3,263 research outputs found

    Validation and Verification of Aircraft Control Software for Control Improvement

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    Validation and Verification are important processes used to ensure software safety and reliability. The Cooper-Harper Aircraft Handling Qualities Rating is one of the techniques developed and used by NASA researchers to verify and validate control systems for aircrafts. Using the Validation and Verification result of controller software to improve controller\u27s performance will be one of the main objectives of this process. Real user feedback will be used to tune PI controller in order for it to perform better. The Cooper-Harper Aircraft Handling Qualities Rating can be used to justify the performance of the improved system

    Nominal Rigidities and The Real Effects of Monetary Policy in a Structural VAR Model

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    The paper proposes an empirical VAR for the UK open economy in order to measure the effects of monetary policy shocks from 1981 to 2003. The identification of the VAR structure is based on short-run restrictions that are consistent with the general implications of a New Keynesian model. The identification scheme used in the paper is successful in identifying monetary policy shocks and solving the puzzles and anomalies regarding the effects of monetary policy shocks. The estimated dynamic impulse responses and the forecast error variance decompositions show a consistency with the New Keynesian approach and other available theories.Structural VAR; Nominal Rigidities; Monetary Policy Shocks; New Keynesian Theory

    Changes of benthic macroinvertebrates in Thi Vai River and Cai Mep Estuaries under polluted conditions with industrial wastewater

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    The pollution on the Thi Vai River has been spreading out rapidly over the two lasted decades caused by the wastewater from the industrial parks in the left bank of Thi Vai River and Cai Mep Estuaries. The evaluation of the benthic macroinvertebrate changes was very necessary to identify the consequences of the industrial wastewater on water quality and aquatic ecosystem of Thi Vai River and Cai Mep Estuaries. In this study, the variables of benthic macroinvertebrates and water quality were investigated in Thi Vai River and Cai Mep Estuaries, Southern Vietnam. The monitoring data of benthic macroinvertebrates and water quality parameters covered the period from 1989 to 2015 at 6 sampling sites in Thi Vai River and Cai Mep Estuaries. The basic water quality parameters were also tested including pH, dissolved oxygen (DO), total nitrogen, and total phosphorus. The biodiversity indices of benthic macroinvertebrates were applied for water quality assessment. The results showed that pH ranged from 6.4 – 7.6 during the monitoring. The DO concentrations were in between 0.20 – 6.70 mg/L. The concentrations of total nitrogen and total phosphorous ranged from 0.03 – 5.70 mg/L 0.024 – 1.380 mg/L respectively. Macroinvertebrate community in the study area consisted of 36 species of polychaeta, gastropoda, bivalvia, and crustacea, of which, species of polychaeta were dominant in species number. The benthic macroinvertebartes density ranged from 0 – 2.746 individuals/m2 with the main dominant species of Neanthes caudata, Prionospio malmgreni, Paraprionospio pinnata, Trichochaeta carica, Maldane sarsi, Capitella capitata, Terebellides stroemi, Euditylia polymorpha, Grandidierella lignorum, Apseudes vietnamensis. The biodiversity index values during the monitoring characterized for aquatic environmental conditions of mesotrophic to polytrophic. Besides, species richness positively correlated with DO, total nitrogen, and total phosphorus. The results confirmed the advantage of using benthic macroinvertebrates and their indices for water quality assessment

    Latin cubes of even order with forbidden entries

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    We consider the problem of constructing Latin cubes subject to the condition that some symbols may not appear in certain cells. We prove that there is a constant γ>0\gamma > 0 such that if n=2tn=2t and AA is a 33-dimensional n×n×nn\times n\times n array where every cell contains at most γn\gamma n symbols, and every symbol occurs at most γn\gamma n times in every line of AA, then AA is {\em avoidable}; that is, there is a Latin cube LL of order nn such that for every 1i,j,kn1\leq i,j,k\leq n, the symbol in position (i,j,k)(i,j,k) of LL does not appear in the corresponding cell of AA.Comment: arXiv admin note: substantial text overlap with arXiv:1809.0239

    Influence of water temperature and salinity on pH during dry season in lower Dong Nai river system, Vietnam

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    This paper uses the gvSIG 2.2.0 software, IDW interpolation method, river and stream network data, and 36 sampling sites to build the maps of three monitored parameters such as pH, water temperature, and salinity in the Lower Dong Nai River system (2009–2010) in dry season. Based on an analysis of these maps and statistical assessment by using the R software, the correlations between pH, temperature, and salinity are clarified. The results show that the pH and temperature values have a tendency to decrease, whereas the salinity tends to increase annually. The pH value has good and significant correlations with the water temperature and salinity in both simple and multiple linear regression models. The results aim to provide a scientific reference for further research on the water environment in this area
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