On adding over-identifying instrumental variables to simultaneous equations

Reducing the number of over-identifying instruments, or adding them to a structural equation, increases estimation dispersion. Added instruments should be insignificant under correct specification, with parameter estimates nearly unaffected, confirmed by Monte Carlo. Selecting instruments does not affect these results.     

The smartization of metropolitan cities: the case of Paris

International Entrepreneurship and Management Journal - Although the smart city literature is continuously increasing these last decades, there is still a need to better understand what make their...     

Tank failure modes and their consequences

The question of tank failure is addressed for both cryogenic (LFG) and atmospheric (Crude Oil) designs. An analysis of the consequences of an assumed axisymmetric mode of failure of a liquid storage tank is presented in an effort to answer the question.     

A new release of the ASTM CHETAH program for hazard evaluation: Versions for mainframe and personal computer

CHETAH, which stands for the Chemical Thermodynamic and Energy Release Program, was introduced in 1974. Since then, the CHETAH program has been widely used in the chemical industry for hazard evaluation. Although its chief aim is to predict deflagration/detonation potential from molecular structure, it can also be used to estimate heats of reaction, heat capacities, and entropies. One of the limitations of the original program was its rigid, punched card oriented format for data input and the lack of an overall hazard rating derived from the several hazard criteria. A new release of this program alleviates these shortcomings and includes other improvements. The main features of the new release are: 1) a totally interactive front end, 2) an interpreter subroutine which uses sophisticated pattern recognition techniques to combine the four hazard criteria into an overall hazard rating, 3) recognition of certain atomic groupings which are known to be sensitive, 4) correct handling of the symmetry number, and 5) an updated data bank. One of the most important features of this release is its availability in an IBM PC compatible version, making the program accessible to more users.     

AN ARBITRAGE INTERPRETATION OF CLASSICAL OPTIMIZATION

The paper mathematically develops the heuristic idea that the first-order necessary conditions for a classical constrained optimization problem are equivalent to a market being arbitrage-free - with the Lagrange multipliers being the arbitrage-free market prices. The arbitrage notions start with the multiplicative Kirchhoff's Voltage Law and then generalize to matrix algebra. The basic result shows the normalized arbitrage-free «market prices» (the Lagrange multipliers) resulting from a classical constrained optimizaton problem can always be obtained as a ratio of cofactors. The machinery also gives an economic interpretation of Cramer's Rule as a competitive equilibrium condition.