## 2 Literature Review  
The method suggested in this research is to minimize the total labor cost of a construction company by deriving a deterministic staff schedule. Human resource is crucial in many operations that are heavily labor-oriented. In addition, it is typically one of the most expensive resources of a company [13; 14]. That means that human resources are regarded as one of the most important factors to manage in every business. [PERSON] [15] conducted the first research on a quantitative approach to a solution for staff scheduling problems. After this study, a variety of research was conducted in many different industries. [PERSON] et al. [16] defined three main staff scheduling parts, namely shift scheduling, days off scheduling, and tour scheduling. Shift scheduling involves scheduling across a daily planning horizon, and one worker has just one shift a day. Days off scheduling is about the schedule of the day off for each worker. Tour scheduling is a combination of shift scheduling and days-off scheduling. Moreover, [PERSON] and [PERSON] [17] revealed that staff scheduling is important to meet demands. In this paper, forecasting models, such as Analysis of Variance (ANOVA) and Auto Regressive Integrated Moving Average (ARIMA) were utilized. The demands derived from forecasting models were used for the mathematical model as input parameters to derive an optimal solution for staff scheduling. Furthermore, [PERSON] and [PERSON] [18] suggested a staffing and shift scheduling approach for nurses in the hospital. In this paper, the mathematical model was suggested for a new integrative nurse staff scheduling while considering the impact of several personnel policies on staffing level decisions to obtain an allocation of nurses. [PERSON] [19] conducted research on staff scheduling by using metaheuristic algorithms to consider the requests of employees. As a result, fair and feasible schedules were generated for staff scheduling. To summarize, various studies have proved that staff scheduling is beneficial for a company with a shifting policy to minimize labor costs. The construction industry is interested in scheduling research to assign employees well. [PERSON] and [PERSON] [20] reported the status of resource-driven scheduling implementation in the Malaysian construction industry. It was revealed that about 60% of construction companies used scheduling to meet the construction project deadline under the limits of resource availability. Even though there are several constraints against using staff scheduling, such as high cost, and lack of understanding for scheduling, the importance of scheduling was proved in that many tried to have scheduling. [PERSON] and [PERSON] [21] focused on a constructive method to solve labor scheduling problems encountered in a construction company. The linear programming technique was used to suggest estimated labor costs for a week and the conditions of part-time labor in each shift. Consequently, the organization could produce a new schedule each week while minimizing labor costs and maximizing labor preferences. Between a diversity of businesses, the hospitality industry is similar to the construction industry in terms of the labor-dependency. [PERSON] et al. [22] performed research on the optimization of staff schedules for a hotel in Turkey. They handled the problem through operation research (OR). As a result, they reduced the labor costs and the number of employees to finish their work during the same period. [PERSON] and [PERSON] [23] studied the optimal allocation of employees to jobs while minimizing total daily labor costs. It proposed a Pareto multistage decision-based genetic algorithm (P-mdGA). As a result, this method helped managers of hotels in need of automatic support to effectively allocate hotel staff to jobs. [PERSON] et al. [24] proved that airline crew assignment to flights can minimize total cost. A particle swarm optimization (PSO) algorithm with a local search heuristic was applied to derive a solution for crew scheduling.