On Non-Squashing Partitions

A partition n = p_1 + p_2 + ... + p_k with 1 <= p_1 <= p_2 <= ... <= p_k is called non-squashing if p_1 + ... + p_j <= p_{j+1} for 1 <= j <= k-1. Hirschhorn and Sellers showed that the number of non-squashing partitions of n is equal to the number of binary partitions of n. Here we exhibit an explicit bijection between the two families, and determine the number of non-squashing partitions with distinct parts, with a specified number of parts, or with a specified maximal part. We use the results to solve a certain box-stacking problem.Comment: 15 pages, 2 fig

Army/NASA small turboshaft engine digital controls research program

The emphasis of a program to conduct digital controls research for small turboshaft engines is on engine test evaluation of advanced control logic using a flexible microprocessor based digital control system designed specifically for research on advanced control logic. Control software is stored in programmable memory. New control algorithms may be stored in a floppy disk and loaded directly into memory. This feature facilitates comparative evaluation of different advanced control modes. The central processor in the digital control is an Intel 8086 16 bit microprocessor. Control software is programmed in assembly language. Software checkout is accomplished prior to engine test by connecting the digital control to a real time hybrid computer simulation of the engine. The engine currently installed in the facility has a hydromechanical control modified to allow electrohydraulic fuel metering and VG actuation by the digital control. Simulation results are presented which show that the modern control reduces the transient rotor speed droop caused by unanticipated load changes such as cyclic pitch or wind gust transients

What Informs Practice and What is Valued in Corporate Instructional Design? A Mixed Methods Study

This study used a two-phased explanatory mixed-methods design to explore in-depth what factors are perceived by Instructional Design and Technology (IDT) professionals as impacting instructional design practice, how these factors are valued in the field, and what differences in perspectives exist between IDT managers and non-managers. For phase 1 of the study, one hundred and sixteen corporate IDT professionals (managers and non-managers) responded to a web-based survey that was designed and developed from: (a) The results of an exploratory study of the practices of corporate instructional designers, (b) the results of an extensive literature review into the theory and practice in the field of IDT, and (c) other survey instruments developed, validated and used in prior studies. Analysis of the data collected in phase 1 of the study resulted in the development of an Evaluation Model for IDT Practice that was used as a framework to answer the research questions. Quantitative analysis included the use of Hotelling’s T2 inferential statistic to test for mean differences between managers and non-managers perceptions of formal and informally trained groups of IDT personnel. Chi squared analysis test of independence, and correlation analysis was used to determine the nature and extent of the relationship between the type of training and the professional status of the participants. For phase 2 of the study, semi-structured interviews were conducted with selected participants and analyzed using the constant comparative method in order to help validate the findings from phase 1. Ensuing analysis of the survey data determined that, both managers and non-managers generally agreed that both formal and on the job training was valuable, and that their peers who were formally and informally trained were competent instructional designers. The qualitative phase of the study and a closer examination of effect sizes suggested the potential for some variation in perceptions. In addition, a statistically significant correlation showed that IDT managers who completed the survey were more likely to be formally trained. Recommendations based on the results included future studies with a larger, more diverse population; future studies to refine the Evaluation Model for ID practice; and that academic ID programs work more closely with practitioners when designing and delivering their curricula

LAW, SCIENCE, AND POLITICS

Law, science, and politics belong together because they are three attributes of the same reality. Science begins in the accurate knowledge of reality. Since both law and politics seek (or ought to seek) justice, the science of law and the science of politics must always recur to the science of justice itself. This study of justice begins with the substantive question which form of society will best achieve worthwhile and fulfilling lives for all. The science of law concerns the permissions, prohibitions, and obligations that will best establish justice in any given society or State. The science of politics concerns the epistemic techniques through which we can best discover and establish justice and the law. Justice is the substance. Law is the rules. Politics is the procedures for establishing a just State and society for all

Offspring of parents with recurrent depression: which features of parent depression index risk for offspring psychopathology?

Background: Parental depression is associated with an increased risk of psychiatric disorder in offspring, although outcomes vary. At present relatively little is known about how differences in episode timing, severity, and course of recurrentdepression relate to risk in children. The aim of this study was to consider the offspring of parents with recurrentdepression and examine whether a recent episode of parental depressionindexesrisk for offspringpsychopathology over and above these other parental depressionfeatures. &lt;p/&gt;Methods: Three hundred and thirty seven recurrently depressed parents and their offspring (aged 9–17) were interviewed as part of an ongoing study, the ‘Early Prediction of Adolescent Depression Study’. The Child and Adolescent Psychiatric Assessment was used to assess two child outcomes; presence of a DSM-IV psychiatric disorder and number of DSM-IV child-rated depression symptoms. &lt;p/&gt;Results: Children whose parents had experienced a recent episode of depression reported significantly more depression symptoms, and odds of child psychiatric disorder were doubled relative to children whose parents had not experienced a recent episode of depression. Past severity of parental depression was also significantly associated with child depression symptoms. &lt;p/&gt;Limitations: Statistical analyses preclude causal conclusions pertaining to parental depression influences on offspringpsychopathology; several features of parental depression were recalled retrospectively. &lt;p/&gt;Conclusions: This study suggests that particular features of parental depression, specifically past depression severity and presence of a recent episode, may be important indicators of risk for child psychiatric disorder and depressive symptoms

A Feature Analysis Framework for Evaluating Multi-Agent System Development Methodologies

This paper proposes a comprehensive and multi-dimensional feature analysis framework for evaluating and comparing methodologies for developing multi-agent systems (MAS). Developed from a synthesis of various existing evaluation frameworks, the novelty of our framework lies in the high degree of its completeness and the relevance of its evaluation criteria. The paper also presents a pioneering effort in identifying the standard steps and concepts to be supported by a MAS-development process and models

Implementing the Simple Biosphere Model (SiB) in a general circulation model: Methodologies and results

The Simple Biosphere MOdel (SiB) of Sellers et al., (1986) was designed to simulate the interactions between the Earth's land surface and the atmosphere by treating the vegetation explicitly and relistically, thereby incorporating biophysical controls on the exchanges of radiation, momentum, sensible and latent heat between the two systems. The steps taken to implement SiB in a modified version of the National Meteorological Center's spectral GCM are described. The coupled model (SiB-GCM) was used with a conventional hydrological model (Ctl-GCM) to produce summer and winter simulations. The same GCM was used with a conventional hydrological model (Ctl-GCM) to produce comparable 'control' summer and winter variations. It was found that SiB-GCM produced a more realistic partitioning of energy at the land surface than Ctl-GCM. Generally, SiB-GCM produced more sensible heat flux and less latent heat flux over vegetated land than did Ctl-GCM and this resulted in the development of a much deeper daytime planetary boundary and reduced precipitation rates over the continents in SiB-GCM. In the summer simulation, the 200 mb jet stream and the wind speed at 850 mb were slightly weakened in the SiB-GCM relative to the Ctl-GCM results and equivalent analyses from observations

Assessing simulations of daily temperature and precipitation variability with global climate models for present and enhanced greenhouse climates

The enhanced greenhouse climates of five different global climate models are examined with reference to the ability of the models to characterize the frequency of extreme events on both a regional and global scale. Ten years of model output for both control and enhanced greenhouse conditions are utilized to derive return periods for extreme temperature and precipitation events and to characterize the variability of the model climate at both regional and global scales. Under enhanced greenhouse conditions, return periods for extreme precipitation events are shorter and there is a general increase in the intensity of precipitation and number of wet spells in most areas. There is a decrease in frequency of cold temperature extremes and an increase in hot extremes in many areas. The results show a reasonable level of agreement between the models in terms of global scale variability, but the difference between model simulations of precipitation on a regional scale suggests that model derived estimates of variability changes must be carefully justified

Spectrum of Sizes for Perfect Deletion-Correcting Codes

One peculiarity with deletion-correcting codes is that perfect $t$-deletion-correcting codes of the same length over the same alphabet can have different numbers of codewords, because the balls of radius $t$ with respect to the Levenshte\u{\i}n distance may be of different sizes. There is interest, therefore, in determining all possible sizes of a perfect $t$-deletion-correcting code, given the length $n$ and the alphabet size~$q$. In this paper, we determine completely the spectrum of possible sizes for perfect $q$-ary 1-deletion-correcting codes of length three for all $q$, and perfect $q$-ary 2-deletion-correcting codes of length four for almost all $q$, leaving only a small finite number of cases in doubt.Comment: 23 page