• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6214-6242
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• 2019

Routing in mobile ad hoc networks is performed in a distributed fashion where each node acts as host and router, such that it forwards incoming packets for others without relying on a dedicated router. Nodes are mostly resource constraint and the users are usually inclined to conserve their resources and exhibit selfish behaviour by not contributing in the routing process. The trust and reputation models have been proposed to motivate selfish nodes for cooperation in the packet forwarding process. Nodes having bad trust or reputation are detected and secluded from the network, eventually. However, due to the lack of proper identity management and use of non-persistent identities in ad hoc networks, malicious nodes can pose various threats to these methods. For example, a malicious node can discard the bad reputed identity and enter into the system with another identity afresh, called whitewashing. Similarly, a malicious node may create more than one identity, called Sybil attack, for self-promotion, defame other nodes, and broadcast fake recommendations in the network. These identity-based attacks disrupt the overall detection of the reputation systems. In this paper, we propose a reputation-based scheme that detects selfish nodes and deters identity attacks. We address the issue in such a way that, for normal selfish nodes, it will become no longer advantageous to carry out a whitewash. Sybil attackers are also discouraged (i.e., on a single battery, they may create fewer identities). We design and analyse our rationale via game theory and evaluate our proposed reputation system using NS-2 simulator. The results obtained from the simulation demonstrate that our proposed technique considerably diminishes the throughput and utility of selfish nodes with a single identity and selfish nodes with multiple identities when compared to the benchmark scheme.

• 한국지능시스템학회논문지
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• 제22권1호
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• pp.12-21
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• 2012

IEEE 802.11 표준 무선 네트워크에서 사용되는 DCF(CSMA/CA) 방식의 MAC 프로토콜은 노드들 사이에서 공평한 채널 접근 확률을 보장하도록 설계되었다. 하지만 최근 급속히 확산되고 있는 무선 환경에서 다른 노드들보다 인위적으로 더 많은 데이터를 전송하는 노드가 존재하는 것이 사실이다. 이들 오동작 노드들은 더 많은 데이터를 보내기 위해서 자신의 MAC 프로토콜 동작을 변형시키거나 다른 노드들의 MAC 동작을 방해한다. 이러한 문제는 이기적(Selfish) 노드 문제라고 정의되어 왔으며, 지금까지의 대부분 연구들에서는 무선 랜 내부의 MAC 프로토콜 동작을 프레임 단위로 분석하여 이기적인 노드를 검색하는 방법을 제안하였으나 모든 종류의 이기적인 노드들을 효과적으로 검출할 수는 없었다. 이러한 단점을 보안하기 위해서 본 논문에서는 통계적 기법 중 하나인 뜨살리스-엔트로피(Tsallis-Entropy)를 사용하여 이기적인 노드 탐색 알고리즘을 제안한다. 뜨살리스-엔트로피는 확률 분포의 밀집도 혹은 분산정도를 효과적으로 나타낼 수 있는 척도이다. 제안한 알고리즘은 무선 랜을 구성하는 AP노드에서 동작하도록 설계되었으며, 무선 노드별로 데이터 간격에 대한 확률 분포를 추출해서 뜨살리스-엔트로피를 계산한 후 임계치와 비교하는 방법으로 이기적인 노드를 검출한다. 논문에서 제안한 이기적 노드 검출 알고리즘의 성능을 평가하기 위하여 다양한 무선 랜 환경(혼잡도, 이기적 노드 동작방법, 임계치)을 고려하여 시뮬레이션을 수행한다. 시뮬레이터는 ns2를 사용하였으며, 실험결과 제안한 방법의 이기적인 노드 검출률 이 매우 높음을 알 수 있다.

• Journal of Communications and Networks
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• 제17권4호
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• pp.440-448
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• 2015

In this paper, we study the problem of selfish behavior of secondary users (SUs) based on cognitive radio (CR) with the presence of primary users (PUs). SUs are assumed to contend on a channel using the carrier sense multiple access with collision avoidance (CSMA/CA) and PUs do not consider transmission of SUs, where CSMA/CA protocols rely on the random deference of packets. SUs are vulnerable to selfish attacks by which selfish users could pick short random deference to obtain a larger share of the available bandwidth at the expense of other SUs. In this paper, game theory is used to study the systematic cheating of SUs in the presence of PUs in multichannel CR networks. We study two cases: A single cheater and multiple cheaters acting without any restraint. We identify the Pareto-optimal point of operation of a network with multiple cheaters and also derive the Nash equilibrium of the network. We use cooperative game theory to drive the Pareto optimality of selfish SUs without interfering with the activity of PUs. We show the influence of the activity of PUs in the equilibrium of the whole network.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.355-370
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• 2014

Cooperative spectrum sensing has been considered as a promising approach to improve the sensing performance in distributed cognitive radio networks. However, there may exist some selfish secondary users (SUs) who are unwilling to cooperate. The presence of selfish SUs could cause catastrophic damage to the performance of cooperative spectrum sensing. Following the social perspective, we propose a Social Tie-based Incentive Scheme (STIS) to deal with the selfish problem for cooperative spectrum sensing in distributed cognitive radio networks. This scheme inspires SUs to contribute sensing information for the SUs who have social tie but not others, and such willingness varies with the strength of social tie value. The evaluation of each SU's social tie derives from its contribution for others. Finally, simulation results validate the effectiveness of the proposed scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권3호
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• pp.542-559
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• 2011

Most game-theoretic works of Aloha have emphasized investigating Nash equilibria according to the system state represented by the number of network users and their decisions. In contrast, we focus on the possible change of nodes' utility state represented by delay constraint and decreasing utility over time. These foregone changes of nodes' state are more likely to instigate selfish behaviors in networking environments. For such environment, in this paper, we propose a repeated Bayesian slotted Aloha game model to analyze the selfish behavior of impatient users. We prove the existence of Nash equilibrium mathematically and empirically. The proposed model enables any type of transmission probability sequence to achieve Nash equilibrium without degrading its optimal throughput. Those Nash equilibria can be used as a solution concept to thwart the selfish behaviors of nodes and ensure the system stability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권1호
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• pp.152-171
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• 2019

In opportunistic networks, nodes may appear some selfishness while transmitting the message, however, most of the existing research works consider the individual selfishness or social selfishness respectively, and these two types of selfishness may coexist in opportunistic networks. In this paper, we propose an Incentive Aware Routing based on Game Theory for selfish OPPNETs, named IAR-GT, which uses Rubinstein-Stahl bargaining game model to incentivize selfish nodes cooperation in data forwarding. IAR-GT scheme not only considers the resources of nodes, but also uses a new method to calculate the social ties between them. Trace-driven simulations show that our incentive aware routing scheme achieves better performances than comparing schemes under two types of selfishness coexistence environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권6호
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• pp.1996-2013
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• 2015

This paper considers a scenario that more D2D users exist in the cell, they compete for cellular resources to increase their own data rates, which may cause transmission interference to cellular users (CU) and the unfairness of resource allocation. We design a resource allocation scheme for selfish D2D users assisted by cooperative relay technique which is used to further enhance the users' transmission rates, meanwhile guarantee the QoS requirement of the CUs. Two transmission modes are considered for D2D users: direct transmission mode and cooperative relay transmission mode, both of which reuses the cellular uplink frequency resources. To ensure the fairness of resource distribution, Nash bargaining theory is used to determine the transmission mode and solve the bandwidth allocation problem for D2D users choosing cooperative relay transmission mode, and coalition formation game theory is used to solve the uplink frequency sharing problem between D2D users and CUs through a new defined "Selfish order". Through theoretical analysis, we obtain the closed Nash bargaining solution under CUs' rate constraints, and prove the stability of the formatted coalition. Simulation results show that the proposed resource allocation approach achieves better performance on resource allocation fairness, with only little sacrifice on the system sum rates.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5322-5342
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• 2016

In vehicle-to-vehicle (V2V) networks, where selfishness degrades node activity, countermeasures for collaboration enforcement must be provided to enable application of a sage and efficient network environment. Because vehicular networks feature both high mobility and various topologies, selfish behavior judgment and establishment of a stable routing protocol become intensely challenging. In this paper, a two-phase-based generous cooperative routing protocol (called GEC) is presented for V2V networks to provide resistance to selfishness. To detect selfish behaving vehicles, a packet forwarding watchdog and an average connection rate based on the multipath weight method are used, where evidence is gathered from different watchdogs. Then, multihop relay decisions are made using a generous cooperative algorithm based on game theory. Finally, through buffering of the multiple end-to-end paths and judicious choice of optimal cooperative routes, route maintenance phase is capable of dealing with congestion and rapidly exchanging traffic. Specifically, it is proved that the GEC is theoretically subgame perfect. Simulation results show that for V2V networks with inherently selfish nodes, the proposed method isolates uncooperative vehicles and is capable of accommodating both the mobility and congestion circumstances by facilitating information dissemination and reducing end-to-end delay.

• 한국정보과학회논문지:시스템및이론
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• 제35권9_10호
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• pp.417-420
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• 2008

우리는 이기적이고 비협조적인 사용자들이 이용하는 시스템의 성능을 최적화하는 문제를 다룬다. 사용자들이 요구하는 작업들은 각각의 속도함수를 가지고 있는 기계들에 스케줄 된다. 여기서 속도함수는 기계에 할당된 작업량에 반비례한다. 시스템의 성능은 기계들이 할당된 작업들의 수행을 끝내는 완료시간의 최대 값으로 평가한다. 이기적인 사용자들은 자신의 작업이 수행될 기계를 고를 수 있고 현재 가장 빠른 기계를 고른다. 그러나 이러한 스케줄은 시스템의 성능을 최적화하지 못한다. 사용자들의 이기적인 행동으로 발생되는 시스템의 성능 저하를 측정하는 기준으로서 Price of Anarchy(PoA)가 소개되었다. 이것은 내쉬 평형의 비용과 최적의 비용의 비율로 정의된다. 이 논문에서 우리는 위 스케줄링 문제에 대한 PoA를 평가한다.

• 미국학
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• 제43권1호
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• pp.99-114
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• 2020

This essay examines how Wallace Thurman envisions throug h Emma Lou a possibility of overcoming self-hatred and moving toward self-acceptance in his novel, The Blacker the Berry. Focusing on Emma Lou's departure from Alva and his deformed son, this essay contends that her "selfish" act is the first step toward self-acceptance. Describing his dark-skinned protagonist's pathetic attempts to belong to light-skinned people, Thurman mercilessly exposes and criticizes Emma Lou's psychological contradictions. Simultaneously, however, Thurman sympathizes with and shows some respect for her endeavors to make a difference in her life. Emma Lou's redemption from her self-hatred can come only when she realizes its detrimental effects on her life and learns to love herself enough to be selfish. By granting Emma Lou an opportunity to conduct a serious self-examination and resolve to sever ties with Alva, Thurman demonstrates a possibility of fighting against the color prejudice found both inside and outside oneself.