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Scholarly Works (5999 results)

  • Thesis
  • Peer Reviewed
UC Berkeley Electronic Theses and Dissertations (2016)

Project changes are often encountered in construction industry and can hurt labor productivity, which in turn can jeopardize project success for all parties. Contractors and owners frequently fail to agree on the merit, responsibility and impact of changes at the time of their occurrence. This failure to agree becomes a major source of claims and litigation.

There are several ways to calculate productivity loss caused by changes. One method to quantify loss of productivity is the MCAA (Mechanical Contractors Association of America) Factor method. The MCAA method has been in use for over forty years, and has gained wide acceptance in the construction industry and before various Courts and Boards of contract appeals. But the model has been rejected in several recent claims. Some researchers commented that this method has several deficiencies that limited its use.

This dissertation aims to make improvements to the existing MCAA model. We document the MCAA model’s history, identify typical mistakes made in its application, and compare it with other studies and previous legal case decisions. Suggested improvements to the model are then offered.

First, based on the observations and analysis of this dissertation, we recommend the following when using the MCAA model: 1) Establish causation for EACH Factor and explain clearly when, where, who, and how productivity was affected; 2) Use fewer Factors rather than more Factors; and 3) Do not blindly rely on the Loss of Productivity (LOP) damage percentages contained in the MCAA manual.

Secondly, this research proposes structural improvements on the MCAA model for its use in a LOP claim: 1) suggested use of a cause-effect visualization tool to establish causation; 2) improved definitions by explaining what each Factor means and how that Factor hinders labors productivity; and 3) suggestions for quantification of LOP impact for each Factor.

Finally, this dissertation proposes procedures and guidelines to use the MCAA method in LOP analysis.

This dissertation will help parties (both the contractor and the owner) better understand the MCAA method in estimating productivity loss so that the measure of the loss of productivity can be less subjective and more transparent. With the improvements provided in this dissertation, LOP can be better quantified and LOP disputes can be solved more quickly and reasonably.

    Cover page: Proposed Improvements to the MCAA Method for Quantifying Construction Loss of Productivity
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2021)
    We calculate the S-multiplets for two-dimensional Euclidean N = (0, 2) and N = (2, 2) superconformal field theories under the TT¯ deformation at leading order of perturbation theory in the deformation coupling. Then, from these N = (0, 2) deformed multiplets, we calculate two- and three-point correlators. We show the N = (0, 2) chiral ring’s elements do not flow under the TT¯ deformation. Specializing to integrable supersymmetric seed theories, such as N = (2, 2) Landau-Ginzburg models, we use the thermodynamic Bethe ansatz to study the S-matrices and ground state energies. From both an S-matrix perspective and Melzer’s folding prescription, we show that the deformed ground state energy obeys the inviscid Burgers’ equation. Finally, we show that several indices independent of D-term perturbations including the Witten index, Cecotti-Fendley-Intriligator-Vafa index and elliptic genus do not flow under the TT¯ deformation.
      Cover page: TT¯ deformation in SCFTs and integrable supersymmetric theoriesCreative Commons 'BY-NC-ND' version 4.0 license
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2022)
      Sharpening the correspondence of Jackiw-Teitelboim (JT) gravity and its dual matrix model description at a finite radial cutoff λ through the TT¯ deformation is of interest. To proceed, we simplify the problem by considering the Airy model and deform Airy correlators in the same way as in TT¯ -deformed JT gravity. We use those correlators to compute the annealed and quenched free energies for both λ > 0 and λ < 0 from an integral representation of the replica trick. At the leading order in λ and low temperatures, we confirm that the genus-zero quenched free energy monotonically decreases as a function of temperature when perturbation theory is valid. We then study the all-genus quenched free energy at low temperatures, where we discover and discuss subtleties due to non-perturbative effects in the Airy model, as well as the contributions from the non-perturbative branch under the TT¯ deformation.
        Cover page: TT¯-deformed free energy of the Airy modelCreative Commons 'BY-NC-ND' version 4.0 license
        • Thesis
        • Peer Reviewed
        UC San Diego Electronic Theses and Dissertations (2018)

        Chapter 1 studies the instrument validity for local average treatment effects. we provide a testable implication for instrument validity in the local average treatment effect (LATE) framework with multivalued treatments. Based on this testable implication, we construct a nonparametric test of instrument validity in the multivalued treatment LATE framework. The test is asymptotically consistent. The size of the test can be promoted to the nominal significance level over much of the null, indicating a good power property. Simulation evidence is provided to show the good performance of the test in finite samples. Chapter 2 constructs improved nonparametric bootstrap tests of Lorenz dominance based on preliminary estimation of a contact set. Our tests achieve the nominal rejection rate asymptotically on the boundary of the null; that is, when Lorenz dominance is satisfied, and the Lorenz curves coincide on some interval. Numerical simulations indicate that our tests enjoy substantially improved power compared to existing procedures at relevant sample sizes. Chapter 3 proposes a sieve focused GMM (SFGMM) estimator for general high-dimensional semiparametric conditional moment models in the presence of endogeneity. Under certain conditions, the SFGMM estimator has oracle consistency properties and converges at a desirable rate. We then establish the asymptotic normality of the plug-in SFGMM estimator for possibly irregular functionals. Simulation evidence illustrates the performance of the proposed estimator.

          Cover page: Essays on Non-parametric and High-dimensional Econometrics
          • Article
          Working Papers (2015)
          This paper studies a nonlinear predictive energy management strategy for a residential building with a rooftop photovoltaic (PV) system and second-life lithium-ion battery energy storage. A key novelty of this manuscript is closing the gap between building energy management formulations, advanced load forecasting techniques, and nonlinear battery/PV models. Additionally, we focus on the fundamental trade-off between lithium-ion battery aging and economic performance in energy management. The energy management problem is formulated as a model predictive controller (MPC). Simulation results demonstrate that the proposed control scheme achieves 96%-98% of the optimal performance given perfect forecasts over a long-term horizon. Moreover, the rate of battery capacity loss can be reduced by 25% with negligible losses in economic performance, through an appropriate cost function formulation.
            Cover page: Nonlinear Predictive Energy Management of Residential Buildings with Photovoltaics &amp; Batteries
            • Article
            • Peer Reviewed
            UC Berkeley Previously Published Works (2022)
              • Peer Reviewed
              UC Berkeley Previously Published Works (2019)
                Creative Commons 'BY' version 4.0 license
                • Article
                • Peer Reviewed
                UC Berkeley Previously Published Works (2020)
                Reversible Boolean function (RBF) is a one-to-one function which maps n-bit input to n-bit output. Reversible logic synthesis has been widely studied due to its connection with low-energy computation as well as quantum computation. In this paper, we give a structured decomposition for even RBFs. Specifically, for n≥q 6, any even n-bit RBF can be decomposed to 7 blocks of (n-1)-bit RBF, where 7 is a constant independent of n and the positions of these blocks have a large degree of freedom. Moreover, if the (n-1)-bit RBFs are required to be even as well, we show for n≥q 10, even n-bit RBF can be decomposed to 10 even (n-1)-bit RBFs. In short, our decomposition has block depth 7 and even block depth 10. Our result improves Selinger's work in block depth model, by reducing the constant from 9 to 7 and from 13 to 10, when the blocks are limited to be even. We emphasize that our setting is a bit different from Selinger's work. In Selinger's constructive proof, each block is placed in one of two specific positions and thus the decomposition has an alternating structure. We relax this restriction and allow each block to act on arbitrary (n-1) bits. This relaxation keeps the block structure and provides more candidates when choosing the positions of blocks.
                  Creative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  UCLA Previously Published Works (2022)
                  JT gravity has a first-order formulation as a two-dimensional BF theory, which can be viewed as the dimensional reduction of the Chern-Simons description of 3d3d gravity. We consider {T\overbar{T}}TT¯-type deformations of the (0+1)(0+1)-dimensional dual to this 2d2d BF theory and interpret the deformation as a modification of the BF theory boundary conditions. The fundamental observables in this deformed BF theory, and in its 3d3d Chern-Simons lift, are Wilson lines and loops. In the 3d3d Chern-Simons setting, we study modifications to correlators involving boundary-anchored Wilson lines which are induced by a {T\overbar{T}}TT¯ deformation on the 2d2d boundary; results are presented at both the classical level (using modified boundary conditions) and the quantum-mechanical level (using conformal perturbation theory). Finally, we calculate the analogous deformed Wilson line correlators in 2d2d BF theory below the Hagedorn temperature where the principal series dominates over the discrete series.
                    Cover page: $T\bar{T}$ in JT Gravity and BF Gauge TheoryCreative Commons 'BY-NC-ND' version 4.0 license
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2022)
                    We define a manifestly supersymmetric version of the TT¯ deformation appropriate for a class of (0 + 1)-dimensional theories with N = 1 or N = 2 supersymmetry, including one presentation of the super-Schwarzian theory which is dual to JT supergravity. These deformations are written in terms of Noether currents associated with translations in superspace, so we refer to them collectively as f(Q) deformations. We provide evidence that the f(Q)) deformations of N = 1 and N = 2 theories are on-shell equivalent to the dimensionally reduced supercurrent-squared deformations of 2d theories with N = (0, 1) and N = (1, 1) supersymmetry, respectively. In the N = 1 case, we present two forms of the f(Q) deformation which drive the same flow, and clarify their equivalence by studying the analogous equivalent deformations in the non-supersymmetric setting.
                      Cover page: TT¯ deformations of supersymmetric quantum mechanicsCreative Commons 'BY-NC-ND' version 4.0 license
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