User-specified Intervals Research Articles

Cryologger Ice Tracking Beacon: A Low-Cost, Open-Source Platform for Tracking Icebergs and Ice Islands.

Icebergs and ice islands (large, tabular icebergs) present a significant hazard to marine vessels and infrastructure at a time when demand for access to Arctic waters is increasing. There is a growing demand for in situ iceberg tracking data to monitor their drift trajectories and improve models used for operational forecasting of ice hazards, yet the high cost of commercial tracking devices often prevents monitoring at optimal spatial and temporal resolutions. Here, we provide a detailed description of the Cryologger Ice Tracking Beacon (ITB), a low-cost, robust, and user-friendly data logger and telemeter for tracking icebergs and ice islands based on the Arduino open-source electronics platform. Designed for deployments of at least 2 years with an hourly sampling interval that is remotely modifiable by the end user, the Cryologger ITB provides long-term measurements of position, temperature, pressure, pitch, roll, heading, and battery voltage. Data are transmitted via the Iridium satellite network at user-specified intervals. We present the results of field campaigns in 2018 and 2019, which saw the deployment of 16 ITBs along the coasts of Greenland and Ellesmere and Baffin islands. The overall success of these ITB deployments has demonstrated that inexpensive, open-source hardware and software can provide a reliable and cost-effective method of monitoring icebergs and ice islands in the polar regions.

Bayesian Mendelian randomization with an interval causal null hypothesis: ternary decision rules and loss function calibration

We enhance the Bayesian Mendelian Randomization (MR) framework of Berzuini et al. (Biostatistics 21(1):86–101, 2018) by allowing for interval null causal hypotheses, where values of the causal effect parameter that fall within a user-specified interval of “practical equivalence” (ROPE) (Kruschke, Adv Methods Pract Psychol Sci 1(2):270–80, 2018) are regarded as equivalent to “no effect”. We motivate this move in the context of MR analysis. In this approach, the decision over the hypothesis test is taken on the basis of the Bayesian posterior odds for the causal effect parameter falling within the ROPE. We allow the causal effect parameter to have a mixture prior, with components corresponding to the null and the alternative hypothesis. Inference is performed via Markov chain Monte Carlo (MCMC) methods. We speed up the calculations by fitting to the data a simpler model than the intended, "true", one. We recover a set of samples from the “true” posterior distribution by weighted importance resampling of the MCMC-generated samples. From the final samples we obtain a simulation consistent estimate of the desired posterior odds, and ultimately of the Bayes factor for the interval-valued null hypothesis, H0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$H_0$$\\end{document}, vs H1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$H_1$$\\end{document}. In those situations where the posterior odds is neither large nor small enough, we allow for an uncertain outcome of the test decision, thereby moving to a ternary decision logic. Finally, we present an approach to calibration of the proposed method via loss function. We illustrate the method with the aid of a study of the causal effect of obesity on risk of juvenile myocardial infarction based on a unique prospective dataset.

Efficient reduced-rank methods for Gaussian processes with eigenfunction expansions

In this work, we introduce a reduced-rank algorithm for Gaussian process regression. Our numerical scheme converts a Gaussian process on a user-specified interval to its Karhunen–Loève expansion, the \(L^2\)-optimal reduced-rank representation. Numerical evaluation of the Karhunen–Loève expansion is performed once during precomputation and involves computing a numerical eigendecomposition of an integral operator whose kernel is the covariance function of the Gaussian process. The Karhunen–Loève expansion is independent of observed data and depends only on the covariance kernel and the size of the interval on which the Gaussian process is defined. The scheme of this paper does not require translation invariance of the covariance kernel. We also introduce a class of fast algorithms for Bayesian fitting of hyperparameters and demonstrate the performance of our algorithms with numerical experiments in one and two dimensions. Extensions to higher dimensions are mathematically straightforward but suffer from the standard curses of high dimensions.

Healthcare Costs of Treating Privately Insured Patients with Acute Myeloid Leukemia in the United States from 2004 to 2014: A Generalized Additive Modeling Approach.

The primary objective of this study was to predict healthcare cost trajectories for patients with newly diagnosed acute myeloid leukemia (AML) receiving allogeneic hematopoietic cell transplantation (alloHCT), as a function of days since chemotherapy initiation, days relative to alloHCT, and days before death or last date of insurance eligibility (LDE). An exploratory objective examined patients with AML receiving chemotherapy only. We used Optum's de-identified Clinformatics® Data Mart Database to construct cumulative cost trajectories from chemotherapy initiation to death or LDE (through 31 December 2014) for US patients aged 20-74years diagnosed between 1 March 2004 and 31 December 2013 (n = 187 alloHCT; n = 253 chemotherapy only). We used generalized additive modeling (GAM) to predict expected trajectories and bootstrapped confidence intervals (CIs) at user-specified intervals conditional on dates of alloHCT and death or LDE relative to chemotherapy initiation. Expected costs (in 2017 values) for a hypothetical patient receiving alloHCT 60days after chemotherapy initiation and followed for 5years were $US572,000 (95% CI 517,000-633,000); $US119,000 (95% CI 51,000-192,000); $US102,000 (95% CI 0-285,000); $US79,000 (95% CI 0-233,000), for years 1-4, respectively, and either $US494,000 (95% CI 212,000-799,000) or $US108,000 (95% CI 0-230,000) in year 5, whether the patient died or was lost to follow-up on day 1825, respectively. Rates of cost accrual varied over time since chemotherapy initiation, with accelerations around the time of alloHCT and death. GAM is a potentially useful approach for imputing longitudinal costs relative to treatment initiation and one or more intercurrent, clinical, or terminal events in randomized controlled trials or registries with unrecorded costs or for dynamic decision-analytic models.

Deterministic simulation and graphical representation of powered material handling vehicle movements to enhance pedestrian safety at the Ford Motor company

ABSTRACT A deterministic Material Flow Analysis (MFA) simulation tool has been developed within Microsoft Excel allowing the user to simply and quickly enter relevant material and logistics data. This data is then processed mathematically stepping through time in user-specified intervals assessing stock levels and vehicle status. The monitoring of the material flow in this manner provides data resolution that has not been achievable within Ford prior to the use of simulation. A further extension was developed enabling effective communication of safety-critical simulation output to be presented diagrammatically as a “Material Flow Heat Map”. Preliminary implementation has shown the tool is effective at both confirming expected and highlighting new, high-traffic hotspots in the plant. Through the development and implementation of these methods, the movement of vehicles is better understood allowing targeted engineering actions to improve productivity and enhance pedestrian safety for both existing and proposed future facilities.

Development of an automated dispenser for the delivery of medicinal or vaccine-laden baits to raccoons (Procyon lotor).

Medicinal baits are distributed to manage zoonotic diseases, including raccoon (Procyon lotor) rabies, but efficient distribution strategies are needed for suburban environments. We developed an automated dispenser that transfers fishmeal polymer baits at user-specified intervals from a magazine to a receptacle fitted with a filter that exploits raccoon dexterity to limit consumption by nontarget species. We introduce the concept of automated dispensers and describe bait removal success rates for raccoons versus nontarget species. We monitored visitation with remote cameras after deploying a dispenser, programmed to present two baits per night, in three disjunct forest patches in northwest Indiana. Raccoons removed 72% of baits; nontarget, white-footed mice (Peromyscus leucopus) removed 11%; Virginia opossums (Didelphis virginiana) removed 9%. Bait removal success varied significantly between raccoons (76%) and opossums (21%), improving bait delivery specificity relative to hand baiting. Accumulation of baits in receptacles resulted in excess (more than one) bait consumption (39% of baits consumed by raccoons were excess), suggesting design improvements are needed to present additional baits only after previous baits have been consumed. Automated dispensers successfully sustained bait availability throughout the operational period. Subsequent research is needed to determine whether a sustained availability of baits achieved with automated dispensers is more effective for the treatment of raccoons in suburban environments than traditional distribution methods.

Deviation test construction and power comparison for marked spatial point patterns

Deviation tests play an important role in testing distributional hypotheses in point process statistics. Such tests are based on differences between empirical summary functions and their theoretical counterparts, which depend on a distance variable r in a user-specified interval I. These differences are summarized to a single number, which serves then as the test statistic u. Statistical experience indicates that different distances r have different influence on u. We propose scalings of the differences to equalize the influence of the distances and show that the power of deviation tests can be improved by them. We further study how the power is affected by the other elements of deviation tests, which are the choice of the summary function, the deviation measure and the interval I. We consider in detail the construction of deviation tests for the particular case of testing the random labeling hypothesis, i.e. independence of the marks of a marked point process. By a large simulation study we come to clear statements about the role of the test elements. Furthermore, we demonstrate the potential of scaling by a data example from the literature.

Creating a Continuously Updated Animated KML Loop with a PHP Mashup

Google Earth (GE) can display timestamped features sequentially to create an animation on its interactive globe. The GE TimeSpan capability has been utilized to show a variety of imagery such as historical maps, or before/during/after imagery of remotely sensed landscapes for easy comparison of changes due to a particular event such as flooding. The period between such events can be minutes, days, or even years, and possibly be available at irregular user-specified intervals. As such, TimeSpan is well-suited to properly display imagery that can be georeferenced, encoded into a Keyhole Markup Language (KML) file, and timestamped for sequential viewing. For imagery that is available at regular intervals, an automated process can be employed to create a continuously updated KML file. Here I describe such a process, a mashup that generates a loop of national weather radar imagery for viewing on Google Earth.

Self-descriptive microphone array

A self-descriptive microphone array includes a microphone array memory, such as, for example a ROM, EEPROM, or other conventional memory, which contains a microphone array device description. This device description includes parametric information which defines operational characteristics and configuration of the microphone array. In further embodiments, the microphone array uses any of a variety of conventional wired or wireless computer interfaces, including serial, IEEE 1394, USB, Bluetooth™, etc., to connect to a computing device. Once connected, the microphone array provides its device description to the computing device. Sound processing software residing within the computing device is then automatically configured for optimally interacting with one or more analog or digital audio signals provided by the microphone array. In another embodiment, the microphone array performs integrated self calibration for automatically updating the device description. The self calibration is performed either upon connection to the computing device, or upon regular or user-specified intervals.

Eyes on the Skies

T he orbital space above Earth contains an astonishing collection of man-made satellites. Tracking all of these objects is no small task. Liftoff is a NASA Web site that provides several software tools to locate, track, and identify Earth-orbiting satellites. At the Web site, three programs are available: J-Pass (identifies satellites passing overhead); J-Track (allows one to track orbiting objects); and J-Track 3D (allows one to view satellites orbiting Earth from a perspective far away in space). Each of these platform-independent applications is written in Java and is accessible from both Internet Explorer and Netscape Communicator browsers (version 4.0 or newer). Users load each software package within their browsers by clicking on the name of the program on a palette at the site. This organizational scheme is a bit confusing because the palette also contains links to other spacecraft-specific information, such as the locations of MIR, the Space Station, and the Shuttle. (When the Shuttle was not flying, clicking on its name gave an error message about a broken link, instead of simply saying the shuttle was on the ground.) Of the three software products, J-Track 3D is the most impressive. Providing the user a viewpoint beyond the position of geosynchronous orbiting satellites (22,000 miles), the program shows a hemisphere of Earth with the satellites around it as points of light (see the figure). Users can either click on a point to learn more about it (such as the satellite's orbit, ground tracking, launch, or data collecting information) or select a satellite by name from the Satellite menu option. Simple controls allow one to rotate the planet in any direction. Satellite positions are updated at user-specified intervals of real time as short as 0.25 seconds. J-Track illustrates the track of satellites superimposed on a two-dimensional (2D) map of the earth, similar to plots one might see on NASA television. Though the information overlaps with that available in J-Track 3D, the advantages of J-Track are that users can specify which spacecraft to follow instead of seeing all of them and that the 2D map of J-Track is easier to view than the globe of J-Track 3D. J-Pass is a tool for anyone interested in watching satellites overhead. It provides users with a list of satellites with time plots and sky maps of when and where each one can be viewed. Users define their location on Earth by specifying longitude and latitude or, in the United States, by using their ZIP code. This clever feature works well and simplifies user interaction with the program. On the downside, the results of having the roots of each program in Java are interfaces that are not exactly cutting edge. Menus appear in different places depending on whether one uses Netscape or Internet Explorer. Each program contained several bugs that were annoying. Ideally, visitors to the site should have a network connection that is faster than a 56K modem to avoid slow downloads, although each program can be used on a modem, if one is patient.

The adaptive Lagrangian particle method for macroscopic and micro–macro computations of time-dependent viscoelastic flows

We propose a new numerical technique, referred to as the Adaptive Lagrangian Particle Method (ALPM), for computing time-dependent viscoelastic flows using either a differential constitutive equation (macroscopic approach) or a kinetic theory model (micro–macro approach). In ALPM, the Eulerian finite element solution of the conservation equations is decoupled from the Lagrangian computation of the extra-stress at a number of discrete particles convected by the flow. In the macroscopic approach, the extra-stress carried by the particles is obtained by integrating the constitutive equation along the particle trajectories. In the micro–macro approach, the extra-stress is computed by solving along the particle paths the stochastic differential equation associated with the kinetic theory model. At each time step, ALPM automatically enforces that all elements of the mesh have a number of Lagrangian particles ranging within a user-specified interval. Results are given for the start-up flow between highly eccentric rotating cylinders, using the FENE and FENE-P dumbbell models for dilute polymer solutions.

Florida Reach-Ins: Environmental Chambers for Entomological Research

Controlled-environment chambers developed by University of Florida's Department of Entomology and Nematology differ from conventional reach-in chambers in that they depend on ambient air for cooling and dehumidification, allowing many chambers to be served by one remote, redundant cooling system. Furthermore, each group of eight chambers is controlled and logged by one XT-type computer, making these functions economical, precise, and flexible. Temperature and humidity can be controlled ±0.1°C and ±1% RH of setpoints. Setpoints can be constant, changed at user-specified intervals, or changed continually between user-specified inflection points. Lights and auxiliary outlet can be programmed to turn on and off at intervals of 1 s. Logged data can be viewed graphically without downloading.

Real-time multichannel neural spike recognition with DSPs

Data acquisition technology that uses relatively inexpensive digital signal processors (DSPs) for the rapid acquisition of neuronal action potential (spike) data was investigated. Three spike sorting techniques were considered. The simplest classification routine tested was peak windowing. Spikes were considered to belong to the same class when their peak amplitude fell within a user-specified interval. Another approach required computing the RMS error between stored templates of each unit's spike waveform and the spike most recently detected. The new spike was classified according to the minimum of the RMS errors computed. In the third algorithm, two optimal coefficient vectors, called principal components, were computed from previously acquired template waveforms and stored. These principal components were used to compute two vector products for each newly detected spike waveform vector. The resulting two values were features that were used to classify the waveform. The test system that was constructed is described, and results obtained with each of the algorithms are compared and evaluated.

For Apple Owners: A Four-Channel, Computer-Managed Physiograph for $600

For approximately $600, Apple IIe owners can purchase equipment for collecting physiological data. Electromyograph (EMG), galvanic skin response (GSR), skin temperature (TEMP), and heart rate (HR) data can be recorded at user-specified intervals, displayed on a monitor, saved to a disk, and printed on paper. The system is flexible, and has been used in classroom demonstrations, relaxation training, and student research projects.

A program designed to facilitate the repetitive acquisition, display, and disk storage of sensory evoked responses.

We present an algorithm that permits automated acquisition, display, and disk storage of single or dual channel sensory evoked potential waveforms using a Pathfinder II evoked response monitor. Once initiated, data acquisition and storage continue at user-specified intervals without additional user input. A cascade screen display provides trend monitoring. The file for data storage is established and searched using standard Pathfinder commands. The algorithm is written in MECOL, the Pathfinder specific programming language. This programming code imposed a number of limitations that had to be overcome to create a versatile and user friendly algorithm. During clinical use in our operating rooms, the program has been found effective and easy to use by both veteran and novice Pathfinder operators. The "hands-off" trend monitoring permitted by this algorithm has reduced the labor-intensive aspect of sensory evoked potential monitoring.

Coding, Storage, and Retrieval of Stratigraphic Data: FORTRAN Mapping Technique: ABSTRACT

A unique technique of coding, storing, and plotting descriptive stratigraphic data uses a series of FORTRAN programs. The basis for the technique is a search-and-store algorithm that may be modified to produce a time-series sequence of lithologic or environmental maps. Coded data are displayed as a 2-dimensional output array in the form of an inked, line-drawn planimetric view of the research area. User-specified intervals of the range of data are represented by symbology, color code, or literal string. The final product is a time series of computer-constructed surfaces representing the geologic evolution of a particular area. These surfaces may emphasize environments of deposition, sediment lithology, or any other stratigraphically derived information (porosity, permeabi ity, consolidation, mineralogy, biostratigraphy, geochemistry). Stratigraphic data are stored as an alphanumeric code. Data are presumed to have been derived from cores or some similar means of vertical sequence control. A single core occupies one line of a data file with an operating field width of 132 columns. Columns 1-9 and 122-132 contain location and identification data. The remaining locations (columns 10-121) consist of repeating 14-column groups. Each group contains codes describing a single stratigraphic unit. Thus, each line of the data file may describe a sequence of 8 stratigraphic units. This technique was used to display the development of the Bay and Atlantic coasts of Delaware from 10,000 b.p. to present. A series of maps has been produced that details the geomorphology of the coast at regular chronologic intervals. This allows a detailed analysis of the evolution of a complex region as a response to known Holocene conditions of rising sea level. End_of_Article - Last_Page 255------------