Smart ports: towards a high performance, increased productivity, and a better environment

ABSTRACT


INTRODUCTION
Maritime logistics services are of great importance in contributing to the increase in international trade, which is for more than 85% transported through sea ports [1]. To accommodate this quantity of goods, it has become necessary to develop these ports to be more efficient and productive. This goal can be reached through the use of smart ports, in which all operations are automated. Smart ports depend in their work on the use of modern information technologies to reach the best level of planning and management both within and among ports, thus easing administrative procedures and enhancing the management of freight traffic [2]. Currently, many researchers are concerned with how to find smart logistics services and propose solutions to achieve them [3].
Many academic or practical research projects have provided new solutions to reduce the complexity of the port operation, an example of these projects is Erasmus smart port in Rotterdam, the Netherlands [4], and the smart port of Hamburg in Germany [5]. The concept of a smart port means the automation of all operations performed by the port, as well as the communication of all port activities through the auto transmission of mobile data in real-time. This leads to doubling the ability of ports to complete and integrate port operations [6]. Therefore, the smart port saves time in documentation and money as a result of reducing This work presents the most important modern technologies that were used as a basis for building the smart port, with mention of the most significant previous works that contributed to the development of each technology. The second section deals with building smart ships, whereas the third section deals with smart bridge cranes and container cranes. In the fourth section, the automation of transport operations in the port is discussed. The fifth section addresses smart containers, followed by the use of modern technologies in the field of energy to raise the efficiency of the port in section six. The seventh and eighth sections shed light on the use of modern communication systems in port operations, and the connection and management of the port through the internet of things (IoT). Finally, the conclusions drawn are stated in section nine.

SMART SHIP
Since ancient times, ports have played a prominent role in the prosperity of cities and thus the economic growth and prosperity of all coastal cities around the world. In Europe, for example, about 74% of goods are imported or exported by ship [9]. During the past two decades, the movement of ships increased, which led to the occurrence of congestion in the sea lanes as a result of the remarkable development of global maritime trade. This caused the number of ships, and eventually the amount of greenhouse gas emissions and environmental pollution, to increase [10]. In order to avoid marine accidents and other undesirable problems such as delays in the process of departure and arrival of ships, there was a need for effective navigation systems that enable communication among ships as well as ports.
Saxon and Stone [11] presented a study which stated that about 48% of ships arrive at least 12 hours later than the scheduled time due to congestion. This leads to more fuel consumption and consequently an increase in cost and pollution. To exemplify, reducing one hour of ship waiting time could save up to $80,000 [12]. The smart management of ships helps minimize the waiting time, the mooring of ships, and helps them to commit to their arrival schedule, by means of selecting the paths and ports, based on their location and the traffic rate. To develop the system monitoring and control of ships, a satellite system of smart sensors and monitoring devices were provided, which increased the amount and reliability of information sent and received to the port. These systems help smart ships to connect to smart ports and organize the berthing process, thus facilitating the loading and unloading process [6], [13].
For ships, the global positioning system (GPS) is an essential tool for navigation in and out of the port area. The importance of real-time data increases during port operations, do as to identify the location and condition of objects for planning and coordinating activities with high efficiency [14], [15]. The retrieved positioning data can be used for prediction (e.g., route prediction, arrival times), as well as being combined with other data sources to achieve contextual data about individual objects and points of interest [16]. Figure 3 represents the process of ships collecting information and exchanging it with other sources through satellites or 3G/4G communication technologies. The ships can communicate with the port and its departments to know the traffic of ships and the docking times. This also enables the port to track goods and identify their status and location [17].  Table 1 draws a comparison between smart ships and traditional ships, where it is noted that smart ships have advantages that help them outperform their traditional counterparts. It is possible to obtain more accurate information about the paths of ships and possible congestion in marine traffic. Through this, it is possible to estimate the time of arrival and delivery for ships, eventually reducing waiting time for ships, as well as the emission of greenhouse gas emissions (GHG) and the carbon footprint resulting from the continuous operation of ships during the waiting period. It can be stated that it mitigates the negative effects on the climate and the environment, and improves the clarity of the air. From the aforementioned points, it can be noted that the use of smart ships allows for more efficient and productive planning of port operations [17]- [19].

SMART GANTRY AND QUAYSIDE CONTAINER CRANES
The increasing demands of customers for low cost and fast shipping have led to the competition of the global economy. To enter that competition, the automatization of the loading/unloading of equipment has the potential to dramatically improve the performance of port operation, as it becomes efficient and high-tech. The most important aspect is ship-to-shore container cranes (STS), which make up the bulk of the investment (70% of total costs in ports). It is used in the cargo loading and unloading system. It is a factor affecting the efficiency of port operations [20].
The control systems in traditional STS cranes depend on placing the load in the required place quickly and safely, which are determined by the personal skill of the workers and can be rather time-consuming. To increase the lifting speed and reduce the time, the cranes need to be fully automated to achieve high productivity. The higher the operating speeds of the lever, the more difficult the control task [20].
In the traditional crane, the crane operator from the top of the cabin looks down to transport containers from one place to another. Over a long period of time through which the work is repeated periodically, it may cause fatigue and exhaustion for the operator. This could eventually lead to accidents in addition to delays in completing work [21]. Two types of cranes frequently used in ports are rail-mounted gantry (RMG) and rubber gantry (RTG). To operate one crane for 24 hours a day, three operators are required to work alternately, implying the need for hundreds of workers as crane operators [22].
To switch from conventional cranes to robotic cranes, advanced sensors are installed on the crane chassis to detect the position of carriages and containers. These sensor systems consist of encoders for reading container data, laser rangefinders, cameras, and programmable logic controllers (PLCs). The PLC collects the location data and compares it to the desired position provided by the yard computer, and in turn directs the crane motors [23], [24]. The automation of cranes contributes to a significant reduction in labor costs, as one operator can operate three to six cranes remotely from the console room via video surveillance. It also helps to ensure operational safety [23]. Table 2 presents the comparison between smart cranes and traditional cranes. It is noted that the use of smart cranes significantly increases the productivity and efficiency of the port, as a result of reducing the cost of labor and speed in carrying out the work, as well as preventing human errors as a result of accuracy in loading and unloading [7], [19].

THE AUTOMATION OF TRANSPORTATION
At the port, the horizontal transportation of containers consists of two separate logistic operations, as outlined below [24]: i) land transport (LS): it is the process of transporting containers from the port gate to the yard and vice versa; ii) waterside transportation (WS): the process of moving containers from ships after unloading by quay cranes (QCs) to the yard and vice versa. The process of road transport is performed by trucks through the main gate of the port to the yard. Since those trucks are non-automated and the truck drivers are off-street labor entering the station driven by outside labor, and not familiar with unmanned cranes, special attention must be paid to ensure the safety at those stations [24]. As for the transport on the waterside, it can be done either by conventional means of transport such as tractors and trailers or by automated platform-type vehicles automated guided vehicles (AGVs). Horizontal transportation on the waterside of the harbor with traditional gantry cranes was done by tractors and trailers. However, the use of conventional transportation appeared to be waning with the use of unmanned cranes due to safety issues while the driver was in the cabin of those vehicles [24]. With the automation of the processes that occur in the smart port, such as storage and cranes inside the port, traditional trucks also ought to be automated and replaced with electronically guided transport platforms. Smart ports prefer the use of AGV to reduce operating costs. However, there are several problems associated with using AGV such as positioning, route planning, obstacle avoidance, and route tracking [25].
The problem of positioning can be solved by using the differential GPS (DGPS) system as a navigation system for unmanned vehicles and systems, especially for AGVs, given that it has robustness and accuracy [26]. It can also be used as a collision warning system. The work in [26] proposed a system to automate entire container transportation operations using unmanned trucks with DGPS and a set of sensors, whereby [26] used optical-based systems, especially laser and radar systems, instead of DGPS systems [13]. Pratama et al. [25] proposed an algorithm for the positioning and obstacle avoidance of AGV using laser measurement systems. As for [27], a new technology is proposed for fusion positioning of ground vehicles that combines a virtual sensor and an electromechanical-based micro-inertial measurement unit. In [28], the distance from the ground to the marked points on the vehicle is measured by using ultrasonic sensors. The path tracking of AGV dumps is done using several technologies including a camera sensor [29], laser navigation system [30], inductive guidance using underground electric wire [31], wall tracking algorithm [32], and semi-guided navigation method using magnetic tapes [33]. From the aspects stated above, it is concluded that transportation automation has many benefits, including reducing labor costs and reducing safety and collision accidents, as well as contributing to improving the environment by reducing gas emissions.

SMART CONTAINERS
To transform traditional containers into smart ones, they need to be equipped with a number of sensors that track containers by collecting data on their geographical location, as well as remote monitoring of events and conditions (such as temperature) for containers throughout their journey. Examples of events that can be noted include whether or not containers have been opened, changes in temperature, emergency situations such as vibrations and falling of fragile goods, and floods and fires that occur during container transport. This technology allows sending immediate alert messages to investors to take the necessary measures [19]. The smart container sends continuous feedback throughout its journey in real-time, helping to plan maintenance or report damage [34]. The smart container technology reduces the berthing time of the ship in the port; thus, it reduces the operating cost by about 10% [12], [35].
At container terminals, DGPS technology has been used. This system extends GPS through the use of fixed reference stations that detect the difference between a known exact location and GPS positioning data [13]. Thus, the exact location of the containers can be determined along with the tracking of container movements within the terminal [36]. There are a number of relevant works found in literature. One of these is the work of [37], wherein RFID seals are used to track commercial container from the point of origin until they reach their destination, thus helping protect goods from damage, theft, and terrorist threats. Figure 4 shows a container with a security seal that reveals any unauthorized attempt to open or tamper with the contents of the container. In study [38], electronic locks, sensors, and alarms are used to send their information by an radio frequency (RF) communication unit to the base station to know the status of the smart container. The GPS unit is linked to determine its location. As for [39], they suggested wireless sensing networks (WSN) technology to obtain the data of the container and then send it over large areas. The work in [40] proposes

1477
WSN as a technique but created a wireless connection that connects containers with a cellular network, i.e., an additional container connection and an in-container connection to communicate from inside to outside the container and vice versa. Table 3 shows the comparison between smart containers and traditional containers. Through smart containers, physical locations can be identified and tracked. Alerts can be created and important information can be sent to the information center. Employees, suppliers, and consumers can also view particular information or get email notifications. Because smart container data is electronically created and end-to-end secured, it is safe and reliable [6], [19]. Table 3. Comparison between smart containers and traditional containers Smart container Traditional container Locate the actual places and keep track of them.
Employees must look for containers Alerts can be set up to shed light on essential information Not possible Allow employees, suppliers, and customers to view specific information or get email notifications.

Not possible
The data is produced electronically and encrypted from end to end, thus it is safe and reliable.
The data can be tampered with because it is generated manually.

ENERGY EFFICIENCY OF SMART PORT
Due to the increasing rise in energy prices, as well as to preserve the climate from environmental changes, many ports seek to enhance energy efficiency by adhering to environmental regulations issued by the authorities for reducing pollutants and greenhouse gas emissions from energy stations [41]. Equipment electrification, alternative fuels, and renewable energy sources, together with operational efficiency, dramatically cut hazardous emissions and constitute the port's future generation [42]. The energy efficiency of a port is proportional to its operational efficiency. The automation of smart port devices and equipment reduces energy consumption and consequently improves energy efficiency [43]. There are a variety of technical solutions that may be used at the port to improve energy efficiency and enhance the environment. Electricity can be used as a source of energy for numerous equipment, electric vehicles, renewable energy, energy storage systems, reefer cooling systems, lighting technologies, and alternative fuels are just a few of these options [41].
While docked, most ships turn off their main engines, and turn on auxiliary engines to supply power for lighting and cooling activities. These engines burn fuel (diesel oil, heavy fuel oil, or liquefied natural gas (LNG)) at idle and emit greenhouse gases. Cold ironing, or the so-called beach card, is the use of electricity supplied through the grid or renewable sources in order to provide the energy required for such activities in ships [44]- [46]. The use of cold ironing in ports has contributed to reducing toxic emissions. On average, 29.3% of carbon dioxide is reduced in port areas [47].
Because direct current may minimize peak demand and average power usage, using direct current (DC) instead of alternating current to operate port cranes is more energy efficient [48]. Energy can also be stored in supercapacitors for later use [49]. Adopting new technologies in improving port lighting instead of traditional lighting (which represents about 3-5% of total energy) improves energy efficiency. The use of light-emitting diode (LED) bulbs instead of high-pressure sodium lamps to light the outlet storage facilities and administration building is an example of this technology [50]. The use of lighting levelling techniques can also save electricity [51].
Renewable energy resources include solar panels, windmills, tidal movement, waves, and underground heat [52]. In [53], it is proposed to cover the surface of the cooling area with solar panels to shade the containers, thus reducing the energy consumption required for cooling, as well as the use of the energy generated from it in operating the port equipment. The Jurong Port in Singapore has generated an annual electrical power of 12 million kWh by using solar panels to cover the warehouse's rooftop, as shown in Figure 5 [54], [55]. Hamburg's Port also covered the roofs of warehouses with solar panels and generated electric power of 500 megawatts per hour annually [56]. As for the latter, it was able to generate 25.4 megawatt using wind energy by installing more than 20 turbines [41]. In the ports of Valencia and Hamburg, the consumption of lighting energy has been reduced by up to 80% through the use of motion-sensitive lights that illuminate when vehicles pass [57]. As can be seen from the above, the smart port makes a substantial contribution to reducing gas emissions and global warming by continuously improving its energy efficiency and incorporating renewable energy into all of its operations. Furthermore, the efficiency of automated port systems and equipment provides for cost savings in energy, and the usage of automated guided vehicles has a substantial environmental impact.

COMMUNICATION SYSTEMS OF SMART PORT
In automated ports, the use of wireless communication systems has become an urgent necessity due to its unique advantages. However, there are some difficult problems faced by these systems during implementation. The biggest challenge is that it is affected by the large metal parts that make up the containers and most of the port equipment. The second challenge is that it is affected by high-energy electrical equipment. Some of these problems can be solved through the development of anti-jamming (antenna) techniques so that the use of wireless communications becomes more widespread [7].

INTERNET OF THINGS IN SMART PORT
According to the IEEE, the internet of things (IoT) is "a combination of sensors and embedded devices linked together to form a network for collecting and sharing data and connected to the internet" [71]. The IoT has been used in most areas of life, including smart farming [72], [73], smart cities [74], healthcare sector [75], smart home, smart river monitoring system [76], smart street lighting [77], and intelligent transport [78]. Some of the primary IoT applications at smart ports include real-time route planning and tracking of smart ships [79], container surveillance [80], transportation applications [81], storage capacity optimization [82], and e-navigation [83].

CONCLUSION
Information and communications technology may be used to boost the performance and operation of smart ports, including smart ships, containers, cranes, AGV, and energy management, which helps increase revenues for the national economy of countries that has seaports. Furthermore, information and communication technology may be used to minimize greenhouse gas emissions in order to soften the atmosphere and make the air purer, which has been a pressing issue in recent years and creates a variety of difficulties such as forest fires, melting ice, and so on. Today, with the use of modern technology, smart ports have become a reality where smart sensor systems improve performance associated with various terminal tasks. The use of wireless network systems in the port station is one of the main factors that contributed to the construction of smart ports, as it was a means of linking between sensors, as well as collecting information and sending it to the data center and vice versa. Various communication solutions currently in use in the automated terminal are mentioned.
Recent technological developments are opening new doors for improvement in performance and efficiency as well as providing a high level of safety and reliability in ports, but they also involve huge demands on the IT/IS core landscape. This work offered a classification of the most recent enabling technologies and information systems used in seaports. Thus, it is important for a better understanding of smart port operations.
Finally, the automation of port equipment and port terminal operations and their transformation into a smart port improves fluidity, reliability, security of information exchange, and real-time decision-making. These approaches also increase the smart port's production and efficiency, lower labor costs, and eventually are of benefit to the environment. As a result, smart technology plays a significant role in port development today and in the future.