Regular-time labor cost

Regular-time labor cost. Recall that workers are paid a regular-time wage of 640 (S4/hour X 8 hours/day X 20 days/month) per month. Because is the number of workers in Period t, the regular-time labor cost over the planning horizon is given by... 

All protection measures must be checked and monitored at regular intervals to guarantee their effectiveness. To keep the labor cost as low as possible, the time interval between inspections should be as long as possible. This requires that the components of the installation, such as transformer-rectifiers, which can often fail... 

Specially, Nah and Kim (2013) have proposed a mixed-integer nonlinear model to determine the number of staffs and time slot allocation. Their objective function is to minimize the labor cost and penalty cost (both waiting time and abandon rate). However, in their study, a constant time is considered for each outbound calls, which could not represent a real situation where each outbound call has different characteristics, e.g, reminding customers of appointments regular of promotion announcement, keep close relation with special customers (for example, greeting on customer birthday), and respond to special requests or queries (Saltzman and Mehrotra 2007). Therefore, in our study, we will consider the additional constraints of different outbound characteristics as well as the administrative jobs. 

This function includes all information about the operational status and maintenance of equipment, vehicles, and facilities. Operational status refers to an availability state (in active service, ready, standby, in/awaiting maintenance, etc.), along with total time in service, time since last regular maintenance, and so on. The ERP system tracks maintenance schedules for the equipment and actual maintenance incidents, both preventive and remedial, and typically an attention list of things that may need inspection and refit. Any maintenance activities include both technical data (nature of fault, repair or change, parts installed, named services performed, etc.) and administrative data (authorization, execution team, date and time, etc.). In addition, this component tracks the schedules, labor, and work assignments of maintenance teams, external maintenance contracts and calls, and actual or assigned costs of maintenance activities. 

A simple model of this form to illustrate the basic types of issues that crm be modeled is given below. Let the decision variables denote the amount of product i to be produced in period t. We will let I l denote the amount of inventory on hand at the end of period t and S, the amount of backlog at the end of period t. The product j produced in period t is assumed to become available ij periods later, that is, we assume a fixed lead time of Tj for product j. The model will rilso determine the amounts of regular and overtime labor to be used, which will be denoted by LR, and LO, respectively. Costs are also incurred when we increase and decrease our labor force, rmd are proportional to the amount of the increase or decrease. Denoting the amount of labor force increase or decrease in period t by A, and A, respectively, we can then state a basic model as follows. 

---