Discrete time series generated by mixtures I: Correlational and runs properties

A broad but parametrically simple model for a stationary sequence of dependent discrete random variables is given and several submodels are discussed. The structure of the model is specified by the marginal distribution of the random variables and several other parameters. The sequence of random variables is formed by a probabilistic linear combination of independent, identically distributed discrete random variables and is in general not Markovian. Second-order joint moments and spectra are obtained for the model, as well as some properties for the lengths of runs. The special case of process in which the variables take on only two values is useful as a model for the counting process in a discrete-time point process. An application to the modelling of erros in the transmission of binary data is briefly discussed. (Author)supported by funds provided directly from the Chief of Naval Research under Grant NR-42-284, and the National Science Foundation under Grant NSF-75-02026http://archive.org/details/discretetimeseri00lewiN

BATTLESPACE/INFORMATION WAR (BAT/IW): a system-of-systems model of a strike operation

This paper presents a low-resolution, high-level modeling methodology for the analysis of the effectiveness of a Blue system of systems operating in a battlespace. The methodology enables quick turn around and efficient exploration of sensitivities of measures of Blue combat success to realistically imperfect Blue intelligence, surveillance and reconnaissance capabilities: limited and imperfect sensor surveillance and reconnaissance, particularly battle damage assessment (BDA), and finite, hence saturable, communications and weapons delivery capability. The model explicitly represents aircraft sorties, fires, sensor/shooter latencies, target losses, imperfect target type classification, imperfect weapon assignment, and BDAvarious levels of the above imperfections can be applied, facilitating tradeoff studies, The model is deterministic/ expected value in nature, although it analytically represents time-dependent stochastic features such as system saturability. Model experimentation suggests the following results. Decreasing shooter latency can result in greater attrition than correspondingly increasing the probabilities of correct BDA or weapon assignment, although at the expense of a greater number of weapons fired per target killed. Erroneous BDA returns dead targets to the shooter targeting list. These dead targets not only result in wasted weapon expenditure but also take sensor/shooter resources away from legitimate live targets. Increasing the probability of correct BDA can result in a greater number of targets killed during a time period than increasing the probability of correct weapon assignment.

Writing at School: Test-Prep Writing and Digital Storytelling

This article presents a study on two students’ from nonmainstream and working class backgrounds writing experiences in two different writing situations: writing for test preparation and writing for digital stories. The students’ writing behaviors, processes and products in these two settings are contrasted. The differences of the students’ writing experiences in this classroom during a four-month period suggest that it may be our teaching that trails behind the time rather than students from diverse backgrounds trailing behind in their school learning. The research findings point out that a test-driven teaching approach tends to limit students’ ability as learners and in contrast, the instruction that values students’ home literacies energizes students’ learning, reaches their potential, and ensures their school success. The article concludes by advocating change in our teaching and curriculum and stresses the importance of inviting students’ home literacies in our curriculum, valuing their interest in our teaching and preparing them to be literate citizens for the 21st century

Sex Chromosome Abnormalities in the Male

This article does not set out to give a comprehensive review of sex chromosome abnormalities in Man, nor even in phenotypic males. Its purpose is more to outline a few general principles and show how they apply to one group of individuals with one class of abnormality, namely males with abnormalities of number of either the X chromosome, or the Y chromosome or of both

Operations analysis of Fleet battle experiments using the Battlespace Information War methodology: preliminary report

This report outlines an approach for quantitative operations analysis of aspects of Fleet Battle Experiments (FBEs) using the methodology underlying the Battlespace Information War (BAT/IW) analytical tool. The general approach of this analysis methodology is to focus on a specific experimental initiative from one or more FBEs, such as Time Critical Targeting (TCT). BAT/IW models are then tailored to the experimental situation using actual data obtained from one or more experiments and the experiment systems architecture. After the models and actual data are reconciled, further analysis tasks are undertaken, such as predictions of the effects of attack intensity, and/or of C4ISR response time reduction. BAT/IW modeling helps analyze and understand the system-level impact of sensor data quality, including timeliness, as one contributor to total operation/campaign success. BAT/IW modeling also accounts for the latency involved in processing information, including communications delays, decision time, waiting, etc. An example is developed to show how operational data obtained during FBE Foxtrot can be quantitatively analyzed to indicate important sensitivities.--Report documentation page.Approved for public release; distribution is unlimited

The Future Theater-Level Model: A Research Project Update

Proceedings of the 1994 Winter Simulation Conference ed. J. D. Tew, S. Manivannan, D. A. Sadowski, and A. F. SeilaResearch has been conducted at the Naval Postgraduate School into new methodologies for joint theater-level combat simulation modeling, emphasizing C3I, operational intelligence, decisionmaking under uncertainty, and aggregated stochastic process modeling. Research outcomes to date as well as a prototype software tool are described in this paper

Modeling and analysis of uncertain time-critical tasking problems

Naval Research Logistics, 53 , No. 6, (Sept. 2006), 588-599.This paper describes modeling and operational analysis of a generic asymmetric services-system situation in which (a) Red agents, potentially threatening, but in another but important interpretation, are isolated friendlies, such as downed pilots, that require assistance and "arrive" according to some partially known and potentially changing pattern in time and space: and (b) Reds have effectively limited unknown deadlines or times of availability for Blue service, i.e., detection, classification, and attack in a military setting or emergency assistance in others. We discuss various service options by Blue service agents and devise several approximations allowing one to compute efficiently those proportions of tasks of different classes that are successfully serviced, or more generally, if different rewards are associated with different classes of tasks, the percentage of the possible reward gained. We suggest heuristic policies of a Blue server to select the next task to perform and to decide how much time to allocate to that service. We discuss this for a number of specific examples

Inferring finite-time performance in the M/G/1 queueing model

A single server is approached by a stream of Poisson arrivals with known arrival rate. The service times are assumed to be independent identically distributed with unknown distribution. One has available a finite sample of service times obtained by observing the system. A nonparametric approach is taken towards estimating the expected waiting time encountered by a new arriving customer at a finite time t, EWt both for stable and unstable systems. The estimator uses approximations to EWt and an empirical version of the well known Laplace transform of EWt for the M/G/1 queue. Empirical transform; Laplace transform of the virtual waiting of the M/G/1 queue; Exponential approximation; Brownian motion with drift. (jes)Prepared for: Office of Naval Research Arlington, VAhttp://archive.org/details/inferringfinitet00jacoOffice of Naval ResearchApproved for public release; distribution is unlimited

Modeling and Statistical Analysis of Bioassay data: Medaka Cell Proliferation Under DEN and TCE

The response of medaka liver to the chemicals DEN and TCE is analyzed statistically. The analysis illustrates the application of methods useful in environmetrics, i.e. environmental statistics. It suggests an overall dose- response effect but not an easily-interpreted dose-response functional relationship.U.S. Army Biomedical Research & Development Laboratory, Ft. Detrick, MDhttp://archive.org/details/modelingstatisti94014gaveRLLDG002J

Experimental validation of COMETA model of mental workload in air traffic control

The sustained increase in air traffic during the last decades represents a challenge to the air traffic management system in general. Thus, it is of utmost importance to develop strategies that can safely increase air traffic controller's handling capacity without increasing task related strain. This research proposes and validates a predictive model of air traffic controller's mental workload. Our model is based on COMETA, a model that considers the effect of the most relevant air traffic events in the cognitive complexity of the task. In the version of COMETA used in this study we include the online effects of the controllers' actions on the state of the airspace. To validate the model, a laboratory experiment was conducted using a simulator to precisely control the task workload factors. We used traffic density and airspace complexity as experimental factors because they are the most commonly acknowledged sources of mental workload in air traffic control literature. The measured dependent variables were selected because they have been found to correlate with mental workload in ATC tasks, namely, ISA and NASA indexes, electrodermal activity, heart rate, and different performance measures. The results demonstrate that our model can successfully predict air traffic controllers' mental workload across a wide range of task workload conditions. In addition, our results provide a clear portrait of the complex interactions between the different sources of task workload and their effects on mental workload. In the conclusion we consider the limitations and opportunities for the application of this model to improve policie