This paper studies the issue of tax evasion in the context of the underground economy. A dynamic general equilibrium model is built where individual households and entrepreneurs decide rationally whether to go underground and under-report their earnings. These behaviors affect tax revenues, which are used to finance productive public services. This model is applied to the Czech Republic, becaus...

Due to the extremely complex working conditions, various health and safety hazards are present in underground coal mines, which cause economic losses heavy casualties. Among these hazards, methane gas explosion combustion recognized as two major miners. Traditional electronic sensors mine monitoring systems have problems such low precision, a large amount of maintenance, dead zones. In past dec...

underground economy affects important indexes such as formal gdp, unemployment, consumption, production and etc. therefore it is necessary to identify elements and factors which affect underground economy to restrict it. surveys and studies indicate the size of iran’s underground economy is high and taxes, quantity and quality of regulations and performance of formal economy are the important f...

The foundation framework for underground spatial data aims to establish the platform for the underground spatial data sharing and integrating. The reasons lie in that: a) the long-term development of city construction has accumulated abundant underground spatial data and information; b) the development and utilization of city underground space demands for clear, detailed and visualized comprehe...

Mine ventilation provides fresh air to underground workers. The dampers can provide a qualified each demand workplace by adjusting the volume, which ensure workers’ health. However, powerful impact damage caused gas explosions in roadway lead deformation and even cause breakdown of system. At same time, effects may worker fatalities. For this reason, dynamic response their need be studied. Base...

coalbed methane (cbm) plays an important role in coal mining safety and natural gas production. in this work, the cbm potential of b2 seam in parvadeh iv coal deposit, in central iran, was evaluated using a combination of local regression and geostatistical methods. as there were 30 sparse methane sampling points in the parvadeh iv coal deposit, no valid variogram was achieved for the methane c...

background: new technologies using hazardous materials usually have certain risks. it is more serious when the technology is supposed to be applied in a large scale and become widely used by many people. the objective of this paper was to evaluate the risk of vapor cloud explosion in a hydrogen production process. methods: potential hazards were identified using the conventional hazard identifi...

Wireless Underground Sensor Networks (WUSN) constitute one of the promising application areas of the recently developed wireless sensor networking techniques. The main difference between WUSN and the terrestrial wireless sensor networks is the communication medium. The propagation characteristics of electromagnetic (EM) waves in soil and the significant differences between propagation in air pr...

Coalbed methane (CBM) plays an important role in coal mining safety and natural gas production. In this work, The CBM potential of B2 seam in Parvadeh IV coal deposit, in central Iran, was evaluated using a combination of local regression and geostatistical methods. As there were 30 sparse methane sampling points in the Parvadeh IV coal deposit, no valid variogram was achieved for the methane c...