2,754 research outputs found
Design of FIR digital filters for pulse shaping and channel equalization using time-domain optimization
Three algorithms are developed for designing finite impulse response digital filters to be used for pulse shaping and channel equalization. The first is the Minimax algorithm which uses linear programming to design a frequency-sampling filter with a pulse shape that approximates the specification in a minimax sense. Design examples are included which accurately approximate a specified impulse response with a maximum error of 0.03 using only six resonators. The second algorithm is an extension of the Minimax algorithm to design preset equalizers for channels with known impulse responses. Both transversal and frequency-sampling equalizer structures are designed to produce a minimax approximation of a specified channel output waveform. Examples of these designs are compared as to the accuracy of the approximation, the resultant intersymbol interference (ISI), and the required transmitted energy. While the transversal designs are slightly more accurate, the frequency-sampling designs using six resonators have smaller ISI and energy values
Military service and crime: new evidence
BACKGROUND: Evidence indicates that a substantial proportion of military personnel are involved in high-risk and antisocial behaviors that place them at jeopardy for criminal justice system involvement. However, prior research on military service and crime has disproportionately focused on veterans from the Vietnam War era (1955–1975), and has tended to focus on either current or former military members.
METHODS: This study employed data from a population-based study (i.e., National Study on Drug Use and Health [NSDUH] between 2002 and 2014). It systematically examines the prevalence of self-reported antisocial behaviors, criminal justice system involvement, and substance abuse among the US civilian population and military service members, including reservists (n = 2206) and those who reported having been separated or retired from military service (n = 20,551). These factors are further examined across the developmental spectrum of adulthood (ages 18–34, 35–49, and 50–64).
RESULTS: Results showed that military members were more prone to lifetime arrests and overall substance misuse. However, additional findings emerged suggesting that, while the military population overall seems to be positively associated with higher criminal activity than that found in the civilian population, these findings were based on a specific subgroup of the veteran population. This subgroup is comprised of individuals who likely did not fit in with the military culture and were discharged from the military early in their careers.
CONCLUSION: Additional research on identifying this subgroup of military members is encouraged to better concentrate on prevention and treatment measures
Four advances in carbon-carbon materials technology
Carbon-carbon composites are a specialty class of materials having many unique properties making these composites attractive for a variety of demanding engineering applications. Chief among these properties are exceptional retention of mechanical properties at temperatures as high as 4000 F, excellent creep resistance, and low density (1.6 to 1.8 g/cu cm). Although carbon-carbon composites are currently in service in a variety of applications, much development work remains to be accomplished before these materials can be considered to be fully mature, realizing their full potential. Four recent technology advances holding particular promise for overcoming current barriers to the wide-spread commercialization of carbon-carbon composites are described. These advances are: markedly improved interlaminar strengths (more than doubled) of two dimensional composites achieved by whiskerization of the fabric reinforcing plies, simultaneously improved oxidation resistance and mechanical properties achieved by the incorporation of matrix-phase oxidation inhibitors based on carborane chemistry, improved oxidation resistance achieved by compositionally graded oxidation protective coatings, and markedly reduced processing times (hours as opposed to weeks or months) accomplished through a novel process of carbon infiltration and coatings deposition based on the use of liquid-phase precursor materials
Modelling Deformations in Car Crash animation
In this paper, we present a prototype of a deformation engine to efficiently model and render the damaged structure of vehicles in crash scenarios. We introduce a novel system architecture to accelerate the computation, which is traditionally an extremely expensive task. We alter a rigid body simulator to predict trajectories of cars during a collision and formulate a correction procedure to estimate the deformations of the collapsed car structures within the contact area. Non-linear deformations are solved based on the principle of energy conservation. Large plastic deformations resulting from collisions are modelled as a weighted combination of deformation examples of beams which can be produced using classical mechanics
Study of aircraft in intraurban transportation systems, volume 1
An analysis of an effective short range, high density computer transportation system for intraurban systems is presented. The seven county Detroit, Michigan, metropolitan area, was chosen as the scenario for the analysis. The study consisted of an analysis and forecast of the Detroit market through 1985, a parametric analysis of appropriate short haul aircraft concepts and associated ground systems, and a preliminary overall economic analysis of a simplified total system designed to evaluate the candidate vehicles and select the most promising VTOL and STOL aircraft. Data are also included on the impact of advanced technology on the system, the sensitivity of mission performance to changes in aircraft characteristics and system operations, and identification of key problem areas that may be improved by additional research. The approach, logic, and computer models used are adaptable to other intraurban or interurban areas
Notes on the Natural History of Lasiurus borealis in Arkansas
Since June 1982 we have studied various aspects of red bat ecology in Arkansas with emphasis on field work in the Ouachita Mountains and examination of specimens submitted to the Arkansas Department of Health Rabies Laboratory (ADHRL).This study reports on continued field work in the Ouachita Mountains using radiotelemetry and updates information regarding red bats submitted to the ADHRL through December 1996. In addition, we revisited a cave previously reported to contain a large number of red bat skull and skeletal remains. We also report remains from another cave system in northcentral Arkansas. These investigations have yielded additional information on distribution, growth and development of young, litter size, use of atypical roosts, active period and hibernation roost site selection, copulation, and incidence of rabies
Collateral Estoppel
The doctrine of collateral estoppel involves the use of an old judgment in a new action to prevent the relitigation of issues resolved by that old judgment. At common law, use of the doctrine required that the party using collateral estoppel and the party against whom it was used be the same as the parties to the prior judgment. This common law requirement of mutuality has been relaxed and since the United States Supreme Court\u27s 1979 decision in ParklaneHoisery Co. v. Shore, the strict common law requirement of mutuality has all but completely vanished. In Parklane the Court sanctioned the use of collateral estoppel by a plaintiff who was a stranger to the original suit against a defendant who was party to that suit. The courts\u27 search for fair results and judicial economy in the application of the doctrine led to this application of the doctrine in circumstances in which the parties were not mutual. This note traces the un- steady course which the doctrine of collateral estoppel traveled before Parklane. The significance of the Court\u27s decision in Parklane is then analyzed. Finally, post-Parklane applications of collateral estoppel are discussed, including the effect of the use of collateral estoppel on the seventh amendment right to jury trial and its impact on substantive areas of law
Design, analysis and test verification of advanced encapsulation systems, phase 2 program results
Optical, electrical isolation, thermal structural, structural deflection, and thermal tests are reported. The utility of the optical, series capacitance, and structural deflection models was verified
Farm-Processed Soybeans in Swine Rations
New Equipment is available for processing soybeans into feed for pigs. The authors list some of the factors you should consider and results they obtained with feeding whole infrared roasted soybeans
Proposing a Pedigree Risk Measurement Strategy: Capturing the Intergenerational Transmission of Antisocial Behavior in a Nationally Representative Sample of Adults
An impressive literature has revealed that variation in virtually every measurable phenotype is the result of a combination of genetic and environmental influences. Based on these findings, studies that fail to use genetically informed modeling strategies risk model misspecification and biased parameter estimates. Twin- and adoption-based research designs have frequently been used to overcome this limitation. Despite the many advantages of such approaches, many available datasets do not contain samples of twins, siblings or adoptees, making it impossible to utilize these modeling strategies. The current study proposes a measurement strategy for estimating the intergenerational transmission of antisocial behavior (ASB) within a nationally representative sample of singletons using an extended pedigree risk approach that relies on information from first- and second-degree relatives. An evaluation of this approach revealed a pattern of findings that directly aligned with studies examining ASB using more traditional twin- and adoption-based research designs. While the proposed pedigree risk approach is not capable of effectively isolating genetic and environmental influences, this overall alignment in results provides tentative evidence suggesting that the proposed pedigree risk measure effectively captures genetic influences. Future replication studies are necessary as this observation remains preliminary. Whenever possible, more traditional quantitative genetic methodologies should be favored, but the presented strategy remains a viable alternative for more limited samples
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