# Production Improvement Rate with Time Series Data on Standard Time at Manufacturing Sites
## 2 Related Work  
### Aps  
Smart manufacturing is at the heart of the Industry 4.0 concept, and production planning and control (PPC) must play a key role in Industry 4.0 activities [9]. The goal of production planning and control (PPC) activities in manufacturing companies is to define what, how much, and when to produce, purchase, and deliver in order to meet customer demands [10]. PPC activities operate as a process that generates value in operational and strategic environments, adapting continuously to complex customer requirements and new supply chain opportunities [11; 12]. The rapid changes in the industrial environment emphasize the evolution of PPC functions [13; 14]. PPC activities include tasks, such as material requirement planning (MRP), enterprise resource planning (ERP), just-in-time manufacturing, collaborative planning, forecasting, and replenishment [15; 16]. With the advancements in information and communication technology (ICT), PPC functions also support planning and control of key aspects of production in the area known as supply chain management (SCM). This includes activities, such as demand forecasting, sales and operations planning (S&OP), MRP, master production scheduling (MPS), and production scheduling [17]. The systems used in this SCM area are sometimes referred to as APS systems.  
Industrial engineering encompasses a range of mathematical and logical techniques that find application in a company's production operations. When these methods are implemented as software systems, they are referred to as production operation systems. Global software developers play a significant role in creating these information systems. One particular category of production operation systems is based on MRP techniques, a field of study dating back to the 1980s. These systems gained widespread use in traditional manufacturing industries in the 1990s. After their success in these industries, they were further developed and actively applied in areas such as SCM, which experienced high demand from the 2000s onward, and in the production operation of the FAB industry. These systems are notable for employing various temporal models and computational engines driven by heuristic algorithms. The associated research behind this technology has found its place in both academic and industrial circles. Numerous software development, solutions, and consulting companies have integrated it into comprehensive SCM solutions, often referred to as APS systems [18], as depicted in Figure 1.  
An APS is a production planning system that executes automated production planning and related labor and resource planning with the following core functions [19; 20].  
* Demand forecasting: Forecasts short- and long-term demand and uses it to manage volatility and targets.  
Figure 1: APS system organization and production operations area.  
* Production planning: APS systems create plans aimed at minimizing inventory and production costs. They achieve this by optimizing the use of facilities and labor, creating efficient production schedules and executing them effectively.
* Resource planning: These systems help in planning for the optimal utilization of production resources, including equipment and labor.
* Materials planning: APS systems facilitate the planning and procurement of raw materials and components. This minimizes production inventory and ensures the timely delivery of products.  
Companies use this technology to achieve efficient production, minimize inventory and costs, increase productivity, and improve customer service.