Dynamic weighted idle time heuristic for flowshop scheduling

The constructive heuristic of Nawaz, Enscore and Ham (NEH) has been introduced in 1983 to solve flowshop scheduling. Many researchers have continued to improve the NEH by adding new steps and procedures to the existing algorithm. Thus, this study has developed a new heuristic known as Dynamic Weighted Idle Time (DWIT) method by adding dynamic weight factors for solving the partial solution with purpose to obtain optimal makespan and improve the NEH heuristic. The objective of this study are to develop a DWIT heuristic to solve flowshop scheduling problem and to assess the performance of the new DWIT heuristic against the current best scheduling heuristic, ie the NEH. This research developed a computer programming in Microsoft Excel to measure the flowshop scheduling performance for every change of weight factors. The performance measure is done by using n jobs (n=6,10 and 20) and 4 machines. The weight factors were applied with numerical method within the range of zero to one. Different weight factors and machines idle time were used at different problem sizes. For 6 jobs and 4 machines, only idle time before and in between two jobs were used while for 10 jobs and 20 jobs the consideration of idle time was idle time before, in between two jobs and after completion of the last job. In 6 jobs problem, the result was compared between DWIT against Optimum and NEH against Optimum. While in 10 jobs and 20 jobs problem the result was compared between DWIT against the NEH. Overall result shows that the result on 6 and 10 jobs problem the DWIT heuristic obtained better results than NEH heuristic. However, in 20 jobs problem, the result shows that the NEH was better than DWIT. The result of this study can be used for further research in modifying the weight factors and idle time selections in order to improve the NEH heuristic

THE ALLOWANCE FOR IDLE TIME

Following the identification of an emergency situation, a downtime allowance was introduced in the Republic of Latvia to compensate for the restrictions imposed on employers and the self-employed. Payment of the allowance is intended only for those employees and self-employed persons who have paid social insurance contributions in previous periods, thus small producers, craftsmen, small farms were left without social support, although their activities were severely restricted or banned altogether. It cannot be argued that the payment of the downtime allowance was linked to the payment of the allowance to dependent children, so that in future the allowance for children in emergency situations is not linked to any other type of support. The analysis of the conditions of downtime allowance shows that the criteria for receiving the allowance are very variable, which interferes employers from orienting themselves to the proposed solutions and applying them in a timely manner, moreover, excessive changes are not related to one of the basic principles of good legislation

Aggregate demand, idle time, and unemployment

This paper develops a model of unemployment fluctuations. The model keeps the architecture of the Barro and Grossman [1971] general disequilibrium model but replaces the disequilibrium framework on the labor and product markets by a matching framework. On the product and labor markets, both price and tightness adjust to equalize supply and demand. There is one more variable than equilibrium condition on each market, so we consider various price mechanisms to close the model, from completely flexible to completely rigid. With some price rigidity, aggregate demand influences unemployment through a simple mechanism: higher aggregate demand raises the probability that firms find customers, which reduces idle time for firms’ employees and thus increases labor demand, which in turn reduces unemployment. We use the comparative-statics predictions of the model together with empirical measures of quantities and tightnesses to re-examine the origins of labor market fluctuations. We conclude that (1) price and real wage are not fully flexible because product and labor market tightness fluctuate significantly; (2) fluctuations are mostly caused by labor demand and not labor supply shocks because employment is positively correlated with labor market tightness; and (3) labor demand shocks mostly reflect aggregate demand and not technology shocks because output is positively correlated with product market tightness

Optimal Time Allocation between Idle and Active Time

Idle time is an essential and valuable factor in the production of any service. While idle time is necessary and helpful for efficient and effective utilization of time, it also has a negative effect that managers try to minimize. This paper illustrates either analytically or numerically the different effects of idle time on total net revenue. It first presents the case in which idle time is determined arbitrarily, and then shows idle time that has no direct negative effect on total revenue but a positive effect on the efficient use of active time