PUZZLE - A program for computer-aided design of printed circuit artwork

Program assists in solving spacing problems encountered in printed circuit /PC/ design. It is intended to have maximum use for two-sided PC boards carrying integrated circuits, and also aids design of discrete component circuits

Improving Efficiency in a Campus Chilled Water System Using Exergy Analysis

This paper evaluates the central chilled water system of the Southern Illinois University Carbondale (SIUC) campus using exergy-based cost accounting to quantify the magnitudes and cost impacts of internal losses with the goals of maximizing chiller capacity utilization and minimizing the unit cost of delivered chilled water. Two independent systems, each comprised of a primary-secondary-tertiary distribution network and cooled by a 12,300 kW (3,500 RT) steam-turbine driven centrifugal chiller, were modeled as control volume networks using steady-state rate balances for energy, exergy, and cost. An extensive set of measurements, collected over the 2006 cooling season, was used as the input data for the models. Results show that while the steam turbines are the largest source of exergy destruction, mixing in the distribution loops is the dominant source of exergy unit cost at low cooling loads, and refrigeration cycle losses dominate costs at high loads. Recommendations include: (1) Convert the chilled water distribution to an all-variable-speed, direct-coupled configuration; (2) During low cooling loads use only one chiller; (3) During high cooling loads, increase the flow rate of water through the evaporators; (4) Favor speed control over inlet guide vanes for capacity modulation; (5) Better insulate steam piping; and (6) Consider replacing the steam turbines with variable speed motors

Review and Analysis of an Energy Efficiency Incentive Program for Commercial Buildings

A program with 13 participants provided reimbursement for improvements to decrease energy use largely in commercial and not-for-profit buildings but also in two government buildings. Electricity and natural gas savings were determined by modeling the energy use by accounting for changes in weather for the 12 months previous to the improvements, and then predicting energy use for the 12 months immediately after the improvements using the same model. The threshold for verifiable energy savings resulting from building improvements was a maximum uncertainty of 50% at the 68% confidence level. Improvements involving original furnace or air conditioner replacement resulted in significant and verifiable reductions in energy use. Energy savings due to lighting improvements were verified for only one of seven buildings in which lighting was upgraded. Verifiable results were obtained in buildings with constant usage patterns, hours of operation, and equipment. Significant changes not related to weather, and improvements resulting in less than 10% savings of the total energy measured at the meter led to non-verifiable results. Other benefits of the program not related to energy cost savings included increasing illumination while maintaining the same electricity use, and improving comfort and noise reduction with additional insulation. The program was very successful in leveraging significant private investment for building improvements. In addition, the program inspired business owners to make further improvements voluntarily after the program ended and also increased interest in similar future programs

Distributional Borel Summability of Odd Anharmonic Oscillators

It is proved that the divergent Rayleigh-Schrodinger perturbation expansions for the eigenvalues of any odd anharmonic oscillator are Borel summable in the distributional sense to the resonances naturally associated with the system

Convergence Radii for Eigenvalues of Tri--diagonal Matrices

Consider a family of infinite tri--diagonal matrices of the form $L+ zB,$ where the matrix $L$ is diagonal with entries $L_{kk}= k^2,$ and the matrix $B$ is off--diagonal, with nonzero entries $B_{k,{k+1}}=B_{{k+1},k}= k^\alpha, 0 \leq \alpha < 2.$ The spectrum of $L+ zB$ is discrete. For small $|z|$ the $n$-th eigenvalue $E_n (z), E_n (0) = n^2,$ is a well--defined analytic function. Let $R_n$ be the convergence radius of its Taylor's series about $z= 0.$ It is proved that $$ R_n \leq C(\alpha) n^{2-\alpha} \quad \text{if} 0 \leq \alpha <11/6.$

A Recurrent Neural Network Survival Model: Predicting Web User Return Time

The size of a website's active user base directly affects its value. Thus, it is important to monitor and influence a user's likelihood to return to a site. Essential to this is predicting when a user will return. Current state of the art approaches to solve this problem come in two flavors: (1) Recurrent Neural Network (RNN) based solutions and (2) survival analysis methods. We observe that both techniques are severely limited when applied to this problem. Survival models can only incorporate aggregate representations of users instead of automatically learning a representation directly from a raw time series of user actions. RNNs can automatically learn features, but can not be directly trained with examples of non-returning users who have no target value for their return time. We develop a novel RNN survival model that removes the limitations of the state of the art methods. We demonstrate that this model can successfully be applied to return time prediction on a large e-commerce dataset with a superior ability to discriminate between returning and non-returning users than either method applied in isolation.Comment: Accepted into ECML PKDD 2018; 8 figures and 1 tabl

Understanding the Random Displacement Model: From Ground-State Properties to Localization

We give a detailed survey of results obtained in the most recent half decade which led to a deeper understanding of the random displacement model, a model of a random Schr\"odinger operator which describes the quantum mechanics of an electron in a structurally disordered medium. These results started by identifying configurations which characterize minimal energy, then led to Lifshitz tail bounds on the integrated density of states as well as a Wegner estimate near the spectral minimum, which ultimately resulted in a proof of spectral and dynamical localization at low energy for the multi-dimensional random displacement model.Comment: 31 pages, 7 figures, final version, to appear in Proceedings of "Spectral Days 2010", Santiago, Chile, September 20-24, 201

The melanoma-specific graded prognostic assessment does not adequately discriminate prognosis in a modern population with brain metastases from malignant melanoma

The melanoma-specific graded prognostic assessment (msGPA) assigns patients with brain metastases from malignant melanoma to 1 of 4 prognostic groups. It was largely derived using clinical data from patients treated in the era that preceded the development of newer therapies such as BRAF, MEK and immune checkpoint inhibitors. Therefore, its current relevance to patients diagnosed with brain metastases from malignant melanoma is unclear. This study is an external validation of the msGPA in two temporally distinct British populations.Performance of the msGPA was assessed in Cohort I (1997-2008, n=231) and Cohort II (2008-2013, n=162) using Kaplan-Meier methods and Harrell's c-index of concordance. Cox regression was used to explore additional factors that may have prognostic relevance.The msGPA does not perform well as a prognostic score outside of the derivation cohort, with suboptimal statistical calibration and discrimination, particularly in those patients with an intermediate prognosis. Extra-cerebral metastases, leptomeningeal disease, age and potential use of novel targeted agents after brain metastases are diagnosed, should be incorporated into future prognostic models.An improved prognostic score is required to underpin high-quality randomised controlled trials in an area with a wide disparity in clinical care