Decision support for the production and distribution of electricity under load shedding

Every day national power system networks provide thousands of MW of electric power from generating units to consumers. This process requires different operations and planning to ensure the security of the entire system. Part of the daily or weekly operation system is the so called Unit Commitment problem which consists of scheduling the available resources in order to meet the system demand. But the continuous growth in electricity demand might put pressure on the ability of the generation system to sufficiently provide supply. In such case load shedding (a controlled, enforced reduction in electricity supply) is necessary to prevent the risk to system collapse. In South Africa at the present time, a systematic lack of supply has meant that regular load shedding has taken place, with substantial economic and social costs. In this research project we study two optimization problems related to load shedding. The first is how load shedding can be integrated into the unit commitment problem. The second is how load shedding can be fairly and efficiently allocated across areas. We develop deterministic and stochastic linear and goal programming models for these purposes. Several case studies are conducted to explore the possible solutions that the proposed models can offer

Pulsating Market Boundaries in Supply Chain Network of Nitrogenous Fertilizers

All the market boundary for a fertilizer plant is function of natural-gas prices (henry-hub), demand of nitrogen based fertilizer at county level, and transportation cost by mode (rail, truck and barge). The demand for nitrogenous fertilizers is largely driven by agriculture, wherein, the composition and pattern of crops varies widely with time and region. Variation and uncertainty in natural-gas prices and transportation cost results in pulsating market boundaries, the area that is served by a fertilizer plant. A combined approach of statistical analysis and geographic information systems (GIS) is used to build a spatial equilibrium model representing structure of supply chain network for United States comprising origins (fertilizer plant, point of imports), destinations (counties), and various mode of transportation (truck, rail and barge). Such approach helps in (a)visualizing the market boundaries, (b) structure of supply chain network of nitrogen based fertilizers, (c)analysis of potential impacts due changes in natural-gas prices

Reinforcement Learning

Brains rule the world, and brain-like computation is increasingly used in computers and electronic devices. Brain-like computation is about processing and interpreting data or directly putting forward and performing actions. Learning is a very important aspect. This book is on reinforcement learning which involves performing actions to achieve a goal. The first 11 chapters of this book describe and extend the scope of reinforcement learning. The remaining 11 chapters show that there is already wide usage in numerous fields. Reinforcement learning can tackle control tasks that are too complex for traditional, hand-designed, non-learning controllers. As learning computers can deal with technical complexities, the tasks of human operators remain to specify goals on increasingly higher levels. This book shows that reinforcement learning is a very dynamic area in terms of theory and applications and it shall stimulate and encourage new research in this field

Investigation of Groundwater Depletion and Leveel Underseepage with Unstructured-Grid Modeling Approach

Unstructured grid is a tessellation of geometric shapes in irregular patterns that provides flexibility in grid design for groundwater modeling. However, groundwater modeling is mostly developed with uniform grid tessellation and layer, which could simplify model structure or cause expensive computational costs in high-resolution simulations. Unstructured grid incorporates non-uniform horizontal and non-uniform vertical discretizations providing the capability to replicate complex hydrostratigraphy, capture geologic features that are crucial for groundwater flow simulation, and reduce computational costs while maintaining a high resolution for areas of interest. This study contains three parts to investigate unstructured-grid approach on constructing high-fidelity groundwater models, comparisons with analytical relief well evaluation, and optimization implementation on relief well operations. The first study develops a three-dimensional (3-D) groundwater model using MODFLOW-USG on an unstructured grid to evaluate relief well performance at the Profit Island vicinity levee and conduct comparative analysis with conventional seepage analysis (i.e., blanket theory). Consequently, this case study indicates that 3-D modeling is a more accountable and precise tool than blanket theory. The second study proposes relief well operations optimization as an alternative to increase levee and floodwall factor of safety against underseepage, which is achieved by a multi-objective mixed-integer non-linear programming implemented with a 3-D unstructured groundwater model. The approach is demonstrated at the Inner Harbor Navigation Canal, New Orleans, Louisiana. Relief well operations optimization provides decision-makers useful tradeoffs between averaged factor of safety deficit, total pumping rate, and the number of pumping wells for making pumping decisions. The third study advances unstructured grid to develop a high-fidelity 3-D groundwater model using a lithology model for the Louisiana Capital Area Groundwater Conservation District (District) on the Southern Hills Aquifer System. Groundwater flow simulation, water budget analysis, uncertainty analysis, and comparisons with satellite data provide comprehensive understanding of groundwater storage variation in the District and evaluate groundwater depletion induced by excessive prolonged groundwater withdrawals in the Baton Rouge area. This study successfully demonstrates the capability of unstructured-grid approach on groundwater modeling to simulate groundwater dynamics within complex subsurface hydrogeological structures, evaluate relief well performances, and optimization implementation

Simulation Modeling

The book presents some recent specialized works of a theoretical and practical nature in the field of simulation modeling, which is being addressed to a large number of specialists, mathematicians, doctors, engineers, economists, professors, and students. The book comprises 11 chapters that promote modern mathematical algorithms and simulation modeling techniques, in practical applications, in the following thematic areas: mathematics, biomedicine, systems of systems, materials science and engineering, energy systems, and economics. This project presents scientific papers and applications that emphasize the capabilities of simulation modeling methods, helping readers to understand the phenomena that take place in the real world, the conditions of their development, and their effects, at a high scientific and technical level. The authors have published work examples and case studies that resulted from their researches in the field. The readers get new solutions and answers to questions related to the emerging applications of simulation modeling and their advantages

Pemurnian Manual Prosedur Ujikaji Makmal Kejuruteraan Kayu, Fakulti Kejuruteraan, Kolej Universiti Teknologi Tun Hussein Onn

Kajian ini bertajuk "Pemumian Manual Prosedur Ujikaji, Makmal Kejuruteraan Kayu, Fakulti Kejuruteraan, Kolej Universiti Teknologi Tun Hussein Onn." Sehubungan dengan kekurangan dari segi penyediaan prosedur dan langkah ketja yang terdapat di dalam manual ujikaji sedia ada yang disediakan oleh Makn1al Kejuruteraan Kayu (MKK), kajian ini dijalankan bertujuan untuk memumikan manual ujikaji sedia ada dengan menggunakan pendekatan grafik. Pemumian Manual Prosedur ujikaji ini adalah berkonsepkan mesra pengguna. Untuk mengetahui kebolehgunaan Manual Prosedur Ujikaji (MPU) yang dihasilkan dan untuk menjawab persoalan kajian yang dibina pengkaji memilih seramai 35 orang responden. Responden berikut terdiri daripada 5 orang stafiaitu dari kalangan pensyarah dan juruteknik serta 30 orang pelajar tahun 4 kursus Ijazah Sarjana Muda Sains Kejuruteraan Awam (Teknologi Berasaskan Kayu) yang sedang menjalani ujikaji di Makmal Kejuruteraan Kayu untuk mata pelajaran Makmal Teknologi Perkayuan (BCM 4061). Kaedah kajian yang digunakan adalah kaedah tinjauan berbentuk kuantitatif dengan menggunakan instrumen soal selidik. Hasil daripada kajian ini temyata MPU yang dihasilkan adalah berkonsepkan mesra pengguna dan Manual Prosedur Ujiakji ini boleh dijadikan panduan kepada pelajar yang menjalani ujikaji di Makmal Kejuruteraan Kayu, Fakulti Kejuruteraan, KUiTTHO

Essays on the US Higher Education

Two-year colleges, or community colleges, are an integral part of the US higher education system. More than 40% of undergraduate enrollment occurs at the two-year level. Moreover, two-year colleges are closely related to four-year programs, as students frequently transfer between two-year programs and four-year programs. In fact, close to 50% of bachelor\u27s degree recipients have enrolled in two-year colleges before transferring to four-year programs. The following essays discuss three topics related to the US higher education system while emphasizing two-year colleges\u27 role in this system. The first chapter studies policies that can address the low completion rate of two-year college students. Utilizing two recent institutional reforms in the University System of Georgia, I show that allowing community colleges to offer bachelor\u27s degrees and consolidating institutions increase two-year students\u27 bachelor\u27s degree attainment by around 3 percentage points, which represents a 20% improvement. Both reforms increased the two-to-four transfer rate, and institutional consolidations also increased bachelor\u27s degree attainment, conditional on transferring. Moreover, I find evidence that a reduced loss of credits during transfer is the driving force of the improvements. In particular, the reforms reduced credits lost during transfer by around 40%. The second chapter examines whether free community college could fulfill its promise to boost upward mobility or create a trap that promotes associate degrees over the more lucrative bachelor’s degrees. Using adminisitrative data from Texas, I build and estimate a model of college choice, educational attainment, and earnings that allows students to transfer between institutions, and captures the complex credit transfer rules between community colleges and four-year colleges. Leveraging this model, I find that providing free community college improves students\u27 welfare and associate degree attainment, but decreases bachelor\u27s degree attainment by 7 percentage points (a 21% decrease) and average life-time income by more than 1%. This is because the policy diverts students to the less lucrative community colleges and subjects more students to imperfect information about the transfer pathways. In particular, students transferring from community colleges to four-year colleges severely underestimate the credit lost before transferring. I propose a cost-equivalent proportional tuition reduction that creates notably larger welfare and income improvements. In addition, I find that eliminating credit lost during transfer and providing perfect information on credit transfer rules significantly improves transfer students\u27 outcomes. Finally, I show that the existence of transfer options is crucial for the overall bachelor’s degree attainment rate and has a modest impact on student welfare. While community colleges educate more than 40% of US undergraduates, anecdotal evidence suggests widespread discrimination against community college graduates. In the third chapter, I use a national labor market audit study to examine the existence and nature of such discrimination. I send out more than 3600 artificial job applications through one of the largest online job platforms in the US. All applicants have four-year Bachelor\u27s Degrees, and a randomly selected subset of the applicants attended community colleges for their first two years of college. I find that the callback rate from accounting firms is 50% lower for applicants with community college experience. This is equivalent to the effect of a drop in college GPA from 3.6 to 3.2. In comparison, sales and marketing positions\u27 callback rate do not exhibit such a discrepancy. Furthermore, I find suggestive evidence that the discrimination is due to irrational bias on community college students\u27 ability. I also find that this bias significantly reduces employers\u27 valuation of the candidates\u27 other qualifications, such as college selectivity

Matching in the oil tanker industry: implications for energy efficiency

This thesis seeks to explain the economic determinants of matches between shipowners and oil traders within a spatially explicit market for shipping crude oil. Previous approaches to modeling the tanker shipping market have employed an aggregate approach in which there is a single trade route and one market clearing price. This reduced form of trade ignores the inherently spatial nature of the tanker shipping market in which the matches, market prices, and speed ships travel reflect the demand for shipping crude oil on different trade routes, the supply of ships available in each location, and agents' opportunity costs and future expectations. A matching model of the crude oil spot tanker market was developed in which the characteristics of ships and traders is reflected in the market price. The method employs a matching model to understand how supply equilibrates with demand to determine the set of shipping contracts exchanged and their prices as a function of the other agents in a competitive market. Results described in this thesis show that the contracts that form in equilibrium depend on the demand for oil cargoes in each load area market and the supply of available ships within proximity to the market. Additionally, agents' opportunity costs and future expectations has also been found to influence the matching and contract prices. When ships are differentiated by physical characteristics (including energy efficiency) and location, results show that ships which are the most favored by physical characteristics cannot compete as strongly with less preferred ships located closer to the market. These findings can be used to inform industry stakeholders about strategic operating and investment decisions. They are also useful for environmental policy makers because they explain the key drivers of ship movements given ships' reliance on carbon-intensive fuel for propulsion