Optimization Methods for Day Ahead Unit Commitment

This work examines a variety of optimization techniques to better solve the day ahead unit commitment problem. The first method looks at the impact of almost identical generators on the problem and how to exploit that fact for computational gain. The second work seeks to improve the fidelity of the problem by better modeling the impact of pumped storage hydropower. Lastly, the relationship between the length of the planning horizon and the quality of the solutions is investigated

Symmetry Detection in Integer Linear Programs

Symmetry has long been recognized as a major obstacle in integer programming. Unless properly recognized and exploited, the branch-and-bound tree generated when solving highly symmetric integer programs (IPs) can contain many identical subproblems, resulting in a waste of computational effort. Effective methods have been developed to exploit known symmetry. This thesis focuses on improving methods that compute the symmetry group of an IP. In the literature, computing the symmetry group of an IP is performed by generating a graph with a similar structure as the IP, and then computing the automorphism group of the graph. Unfortunately, these graphs may be much larger than the IP problem, resulting in a possible waste of computational resources. The approach of this thesis is to detect the group of an edge-colored graph generated by the IP. This avoids the need for additional nodes to track coefficients, reducing the search space. Actually finding the group will be done by adapting and expanding a symmetry detection algorithm to work with these edge-colored graphs

Performance Models for Split-execution Computing Systems

Split-execution computing leverages the capabilities of multiple computational models to solve problems, but splitting program execution across different computational models incurs costs associated with the translation between domains. We analyze the performance of a split-execution computing system developed from conventional and quantum processing units (QPUs) by using behavioral models that track resource usage. We focus on asymmetric processing models built using conventional CPUs and a family of special-purpose QPUs that employ quantum computing principles. Our performance models account for the translation of a classical optimization problem into the physical representation required by the quantum processor while also accounting for hardware limitations and conventional processor speed and memory. We conclude that the bottleneck in this split-execution computing system lies at the quantum-classical interface and that the primary time cost is independent of quantum processor behavior.Comment: Presented at 18th Workshop on Advances in Parallel and Distributed Computational Models [APDCM2016] on 23 May 2016; 10 page

The lesbian, gay, bisexual and transgender community online: discussions of bullying and self-disclosure in YouTube videos

Computer-mediated communication has become a popular platform for identity construction and experimentation as well as social interaction for those who identify as lesbian, gay, bisexual or transgender (LGBT). The creation of user-generated videos has allowed content creators to share experiences on LGBT topics. With bullying becoming more common amongst LGBT youth, it is important to obtain a greater understanding of this phenomenon. In our study, we report on the analysis of 151 YouTube videos which were identified as having LGBT- and bullying-related content. The analysis reveals how content creators openly disclose personal information about themselves and their experiences in a non-anonymous rhetoric with an unknown public. These disclosures could indicate a desire to seek friendship, support and provide empathy

Dusty: an assistive mobile manipulator that retrieves dropped objects for people with motor impairments

People with physical disabilities have ranked object retrieval as a high priority task for assistive robots. We have developed Dusty, a teleoperated mobile manipulator that fetches objects from the floor and delivers them to users at a comfortable height. In this paper, we first demonstrate the robot's high success rate (98.4%) when autonomously grasping 25 objects considered important by people with amyotrophic lateral sclerosis (ALS). We tested the robot with each object in five different configurations on five types of flooring. We then present the results of an experiment in which 20 people with ALS operated Dusty. Participants teleoperated Dusty to move around an obstacle, pick up an object, and deliver the object to themselves. They successfully completed this task in 59 out of 60 trials (3 trials each) with a mean completion time of 61.4 seconds (SD=20.5 seconds), and reported high overall satisfaction using Dusty (7-point Likert scale; 6.8 SD=0.6). Participants rated Dusty to be significantly easier to use than their own hands, asking family members, and using mechanical reachers (p < 0.03, paired t-tests). 14 of the 20 participants reported that they would prefer using Dusty over their current methods

Synthesis of Molybdenum and Tungsten Alkylidene Complexes That Contain the 2,6-Bis(2,4,6-triisopropylphenyl)phenylimido (NHIPT) Ligand

Molybdenum and tungsten alkylidene complexes that contain the sterically demanding hexaisopropylterphenylimido ligand, N-2,6-(2,4,6-i-Pr[subscript 3]C[subscript 6]H[subscript 2])[subscript 2]C[subscript 6]H[subscript 3] (NHIPT), have been prepared from Mo(N-t-Bu)[subscript 2]Cl[subscript 2](1,2-dimethoxyethane) or W(N-t-Bu)[subscript 2]Cl[subscript 2](pyridine)[subscript 2], employing tert-butylimido ligands as sacrificial proton acceptors. These complexes include M(NHIPT)(CH-t-Bu)Cl[subscrip 2] (M = Mo, W), Mo(NHIPT)(CH-t-Bu)(pyrrolide)[subscript 2], and Mo(NHIPT)(CH-t-Bu)(pyrrolide)(OC[subscript 6]F[subscript 5])(CH[subscript 3]CN). In all cases only anti alkylidene isomers are observed in solution, as a consequence of the steric demands of the NHIPT ligand. An X-ray structure of W(NHIPT)(CH-t-Bu)Cl[subscript 2] showed it to be a monomer with a disordered alkylidene that is 86% in the anti configuration and 14% in the syn configuration.National Science Foundation (U.S.) (Grant CHE-1111133)National Institutes of Health (U.S.) (Grant GM-59426)National Science Foundation (U.S.) (Grant CHE-0946721

Syntheses of Tungsten tert-Butylimido and Adamantylimido Alkylidene Complexes Employing Pyridinium Chloride as the Acid

Routes to new tungsten alkylidene complexes that contain tert-butylimido or adamantylimido ligands have been devised that begin with a reaction between WCl[subscript 6] and 4 equivalents of HNR(TMS) to give [W(NR)[subscript 2]Cl(μ-Cl)(RNH[subscript 2])][subscript 2] (R = t-Bu or 1-adamantyl). Alkylation leads to W(NR)[subscript 2](CH[subscript 2]R′)[subscript 2] (R′ = t-Bu or CMe[subscript 2]Ph), which upon treatment with pyridinium chloride yields W(NR)(CHR′)Cl[subscript 2](py)[subscript 2] complexes, from which W(NR)(CHR′)(pyrrolide)[subscript 2] and two W(N-t-Bu)(CHR′)(pyrrolide)(OAr) complexes (OAr = hexamethyl- or hexaisopropylterphenoxide) have been prepared.National Science Foundation (U.S.) (CHE-1111133)National Science Foundation (U.S.) (Grant CHE-0946721

Synthesis of 2,6-Hexa-Tert-Butylterphenyl Derivatives, 2,6-(2,4,6-t-Bu₃C₆H₂)₂C₆H₃X, Where X = I, Li, OH, SH, N₃, or NH₂

A “double benzyne” reaction between 1,3-dichloro-2-iodobenzene and 2,4,6-t-Bu₃C₆H₂MgBr followed by the addition of iodine led to 2,6-(2,4,6-t-Bu₃C₆H₂)₂C₆H₃I (HTBTI) in 65% yield. Lithiation of HTBTI with Li-t-Bu gave Li(Et₂O)₂HTBT from which HTBTSH, HTBTN₃, HTBTNH₂, and HTBTOH were prepared. An X-ray structure of W(OHTBT)₂Cl₄ shows that the two HTBTO ligands are trans to one another with the t-Bu₃C6H₂ groups on one HTBTO interdigitated with the t-Bu₃C6H₂ groups on the other HTBTO.National Institutes of Health (U.S.) (Award GM-59426