An Internet Access Solution: MANET Routing and a Gateway Selection Approach for Disaster Scenarios

After natural and man-made disasters, the telecommunication infrastructure is usually severely damaged, thus hampering communication and rescue services. It is impossible for disaster victims to make use of communication devices such as cellular phones, iPads, or their laptops to make a connection with the outside world (Internet). With infrastructure less and decentralized features, the mobile ad hoc network (MANET) can play an important role in improving communication in post-disaster affected areas. Therefore, the important functionalities of a MANET that allow users to create dynamically configurable wireless networks without fixed infrastructure using common devices such as mobile phones is necessary. This paper reports on the development of new techniques for routing selection and gateway load balancing in MANETs. Network fairness, throughput, and packet delays are measured empirically. The proposed mechanisms can reduce network congestion and consequently improve communication in affected areas.     

Knowledge-Based Simulation for Business Process Redesign

This research focuses on knowledge-based simulation modeling for process redesign. Though the proposed technique can be utilized for ‘starting with a clean slate’, it is particularly well suited for situations where an existing process is already documented, and an attempt is being made to improve or redesign this process. We present a methodology that utilizes the basic process structure (represented in a matrix form), and using a rule-based knowledge acquisition system, interacts with the analyst to construct the process knowledge base. Once all the knowledge has been acquired, the system automatically generates an executable simulation model. Major benefits of this algorithmic approach include (1) reduced model building time, (2) increased analyst productivity, and (3) the assurance that basic process characteristics are not accidentally omitted in the simulation model. To test the validity and applicability of the proposed technique a prototype system has been developed that generates simulation programs in SLAM.© 1997 John Wiley & Sons, Ltd.     

Dealer financial conditions and lender-of-last-resort facilities

We examine the financial conditions of dealers that participated in two of the Federal Reserve's lender-of-last-resort (LOLR) facilities—the Term Securities Lending Facility (TSLF) and the Primary Dealer Credit Facility (PDCF)—that provided liquidity against a range of assets during 2008–2009. Dealers with lower equity returns and greater leverage prior to borrowing from the facilities were more likely to participate in the programs, borrow more, and, in the case of the TSLF, at higher bidding rates. Dealers with less liquid collateral on their balance sheets before the facilities were introduced also tended to borrow more. The results suggest that both financial performance and balance sheet liquidity play a role in LOLR utilization.     

U.S. presidential cycles and the foreign exchange market

We examine the association between the foreign exchange rate of the US dollar and US presidential cycles. Results show that Republican presidencies tend to start with a strong dollar, which then depreciates over the course of the presidency. In contrast, Democratic presidencies tend to begin with a weak dollar that then appreciates. These patterns result in an apparent presidential effect in US foreign exchange rates, the direction of which depends on whether exchange rates are measured by levels or by returns.     

Nowcasting India’s Quarterly GDP Growth: A Factor-Augmented Time-Varying Coefficient Regression Model (FA-TVCRM)

Governments, central banks, private firms and others need high frequency information on the state of the economy for their decision making. However, a key indicator like GDP is only available quarterly and that too with a lag. Hence decision makers use high frequency daily, weekly or monthly information to project GDP growth in a given quarter. This method, known as nowcasting, started out in advanced country central banks using bridge models. Nowcasting is now based on more advanced techniques, mostly dynamic factor models. In this paper we use a novel approach, a Factor Augmented Time Varying Coefficient Regression (FA-TVCR) model, which allows us to extract information from a large number of high frequency indicators and at the same time inherently addresses the issue of frequent structural breaks encountered in Indian GDP growth. One specification of the FA-TVCR model is estimated using 19 variables available for a long period starting in 2007–08:Q1. Another specification estimates the model using a larger set of 28 indicators available for a shorter period starting in 2015–16:Q1. Comparing our model with two alternative models, we find that the FA-TVCR model outperforms a Dynamic Factor Model (DFM) model and a univariate Autoregressive Integrated Moving Average (ARIMA) model in terms of both in-sample and out-of-sample Root Mean Square Error (RMSE). Further, comparing the predictive power of the three models using the Diebold-Mariano test, we find that FA-TVCR model outperforms DFM consistently. In terms of out-of-sample forecast accuracy both the FA-TVCR model and the ARIMA model have the same predictive accuracy under normal conditions. However, the FA-TVCR model outperforms the ARIMA model when applied for nowcasting in periods of major shocks like the Covid–19 shock of 2020–21.

     

Growth dynamics in a model of endogenous time preference

We incorporate endogenous time preference in a simple Diamond-type economy with production and analyze the resulting dynamics both for the competitive and command equilibrium. We assume an individual's rate of time preference is decreasing in consumption (decreasing marginal impatience) and show that this intuitively more appealing assumption is consistent with a stable, non-trivial competitive equilibrium. Analysis of the competitive equilibrium indicates that the observed ‘non-convergence’ of cross-country per capita income could partially be explained by cross-country differences in ‘innate patience’. Examination of the local dynamics around the ‘optimal’ solution suggests that this particular preference structure exhibiting diminishing marginal impatience may generate endogenous business cycle phenomenon.     

Banks,relative performance,and sequential contagion

We develop a multi-period general equilibrium model of bank deposit, credit, and interim inter-bank loan markets in which banks initially specialize in their choices of debtors, leading to under-diversification, but nevertheless become entwined via inter-bank markets, leading to the fortunes of one bank affecting the profits and default rates of the other in a sequential manner. Lack of (full) diversification among credit risks arises in our model owing to a relative profit argument in each banker’s utility function, which is otherwise risk- and default-averse. We examine its implications for the welfare of depositors and debtors. An erratum to this article can be found at     

Modelling safety of gantry crane operations using Petri nets

Being a powerful tool in modelling industrial and service operations, Petri net (PN) has been extremely used in different domains, but its application in safety study is limited. In this study, we model the gantry crane operations used for industrial activities using generalized stochastic PNs. The complete cycle of operations of the gantry crane is split into three parts namely inspection and loading, movement of load, and unloading of load. PN models are developed for all three parts and the whole system as well. The developed PN models have captured the safety issues through reachability tree. The hazardous states are identified and how they ultimately lead to some unwanted accidents is demonstrated. The possibility of falling of load and failure of hook, sling, attachment and hoist rope are identified. Possible suggestions based on the study are presented for redesign of the system. For example, mechanical stoppage of operations in case of loosely connected load, and warning system for use of wrong buttons is tested using modified models.     

The effect of leverage on the tax-cut versus investment-subsidy argument

Two common methods of attracting corporate investment are investment incentives and tax incentives. It is important to use the two incentives in the correct proportions, otherwise the government will give up too much value in the process of attracting investment. This paper examines the effect of tax cut and investment subsidy on the government's net benefit from a project. Earlier studies concluded that it was optimal to use only investment subsidy and no tax cuts. We show that this is not true when debt financing is possible, and it is generally optimal (from the government's perspective) to use a combination of tax reduction and investment subsidy. The optimal tax rate and optimal investment subsidy are identified and analyzed in the paper. It is shown that using a sub-optimal combination of incentives can result in substantial reduction of benefits for the government.