a number of steps are used collectively to meet the separations objective. One type of equipment configuration, the distillation-membrane hybrid, has been studied for binary and multicomponent systems. In this hybrid, the distillation column performs the bulk of the separation, because of the favorable economics of distillation. The membrane is used to bypass the process boundaries and difficult regions. Methods for applying and screening these hybrids were developed. Several configurations were examined conceptually. Case studies were performed on the following systems: water-acetic acid, ethanol-water, propylene-propane, benzene-heptane-octane, methanol-ethanol-water. Separations synthesis using all possible separation units (crystallization, membranes, distillation, decantation, extraction, etc.) was then examined. A design methodology for generating flowsheets of process alternatives to separate multicomponent systems was developed based on representing process boundaries with linear hyperplanes. This approximation allowed the generation of process alternatives using relatively simple calculations.

This dissertation studies several security issues in data networks, to reveal the vulnerability, to propose defense mechanisms, to provide better tools for analysis, and to develop good security architecture. This dissertation consists of the following three parts: (1) Internet-like topologies which capture the inherent properties are desirable for studying the resilience of Internet against malicious attack or normal failure. A novel hierarchical Internet topology generator is proposed to capture the inherent properties of Internet topology: power law degree distribution and hierarchical structure. (2) An analysis on the inherent trust built in TCP shows that the client could stretch a TCP connection tens of times and keep occupying the resource in the server with little abnormality to be detected. This could be potentially used in denial of service attack. (3) Some security setting like Bounded Storage Model calls for high-speed random number generating, while the current real random number generator would not be able to offer. A hybrid random-bit sequence generated by a pseudo-random number generator with the parameters specified randomly might be useful in this setting. A study on hybrid system using Linear Congruential Recurrence is presented, and hopefully it will provide insight for the study on hybrid system using one-way function.

Plantwide control refers to the control of entire plants, consisting of many interconnected unit operations. Synthesizing a plantwide control system requires evaluating numerous alternatives involving controlled variables, control structures, controller designs and tunings, etc. A hierarchical procedure for systematically synthesizing a plantwide control has been proposed by Zheng et al. [82]. In this procedure, the plantwide control problem is decomposed into six steps along which decisions are made based on economics. While many tools (e.g., a short-cut method for controlled variable selection, quantification of dynamic operability, etc.) have been developed by these authors to ease the implementation of the procedure on industrial processes, more tools need to be developed. For example, we need to develop systematic procedures for ensuring feasibility of the control structures, for selecting primary and secondary controlled variables and for designing controllers for systems with recycles. Furthermore, model uncertainty, which is important practically, needs to be taken into account to make these tools useful. The goal of this thesis is to accomplish these tasks. To this end, we address how model uncertainty affects the steady-state as well as the dynamic control structure.

Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 118-120). / Existing metric selection methodologies and performance measurement frameworks provide practicing managers with good checklists and tools to evaluate and design their enterprise performance measurement systems (EPMS) and metrics. However, these methodologies and frameworks do not delve deep enough into the operational aspects of EPMS and metrics. This work addresses this research gap by proposing a practical Metric Design Framework with accompanying Metric Design Tools and a Metric Design Guide to operationalize metrics to ensure better strategic alignment, monitoring and reporting of business activities, and proactive decision-making. Singapore Technologies Aerospace Engineering Development Center (STA EDC) is the enterprise involved in action research, the research methodology used in this work. The background of STA EDC is included to provide the context and purpose. There are four major action research cycles including EPMS Ten Lenses (cycle 1), Metric Design Tools (cycle 2), Metric Building Blocks and Elements (cycle 3), and Metric Design Guide (cycle 4). The details and results for each action research cycle are discussed. In essence, the Nightingale Rhodes Enterprise Architecting Framework (NREAF) [1] serves as a starting point, where the Enterprise Architecting (EA) Ten View Elements/Lenses are modified for EPMS in cycle 1. In cycle 2, the STA EDC EPMS and metrics are evaluated using the EPMS Ten Lenses, and Metric Design Tools such as the Strategic Alignment Tool, EPMS Value Flow Map, Measurement Scope Tool, and 3x3 Info Decision Matrix are developed. Cycle 3 saw the development of the Metric Building Blocks and Metric Elements, while cycle 4 demonstrated the application of the proposed Metric Design Framework and Tools in the form of a Metric Design Guide. The proposed framework and tools are then validated with practicing managers at STA EDC. Based on the feedback and validation from practicing managers, the proposed framework and tools show great potential in terms of comprehensiveness/completeness, usability, and utility. However, the key challenge lies with implementation. Management's commitment and buy-in from various EPMS stakeholders are necessary. While minor modifications and/or additions to the proposed framework and tools are expected during implementation, the endeavor is worthwhile because a firm becomes what it measures. / by Kai Siang Teo. / S.M.

Thesis (M. Eng in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2008. / Includes bibliographical references (leaves 66-67). / When a company grows rapidly, the existing infrastructure of the supply chain system set up long ago, faces an increasing pressure to meet new challenges and needs to be restructured. A seasonal seed manufacturing company, such as Seed Corp, has only five months of manufacturing time in the Fall each year. Customers usually do not want the seed delivery until Spring. Such companies face a tremendous pressure to find space to store their products during the manufacturing peak season. Companies must search for good strategies to meet these challenges. This thesis assesses the framework for selection of distribution strategies, reviews the these strategies, and analyzes the benefits and challenges among them. This research analyzes trade-offs between centralized and decentralized distribution systems, as well as between service level and cost. The analysis focuses on the response time and total cost for four distribution options. We have chosen Seed Corp as a case study. As the result of the research, the thesis suggests distribution strategies to meet the company's supply chain challenges. Finally, we recommend the further areas that need to be explored. / by Chunlin Li. / M.Eng in Logistics