Pursuing the goal of effective Maritime Law Enforcement (MLE) requires coastal nations to establish suitable monitoring procedures aimed at vessels within their jurisdictions. These pro- cedures are underpinned by a so-called response selection process, where, following the detection and evaluation of potentially threatening events involving vessels of interest (VOIs) at sea, MLE resources, such as high-speed interception boats, military vessels, helicopters, and/or seaplanes, are dispatched by coast guards and related authorities to intercept and investigate these threats. MLE resources are generally either allocated for the purpose of intercepting VOIs at sea (such resources are said to be in an active state), or are strategically allocated to certain patrol circuits or bases until needed for future law enforcement purposes (such resources are said to be in an idle state). Additionally, MLE resources may temporally be unavailable for law enforcement operations over certain periods of time due to routine maintenance, infrastructure damage, un- availability of crew or depleted autonomy prerequisites. MLE resources which are both idle and assigned to a patrol circuit are said to be on stand-by. In this dissertation, the MLE re- sponse selection operations considered focus almost exclusively on the management of active MLE resources.
Shortages of law enforcement infrastructure, large jurisdiction coverage areas, high operating costs of MLE resources, the requirement of using complex threat detection and evaluation sys- tems, scarce maritime intelligence and a lack of adequately trained operators are examples of factors contributing to the difficulty of effective MLE by coastal nations, inevitably affecting their overall ability to achieve effective counter-threat performance at sea. A simplified hypo- thetical MLE scenario, depicting the kind of visual information that an MLE response selection operator may be observing on a human-computer interface in order to assist him in making MLE response selection decisions, is portrayed in Figure 1.2.
Active MLE Resources Idle MLE Resources VOIs Bases Patrol Circuits MLE Boundaries Land Sea
Figure 1.2: Top view of a hypothetical MLE environment.
MLE operations often comprise complex tasks, typically involving a number of explicitly or implicitly identified subtasks, each with specific resource capability requirements that need to be matched with the capabilities of available MLE resources in order to ensure successful VOI interception [54]. These tasks are stochastically distributed in both time and space, making the
1.2. Informal problem description 5
coordination of these MLE resources, which operate in a harsh and unpredictable environment, a very challenging problem. Additionally, the ability to adapt dynamically to changes in the availability of MLE resources and the services they provide is critical for the success of MLE efforts.
The assignment of MLE resources to intercept VOIs requires the formation of so-called visitation routes. These are ordered sets containing specific subsets of VOIs that are scheduled to be intercepted and investigated by specific MLE resources over the course of a certain time horizon. This concept is known in the literature as vehicle routing. Initial MLE resource deployment is, however, typically carried without full information in respect of the current and future maritime situation. Ancillary information is expected to be gathered from external sources on a continual basis and contribute to the evolution of VOI threat assessment, providing operators with access to actionable information. In order to achieve MLE efficiency, it is therefore required that these decisions be made and coordinated in such a way as to enable the rapid and semi-autonomous re-deployment of MLE resources at various points in time as the sea picture unfolds. This phenomenon is known in the literature as system dynamism. Moreover, several input data are not known with certainty, but are rather described by random variables with known or estimated probability distributions. This phenomenon is known in the literature as system stochasticity. The notions of MLE resource routing and system dynamism mentioned above are elucidated by means of a hypothetical MLE response selection scenario whose evolution over time is illustrated in Figure 1.3. At first, an initial set of MLE resource visitation routes (denoted by directed dotted arcs) is generated, as shown in Figure 1.3(a), in which MLE resources are each allocated to a subset of VOIs. Here, the arrows pointing outwards from VOIs (denoted by black triangles) represent their respective velocity vectors (not to scale), while their estimated interception points are denoted by gray triangles. Later on in this scenario, however, after the MLE resources have only covered parts of their visitation routes, suppose that two new events are observed in the system, as shown in Figure 1.3(b). In the first event, one of the VOIs in the north of the jurisdiction area, which was previously immobile, begins to accelerate towards the west. In the second event, a new VOI is detected in the south-east of the jurisdiction area and its threatening nature is evaluated. Given this new information, the current MLE routing solution is re-assessed, and the initial, partially completed visitation routes, are replaced with a new set of more appropriate routes, as shown in Figure 1.3(c).
In order to achieve this level of dynamism, it is necessary to analyse the situation at sea whenever new events are observed and to update the current response for dealing with the potential threats. A semi-autonomous MLE response selection Decision Support System (DSS) may be employed to assist human operators in solving the so-called MLE response selection problem described above — which encompasses allocation and routing decisions for MLE resources for the purpose of intercepting and investigating VOIs. The purpose of such a DSS is to provide the operators with a set of high-quality response selection alternatives in limited time, particularly when dealing with decisions involving large numbers of VOIs that are subject to a high level of stochasticity with respect to their nature and hence uncertainty. The output of such a DSS may then be used in conjunction with operator judgment to select a single, most preferred alternative from a non-dominated set of solutions, typically in a multiobjective decision space.
Since each coastal nation has its own values, preferences and perceptions of the desirability of trade-offs between a miriad of objectives when dealing with VOIs, MLE responses following the detection and evaluation of new events at sea typically vary from nation to nation. These responses should, however, be coherent and carried out according to a pre-determined protocol, based on a set of goals and objectives appropriate for the coastal nation in question. A deep understanding of the specific strategic aims and subjective preferences of a coastal nation’s MLE
Land Sea
(VOI not pursued)
MLE resources VOI positions VOI intercepts Bases
(a) Initial set of routes allocating MLE resources to subsets of VOIs.
Land Sea
(New VOI) (VOI velocity change)
MLE resources VOI positions VOI intercepts Bases
(b) Partially completed initial set of visitation routes when the two new events are observed.
Land Sea MLE resources VOI positions VOI intercepts Bases
(c) Set of routes after re-evaluation of the situation, taking into account new information as a result of significant changes in the maritime picture.
1.2. Informal problem description 7
efforts is therefore necessary in order to identify a suitable set of fundamental objectives for use in the creation of that nation’s MLE response strategy.
Furthermore, it is typically the case that the entire MLE response selection process of a coastal nation is not conducted by a centralised operator assisted by a single DSS, but is rather or- chestrated by multiple role players, called MLE decision entities in this dissertation. These decision entities may perceive the quality of MLE response selection operations in their own, different ways, as they each tend to pursue their own goals and subjective perception of what is deemed important while carrying out MLE operations. In particular, these decision entities may perceive the threatening intensities of VOIs differently, function largely independently from one another, follow their own guidelines or rules of engagement, and utilise their own subsets of MLE resources.
Various MLE resource assignment scenes from around the world are illustrated in Figure 1.4. The high-speed vessel represented in Figure 1.4(a) is one that is used to patrol the waters around Cape Town. Patrolling allows MLE resources to be placed strategically, on expectation, until assigned to investigate one or more VOIs at sea as the need arises. There is, of course, a trade-off involved in having certain MLE resources patrol territorial waters between the costs of operating those MLE resources effectively (instead of being idle at a base) and the expected response times of these MLE resources once becoming active again.
The five vessels aligned in Figure 1.4(b) represent five different types of MLE resources available to the Canadian Coast Guard. A coastal nation typically possesses a fixed number of MLE resources, each belonging to a certain type or class of MLE resource with unique characteristics (such as maximum speed, travel costs per kilometre, level of autonomy at sea and ability to respond to certain types of threats). Two further such characteristics are the set-up time and set-up cost — an MLE resource is required to undergo a careful preparation process (including refueling, briefing of the crew and the preparation of on-board equipment), which takes up a certain amount of time and incurs certain costs in the process, prior to being dispatched on a mission. An example of an MLE resource in the set-up process at a base is illustrated in Figure1.4(c).
Some VOIs may only be detected far out in the jurisdiction area of a coastal nation. In such cases, it may be necessary to dispatch long-range MLE resources to intercept those VOIs. Search- oriented MLE resources, such as seaplanes or unmanned airplanes, may be deployed to visually scout out the precise locations of VOIs that are difficult to track by radars and relay this and other information back to the intercepting vessel commander. Such resources can be seen in Figures 1.4(d) and 1.4(e). Moreover, the threatening nature of a VOI may not always be known a priori, in which case these scouting MLE resources — unmanned airplanes in particular due to their stealth, speed, and high-altitude autonomy — may also be utilised to assess the VOI threat situation visually and relay relevant information back to a threat evaluation operator. Finally, as was discussed in §1.1.2, coastal nations around the world are faced with many dif- ferent types of threats of differing intensities. Piracy and oil pollution are usually seen as very harmful threats; examples of neutralising such threats are illustrated in Figures 1.4(f) and 1.4(g), respectively. Certain situations may also require an operator to allocate multiple MLE resources to a VOI in order to successfully neutralise it, such as in the scene depicted in Figure 1.4(h), in which two Japanese Coast Guard MLE resources are utilised to neutralise a VOI carrying dangerous Chinese activists.
(a) Light, high-speed patrol vessel used in waters around Cape Town [22].
(b) Various types of MLE resources available to the Canadian Coast Guard [57].
(c) US coast guards in the process of setting up several MLE resources prior to dispatch [94].
(d) Seaplanes are effective scouts when deployed in parallel with long-range MLE resources [94].
(e) Unmanned airplanes are popular for acquiring threat evaluation information [70].
(f) Interception of a suspicious boat thought to carry ammunition off the coast of Somalia [59].
(g) Preventative measures against a potential oil spill situation off the Panama coast [99].
(h) Combined assignment of MLE resources onto a high-alert VOI in the East-China sea [63].