These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sleeper cell.
Send us feedback. See more words from the same year. Accessed 12 Nov. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Log in Sign Up. Save Word. Definition of sleeper cell. Examples of sleeper cell in a Sentence Recent Examples on the Web Authorities never found a terrorist sleeper cell in Lodi.
What gives Al Qaeda its global reach is its ability to appeal to Muslims irrespective of their nationality, enabling it to function in eastern Asia, Russia, western Europe, sub-Saharan Africa and North America with equal facility.
Unlike conventional military forces which are often hierarchical and centralized, terrorist militant units are often small, dispersed and seemingly disorganized. Nevertheless, they have been able to effectively counter much larger conventional armies. Large terrorist organizations operate in small, dispersed cells that can deploy anytime and anywhere [ 11 ]. Dispersed forms of organization allow these networks to operate elusively and secretly.
The apparent structure of Al Qaeda is not exclusive to such militant or terrorist groups. Indeed, they bear a family resemblance to the structure of other resistance groups.
For example, a study published in by L. Gerlach and V. Hine [ 12 ] concluded that U. By polycentric I mean that it has many different leaders or centers of direction By networked I mean that the segments and the leaders are integrated into reticulated systems or networks through various structural, personal, and ideological ties.
Networks are usually unbounded and expanding This acronym [SPIN] helps us picture this organization as a fluid, dynamic, expanding one, spinning out into mainstream society. However, unlike many protest movements, terrorist and criminal networks often wish to remain covert. The need for security dictates that terrorist organizations must be structured in a way that minimizes damage to the organization from arrest or removal of one or more members [ 13 ]. This damage may be direct making key expertise, knowledge or resources inaccessible for the organization or indirect exposing other members of organization during interrogations.
There are several factors that allow a terrorist organization to remain covert, including: Strong religious in case of Islamic groups or ideological in case of Sendero Luminoso and other South American guerilla groups views that allow members to form extremely strong bonds within a cell. Physical proximity among cell members, often to the extent of sharing living quarters, working and training together. Lack of rosters on who is in which cell. Cell members being given little knowledge of the organizational structure and the size of the organization.
Little inter-cell message traffic. Information about tasks issued on a need-to-know basis, so very few people within the organization know about the operational plans in their entirety. Cells are often formed on the basis of familial or tribal ties, or strong interpersonal ties forged in training. However, a need-to-know information policy can be counterproductive when an organization needs to complete a task that is larger than any one cell.
Further, such policies tend to lead to duplication of effort and reduce the ability of one cell to learn from another. To fix these inefficiencies, terrorist organizations have been known to employ "sleeper links" - where a small number of members of each cell have non-operational ties such as family ties, ties emerging from common training, etc.
These links are rarely activated, and are used mainly for coordinating actions of multiple cells in preparation for a larger operation.
On the one hand, in part to remain covert, Al Qaeda has structured itself as a leaderless design characterized its organic structure, horizontal coordination, and distributed decision making.
However, the need to maintain a strong ideological foundation and resolve coordination issues has led to the need for strong leadership. One apparent solution has been to have multiple leaders diffused throughout the network and engaged in coordinating activities, without central control or a hierarchy among the cells. Whether the leaders are themselves hierarchically organized, even though the cells are not, is less clear. Under constant pressure from various world governments, terrorist organizations have evolved a structure that appears to be resilient to attacks.
However, information on these terrorist organizations, their membership, the connections among the members, and so on is, at best, incomplete. Available information is often obtained during post factum investigations of terrorist acts, and may offer little insight into the "main body" of the organization or the way in which it is evolving. Cellular Networks and Terrorist Organizations Substantial intelligence effort is needed to piece together the massive amount of often misleading information - both post factum and "logs" of activity - to generate a picture of the entire organization.
Nevertheless, the picture that is emerging suggests that terrorist organizations are organized at the operational level as cellular networks rather than as hierarchies [ 15 ]. Cellular networks are different from traditional organizational forms in that they replace a hierarchical structure and chain of command with sets of quasi-independent cells, distributed command, and rapid ability to build larger cells from sub-cells as the task or situation demands.
In these networks, the cells are often small, only marginally connected to each other, distributed geographically, and may take on entirely different tasks.
Each cell is functionally self-sufficient, and is capable of executing a task independently. Cells are loosely interconnected with each other, for purposes of exchanging information and resources. However, the information is usually distributed on a need-to-know basis and new cell members rarely have the same exact skills as current members. This essentially makes each individual cell expendable. The removal of a cell generally does not inflict permanent damage on the overall organization or convey significant information about other cells.
Essentially, the cellular network appears to evolve fluidly in response to anti-terrorist activity. The fact that covert networks are often built from self-similar and somewhat self-sufficient cells leads to a hypothesis that cells throughout the network contain structurally equivalent [ 16 ] and essential roles, such as ideological or charismatic leaders, strategic leaders, resource concentrators, and specialized experts as needed given the modus operandi of the cell or its environment.
Given this hypothesis, we can further reason that operations of a particular cell will be affected in a negative way by removal of an individual filling one of these roles. Using this as a base for further exploration, we venture to show in this paper that cellular networks indeed contain vitally important and structurally equivalent roles, which can be detected through the use of dynamic social network analysis on the organizational MetaMatrix.
Profile of a Covert Network From a combination of pressures to operate efficiently and pressures to remain covert, an organizational network emerges that combines massive redundancy with secrecy, separating into densely connected cells that are sparsely interconnected with each other through the leaders. No clear hierarchy emerges from observation of these networks, other than a definite role of a cell leader, who is often the only contact that the cell has with the outside world.
The best profile of the structure of terrorist networks, based on publicly available data, is the following [ 7 ]: The network consists of cells with very low interconnection between cells. Destabilization of Covert Networks The most common class of attacks against covert networks is comprised of strategies aimed at isolating or incapacitating a particular actor or leader, or an attack on the networks' infrastructure, training or weapons facilities.
For an attack on the infrastructure of a terrorist group to be successful, it has to be carefully targeted to not simply dismantle the command-and-control infrastructure, but to fully disconnect cells from crucial operational information or resource flow.
Such precision targeting requires knowledge of the organizational structure of the network including redundancies and latent links , the task structure i. Distributed cellular nature of covert networks means that targeted actor attacks require such precision targeting. Social Network Analysis and Network Destabilization Traditional social network analysis SNA techniques have focused on analysis of communication networks between individuals.
However, most SNA studies have been conducted on single-mode networks i. Also, most studies have been concerned with analysis of a single network. A further complication is that traditional social network measures are not designed for time-series analysis of dynamic networks.
While static analysis may be adequate for slow-changing interpersonal networks, covert networks are characterized by their fluidity and dynamism. Thus, analysis of covert networks needs to be approached from a dynamic perspective, tracking change inside the network as well as its static parameters. Nevertheless, from an organizational perspective, it is important to look beyond social networks. Krackhardt and Carley [ 17 ] proposed concentrating knowledge about an organization in a format that could be analyzed using standard network methods, called the MetaMatrix.
The MetaMatrix analysis represents organizations as evolving networks in which the nodes in the social network are actively engaged in realistically specified tasks.
This conceptualization made it possible to link performance to social networks and ask, at a concrete level, how changes in the social network could effect changes in performance. Carley [ 18 ] [ 19 ] generalized this approach and extended the perspective into the realm of knowledge networks, enabling the researcher to ask how changes in the social network could effect changes in the distribution of information and the resultant impact of knowledge disruption strategies on organizational performance.
By taking an information processing perspective, we are explicitly linking knowledge management and social networks [ 1 ] and enabling network evolution through learning mechanisms. From a conceptual and data perspective, this means that we examine the co-evolution of all networks in the MetaMatrix as described in table 1. Moreover, we explicitly focus on the fact that the organization, and so these underlying networks, evolve.
People Knowledge Tasks People Stuctural knowledge: Command and control structures, information pathways and relationships between organization members. Knowledge Distribution: Who has access to what knowledge within the organization. Task Assignment: Who does which tasks within the target organization. Knowledge Knowledge Precedence: Which types of skills go together.
Skill Requirements: Which skills are needed to accomplish a particular task. Task Task Precedence: On a tactical level, the sequencing and precedence of tasks that the target organization can accomplish. A number of social networks metrics have been proposed for identifying the key actors who should be targeted in order to destabilize covert networks. Such metrics include, but are not limited to, those focused on centrality, random attacks, and from a more dynamic network perspective, cognitive demand [ 7 ].
Identifying an actor as key, using one of these metrics and then isolating that actor is a destabilization strategy. We now consider several such strategies. The centrality approach , consisting of measuring the centrality [ 20 ] of each node in the network, then selecting a small number of most central nodes as targets for further action, is an intuitive approach to finding a core group of leaders within a terrorist network. However, it is known from available intelligence that terrorist networks function in tightly connected cells and maintain only loose connections with the rest of the organization.
Therefore, a search for highly central individuals is more likely to turn up a large number of agents that do not constitute the leadership circle, but are members of a densely connected cell.
Moreover, as Borgatti [ 21 ] stated, none of the centrality metrics is guaranteed to disconnect the network into discreet components. Bienenstock and Bonacich [ 22 ] have conducted a simulation study on vulnerability of networks to random and strategic attacks.
The study suggests that as average connectedness of each individual node rises and high betweenness nodes are methodically attacked, the impact on overall performance of the network is minimal. However, if neighborhoods nodes connected to a high-centrality node are attacked along with the node, the opposite is true. The implication of that result is that the cells of covert networks that are connected by a few individuals with high betweenness are very vulnerable to discovery of these individuals.
Johnson et al. The results of this study suggest that perhaps the structural position of a gatekeeper is not important to the functioning of an isolated cell. However if two cells of the organization are to function in concert, the best position for the charismatic leader is in a gatekeeper role.
The cognitive load approach described by Carley [ 6 ] combines static measures of centrality with dynamic measures of information flow, task performance and resource distribution.
These measures are based on the meta-matrix knowledge about the organization and have been shown to accurately detect emergent leaders. Consequently, cognitive load metrics can potentially be useful for detecting key members of terrorist networks. Based on the foregoing review of the literature we have identified a suite of destabilization strategies. Each strategy identifies actor criticality in a different way. All strategies rely on data in one or more cells in the meta-matrix. The identified strategies are: Highest degree centrality: Isolate one agent from the covert network that has the highest degree centrality [ 20 ].
Highest betweenness centrality: Isolate one agent from the covert network that has the highest betweenness centrality [ 20 ]. Highest task accuracy: Isolate the best performing agent in the organization. This corresponds to standard police practice of arresting agents implicated in commission of a terrorist act.
Amount of unique knowledge: Isolate the agent that has the highest expertise. When a destabilization strategy is applied, an actor is identified and isolated. This results in one or more changes in the underlying networks in the meta-matrix and possibly a cascade of future changes [ 24 ]. Since the overall network is a complex adaptive system there is no guarantee that such cascades will destabilize the overall network, particularly in the long run. Thus, an examination of these destabilization strategies needs to be done in a dynamic context.
NetWatch: A Multi-Agent Network Model of Covert Network Surveillance and Destabilization NetWatch is a multi-agent network model for examining the destabilization of covert networks under varying levels and types of surveillance. Computational models, particularly, multi-agent network models, are a valuable tool for studying complex adaptive systems like organizations in general [ 14 ] [ 25 ] and covert networks in particular [ 7 ].
In multi-agent models, social behavior grows out of the ongoing interactions among, and activities of, the intelligent adaptive agents within the system. From the meta-matrix perspective, actions of each agent or actor are constrained and enabled not just by the activities of other agents but by what resources or knowledge they have, what tasks they are doing, the order in which tasks need to be done, the structure of communication and authority, and so on.
Further, the agents are intelligent, adaptive and computational information processing systems. The goals of NetWatch are to: Simulate the communication patterns, information and resource flows in a dynamic covert cellular network; Model the process of gathering signal intelligence on a cellular network and evaluate a variety of heuristics for intelligence gathering; Model and evaluate strategies for destabilizing a covert network based on intelligence obtained; Model reactions of a covert network to these destabilization strategies.
The social and cognitive underpinnings of the actors and the network in which they operate are based upon the CONSTRUCT model of the co-evolution of social and knowledge networks [ 18 ] [ 24 ]. The agents in the model perform a classification task that is information-intensive i. In the beginning of the simulation, agents are endowed with relatively little knowledge and must engage in learning behaviors in order to increase their task performance.
Agents learn by interaction: trading facts with other agents or asking direct questions in hope of getting an accurate answer. Agents also forget little-used facts. In keeping with the research in cognitive science, the agents representing humans are both cognitively and socially constrained [ 26 ] [ 27 ] [ 28 ] [ 29 ]. Thus, their decision-making ability, actions, and performance depend on their knowledge, structural position, procedures and abilities to manage and traverse these networks.
Unlike Construct agents, the NetWatch agents are implemented as non-deterministic finite automata, with states of the automaton representing low-level behaviors and transitions governing the way the agent switches between them. Some transitions are deterministic, others rely on probabilistic equations. Low-level behaviors include chatter, knowledge seeking, resource seeking, task execution and information reporting.
Chatter is the simplest of the low-level behaviors. It can be thought of as non-goal-directed socializing, where some information is exchanged but it may or may not be relevant to the task the agent is engaged in. Partners for chatter interaction are randomly picked from the agent's ego network peer group.
Chatter uses the Knowledge Exchange Protocol see section 4. Knowledge and Resource seeking behaviors use the same protocol as chatter, however assign a higher priority to the messages. Communication partners are determined by estimating the probability of a successful interaction, informed by the MetaMatrix representation of the agent's ego network. Processes that govern selection of partners are described in section 4.
Task execution is described in detail in section 4. It is governed by a simple challenge-response protocol that is executed over one time period. Task messages have the highest priority in the system and will preempt both knowledge exchange and chatter messages. It is important to note that due to asynchronous execution of agents and multi-tiered message priorities, it is possible that some interactions will never complete or will complete after a significant delay.
Each agent stores incoming unprocessed messages in a queue sorted by message priority. Thus, if an agent is overwhelmed with tasks or goal-oriented information exchange, most chatter requests will never be processed. To prevent deadlocks, each of the messages is time-stamped at the time of sending, and interactions are set to time out after a fixed number of time periods. Also, agents are capable of handling multiple interactions at the same time, with task preempting based on priority of incoming messages.
For example, if an agent was in the middle of a chatter interaction when a resource request or a task request arrived, the chatter will not be resumed until higher-priority interactions have been finished. Formal and Informal Networks in NetWatch In NetWatch, the formal structure of the organization is specified as a directed weighted graph that specifies the communication channels that are open as well as their throughput or cost of communication.
The directed nature of the graph allows one to specify one-way relationships and chain-of-command relationships. The beliefs about the informal structure are individual to every agent, and also consist of a weighted directed graph.
However, when an agent joins a network, its informal relationship graph is empty, and it must learn about the informal network before it can be used for communication.
In NetWatch, the agents' interactions are governed by the formal structure of the organization, and agents' beliefs about the informal structure.
A sleeper cell is a group of operatives, spies or terrorists, living in secret among a targeted community waiting for instructions or an opportunity to act. Sleeper agents remain dormant or inactive until the time to act, doing no other espionage work. A group of sleeper agents is a sleeper cell. The term goes back at least to a New York Times book review. Over time, sleeper cell has been used less to describe espionage and more to describe terrorism. The use of sleeper cell to refer to a terrorist group took off in , following the September 11 attacks carried out by members of the terror group al-Qaeda living in the United States.
Former State Department Agent Scott Stewart pointed out in an article for the think tank Stratfor formerly Strategic Forecasting , that the September 11 terrorists were not a sleeper cell by the classic definition, because they began planning and acting shortly after entering the US. That said, the term has been frequently used in recent years to describe any terrorist group living secretly among its target population. Shortly after the September 11 attacks, four Middle Eastern men were arrested in Detroit and charged with planning a terror attack.
Media reports referred to the men as a sleeper cell , as did court documents.
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