A phenological study of springtime events was made over a 61-year period at one site in southern Wisconsin. The records over this long period show that several phenological events have been increasing in earliness; we discuss evidence indicating that these changes reflect climate change. The mean of regressions for the 55 phenophases studied was -0.12 day per year, an overall increase in phenol...

In this paper, we present a genetic algorithm approach that considers the single machine scheduling problem. There are n jobs, in which each job j ( 1 2 j n = , ,..., ) has a normal processing time j p , a due date j d , earliness penalty j α , and tardiness penalty j β . The objective is to find the sequence of jobs that minimizes the weighted sum of earliness and tardiness penalty costs, with...

The objective of this paper is to propose a scheduling problem for multiple automated guided vehicles (AGVs) in a manufacturing system. Considering the due date of AGVs requiring for material handling among shops in a job shop layout, their earliness and tardiness are significant in satisfying the expected cycle time and from an economic view point. Earliness results in AGVs waiting and tardine...

The objective of this study was to select genitors based on F1 and F2 generations, evaluated in different environments, to obtain segregating populations for the identification of strains showing improved earliness, yield, and carioca-type grains. Nine bean strains were crossed in a partial diallel scheme (4 x 5), in which group 1 included 4 strains with early cycles and group 2 included 5 elit...

We study problems of scheduling n unit-time jobs on m identical parallel machines, in which a common due window has to be assigned to all jobs. If a job is completed within the due window, then no scheduling cost incurs. Otherwise, a job-dependent earliness or tardiness cost incurs. The job completion times, the due window location and the size are integer valued decision variables. The objecti...

This paper describes a constraint programming approach to solving a scheduling problem with earliness and tardiness cost using a problem specific search procedure. The presented algorithm is tested on a set of randomly generated instances of the job shop scheduling problem with earliness and tardiness costs. The experiments are executed also for three other algorithms, and the results are then ...

This study considers the job scheduling problem of minimizing the Weighted Waiting Time Variance (WWTV) of jobs. It is an extension of WTV minimization problems in which we schedule a batch of n jobs, for servicing on a single resource, in such a way that the variance of their waiting times is minimized. WWTV minimization finds its applications for job scheduling in manufacturing systems with e...

This paper presents two new multiple-time grid, continuous-time mixed integer linear program (MILP) models for the short-term scheduling of multistage, multiproduct plants featuring equipment units with sequence dependent changeovers. Their main difference results from the explicit consideration of changeover tasks as model variables rather than implicitly through model constraints. The former ...