5,939 research outputs found

    Generalized Supersymmetric Perturbation Theory

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    Using the basic ingredient of supersymmetry, we develop a simple alternative approach to perturbation theory in one-dimensional non-relativistic quantum mechanics. The formulae for the energy shifts and wave functions do not involve tedious calculations which appear in the available perturbation theories. The model applicable in the same form to both the ground state and excited bound states, unlike the recently introduced supersymmetric perturbation technique which, together with other approaches based on logarithmic perturbation theory, are involved within the more general framework of the present formalism.Comment: 13 pages article in LaTEX (uses standard article.sty). No Figures. Sent to Ann. Physics (2004

    Enhancing heart disease prediction using a self-attention-based transformer model

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    Cardiovascular diseases (CVDs) continue to be the leading cause of more than 17 million mortalities worldwide. The early detection of heart failure with high accuracy is crucial for clinical trials and therapy. Patients will be categorized into various types of heart disease based on characteristics like blood pressure, cholesterol levels, heart rate, and other characteristics. With the use of an automatic system, we can provide early diagnoses for those who are prone to heart failure by analyzing their characteristics. In this work, we deploy a novel self-attention-based transformer model, that combines self-attention mechanisms and transformer networks to predict CVD risk. The self-attention layers capture contextual information and generate representations that effectively model complex patterns in the data. Self-attention mechanisms provide interpretability by giving each component of the input sequence a certain amount of attention weight. This includes adjusting the input and output layers, incorporating more layers, and modifying the attention processes to collect relevant information. This also makes it possible for physicians to comprehend which features of the data contributed to the model's predictions. The proposed model is tested on the Cleveland dataset, a benchmark dataset of the University of California Irvine (UCI) machine learning (ML) repository. Comparing the proposed model to several baseline approaches, we achieved the highest accuracy of 96.51%. Furthermore, the outcomes of our experiments demonstrate that the prediction rate of our model is higher than that of other cutting-edge approaches used for heart disease prediction

    Impact of Seismic Risk on Lifetime Property Values

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    This report presents a methodology for establishing the uncertain net asset value, NAV, of a real-estate investment opportunity considering both market risk and seismic risk for the property. It also presents a decision-making procedure to assist in making real-estate investment choices under conditions of uncertainty and risk-aversion. It is shown that that market risk, as measured by the coefficient of variation of NAV, is at least 0.2 and may exceed 1.0. In a situation of such high uncertainty, where potential gains and losses are large relative to a decision-maker's risk tolerance, it is appropriate to adopt a decision-analysis approach to real-estate investment decision-making. A simple equation for doing so is presented. The decision-analysis approach uses the certainty equivalent, CE, as opposed to NAV as the basis for investment decision-making. That is, when faced with multiple investment alternatives, one should choose the alternative that maximizes CE. It is shown that CE is less than the expected value of NAV by an amount proportional to the variance of NAV and the inverse of the decision-maker's risk tolerance, [rho]. The procedure for establishing NAV and CE is illustrated in parallel demonstrations by CUREE and Kajima research teams. The CUREE demonstration is performed using a real 1960s-era hotel building in Van Nuys, California. The building, a 7-story non-ductile reinforced-concrete moment-frame building, is analyzed using the assembly-based vulnerability (ABV) method, developed in Phase III of the CUREE-Kajima Joint Research Program. The building is analyzed three ways: in its condition prior to the 1994 Northridge Earthquake, with a hypothetical shearwall upgrade, and with earthquake insurance. This is the first application of ABV to a real building, and the first time ABV has incorporated stochastic structural analyses that consider uncertainties in the mass, damping, and force-deformation behavior of the structure, along with uncertainties in ground motion, component damageability, and repair costs. New fragility functions are developed for the reinforced concrete flexural members using published laboratory test data, and new unit repair costs for these components are developed by a professional construction cost estimator. Four investment alternatives are considered: do not buy; buy; buy and retrofit; and buy and insure. It is found that the best alternative for most reasonable values of discount rate, risk tolerance, and market risk is to buy and leave the building as-is. However, risk tolerance and market risk (variability of income) both materially affect the decision. That is, for certain ranges of each parameter, the best investment alternative changes. This indicates that expected-value decision-making is inappropriate for some decision-makers and investment opportunities. It is also found that the majority of the economic seismic risk results from shaking of S[subscript a] < 0.3g, i.e., shaking with return periods on the order of 50 to 100 yr that cause primarily architectural damage, rather than from the strong, rare events of which common probable maximum loss (PML) measurements are indicative. The Kajima demonstration is performed using three Tokyo buildings. A nine-story, steel-reinforced-concrete building built in 1961 is analyzed as two designs: as-is, and with a steel-braced-frame structural upgrade. The third building is 29-story, 1999 steel-frame structure. The three buildings are intended to meet collapse-prevention, life-safety, and operational performance levels, respectively, in shaking with 10%exceedance probability in 50 years. The buildings are assessed using levels 2 and 3 of Kajima's three-level analysis methodology. These are semi-assembly based approaches, which subdivide a building into categories of components, estimate the loss of these component categories for given ground motions, and combine the losses for the entire building. The two methods are used to estimate annualized losses and to create curves that relate loss to exceedance probability. The results are incorporated in the input to a sophisticated program developed by the Kajima Corporation, called Kajima D, which forecasts cash flows for office, retail, and residential projects for purposes of property screening, due diligence, negotiation, financial structuring, and strategic planning. The result is an estimate of NAV for each building. A parametric study of CE for each building is presented, along with a simplified model for calculating CE as a function of mean NAV and coefficient of variation of NAV. The equation agrees with that developed in parallel by the CUREE team. Both the CUREE and Kajima teams collaborated with a number of real-estate investors to understand their seismic risk-management practices, and to formulate and to assess the viability of the proposed decision-making methodologies. Investors were interviewed to elicit their risk-tolerance, r, using scripts developed and presented here in English and Japanese. Results of 10 such interviews are presented, which show that a strong relationship exists between a decision-maker's annual revenue, R, and his or her risk tolerance, [rho is approximately equal to] 0.0075R[superscript 1.34]. The interviews show that earthquake risk is a marginal consideration in current investment practice. Probable maximum loss (PML) is the only earthquake risk parameter these investors consider, and they typically do not use seismic risk at all in their financial analysis of an investment opportunity. For competitive reasons, a public investor interviewed here would not wish to account for seismic risk in his financial analysis unless rating agencies required him to do so or such consideration otherwise became standard practice. However, in cases where seismic risk is high enough to significantly reduce return, a private investor expressed the desire to account for seismic risk via expected annualized loss (EAL) if it were inexpensive to do so, i.e., if the cost of calculating the EAL were not substantially greater than that of PML alone. The study results point to a number of interesting opportunities for future research, namely: improve the market-risk stochastic model, including comparison of actual long-term income with initial income projections; improve the risk-attitude interview; account for uncertainties in repair method and in the relationship between repair cost and loss; relate the damage state of structural elements with points on the force-deformation relationship; examine simpler dynamic analysis as a means to estimate vulnerability; examine the relationship between simplified engineering demand parameters and performance; enhance category-based vulnerability functions by compiling a library of building-specific ones; and work with lenders and real-estate industry analysts to determine the conditions under which seismic risk should be reflected in investors' financial analyses

    Logarithmic perturbation theory for quasinormal modes

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    Logarithmic perturbation theory (LPT) is developed and applied to quasinormal modes (QNMs) in open systems. QNMs often do not form a complete set, so LPT is especially convenient because summation over a complete set of unperturbed states is not required. Attention is paid to potentials with exponential tails, and the example of a Poschl-Teller potential is briefly discussed. A numerical method is developed that handles the exponentially large wavefunctions which appear in dealing with QNMs.Comment: 24 pages, 4 Postscript figures, uses ioplppt.sty and epsfig.st

    Lean manufacturing culture: The role of human perceptions of standardized work

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    The final publication is available at IOS Press through http://dx.doi.org/10.3233/978-1-61499-902-7-523.Lean implementation and its sustainability are strongly coupled with organizational culture and consequently the culture defines success. Organizational culture is strongly linked with organizational dynamics. Work standardization is one of the lean tools whose role in terms of organizational performance improvement has been claimed in the literature; however, its implications in terms of employee's perceptions are still controversial. This study aims at investigating the effect of position on employee's perception about the standardized work. Four textile manufacturing companies in Pakistan were selected for the purpose of data collection, where the implementation level of the tool and organizational maturity towards lean adoption were initially measured. A questionnaire was administered to 326 employees from these organizations. The overall data sample was divided into two categories (white-collar and blue-collar). Data analysis was by F-tests (for identifying significance levels) and separate regression analyses (for identifying variables associated with negative perceptions of employees). A significant difference was found between white-collar employees, who were generally positive about the standardization of work, and the blue-collar employees that had negative perceptions. Moreover, the study concluded that positive perceptions about standardized work are directly linked with job satisfaction and inversely linked with job stress

    The Onsager Algebra Symmetry of Ď„(j)\tau^{(j)}-matrices in the Superintegrable Chiral Potts Model

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    We demonstrate that the Ď„(j)\tau^{(j)}-matrices in the superintegrable chiral Potts model possess the Onsager algebra symmetry for their degenerate eigenvalues. The Fabricius-McCoy comparison of functional relations of the eight-vertex model for roots of unity and the superintegrable chiral Potts model has been carefully analyzed by identifying equivalent terms in the corresponding equations, by which we extract the conjectured relation of QQ-operators and all fusion matrices in the eight-vertex model corresponding to the TT^T\hat{T}-relation in the chiral Potts model.Comment: Latex 21 pages; Typos added, References update

    Autonomous Intersection Driving with Neuro-Evolution

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    Neuro-Evolution (NE) has been used to evolve controllers in land-based vehicles that accomplish various tasks. However, there has been little work on evolving coordinated movement for maximizing traffic flow through intersections. This study used NE to synthesize collective driving behaviors for given road networks (interconnected intersections), where there were no traffic signals to assist with vehicle coordination and navigation. Rather, NE automates controller design where collective driving behavior emerges in response to the task of maximizing traffic throughput and minimizing delays at intersections

    Association between mean platelet volume levels and inflammation in SLE patients presented with arthritis

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    Background: Systemic lupus erythematosus (SLE) may be characterized by periods of remissions and chronic or acute relapses. The complexity of clinical presentation of the SLE patients leads to incorrect evaluation of disease activity. Mean platelet volume (MPV) has been studied as a simple inflammatory marker in several diseases. There is no study in the literature about MPV levels in adult SLE patients with arthritis.Objectives: We aimed to investigate the MPV levels in the SLE population with arthritis during and between activations.Methods: The study consisted of 44 SLE patients with arthritis in activation period (Group 1), the same 44 SLE patients with arthritis in remission period (Group 2) and 44 healthy controls (Group 3). Erythrocyte sedimentation rate (ESR), creactive protein (CRP), white blood cell count, platelet count, and mean platelet volume (MPV) levels were retrospectively recorded from patient files.Results: The mean ages of the SLE subjects were 42 ± 16 years, while the mean ages of controls was 41 ± 17 years. MPV was significantly lower in Group 1(7.66±0.89fL) than in Group 2 (8.61±1.06 fL) and Group 3(8.62±1.11fL) (p&lt;0.0001). The differences between groups reached statistical significance.Conclusions: We suggest that MPV levels decrease in patients with arthritis of SLE activation when compared to the same patients in remission and healthy controls.Key words: Systemic lupus erythematosus, Arthritis, Mean platelet volum

    Hydration temperature rise and thermal stresses induced in segment-on-pier of prestressed concrete box girder bridge

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    The heat generation from chemical reactions of hardening concrete causes temperature rise and thermal expansion. When the concrete temperature eventually cools down to the ambient, thermal contraction would result. If the tendency of volume change and associated thermal movement are restrained, thermal stresses would be induced and this would lead to early thermal cracking. The issue of thermal cracking should be duly considered in mass concrete construction. Regarding concrete bridge construction, the piles, pile caps, bridge piers, crosshead girders, and bridge diaphragms are typical examples of mass concrete elements. A bridge project in real-life is selected for study in this paper, with focus on the segment-on-pier accommodating the diaphragm of prestressed concrete girder deck. The segment was instrumented to measure its actual early age temperature rise on site. Finite element simulation and analysis was conducted to evaluate the time variations of temperature distributions and thermal stresses induced in the bridge segment. The risk of thermal cracking can be indicated by the measurement and analysis results. The techniques employed in this study are useful for planning of temperature control measures in similar projects
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