We prove that a pushing-block puzzle called PUSHPUSH-k is PSPACE-complete for any fixed k ≥ 1. In this puzzle, a robot moves on a finite grid. Each grid position is either empty or occupied by a single obstacle block. While moving, the robot may push obstacle blocks in direction of its movement, subject to certain constraints. In particular, once an obstacle block starts moving, it continues to...

PRELIMINARY AND INCOMPLETE: PLEASE DO NOT CITE Big Push models suggest that local product demand can create multiple labor market equilibria: one featuring high wages, formalization, and high demand and one with low wages, informality, and low demand. I demonstrate that minimum wages may coordinate development at the high wage equilibrium. Using data from 1990s Indonesia, where minimum wages in...

The rapid evolution of voice and data technology is significantly changing the business environment. The introduction of services such as instant messaging, integrated voice and email, and follow me services has contributed to a work environment where employees can communicate much more efficiently, thus increasing productivity. To meet the demands of the changing business environment businesse...

This paper reports results from an investigation into the suction caissons failure mechanisms under vertical pull-out loads. An insight to the failure mechanisms of suction caissons paves the path for developing analytical solutions to their pull-out capacity. The numerical models of suction caissons have first been calibrated by and verified against several experimental data from other researc...

This article analyses the push and pull factors that bring visitors to the Iranian national parks. The study used a structured questionnaire to collect data on these factors and the socio-demographic profile of the visitors. Survey conducted in Boujagh National Park, an area of 3177 hectares located in the north of the Iran, produced 400 questionnaires. The factor analysis identified four push ...

there are many techniques for reconstruction after total pharyngolaryngoesophagectomy. the use of a transposed stomach to restore gastrointestinal continuity, and this combined cervical and abdominal approach for pharyngolaryngoesophagectomy and gastric pull up has become one of the most popular. this retrospective study is a review of 50 consecutive iranian patients who underwent pharyngolaryn...

This paper investigates the parametric excitation of a micro-pipe conveying fluid suspended between two symmetric electrodes. Electrostatically actuated micro-pipes may become unstable when the exciting voltage is greater than the pull-in value. It is demonstrated that the parametric excitation of a micro-pipe by periodic (ac) voltages may have a stabilizing effect and permit an increase of the...

The effect of zinc phosphate (ZP) and zinc calcium phosphate (ZCP) coatings on the reinforcing mechanisms of smooth steel fiber in cementitious matrix have been studied. The results of pull out tests illustrated that by coating smooth steel fiber the pull-out load may be increased up to 100%. The effect of zinc phosphate coating on interface bonding was more than zinc-calcium phosphate coating....