Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. Modern Physics Letters B 2050298 (20 pages) © World Scientific Publishing Company DOI: 10.1142/S021798492050298X A novel method for destabilization of terrorist network Saurabh Singh∗ Department of Computer Science and Engineering, Jabalpur Engineering College, Jabalpur, Madhya Pradesh 482001, India ssingh@jecjabalpur.ac.in Shashi Kant Verma Computer Science Department, Govind Ballabh Pant Institute of Engineering and Technology, Pauri Garhwal, Uttrakhand 246194, India skverma.gbpec@rediffmail.com Akhilesh Tiwari Department of CSE & IT, Madhav Institute of Technology and Science, Gwalior, Madhya Pradesh 474005, India atiwari.mits@gmail.com Received 19 February 2020 Revised 11 March 2020 Accepted 16 March 2020 Published 3 June 2020 Criminal network investigation is an ignited research area nowadays. There are several types of criminal network. Terrorist network is one of them. Exploring terrorist network is a demand of several investigating agencies. Different properties of network can be better considered to probe network properly using multi criteria decision-making methods. Grey Relational Analysis (GRA) method is a structural technique for organizing and analyzing complex decisions based on typical mathematics. This process can be employed for analyzing available datasets and designing useful conclusions. If network is explored and visualized, it can be destabilized efficiently. Identified members can be studied and thus their future actions can be prevented. These generalized designs can be used by government agencies for destabilization of terrorist group. This system is especially useful for countries like India that face a constant threat from various group of terrorists. This generalization can further be used to destabilize various criminal networks and their activities can be prevented. Thus, life and property of individuals can be saved. Keywords: Criminal networks; Covert networks; social networks; GRA method; betweenness centrality; closeness centrality; eigenvector centrality; PageRank centrality. PACS Number(s): 89.65.-s, 89.75.-k, 89.20.Ff ∗ Corresponding author. 2050298-1 S. Singh et al. Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. 1. Introduction To add to the miseries of uprising all around, Terrorism has become biggest threat to the world. Terrorism is an illicit activity by a certain group of people, which wind up taking life of many innocent citizens.1,2 Mass violence, acts of terrorism, community trauma in various forms like shooting, bombing or by another type of attack profoundly affects families and children.3 On deep analysis of this terrorism attacks, it is found that people from various countries following an idea come up together to form a large organization, which work on various layers of network and these networks too are of various categories.4,5 The terrorist organization executes their plans by building a strong communication channel between its various members. They create a strong line of communication to ensure that the exchange of information and instruction is hidden from outside world.6,7 The availability of the citizens data on the cheap communication resources becomes a major source of information for the terrorists to plan all their activities. Thus, a strong communication channel between terrorism organization and leaking of citizen’s data results into a huge loss of life and property.8,9 To accomplish their dangerous thoughts, terrorists forms a terrorist network so as to link people present in diverse geographical points to strategize their master plan ensuring a masked identity from the government.10,11 Internet and other cellular networks form an active communicational network, supporting enormous number of devices such as mobile and other intelligent communication devices acting as stationary nodes. The concept of terrorist network is generally amalgamated with Covert network.12 A Covert network is a social network that involves influential miscreants who conceal their identity. The sharing of events among the representatives of the network is done in a very secretive manner. Rather, the Covert channel cannot be controlled or detected by the security mechanism that underlines a secure analogy between the Covert network and Terrorist network.13 Terrorist Organization have been moving ahead toward a network structure goal of more security through social and geographical decentralization. The intra-terrorist network works in highly conceivable manner to stay isolated from data breaches. To further this cause, the member protects their identity that may be done by the anonymous name, which means you are not leaving any traces of who you are. Anonymity aids to hide the strategies and mastermind from the investigating authorities. Many terrorist organizations get financial aids from various other cooperate organization, removing this cooperate organization will affect the whole terrorist network.14 Terrorist organizations are composed of quasi-independent cell rather than partitioning them in discrete levels. In sense, the terrorist network is built so strategically that gives them profound assurance of not getting captured by anyone. Hence, they preferably construct a decentralized network where individual importance depends 2050298-2 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. A novel method for destabilization of terrorist network on the information that can be extracted from the person not necessarily the person being a terrorist. The job done in this network is always in prone to be caught by the authorities, because one suspect under their arms can shatter the full-fledged network. Hence, determination of structure (hierarchy) seems irrelevant. If once the network gets enfeebled, it becomes far easy to identify the people working in difficult field, which further cause consequences to the whole network. The threat of terrorist network is wreaking havoc in the society. Determination of the terrorist network helps us to avoid the circumstances of the upcoming calamity. This will maintain the peace and tranquility of the surroundings. The global terror network that led to attack of 9/11 has triggered the major initiatives of the United States to combat terrorism.15 This has caused a massive explosion that resulted in burning debris all over the surrounding and onto the street below. This series of airline hijacking and suicidal attacks caused extensive death and destination. By data analysis, it was found out that terrorists were in close contacts and used to communicate in encrypted language. Similarly, the 4-day militant attack of 26/11 in Mumbai (India) leads to killing of many innocents. The terrorist usually makes use of Internet to collect information regarding the place to be attacked, traveling tickets, to steal social security numbers, etc. Terrorists have tried every possible way to remain undetected from Internet. For instance, they have sent a graphic file or a digital song file, which has encrypted message hidden over it. Hence, the wide terrorist network becomes tough to tackle. In the series of well-devised plans to ruin the particular place, the attack of 7/7 London bombing incident, which includes four suicide bombers with rucksacks full of explosives attached central London, resulted in loss of many and affected the survival of all who lives in surrounding places. It has also been regarded as one of the worst attacks. Moreover, there has been many catastrophic events, which depredate the freedom of people. The use of intentional violence for religious and political purposes has gained mainstream popularity, especially it is used to gain much media coverage. Over the previous decades, the average deaths counted annually is approximately 21,000. However, there can be year-to-year variability. Though terrorist attacks are usually regionally focused, but statistics reveal that no part of the country has remained untouched from the fright of terrorist attack. The list of massacre’s are uncountable and fatalities took beneath are even more. Initially, to put this violence to an end, terrorist network has played a requisite role, which helps in determining the correlation of the attackers involved. Communication has been a biggest source of dataset, which unwrap the ideology of each individual. So, Terrorist Network has been developed with many features, which puts on a strenuous challenge before us to shatter the network. In this fleet footed world, computers have emerged as a life-changing tool by increasing productivity of an organization, providing its accurate and powerful processing and computational capabilities. Since calculations and processing of large 2050298-3 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. S. Singh et al. amount of data are required in tracing the terrorist and criminal movements, thus computer shows its dominance in this field too through application of its computational and mathematical concepts to analyze the terrorist network. Pictorial analysis is always easier to grasp rather than numerical analysis of any dataset. Graph is such an illustration that represents data pictorially. Thus, graph theory is of great importance not only in mathematics, but also in Computer Science. Graphs are mathematical structure that exhibit relationship between objects. It is a framework that consists of two components: vertices and edges. Vertices represent objects, on the other hand edges symbolizes relationship between those objects.16 Edges may or may not have a particular direction and weight to determine their significance in graph.17 Various methods have been examined under multi-criteria decision-making (MCDM), which evaluates each method and do a critical comparison with respect to maintenance management. MCDM method includes Analytic Hierarchy Process (AHP), Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Elimination and Choice Expressing Reality (ELECTRE) and Grey Relational Analysis (GRA). Out of all the four methods, GRA is one of the best methods that measures the degree of grey relation. It provides technique for determination of good and appropriate solution to real-world problems inspite of attempting for best solution. It is used to bring solution of the uncertainty problems under the discrete data. The more positive the ideal solution is, the more will be its degree of grey relation and vice versa. Also, GRA method easily captures the dynamic objective features of different factors, which helps to save lot of time and cost. Hence, GRA method helps in management to make vital decision under Business environment. 2. Literature Survey With the ceaseless sustained rise in terrorism, varied organizations are obliged to work to elucidate this bemusing network. Terrorist network analysis has been eminence round the clock, especially since 9/11 attack. Inflating such an excruciating act has placed the counterpart at a frantic situation, where quick pedantry and expansion in techniques is the only option to keep out of harm’s way. Thinkers are working around the clock to fight this formidable strength. Some of these approaches are chronicled in this section. To accomplish a summarizing view of such a network for analysis, unification of data is required. But due to different organizations owning different social network data, this gets onerous cause individual body inhibiting sensitive data to maintain privacy sphere. Tang and Yang18 deals with this issue by suggesting a generalization algorithm, which gives room to a body to keep open only that part of the data whose sharing does not affect the privacy and sharing it so as to assist creating integrated global network that can be available to undertake analysis. This is achieved by creating subgraphs and then generalizing these subgraphs to let them integrate to 2050298-4 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. A novel method for destabilization of terrorist network modulate social network. These subgraphs are insensitive, but relevant data that both safeguards privacy and enables integration of global social data. Li, Sun, Guo and Li19 used combination of varied techniques and methodology to hold out the key individuals in terrorism such as Social Network Analysis (SNA) and Fuzzy Analytical Network Process (FANP). The rating of individuals is done by broaching measures from total degree, betweenness, closeness, which is further embedded in a devised indexing system of network computer by ORA. Further, the methods of artificial judgment and fuzzy science is applied to the method laterally explicated. It is ascertained a good method to meet the circumstances, where the information mustered may be uncertain. This model was referred to embassy bombing of Kenya and Tanzania, where it proved luminary in detecting the key elements of terrorism. Dawoud, Alhajj and Rokne20 suggest that the aim of this peculiar paper is to indicate that understanding of the basic hierarchical structure of such excruciating network is key in determining the strength and weakness of a group or organization. This helps exceedingly in determining capabilities of such networks. Previously, this methodology was applied to legal organizations that has got most of its information transparent. But the work extends when this comes to an illegitimate constraint, where the network hierarchy is hidden. The role of such methodology comes into play when particular nodes of such network hide their identity, rule and organizational structure. Determining the degree of network and their strength is what this algorithm helps with. Ozgul, Erdem and Bowerman21 on the other hand, fabricated a model to prognosticate and detect the particulars behind the unsolved cases. The model is called the Crime Prediction Model (CPM). The model tries placing few solved and unsolved cases in the same clusters based on the basis of the time, location, motive of the crime, etc. These clusters are referred to attain classification module. If unsolved and solved cases from a particular cluster is found adequately similar, the same group or organization as a solved case is regarded responsible or somehow associated with the unsolved crimes. The Internet is flourishing at the steepest way than anything has ever expanded.22 Capitalizing the same, dark web has sheltered all the anti-humanities around. Terrorist networks also have set their empire to commute their messages. The establishment of a system to analyze dark web can be worth devising for counter-terrorism and avoiding menaces. Sachan23 suggested a dark web analysis method that piles up message data from the dark web forum and tables are created so as to list message posters and are categories on the basis of their activity level like exchanging ideology, spreading propaganda and recruiting new members. Joining dots from these dark web forums can help getting to the core of such networks. A network is connections between various people that provide them convince to communicate. Likewise, terrorist connects with the help of terrorist network. Their networks have a complex design to ensure masked identity of the terrorist. 2050298-5 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. S. Singh et al. Unlike other, networks too have links and nodes. Each paper of the network help in tracing the people involved. The links in terrorist network provide much important information regarding their organization as explained by Wiil, Gniadek and Memon.24 Unlike any other organization, terrorist organization too always have a backup. If some terrorist is removed from the network, definitely other will take their place. We can analyze that which person is going to be replaced and by whom. Spenzzano and Mannes25 worked on algorithm for PSP, which includes all the requirement in the person for replacing the existing one. Visual analysis of social media data can be visually analyzed by firstly selecting the relevant data, then processing it and fixing the geo-location coordinate.26 Then data mining is done and various patterns are analyzed, and finally the social media data can be visualized as explained by Schreck and Keim.27 This method can be applied to terrorist network and data to visualize it and to make the analysis easy. The analysis is done on various crime-related networks and communities are studied using random walk-based algorithm by Alzahrani and Horadam.28 These identifications of various criminal communities can help to get many important information, and help in finding the terrorist coterie. Every organization need a financial support to run smoothly similar as in the case of terrorist organization. The analysis on the source of funding of terrorist organization will help us to get up them. Thus, various data-mining and social networking can be applied and pattern of terrorist financial transaction is studied to get more information regarding the terrorist network by Sakharova.29 Ozgul and Atzenbeck,30 developed crime analogy-based similarly measures (COSMs). It aims to detection of criminal by the demography features, i.e. origins and ethic. Basically, COSM is used for data study of Istanbul terrorist group. It can be applicable to the similar crime networks to build a dataset. Hence, detection of criminals can be done. Especially for Chinese economy,31 Yuan and Zhang worked on GRA method by using the weight entropy. With the motive of investigating the relative data on electronic commerce, GRA method has been introduced. The “degree of incidence” is the term, which is to be obtained for different datasets and result is verified. To enhance the quality and quantity of product, the maintenance perspective has been implemented in the MCDM.32 The paper includes different available methods and has compared on the basis of accuracy, consistency, problem structure, concept, etc. Hence, accurate results can be obtained with very minimal efforts and investments. Comprises of different MCDM methods and a comparative study have been done among the available alternatives. Differentiation has been done based on various parameters that are strengths and weakness. It simply tells about the importance of MCDM in solving the complex real problems.33 2050298-6 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. A novel method for destabilization of terrorist network The terrific incident of 26/11 has tragic outcomes, which affected the lives of many.34 This paper has analyzed the terror attack based on the mathematical technique, i.e. SNA. This includes data tracing of telephonic communications between the attackers who were a part of the terrorist attack. The communication gives the idea of central node, which refers to the master planner of the attack and also tells about the interconnection of different persons involved. 3. Methodology Laterally, explicated GRA method is brought into effective actions to discern the most noteworthy node in foreshortening terrorist network. The screened node after availing GRA is further taken into consideration by the authorities to take felicitous action. Thereby designating nodes based on criteria, particularly for this paper graph, properties such as betweenness centrality, closeness centrality, eigen value centrality and page rank centrality are taken into account. The Betweenness Centrality attribute of a graph comprehends the foremost node. The node with maximum Betweenness centrality is the one that functions as bridge between two specific nodes and shortest path between them for the maximum number of times. This particular node can be earmarked to warp the terrorist network as this node bears maximum control over network flow. For instance, in Fig. 1, every shortest path bridging node 1 and node 6 confronts node 5, thereby ascertaining maximum Betweenness Centrality. Closeness Centrality defines how close a specific node is to all the other nodes. It can be calculated as the reciprocal of the sum of distance between a node and all other nodes in the graph.35 The more centralized a node is, the more it is connected to the rest of the nodes and is responsible for data sharing. Thus, it can be a destination for agencies to target. In Fig. 2, node 1 is clearly the centermost, as it is close to all the other nodes in the graph. Eigenvalue Centrality determines the influence of a node in a particular network compared to other nodes. Relative scores are assigned to the nodes on the term that a node connects more high-scoring nodes. Fig. 1. Betweenness Centrality. 2050298-7 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. S. Singh et al. Fig. 2. Closeness Centrality. Fig. 3. Eigenvalue Centrality. In Fig. 3, although node 2 bridges to node 1 only but ascertaining maximum Eigenvalue Centrality as node 2 is in turn connected to many nodes. Those individuals or organizations connecting either too many or are isolated otherwise are scored less. Although, the nodes in connection with such nodes that have many connections themselves are scored high. PageRank Centrality gives preferences to a node on the basis of incoming neighbors. The nodes are well normalized and are interpreted accordingly, predicting the transition from one node to other as shown in Fig. 4. Fig. 4. PageRank Centrality. 2050298-8 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. A novel method for destabilization of terrorist network Fig. 5. Framework of GRA. The framework of the GRA method is shown in Fig. 5. The execution steps are as follows: • Step 1: Normalization of Matrix: Matrix is normalized such that each cell acquires respective parameter. • Step 2: Weighting the Normalized Matrix: A weighted normalization matrix is obtained from the specified weights by multiplication of weights with respective cell of normalized value. • Step 3: Grey Relational Generating: Case (a): If the expectancy is the higher-the-better x∗ (k) = x0i (k) − min x0i (k) max x0i (k) − min x0i (k) (1) Case (b): If the expectancy is the lower-the-better x∗ (k) = max x0i (k) − x0i (k) max x0i (k) − min x0i (k) where i = 1, . . . , m; k = 1, . . . , n. m = number of criteria n = number of alternatives 2050298-9 (2) S. Singh et al. Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. Algorithm 1. Algorithm to de-stabilize the network. Input: Terrorist Network Graph G(V, E), List of selected criteria – between centrality, closeness centrality, Pagerank centrality, Eigenvector centrality Output: Ranking of most significant node • Step 4: Find the Grey relational Coefficient: ϕi (k) = ∆ min +θ∆ max ∆0,i (k) + θ∆ max (3) ∆0,i (k) is the deviation sequence, • Step 5: Find the Grey relational Grade: n 1X γi = ϕi(k) n (4) k=1 • Step 6: Calculate the Rank of each alternative: Sort the Grey relational grade in descending order and assign rank accordingly from 1 to m. 3.1. Pseudocode • • • • • • • • • • • • • • • • • • • • • • • initialize input data input data[m][n] for i = 0 to n min[i]= min(input data[0:m][i]) max[i]= max(input data[0:m][i]) for i = 0 to n for j = 0 to m norm data[i][j]= (input data[i][j]-min[i])/(max[i]-min[i]) for i = 0 to n min[i]= min(input data[0:m][i]) max[i]= max(input data[0:m][i]) for i = 0 to n for j = 0 to m dev seq[i][j]=max[i]-norm data[i][j] for i = 0 to n min[i]= min(input data[0:m][i]) max[i]= max(input data[0:m][i]) for i = 0 to n for j = 0 to m GRC[i][j]=(min[i]+(0.5)*max[i])/ (dev seq[i][j]+(0.5)*max[i]) Find Grey relational grade for i = 0 to n for j = 0 to m 2050298-10 A novel method for destabilization of terrorist network Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. • GRG[i]=(1/n)*sum(GRC[i]) • Find Rank • Rank=sort(GRG) 3.2. Time complexity analysis 3.2.1. Generating of Grey Relation • • • • • • • • • Let n will be the no. of criteria and m will be no. of alternatives. For finding min for each criteria = m1 For finding max for each criteria = m2 So, for n criteria = (m1+m2)n = 2mn As size of m1 = m2. Time to minus = C1 Time to divide = C2 For m alternatives and n Criteria = mn(C1 + C2) Time Complexity for 1st step = 2mn + nm(C1+C2) = O(mn) 3.2.2. Finding Grey Relation Coefficient • • • • • • • • • • For finding min for each criteria = m1 For finding max for each criteria = m2 So, for n criteria total time complexity = (m1+m2)n = 2mn As size of m1 = m2. Time to minus = C1 For m criteria and n alternatives = (mn)C1 Time for addition = C2 Time to divide = C3 For m alternatives and n criteria = mn(C2 + C3) Time Complexity for 2nd step = 2mn + mnC1 + mn(C2+C3) = O(mn) 3.2.3. Finding Grade of Grey Relation • • • • • Time to sum = C1 For n criteria = nC1 Time to divide = C2 For m alternatives = m(nC1 + C2) Time Complexity for 3rd step = m(nC1 + C2) = O(mn) 3.2.4. Final Ranking • Time to sort m alternatives = m(logm) • Time Complexity for 4th step = O(mlogm) Time Complexity from 1st step to 4th step = O(mn) 2050298-11 S. Singh et al. Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. 4. Results and Simulation This work includes terrorist network dataset of 26/11 attacks in Mumbai25 to visualize execution of GRA method. It is a binary dataset, showing link between two terrorists. Government of India report36 had been analyzed properly to collect the associations among terrorists. Binary dataset that is generated after careful analysis of Ref. 36 is used in Ref. 34. Final dataset is shown as adjacency matrix in Appendix A. With the help of ORALITE software, the data are envisioned a network (Fig. 6). For better readability, some alias (reference names) have been created, which is defined in Table 1. Out of various centrality measures calculated using ORA-LITE software, only four (Betweenness centrality, Closeness centrality, Page rank centrality and Eigen vector centrality) centralities are used. Fig. 6. Network image of 26/11 terrorist attacks in Mumbai. Table 1. All certain terrorists mapped in the following fashion. A B C D E F G H I J K L M are Abu Kaahfa Wassi Zarar Hafiz Arshad Javed Abu Shoaib Abu Umer Abdul Rehman Fahadullah Baba Imran Nasir Ismail Khan Ajmal Amir Kasab 2050298-12 A novel method for destabilization of terrorist network Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. Table 2. Centralities calculated using ORA-LITE software. Name Betweenness Centrality Closeness Centrality PageRank Centrality Eigenvector Centrality A B C D E F G H I J K L M 0.136 0.503 0.08 0.003 0 0 0.003 0 0.072 0 0 0 0 0.279 0.308 0.279 0.267 0.261 0.267 0.267 0.24 0.245 0.25 0.25 0.083 0.083 0.087 0.187 0.076 0.089 0.084 0.069 0.089 0.032 0.071 0.031 0.031 0.077 0.077 0.246 0.612 0.23 0.469 0.469 0.469 0.469 0.088 0.131 0.142 0.142 0.154 0.154 Table 3. Normalized table. Name Betweenness Centrality Closeness Centrality PageRank Centrality Eigenvector Centrality A B C D E F G H I J K L M 0.270378 1 0.159046 0.005964 0 0 0.005964 0 0.143141 0 0 0 0 0.871111 1 0.871111 0.817778 0.791111 0.817778 0.817778 0.697778 0.72 0.742222 0.742222 0 0 0.358974 1 0.288462 0.371795 0.339744 0.24359 0.371795 0.00641 0.25641 0 0 0.294872 0.294872 0.301527 1 0.270992 0.727099 0.727099 0.727099 0.727099 0 0.082061 0.103053 0.103053 0.125954 0.125954 The four columns indicate the parameters to be considered to make the decision. Values for four columns have been taken from the report of ORALITE software as shown in Table 2. The method of GRA involves following steps: • Step 1: Normalization of matrix In this step, column values are normalized on the scale of 0 to 1. So, the resultant table is shown as Table 3. • Step 2: Weighting the normalized matrix In this step, each column is multiplied by its weights. Weights are value that determines the importance of the corresponding parameter in decision-making. Weight assignment is shown in Table 4. After assignment of each criterion, resultant table is shown as Table 5. 2050298-13 S. Singh et al. Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. Table 4. Weights for each parameter. Centrality Closeness Centrality PageRank Centrality Eigenvector Centrality Sum Table 5. 0.3 0.3 0.2 0.2 01 Weighted table. Name Betweenness Centrality Closeness Centrality PageRank Centrality Eigenvector Centrality A B C D E F G H I J K L M 0.081113 0.3 0.047714 0.001789 0 0 0.001789 0 0.042942 0 0 0 0 0.261333 0.3 0.261333 0.245333 0.237333 0.245333 0.245333 0.209333 0.216 0.222667 0.222667 0 0 0.071795 0.2 0.057692 0.074359 0.067949 0.048718 0.074359 0.001282 0.051282 0 0 0.058974 0.058974 0.060305 0.2 0.054198 0.14542 0.14542 0.14542 0.14542 0 0.016412 0.020611 0.020611 0.025191 0.025191 Table 6. Deviation sequence. Name Betweenness Centrality Closeness Centrality PageRank Centrality Eigenvector Centrality A B C D E F G H I J K L M 0.918887 0.7 0.952286 0.998211 1 1 0.998211 1 0.957058 1 1 1 1 0.738667 0.7 0.738667 0.754667 0.762667 0.754667 0.754667 0.790667 0.784 0.777333 0.777333 1 1 0.928205 0.8 0.942308 0.925641 0.932051 0.951282 0.925641 0.998718 0.948718 1 1 0.941026 0.941026 0.939695 0.8 0.945802 0.85458 0.85458 0.85458 0.85458 1 0.983588 0.979389 0.979389 0.974809 0.974809 • Step 3: Generation of Grey relation In this step, deviation sequence table is calculated. All the column values are subtracted by maximum value in the same column. In our case, the normalized table has maximum value 1 for all the columns. Hence, Deviation Sequence in calculated by subtracting all values by 1. Deviation Seq. = X max - X 2050298-14 A novel method for destabilization of terrorist network Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. Table 7. Grey Relation Coefficient. Name Betweenness Centrality Closeness Centrality PageRank Centrality Eigenvector Eigenvector A B C D E F G H I J K L M 0.352389 0.416667 0.344285 0.333731 0.333333 0.333333 0.333731 0.333333 0.343157 0.333333 0.333333 0.333333 0.333333 0.40366 0.416667 0.40366 0.398512 0.395987 0.398512 0.398512 0.387397 0.389408 0.391441 0.391441 0.333333 0.333333 0.35009 0.384615 0.346667 0.350719 0.34915 0.344523 0.350719 0.333618 0.345133 0.333333 0.333333 0.346975 0.346975 0.347296 0.384615 0.345829 0.369118 0.369118 0.369118 0.369118 0.333333 0.337021 0.337977 0.337977 0.339027 0.339027 Table 8. Grade of Grey Relation. Name Grey Relation Grade A B C D E F G H I J K L M 0.363359 0.400641 0.36011 0.36302 0.361897 0.361372 0.36302 0.34692 0.35368 0.349021 0.349021 0.338167 0.338167 Here, X = original value, X max = maximum value in the corresponding column. Then resultant table is Table 6. • Step 4: Finding Coefficient of Grey Relation In this step, a grey relation coefficient is calculated for each value by this formula: Φi (k) = ∆min + Θ∆max ∆0,i (k) + Θ∆max (5) Here, ∆min = 0, ∆max = 1, ∆0,i (k), and Θ = Identification Coefficient (It is assumed as 0.5). Then resultant table is visualized as Table 7. • Step 5: Finding Grade of Grey Relation In this step, the average value of all the columns in Grey Relation Coefficient table is calculated for each row. This value is called Grey Relation Grade as shown in Table 8. 2050298-15 S. Singh et al. Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. Table 9. Sorted Grade of Grey Relation. Name Grey Relation Grade (sorted) Wassi Abu Kaahfa Abu Umer Hafiz Arshad Javed Abu Shoaib Zarar Fahadullah Baba Imran Nasir Abdul Rehman Ajmal Amir Kasab Ismail Khan 0.4006410256410256 0.36335860977911794 0.3630202823582347 0.3630202823582347 0.36189705769356173 0.36137164599960303 0.36011004648074507 0.35367975049476724 0.3490211159730346 0.3490211159730346 0.3469204595531487 0.33816716768712746 0.33816716768712746 Table 10. Name Final selection of alternatives. Grey Relation Grade (top five) Wassi Abu Kaahfa Abu Umer Hafiz Arshad Javed 0.4006410256410256 0.36335860977911794 0.3630202823582347 0.3630202823582347 0.36189705769356173 • Step 6: Final selection of alternative to destabilize the network To get the final ranking, all the rows of Table 8 are sorted in ascending order of Grey Relation Grade. Top elements in this table are the most important according to GRA Algorithm as shown in Table 9. Then, top five alternatives are selected to destabilize the terrorist network as shown in Table 10. Fig. 7. Visualization of Grey relation grade. 2050298-16 Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. A novel method for destabilization of terrorist network Fig. 8. Fig. 9. Visualization of sorted alternatives. Visualization of final selection of alternatives. Grey relation grade of all the alternatives is envisioned in Fig. 7. On the basis of grade alternatives are sorted and displayed in Fig. 8. Top five alternatives are selected to destabilize the terrorist network as shown in Fig. 9. Removal of these nodes (alternatives) would destabilize the network as these are most influencing nodes. 2050298-17 S. Singh et al. Mod. Phys. Lett. B Downloaded from www.worldscientific.com by UPPSALA UNIVERSITY on 06/04/20. Re-use and distribution is strictly not permitted, except for Open Access articles. 5. Conclusion and Future Work The GRA model is very productive to find deserving alternative out of given alternatives. Power of GRA method is ease of use. Also, GRA method requires less computational effort, so it is speedy in nature. Data of 26/11 attacks of Mumbai,34 India, are analyzed here and findings are found very useful. Fetched results are very informative and it can better explore the network up to some level. Results showing Wassi, Abu Kaahfa, Abu Umer, Hafiz Arshad and Javed are most important nodes and confirmed by Ref.36 Present work is very satisfying to find loopholes of criminal network and to destabilize further. However, GRA method is working well in criminal investigation, but to pinpoint process of destabilization of the network, some supporting optimization methods are required. Scalability of present method should also be tested. After going through various literatures and present work, it can be concluded that destabilization of network is being done using one method only. Approach of multiple methods is required. Multiple methods can be applied simultaneously or in pipeline fashion. So how to apply approach is also a question of further research. Work presented here is useful for criminal network investigation, but might be the basis of investigation of counterfeit information that is spreading on social networks. Investigation of counterfeit message and getting source of it is a big crisis in the coming days. Appendix A 26/11 Mumbai Attacks Dataset A. H. A. A. A. B. I. A. A. Kaahfa Wassi Zarar Arshad Javed Shoaib Umer Rehman Fahadullah Imran Nasir Khan Kasab A. Kaahfa 0 1 1 0 0 0 0 0 0 0 0 0 0 Wassi 1 0 1 1 0 0 1 0 0 1 1 0 0 Zarar 1 1 0 0 0 0 0 0 0 0 0 0 0 H. Arshad 0 1 0 0 1 1 1 0 0 0 0 0 0 Javed 0 0 0 1 0 0 1 0 0 0 0 0 0 A. Shoaib 0 0 0 1 1 0 1 0 0 0 0 0 0 A. Umer 1 1 0 1 1 1 0 0 0 0 0 0 0 A. 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