## 2 Synchronization Issues with Various Part-to-Picker Systems and a Literature Review
### Synchronization Problems in Warehouses
[PERSON], [PERSON], and [PERSON] simulated the consolidation and packing process using a put wall for manual order consolidation. It helped to reach the goal of optimizing bin release sequences and minimizing order completion durations [32]. Their objective in another study in 2018 was to evaluate a simple optimization issue to reduce the dispersion of orders in the release sequence. And this allowed for the selection of orders to be quickly assembled at packing stations [33]. To reduce order spread and evaluate the effects of various layout options, it takes into account the minimum  
Figure 3: An illustration of a selection procedure based on order and rack arrangement [30]. Figure 2: The movable robot system for shifting racks [30]. order spread sequencing problem. Future research should compare the configuration of the consolidation process with other configurations. The online merchant examines and separates all received products before storing them independently in a chaotic, shared storage strategy, as shown in Figure 5. Items are distributed randomly on the shelves of the picking area in a mezzanine system. [PERSON] et al. presented various control strategies in 2019 that reduced positioning error in small-scale conveying systems. Vision-based feedback was the proposed method for controlling the right material flow on the conveyor [34]. Traditional conveyor technology is not suitable for future production and logistics systems due to its rigidity, inflexibility, less maintenance-friendliness, and cost. By examining camera depth images, the position and orientation of the objects were estimated in this paper's closed-loop control system. The object's linear and angular velocities will be selected by the controller based on the user's trajectory. The initial results are encouraging and suggest the potential of a camera-based feedback system for highly adaptable and modular conveyor systems. New categories of robotic and automated handling systems were evaluated by [PERSON] et al, including robotic mobile fulfillment systems, shuttle-based storage and retrieval systems, and compact storage systems [8]. It concluded that new models and techniques are required to address the design and operational control challenges of such systems. And new  
Figure 4: Scheme of arrangement for the pretend warehouse [30]. Figure 5: A visual representation of the warehouse industry [33]. robotized warehouses will necessitate a review of warehouse design, planning, and control logic. Additionally, it covered the benefits of automation, including space and labor cost savings, availability around the clock, and cost savings on other operational expenses. Lastly, it focused on cutting-edge technologies like sustainable warehouses, integrated systems, automated replenishment and sequencing, and human-machine interaction. [PERSON] et al. examined the scientific literature on warehouse operations that met the needs of store-based retail chains in their study in 2021. Additionally, they identified the most efficient warehousing solutions for physical stores [35]. The fundamental requirements for warehouses are outlined in this document. The key decision making issues in setting up and running a unique warehousing system are clarified by checking the agreement of those requirements. Furthermore, it examined the previous literature. Pick-and-pass systems for large orders, crane-supplied pick faces, bulk picking and store consolidation, put systems, pick-to-parts, systems, and vehicle support are just a few of the topics covered. When handling high-volume-low-mix store orders and low-volume-high-mix online orders simultaneously, integrated warehouses are used to pool inventory and bundle transport. They can result in a loss of picking efficiency. Other options include establishing additional channel-specific distribution facilities, contracting with outside logistics companies, or implementing multiple parallel warehousing systems in a single distribution facility.