Ridge Estimators for Distributed Lag Models

The paper explains how the Almon polynominal lag specification can be made stochastic in two different ways - one suggested by Shiller and another following the lines of Lindley and Smith. It is shown that both the estimators can be considered as modified ridge estimators. The paper then compares these modified ridge estimators with the ridge estimator suggested by Hoerl and Kennard. It is shown that for the estimation of distributed lag models the ridge estimator suggested by Hoerl and Kennard is not useful but that the modified ridge estimators corresponding to the stochastic versions of the Almon lag are promising. The paper has two empirical illustrations.

Analysis of Qualitative Variables

A variety of qualitative dependent variable models are surveyed with attention focused on the computational aspects of their analysis. The models covered include single equation dichotomous models; single equation polychotomous models with unordered, ordered, and sequential variables; and simultaneous equation models. Care is taken to illucidate the nature of the suggested "full information" and "limited information" approaches to the simultaneous equation models and the formulation of recursive and causal chain models.

In Situ Plant Uptake of Excess Nutrients and Consequential Alteration of Rhizosphere Dynamics

The use of phytoremediation in ecological remediation projects has numerous benefits including soil stabilization and nutrient uptake. Recently, microdialysis, a diffusion-based sampling technique commonly used in biomedical research, has been recognized as a candidate for monitoring chemical changes in the rhizosphere. The real-time, in situ data it provides about nutrient diffusion may improve the management and success of restoration projects. Therefore, the objective of this study was to employ the technique of microdialysis in the novel application of quantifying the diffusive flux of inorganic nitrogen compounds in the rhizosphere of native plants of Arkansas. The microdialysis technique was first optimized for the soil setting, which included flow rate determination and experimentation with soil saturation and the addition of prepared and natural spikes. Switchgrass (Panicum virgatum) and Reed canarygrass (Phalaris arundinacea) plants were planted in soil obtained from Lake Keith and maintained in a greenhouse along with a soil control. Two different watering regimes were established and microdialysis samples were collected six times during a 2-week experiment while watering with nitrate-N-rich (5-6 µg/mL) water acquired from Lake Keith. Samples were analyzed for nitrate-N and ammonium-N fluxes using colorimetric assays. Fluxes of nitrate-N in the Reed canarygrass rhizosphere increased throughout the experiment such that they were different from the Switchgrass treatment by the second sampling day and were different from both Switchgrass and the control during the second week of experimentation. Ammonium-N in all samples was below detection limits. Overall, this study revealed that in situ nitrogen sampling can be accomplished successfully using the microdialysis technique and that Switchgrass is a likely candidate for future phytoremediation applications, as shown by temporal nitrate-N distributions and total nitrogen analysis of above- and belowground biomass

Disequilibrium, Self-Selection and Switching Models

The present paper outlines the similarities in the structure of self-selectivity models and disequilibrium models. Both these models fall under the category of switching models—with sample separation known and sample separation unknown. Curiously enough the econometric models with self-selectivity are all switching models with sample separation known, whereas the econometric models with disequilibrium are mostly formulated as switching models with unknown sample separation. The paper argues that the reasons for this are that not much attention is devoted to the reasons for the existence of disequilibrium and the models are all formulated as "rationing" models. It is suggested that many empirical applications of disequilibrium fall in the category of "trading" models and here the sample separation is known and the reasons for the existence of disequilibrium are also clear

Causalities of the Taiwan Stock Market

Volatility, fitting with first order Landau expansion, stationarity, and causality of the Taiwan stock market (TAIEX) are investigated based on daily records. Instead of consensuses that consider stock market index change as a random time series we propose the market change as a dual time series consists of the index and the corresponding volume. Therefore, causalities between these two time series are investigated.Comment: 8 pages, 15 figure

Methods of Estimation for Models of Markets with Bounded Price Variation

The paper describes methods of estimation for models of markets with controlled prices. Many practical situations involving disequilibrium are due to price ceilings or price floors or both and thus fall.in the category of the models described here. The paper also distinguishes between "rationing models" where the short side of the market prevails, and "trading models" where no trading takes place if there is excess demand or excess supply

Modeling of OpenFlow based software defined networks using Mininet

Software-defined networking (SDN) has become one of the most important architectures for the management of large scale complex networks, which may require re-policing or re-configurations from time to time. By decoupling the control plane from data plane, SDN achieves easy re-policing. Hence, the network switches or routers forward packets simply by following the flow table rules which are set by the control plane. OpenFlow is the most popular SDN protocol or standard and has a set of design specifications. SDN or OpenFlow is a relatively new area, and it has attracted both academia and industry. This research work uses a network emulation tool called ‘Mininet’, for the implementation of SDN using OpenFlow. This tool allows to create the virtual switches, hosts, controllers and links. Using all these components, a network of the desired topology and scale can be created. The focus of this research is to update the labs created for the coursework in Electrical and Computer Engineering department. The tools used in the labs are outdated and are required to be changed, tested and presented. In addition, new labs with new concepts have also been added

Effect of posture on intra ocular pressure: a pilot study

Background:The objective of the present study was to investigate the change in IOP with respect to posture using Schiotz tonometer. IOP values differ in the same individual when measured with the subject sitting or supine and IOP have been reported to be higher with the subject supine than when sitting.Methods:The entire work was accomplished with the 100 male subjects with age ranging between 20 and 40 years. The IOP values were recorded from the individuals using Schiotz tonometer (Improved). The intraocular pressure was recorded in the lying position followed by a rest of 2 minutes in the sitting position.Results:The Mean IOP in supine position in Right & Left eyes was 16.261 ± 2.47 mmHg & 16.14 ± 2.53 mmHg respectively. The Mean IOP in sitting position in right & left eyes was 14.04 ± 2.52 mmHg & 13.88 ± 2.81mmHg respectively. In our study, the mean IOP was decreased by 2.22 mmHg (13.65%) & 2.26 mmHg (14.01%) in right and left eye’s on changing the posture from supine to sitting.Conclusion:From the results of our study, it can be concluded that posture has a definite effect on IOP & the mean IOP was more in supine position than in sitting position