Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

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An Open Locating-Dominating Set (OLD set) is a subset of vertices in a graph such that every vertex in the graph has a neighbor in the OLD set and every vertex has a unique set of neighbors in the OLD set. This can also represent where sensors, capable of detecting an event occurrence at an adjacent vertex, could be placed such that one could always identify the location of an event by the specific vertices that indicated an event occurred in their neighborhood. By the open neighborhood construct, which differentiates OLD sets from identifying codes, a vertex is not able to report if it is the location of the event. This construct provides a robustness over identifying codes and opens new applications such as disease carrier and dark actor identification in networks. This work explores various aspects of OLD sets, beginning with an Integer Linear Program for quickly identifying the optimal OLD set on a graph. As many graphs do not admit OLD sets, or there may be times when the total size of the set is limited by an external factor, a concept called maximum covering OLD sets is developed and explored. The coverage radius of the sensors is then expanded in a presentation of Mixed-Weight OLD sets where sensors can cover more than just adjacent vertices. Finally, an application is presented to optimally monitor criminal and terrorist networks using OLD sets and related concepts to identify the optimal set of surveillance targets.

This thesis argues that organized crime is a sociological phenomenon with criminological dimensions that constitutes a threat to public security and order, economic development, social integrity, democracy and peace in Turkey, and consequently to the national security of the country. Sociological and political causes of organized criminality will be assessed through a multidimensional approach based on the identification of different conceptual areas and related indicators that characterize organized crime groups.

資訊時代下全球化造成了流動空間的出現，亦促進了網絡社會的崛起；其影響不僅擴及政治、社會、經濟層面，更形成了全球犯罪經濟的現象。臺灣境內詐欺犯罪從過去當面直接接觸，轉為透過電信或網路間接接觸的詐騙形式；在政府的全面查緝及兩岸共同打擊犯罪之下，近年來電信詐欺集團呈現向外擴散跨越國境乃至全球的趨勢。此類全球犯罪網絡的相關實證研究至今仍極為缺乏，因此，本研究旨在討論前述犯罪機會、空間分工及社會網絡如何形成跨境電信詐欺犯罪網絡，及其背後的特殊運作機制。 　　經由文獻探討法、現有資料統計分析法及深度訪談18名受訪者（受刑人11名、偵查人員4名、駐外聯絡官3名），本研究發現犯罪機會同時影響空間分工及社會網絡，這三個重要指標亦型塑了跨境電信詐欺的犯罪網絡。詐欺集團利用各類犯罪機會（犯罪者、標的物、監控缺乏及手法工具的聚合，其中監控包含國家、網路與金融管制層面），結合空間移動、分工與第三地機制，社會網絡強弱連帶與第三方機制，形成特殊運作機制，促使詐欺網絡成為無遠弗屆的全球犯罪體系；核心組成員與第三方既是連結也是斷點的關係，更是其中的運作關鍵。透過此種犯罪網絡分析，可深入瞭解全球跨境犯罪的運作概略，進而形成應對防治作法及刑事政策建議。 / In the Information Age, globalization has brought about the emergence of space of flows and the rise of network society. Its influence not only extends to the political, social, and economic levels, but also forms the global criminal economy. In Taiwan, fraud has occurred from direct contact format (such as face-to-face) to indirect ones (such as via telephones and the Internet). Owing to the government's comprehensive investigation and the cross-strait joint criminal judicial co-operation, the telecoms fraud groups recently have traveled across borders and even to the whole world. As the relevant research based on empirical data is scant, this research aims to discuss how criminal opportunities, spatial division of labor, and social networks construct a cross-border telecommunications fraud criminal network and the special operational mechanism behind it. In this research, I reviewed the relevant literature, analyzed empirical data, and then conducted in-depth interviews with 18 respondents which include 11 prisoners, 4 criminal investigators and 3 police liaison officers. It is concluded that criminal opportunities would influence the spatial division of labor and social networks within criminal groups; these three important indicators formulate the criminal network of cross-border telecommunications fraud. A special operational mechanism combining various criminal opportunities (the convergence of offenders, targets, absence of guardians, and means; in which guardians include the level of national, cyber and financial regulations), spatial mobility and division of labor with the third-place mechanism, and strong and weak ties of social networks with the third-person mechanism, transforms fraud networks into a far-reaching global criminal system. The relationship between core group members and the third-person is not only a link but also a breakpoint, and it is undoubtedly the operational key. Ultimately, this research paints a clear picture of the global criminal networks and thus will possibly benefit the development of future criminal prevention and correction policies.

Le présent mémoire s’intéresse à la déstabilisation d’un réseau de distribution de stupéfiants. Il est basé sur l’étude d’une enquête policière réalisée dans une grande ville canadienne. L’objectif principal de cette enquête était le démantèlement d’un réseau criminel perçu comme étant hiérarchisé. Différentes stratégies ont été mises en œuvre par les enquêteurs afin de déstabiliser le réseau. Cinq de ces stratégies sont étudiées dans cette recherche. Des analyses de réseaux et l’évaluation de l’évolution des opérations de distribution de stupéfiants démontrent que, parmi les stratégies déstabilisatrices, le retrait sélectif (arrestation) et l’ajout (infiltration) de participants dans le réseau sont les plus efficaces. Les résultats détaillés montrent l’importance de préparer des enquêtes systématiques et réfléchies en vue de déstabiliser un réseau. Bien que les rafles massives de participants soient intéressantes, il est essentiel d’en soulever les limites. Le fait de se concentrer sur des enquêtes planifiées permettra non seulement de répondre aux objectifs de l’enquête en cours, mais également de comprendre et développer des pratiques de déstabilisation à long terme au niveau du marché criminel en général (méta-réseau). / This research focuses on the disruption of a drug distribution network and is based on a case study of a law-enforcement investigation conducted in a major Canadian city. The aim of the investigation was to dismantle a criminal network that was perceived to be hierarchically structured. Different strategies were applied by the investigating team to disrupt the network. Five of these strategies are studied in the present research. Network analyses and an assessment of the evolution of the drug distribution operation demonstrate that, amongst the set of disrupting strategies, those aimed at the selective removal (arrests) and addition (infiltration) of actors to the network were most effective. The details surrounding such findings highlight the importance of preparing well-planned and systematic investigations following such guidelines, while also pointing to the limits of massive crackdowns that lead to the arrests of all participants in a criminal network. Conceiving such a focus will not only meet the short-term objectives of a police investigation, but also allow for an understanding that is crucial to develop long-term disruptive practices of not simply the operation under investigation but the wider criminal network environment surrounding it.

Le présent mémoire s’intéresse à la déstabilisation d’un réseau de distribution de stupéfiants. Il est basé sur l’étude d’une enquête policière réalisée dans une grande ville canadienne. L’objectif principal de cette enquête était le démantèlement d’un réseau criminel perçu comme étant hiérarchisé. Différentes stratégies ont été mises en œuvre par les enquêteurs afin de déstabiliser le réseau. Cinq de ces stratégies sont étudiées dans cette recherche. Des analyses de réseaux et l’évaluation de l’évolution des opérations de distribution de stupéfiants démontrent que, parmi les stratégies déstabilisatrices, le retrait sélectif (arrestation) et l’ajout (infiltration) de participants dans le réseau sont les plus efficaces. Les résultats détaillés montrent l’importance de préparer des enquêtes systématiques et réfléchies en vue de déstabiliser un réseau. Bien que les rafles massives de participants soient intéressantes, il est essentiel d’en soulever les limites. Le fait de se concentrer sur des enquêtes planifiées permettra non seulement de répondre aux objectifs de l’enquête en cours, mais également de comprendre et développer des pratiques de déstabilisation à long terme au niveau du marché criminel en général (méta-réseau). / This research focuses on the disruption of a drug distribution network and is based on a case study of a law-enforcement investigation conducted in a major Canadian city. The aim of the investigation was to dismantle a criminal network that was perceived to be hierarchically structured. Different strategies were applied by the investigating team to disrupt the network. Five of these strategies are studied in the present research. Network analyses and an assessment of the evolution of the drug distribution operation demonstrate that, amongst the set of disrupting strategies, those aimed at the selective removal (arrests) and addition (infiltration) of actors to the network were most effective. The details surrounding such findings highlight the importance of preparing well-planned and systematic investigations following such guidelines, while also pointing to the limits of massive crackdowns that lead to the arrests of all participants in a criminal network. Conceiving such a focus will not only meet the short-term objectives of a police investigation, but also allow for an understanding that is crucial to develop long-term disruptive practices of not simply the operation under investigation but the wider criminal network environment surrounding it.

Studien syftade till att undersöka förekomsten samt utformningen av samarbeten mellan kriminella nätverk, samt vad dessa aspekter har för betydelse för brottsligheten. Vidare ämnade studien att kvalitativt undersöka de kriminella nätverkens penningtransaktioner till utlandet, samt hur dessa kunde kopplas till tidigare forskning, med avsikt att få en djupare förståelse kring internationell ekonomisk brottslighet. Centralt för detta arbete var det material som undersöktes i form av domslut, med tillhörande förundersökningsprotokoll, gällande valutaväxlingskontoret World Exchange. Den valda metoden social nätverksanalys (SNA) användes för att kartlägga nätverkspositioner och deras relationer. En kvalitativ analys applicerades beträffande de internationella transaktionerna som fördjupades med hjälp av den tillgängliga Encrochatbevisningen. Resultaten visade på att det förekommer en viss grad av gruppöverskridande brottsliga samarbeten - nexus - mellan de studerade nätverken. De mer tongivande nätverken, inom kontexten för transaktionerna inom World Exchange, påvisades även inneha en central position gällande de ekonomiska transaktioner som överfördes till utlandet. / The study aimed to investigate the existence and design of nexus between criminal networks and what significance these aspects have for criminality. Furthermore, the study aimed to qualitatively examine the criminal networks money transactions abroad, and how these could be linked to previous research, with the intention of gaining a deeper understanding of international economic crime. Central to this work was the material examined in the form of verdicts, with accompanying preliminary investigation protocols, concerning the currency exchange office World Exchange. The chosen method Social Network Analysis (SNA) was used to map network positions and their relationships. A qualitative analysis was applied to the international transactions that were deepened using the available Encrochats. The results showed that there is a certain degree of cross-group criminal cooperation - nexus - between the studied networks. Additionally, the results exhibited that the more dominant networks, within the context of the transactions within World Exchange, also held a central position regarding the financial transactions transferred abroad.