The Maximum Traveling Salesman Problem with Submodular Rewards

In this paper, we look at the problem of finding the tour of maximum reward on an undirected graph where the reward is a submodular function, that has a curvature of $\kappa$, of the edges in the tour. This problem is known to be NP-hard. We analyze two simple algorithms for finding an approximate solution. Both algorithms require $O(|V|^3)$ oracle calls to the submodular function. The approximation factors are shown to be $\frac{1}{2+\kappa}$ and $\max\set{\frac{2}{3(2+\kappa)},2/3(1-\kappa)}$, respectively; so the second method has better bounds for low values of $\kappa$. We also look at how these algorithms perform for a directed graph and investigate a method to consider edge costs in addition to rewards. The problem has direct applications in monitoring an environment using autonomous mobile sensors where the sensing reward depends on the path taken. We provide simulation results to empirically evaluate the performance of the algorithms.Comment: Extended version of ACC 2013 submission (including p-system greedy bound with curvature

Effects of Terms of Trade and its Volatility on Economic Growth: A Cross Country Empirical Investigation

This study examines the effects of terms of trade and its volatility on economic growth for a sample of 94 developed and developing countries, using five year average annual data from 2004 to 2008. The cross country ordinary least square estimation results indicate significant positive effect of terms of trade on economic growth. Furthermore, volatility of terms of trade has significant positive effect on economic growth. To test the robustness of initial results, sensitivity analysis has been performed using different additional variables, sample size and various proxies of volatility variable. The initial results were found robust despite the inclusion of various variables in the basic model and use of various proxies for volatility of terms of trade.Terms of trade, Volatility, Economic Growth

The Economics of Outsourcing in a De-integrating Industry

Many large firms in low scale economy industries are actively considering outsourcing options, in the face of competition from smaller more efficient players. Based on a review of the theoretical literature and a case-study of outsourcing decisions at two large vertically integrated footwear manufacturers in Pakistan, a framework is developed for determining which set of products and activities to outsource and which to keep in-house. The framework suggests activities being considered for outsourcing be evaluated in terms of level of proprietary knowledge, economies of scale, inefficiencies of vertical integration, transactional costs, and the existence of reliable vendors. It is suggested that activities with low levels of proprietary knowledge and activities where cost savings due to outsourcing justify the increased transaction costs, should be outsourced.footwear, Outsourcing, Pakistan, case-study

Haematological causes of thrombocytopenia in children at Aga Khan University Hospital, Karachi

Objective: To identify the haematological causes of thrombocytopenia in children admitted at a tertiary care hospital.Methods: The prospective, descriptive study was carried out at the Aga Khan University Hospital, Karachi, from September 3, 2009 to March 3, 2010, and comprised children between one month and 14 years of age with platelet count less than15000. After reviewing the record, a questionnaire was filled and data was analysed using SPSS 15.Results: Out of 108 patients in the study, 69(64%) were male and 39(36%) were female. The overall mean age was 69±46.54 months (range: 12-168 months). The mean platelet count was 59.8±46.1/l (range: 1,000-149,000/l). Besides, 24 (22.2%) children had mild thrombocytopenia, 34(31.5%) had moderate and 50(46.3 %) had severe thrombocytopenia. The causes of haematological thrombocytopenia in descending order of frequency was acute lymphoblastic leukaemia 17(15.7%), idiopathic thrombocytopenic purpura 10(8.3%) and aplastic anaemia 5(4.6%).Conclusion: Acute lymphoblastic leukaemia was the commonest cause of haematological thrombocytopenia followed by idiopathic thrombocytopenic purpura and aplastic anaemia

Monetary-fiscal-trade policy and economic growth in Pakistan: time series empirical investigation

This study empirically examines the effect of monetary, fiscal and trade policy on economic growth in Pakistan using annual time series data from 1981 to 2009. Money supply, government expenditure and trade openness are used as proxies of monetary, fiscal and trade policy respectively. Cointegration and error correction model indicate the existence of positive significant long run and short run relationship of monetary and fiscal policy with economic growth. Result also indicates that monetary policy is more effective than fiscal policy in Pakistan. In contrast, trade policy has insignificant effect on economic growth both in the short run and in the long run. In light of the findings, it is suggested that the policy makers should focus more on monetary policy in order to ensure economic growth in the country. It is also recommended that further research should be conducted to find out such components of exports and imports which lead to the ineffectiveness of trade policy to enhance economic growth in Pakistan.Monetary, Fiscal, Trade, Economic Growth

A Parser Generator Based on Earley\u27s Algorithm

Most parser generators are programs that take a context-free grammar specification for a language and generate a parser for that language. Usually, the parsers generated by these parser generators are based on some variations of LL(k) or LR(k) parsing algorithms. The parser generators discussed in this paper creates parsers based on Earlcy\u27s Algorithm. This parser generator creates parsers from any arbitrary context-free grammar specifications; even from ambiguous, cyclic, and unbounded look ahead grammar. These parsers are more powerful than LL(k) and LR(k) parsers and enable the user to create many new applications

UPPER GREAT LAKES TRANSPORTATION IMPACT FORECASTING SYSTEM

Community/Rural/Urban Development,