Technology in Warehouse Management
Brandon J Willis
The University of Southern Mississippi

Technology in Warehouse Management
Abstract: The purpose of this research is to identify some technologies in the warehouse and how they are used in the everyday warehouse operations. The first section briefly goes over the history of warehousing. The following section describes a Warehouse Management System and its cost. Then the different technologies that are used in the warehouse are explained followed with the benefits of each and the conclusion. 1 Introduction
For centuries there has been a need for warehousing. Most of every product or item that one will acquire will pass through at least one warehouse before it ends up on a store shelf. With the need for warehouses increasing, there comes the need for the technology to run those warehouses to become more efficient. Warehouses have gone from being a small facility to being hundreds of thousands of square feet and can house thousands of different products and items. This is where new advances in Warehouse Management Systems come into play.
There are many picking and storage systems and software available in the market today. This has not always been the case when it comes to warehousing. In order for the efficiency of a warehouse to become better the warehouses have to grow around the new technologies that are being offered. Warehouse efficiency has been the main focus for management in today’s global market and the need to be able to move product through the warehouse as quickly as possible is more important than ever before. The need to increase of the accuracy and productivity of order pulling is greater than ever before and so the need for new technologies is greater than before. In this paper we will discuss the history of warehousing, the Warehouse Management System, the different technologies used in the warehouse, and the benefits that these technologies provide to a warehouse. 2 History of Warehousing A warehouse by today's definition is a structure or room for the storage of merchandise or commodities [11]. Warehouses have been around for hundreds of years. It is believed that the first warehouses are linked to the age of agriculture and began in ancient Egypt [9]. The first warehouses served as granaries and structures to store food. They were crude and not sophisticated at all. As one can imagine, the inventory was not as well kept back then as it is today. But even then, just as we do today the warehouses are strategically placed as to be able to retrieve items as quickly as possible. But of course during the period the ancient Egyptians did not think as these rooms or buildings as a warehouse but more like a storage room. Figure 2.1 show what the ancient Egyptian warehouse may have looked like based on archeological findings.
Figure 2.1 Picture of what an Ancient Egyptian Warehouse may have looked like [25].

Fast forward to when European explorers began shipping and trading between their continent and other countries around the World. Once these trade routes were established and large shipments needed to be shipped then warehouses became a necessity to create facilities to store inventory. These warehouses in those days were mostly in ports because in that time most of the trade was done by ship across bodies of water. These warehouses were still crude compared to the present and all of the records were kept in books. Warehouse management was originally a manual process and inventory records were kept track of with pen and paper, which took a lot of time and often were not accurate [10]. You can see just how tedious record keeping was back in those days, especially in a warehouse that had large volumes of movement. The warehouses during this time didn't move most of the items that we move today, most of the items that were moved were fabrics, grain, alcohol, and livestock.
As the progression of warehousing continues, the railways were born and introduced a whole different way to trade. In order to facilitate the greater amounts of cross country travel, rail warehouses were established. But even with warehouses expanding across the country, record keeping was still done with pen and paper and was still highly inaccurate. As transportation and urbanization continued to grow, so did the needs for more depots to be built. These new depots were built in locations that were easier to access and in areas that are closer to the customers that would be using the products. By this time, warehouses were used to store and move not only what was mentioned before, but more valuable commodities and larger shipments of food a material to meet the demand of the growing economy. Figure 2.2 Railway warehouses in the 1800s [23].

Around the mid 20th century warehousing experienced significant growth. With the surge of mass production and machine operated factories helped contribute to this growth. At this time there were more products available in the market and they needed to be stored and shipped across the country and to other countries around the world. More products mean that there needed to be more storage facilities, and more importantly the need for more efficient, means of storing and retrieving product. In the present warehouses are not really referred to as such anymore, they are being known as a distribution center. The goal is to not store products for long periods of time like it was done in the past, but to receive items and distribute them as quickly and efficiently as possible. At this point in time the warehouse progressed and so did the way records were kept and the warehouse management system was able to advance as well [9]. With technology improving, machines taking over along with heavy equipment in the warehouse, they began to be more efficient and the warehouse management system was highly sought after. Today, companies are beginning to move from a standard warehouse management system, to adopting a supply chain solution which can handle their automation, integration, order management, transportation and distribution and production efficiency [10].
Figure 2.3 example of today's warehouse [29].

Warehouses and distribution centers have become an essential piece of any supply chain, and are constantly being pressured to do more work with fewer resources [8]. The customer in today’s market are not only smarter about the money they spend but also tougher and they expect the get their orders with increasing speed, no mistakes, decreased cost, and a greater selection and customization to their orders. With this in mind managers and to come up with a way to be able to do these things and still be efficient. The labor in the warehouse is generally cheaper than that of manufacturing. Taking this into account managers decided to start tasking smaller manufacturing duties to warehouse associates in order to save the company more money. With all of these factors there was the need to have a system that can handle all of these different attributes in the warehouse. Now that we have briefly went over the history of warehousing, the next section will discuss the warehouse management system and the technologies that go with it that helped increase the efficiency of the warehouse.
3 Warehouse Management Systems
The progression of warehouse management systems is very similar to the progression of other computer programs on the market [12]. Warehouse Management Systems are highly specialized business applications whose primary purpose is to control the flow of inventory, within, and out of a company's Distribution Center or warehouse [18]. A Warehouse Management System is a key component of the supply chain and primarily aims to help make ready the associated purchases, this includes shipping product, receiving product and putting away and picking the product. The Warehouse Management System was initially used to control moving and storing inventory. But in today’s supply chain the role of the Warehouse Management System is changing. The Warehouse Management System is expanding to include light manufacturing, transportation management, order management and complete accounting systems [18]. Since the Warehouse Management System keeps receiving added functionality the primary purpose of the Warehouse Management System is to control how the inventory is moved and stored. Warehouse management systems are large, complicated, data intensive, they are apt to necessitate a large amount of initial setup, a great deal of system resources to operate, and lots of continuing data management to be capable and efficient [12]. Figure 3.1 below illustrates the primary functions that a Warehouse Management System is expected to help perform in today’s supply chain. Figure 3.1 shows the order in which a Warehouse Management System works [24].

There are many claims that are made about utilizing a Warehouse Management System. These claims are that a Warehouse Management System will reduce inventory, that they will reduce labor cost, increase storage capacity, increase customer service, and increase inventory accuracy. In reality the implementation of a Warehouse Management System along with automated data collection will likely give you increases in accuracy, reduction in labor cost ( provided the labor required to maintain the system is less than the labor saved on the warehouse floor), and a greater ability to service the customer by reducing cycle times [12]. However the expectations of inventory reduction and the ability to store more products will be less likely to occur. The setup requirements for a Warehouse Management System can and most likely will be an extensive process. The attributes of each item and the items location must be preserved either at the detail level or by classing similar items and locations into the same class [12]. On the other hand there are many Warehouse Management Systems available in today’s’ market. Each system varies in price and each system operates a different capacity or market. They have systems specifically for retail and some specifically for manufacturing. The initial cost of these systems can vary between $27,000.00 to over $250,000.00 [5]. This cost does not even include the cost of maintaining the system. A Warehouse Management System is a project, not just a typical out of the package software system. It must be tended to and grown with a company. The success of a Warehouse Management System depends on how much work and how dedicated the company is that controls it. Now that we have a good understanding of a Warehouse Management System and how it works, we will now talk about some of the technologies that are deployed in a warehouse in order to make them more efficient on a day to day basis.
4 Warehouse Technologies There are several types of technologies that are used in an everyday warehouse. These different technologies are used to help improve stocking or put-away, picking or pulling and receiving product. Figure 4.1 shows the different areas in which a Warehouse Management System operates in and that technology is used to help make efficient. Within these areas there are several different options a company can choose.
Figure 4.1 illustrates the different task that a modern Warehouse Management System is needed to perform [22].

4.1 Barcodes Since warehousing began, there was a need to be able to quickly and efficiently manage the inventory with-in it. The Barcode has been around for many decades and the first step in bar codes occurred in 1948 from a gentleman by the name of Bernard Silver. Bar code use a series lines marked on a label that is then read by a beam of light by a scanner. These series of lines represent a number sequence that is stored in a Warehouse Management System that contains all of the information on a particular item. Figure 4.2 shows a bar code and decipher the information that each section holds.
Figure 4.2 shows a barcode and decodes each piece of the barcode [15].

The first fully operational bar code scanner was installed in the Spring1969 by computer Identics, but was a highly expensive technology at the time. The need to standardize all products would be the event that would help bar code takes off. A minimum of 85 percent of all products would have to carry bar codes before the system to pay off., and when suppliers reached that level, in the late 1970s, sales of the systems started to take off [14]. In 1978 less than one percent of grocery stores nationwide had scanners, by mid-1981 the figure was 10 percent; three years later it was 33 percent and today more than 60 percent of all stores are equipped [14].
Having bar codes in today’s warehouse helps to reduce cost and increase the control of their operation. There are several benefits to having a bar code system. The first benefit is to be able to decrease clerical cost due to reduced need for manual data-entry functions [2]. There are also fewer errors, thanks to improved inventory tracking and positive verification of activities. It also increase overall inventory accuracy and has the ability to track employee performance that can increase productivity. The last benefit is to improve scheduling of warehouse activities.
There are many bar codes that can be observed in a single warehouse. There are location bar codes that can tell the user where a particular item is supposed to be in a warehouse. The next are floor bar code labels that are found on the warehouse floor. The next one is a pallet bar code label that are placed on the pallets, boxes or crates for the ease of identifying and being able to track inventory as they move from one location to another in the warehouse. The last type of bar code that is used in a warehouse setting is a retro-reflective bar code label. These labels are larger than the standard bar code label so that they can accommodate long-range scanning. These labels are typically mounted on a wall or hung from the warehouse ceiling at heights up to 35 feet [17].
4.2 Bar code Scanners A bar code scanner is referred to as a couple of different names. They are referred to as a bar code reader, price scanner and a point-of-sale (POS) scanner [13]. A bar code reader consists of a scanner, a decoder, and a cable used to connect to a computer. Because a bar code reader merely captures and translates the bar code into numbers and/or letters, the data must be sent to a computer so that a software application can make sense of the data [13]. A bar code reader works by directing a beam of light across the bar code and it measures the amount of light that is reflected back [13]. The scanner then converts the reflected light into electrical energy, the electrical energy is then captured and converted to data by a decoder and forwarded to a computer for processing [13]. There are five basic types of bar code scanners available on the market. These basic types are pen wands, slot scanners, Charge-Couple Device (CCD) scanners, image scanners, and laser scanners.

4.2.1 Pen Wand Scanner
The simplest bar code reader is the pen wand. The pen wand is very durable and one way it can be as durable as it is because it has no moving parts that can be broken. But there is one negative side to having a pen wand. The pen wand must maintain contact with the bar code surface being scanned in order to read the bar code. This isn’t like some of the other systems that will be discussed later. The user must move the scanner across the bar code at a constant speed and certain angle in order for it to be read. These scanners range in price from $20.00 to $200.00 a piece. Figure 4.4 below shows an image of a pen wand.

Figure 4.3 shows an example of a pen wand [28].

4.2.2 Slot Scanner
The next bar code reader is the slot scanner. The slot scanner is a stationary scanner and is securely mounted to a surface. The item's bar code is passed underneath the scanner so that the bar code can be read. These scanners used when identification cards must be scanned. A main application for a slot scanner is for employee identification cards for Government agencies or other companies. These scanners can range from a very basic setup at $75.00 to a high tech touch and color screen scanner that can be as much as $2,000.00. Figure 4.5 shows an example of a basic slot scanner.
Figure 4.4 this is an example of a slot scanner [21].

4.2.3 Charge-Couple Device (CCD) Scanner These readers are similar to the pen wand for the exception that they have a better read-range. These scanners typically have a “gun” type interface and they have to be held no more than one inch from the bar code [13]. These scanners also use a technology that helps them reduce errors. The Charge-couple device will scan the bar code in question a few hundred times and this is what helps to reduce read errors. But these scanners can only read bar codes as large as the scanning face. These scanners are typically used in retail outlets such as Wal-Mart and Winn Dixie. The image below is an example of a “gun” style charge-couple device scanner and these scanners can range in price from $50.00 to $1,000.00.
Figure 4.5 is an example of a Charge-Couple device scanner [26].

4.2.4 Image Scanner An Image scanner is also referred to as a camera reader. An Image scanner uses a camera to capture an image of the bar code. It then uses am installed software that helps to breakdown the bar code and identify the information that the bar code contains. The distance that these scanners can read bar codes is between 3 to 9 inches away on average. The cost of an image scanner is usually lower than a laser scanner but this varies on the sophistication of the laser scanner. Cell phones are beginning to popularize these scanners. Almost every new smart phone contains a bar code scanning application, and if they do not contain one, they are usually free. Having a bar code scanner on a cell phone allows the user to scan any bar code they come across and compare that product to other prices and outlets nationwide. A typical Image scanner can cost between nothing at all if one were to use a cell phone application to upwards of $500.00 for a complete system. Figure 4.7 shows an example of a cell phone that has the image bar code scanner application installed on it. Most of the time this application comes pre-installed on new smart phones.
Figure 4.6 show an example of a cell phone with an image scanner application installed on it [19].

4.2.5 Laser Scanner A laser scanner is kind of universal in that it can be wither hand held or mounted to a surface. Laser scanners have a much farther reading distance than any other scanner available on the market, but typically are used for instances of less than a foot away. The laser scanner uses a system of mirrors and lenses to allow the scanner to read the bar code regardless of orientation, and can easily read a bar code up to 24 inches away [13]. To reduce the possibility of errors, a laser scanner, may perform up to 500 scans per second [13]. There are also long range laser scanners available that can read a bar code up to 30 feet away. Laser scanners are the most efficient bar code scanner available. These are also available both wired and wireless. The costs of these are in line with all of the other bar code scanners ranging from $100.00 to $1,000.00 with the most common systems costing around $200.00. Figure 4.8 show what a laser scanner may look like. Figure 4.7 is an example of a wireless laser barcode scanner [20].

4.3 Automated Technologies Automation is another big breakthrough in warehousing technology. It allows for the movement and storage of goods automatically with little to no human interaction. Properly carried out, a warehouse automation project can be a home run that drives a company towards increased profitability. But on the other hand if an automation project is thought out poorly then it can and will cause a company to go out of business. These systems are complex and expensive to buy and operate. An automated warehouse allows distributors to service their customers more effectively. 4.3.1 Automated Storage and Retrieval Systems (AS/RS)
AS/RS technology can be broken into two broad categories. These two categories are pallet handling (unit load) systems and tote handling (mini-load) systems. The world's most advanced logistics operations are characterized by automated, direct put-away to storage systems [6]. These automated systems rely on the Warehouse Management System in order to operate well. When a shipment arrives, either a conveyor is put inside of a truck and boxes are physically set on the conveyor or the pallets are slid off of the truck on rollers inside of the warehouse. For either method, the boxes are scanned and carried off automatically to where the Warehouse Management System wants the packages or pallets to be stored in order to increase efficiency for that particular item. In pallet handling systems, a storage and retrieval mechanism transports full pallets into and out of a pallet racking system. In the tote handling systems, the AS/RS can usually bring a single tote or case of product to a forward pick area and can be used for both replenishment and primary picking. The initial cost of purchasing an automated storage and retrieval system can be somewhere around $200,000.00 [6].
Figure 4.8 is an example of Automated Storage and Retrieval Systems (AS/RS) [30].

Also available are automated guided vehicles. Automated guided vehicles offer multiple benefits for beverage facilities, including reduction in labor and operating cost through more cost effective product handling, increased productivity and better quality assurance [3]. In 2012 automated guided vehicles accounted for 75 percent of all automated guided vehicle systems and distribution center operations accounted for the remaining 25 percent [3].
4.3.2 Voice Directed Picking Voice-directed picking was widely introduced in distribution center environments in the 1990’s and now is used heavily in certain industries such as grocery distribution [1]. Voice directed warehouse applications are proven to improve distribution efficiency in all types of industries ranging from grocery and food service distribution to apparel and industrial supply [31]. A typical voice application combines a voice-directed workflow with a system that provides audio prompts to the user directing them to what to do. The system also has speech recognition technology that understands a user’s spoken response. The voice directed system is a type that is better suited in those warehouses where workers benefit from still being able to use both of their hands to perform their task and not have to take their eyes off of their work [1]. Image 4.9 below shows an example of how much more productive a worker can be by being able to constantly use both of their hands and not having to pick up a clipboard after every pick. The voice applications will seamlessly integrate with warehouse management systems and help to drive new levels of associate productivity and accuracy across picking and other warehouse task. With being able to integrate a voice directed system with an existing Warehouse Management system, the cost of these systems are relatively low compared to light to pick or automated systems.
Figure 4.9 this image show an example of voice directed picking [32]. 4.3.3 Pick-to-Light Systems Pick-to-light technology has been widely used for order fulfillment since the early 1980’s. Around 15 years ago pick to light systems were beginning to gain wider acceptance and a common application might include around 20,000 light modules and could only be afforded by fortune 100 companies [15]. Because the pick-to-light system is a visual system it delivers more efficient and more productive picking than voice does. This system is most widely used in high-speed pick operations with a very high SKU density in the forward pick area and it also has application in full case pick, pallet pick, and put away situations. Most light modules in today’s systems come in two different colors. These colors are usually red or green to direct the user to SKUs stored in locations either above or below the unit. Optical sensors are also available to install on lift trucks. These systems help to increase picking accuracy to almost 100 percent [16].

Figure 4.10 is what a typical pick to light system will look like in the warehouse [33].

5 Benefits to Warehouse All of these technologies offer different benefits to a warehouse and each one has its own pros and cons along with the ideal settings that they should be used in. The bar code turned the warehousing industry around. With this technology, items became easier to keep track of and were able to be received and shipped faster than ever before. Being able to scan a code and retrieve all of the information for an item was a breakthrough in warehouse technology. The different scanners that are available on the market today vary for the type of use that they are intended for. The warehouse should do a thorough breakdown of operations to decide when or if they need bar code technology in their warehouses. Bar codes are proven to reduce clerical cost and to help increase efficiency.
The Automated storage and retrieval system (ASRS) has a hefty up-front cost, but this system is shown to correlate well to reduce labor cost and improve on-time and complete orders. The AS/RS also serves as application as a buffering tool to stage and sequence product before shipment. Because the AS/RS has such a large storage capacity, it can help a company remain in their existing space rather than make an even more expensive move to a new facility. To sum it all up the ASRS can greatly improve efficiency in an existing facility that is planning on expanding. This system is cheaper than purchasing a new facility and should be one of the first systems to look at when it comes to expanding.
The pick-to-light system was the only electronic technology that strongly correlated to success in all three best in class areas [1]. The pick-to-light system has shown to reduce labor costs by boosting the lines-picked-per hour per worker. This technology can improve on-time and complete shipments by increasing overall system throughput. The accuracy of order picking is also improved. This is accomplished because the workers do not have to take their eyes off of their work to look down at written instructions or to try to decipher where an item is in a warehouse.
Voice-directed picking is another system that very strongly helps to improve accuracy for some of the same reasons as the previous systems. The worker constantly maintains eye contact with the task at hand and does not need to keep looking down at a clipboard. The worker can also operate hands free, since all they need to do is listen they can move faster through the picking process. This of course helps with productivity and helps keep the cost of picking lower.
5 Conclusions
In conclusion we have discussed the history and purpose of a warehouse, The Warehouse Management System, the technologies involved in today’s warehouse and the benefits of these technologies. From reading this paper one can see the evolution that the warehouse has went through over the last few hundred years and can realize the importance of an efficient warehouse. The systems in today’s warehouse have grown more complex over the last hundred years and going to be even more complex over the next hundred years. With the invention of the computer and the internet warehouse improvement will be more integrated between companies than ever before and the need for a good, reliable warehouse management system is in high demand.
All warehouse systems are designed to lower the cost of warehouse operations. But each system has an initial cost and support cost that goes with it. The main thing that a company must do in order to improve their warehouse the most is to complete an analysis and go over the pros and cons of each system. This way they can agree on a decision on a system or systems that will benefit their company the most and bring savings to the company year after year with minimal cost. But one thing to remember when choosing a system is that the cheapest system is not always the best system to choose. This is why an analysis is so important to undertake before a decision is made. If a company must, they can hire an external company to perform the analysis for them so they will have a complete bias decision made and a report presented in front of them that can help them choose the right system for them. In today’s market, if they wish to compete they must be able to perform efficiently in the warehouse. The customers of today are all about the speed in which they get the product they order.

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