In terms of security and privacy,mobile ad-hoc network(MANET)continues to be in demand for additional debate and development.As more MANET applications become data-oriented,implementing a secure and reliable data tran...In terms of security and privacy,mobile ad-hoc network(MANET)continues to be in demand for additional debate and development.As more MANET applications become data-oriented,implementing a secure and reliable data transfer protocol becomes a major concern in the architecture.However,MANET’s lack of infrastructure,unpredictable topology,and restricted resources,as well as the lack of a previously permitted trust relationship among connected nodes,contribute to the attack detection burden.A novel detection approach is presented in this paper to classify passive and active black-hole attacks.The proposed approach is based on the dipper throated optimization(DTO)algorithm,which presents a plausible path out of multiple paths for statistics transmission to boost MANETs’quality of service.A group of selected packet features will then be weighed by the DTO-based multi-layer perceptron(DTO-MLP),and these features are collected from nodes using the Low Energy Adaptive Clustering Hierarchical(LEACH)clustering technique.MLP is a powerful classifier and the DTO weight optimization method has a significant impact on improving the classification process by strengthening the weights of key features while suppressing the weights ofminor features.This hybridmethod is primarily designed to combat active black-hole assaults.Using the LEACH clustering phase,however,can also detect passive black-hole attacks.The effect of mobility variation on detection error and routing overhead is explored and evaluated using the suggested approach.For diverse mobility situations,the results demonstrate up to 97%detection accuracy and faster execution time.Furthermore,the suggested approach uses an adjustable threshold value to make a correct conclusion regarding whether a node is malicious or benign.展开更多
The Network Layer in wireless mesh networks is responsible for routing packets making it a prime target for intruders and hackers. Black-hole attack is a type of denial-of-service attack which when carried out can dis...The Network Layer in wireless mesh networks is responsible for routing packets making it a prime target for intruders and hackers. Black-hole attack is a type of denial-of-service attack which when carried out can disrupt the services of this layer. This paper takes a look at some important detection and mitigation techniques and presents the drawbacks. After analysis of current mechanisms, the paper proposes RID-AODV, a security solution for multiple black-hole attack in wireless mesh networks. Based on the backbone of AODV, RID-AODV combines the ability of route skipping of IDSAODV and route failure correction using reverse route establishment of RAODV. The enhanced protocol RID-AODV, AODV, IDSAODV, and RAODV are implemented in a simulated environment using ns-2.35 simulator. The networks for each protocol are bombarded with up to ten black-hole nodes starting from zero. The results obtained are then analyzed and compared and a discussion is presented.展开更多
We present the results of the spectral fits made to 59 Rossi X-ray Timing Explorer （RXTE） observations of the Galactic X-Ray Black-Hole Candidate XTE J1650–500 covering the first 30d of its 2001/2002 outburst when ...We present the results of the spectral fits made to 59 Rossi X-ray Timing Explorer （RXTE） observations of the Galactic X-Ray Black-Hole Candidate XTE J1650–500 covering the first 30d of its 2001/2002 outburst when the source was in a transition from the hard state to the soft state. The photon spectra can be well fit- ted with a phenomenological model of a power-law/cutoff power-law and a physical model of bulk-motion Comptonization. The spectral properties smoothly evolve away from the hard state and then stay in the soft state. The fitting results of the physical model reveal the peak of the burst had a flux of 2.90 × 10-8 erg cm-2 s-1 in the 2–100 keV energy range and was observed on 2001 Sep. 9; it transitioned to the hard state. The total flux decays by a factor of ～3 as it evolves into the soft state. The photon index Γ increases from ～1.5 in the hard state and stays at ～2.5 in the soft state. We found that the effective area of the high-energy X-ray emission region （the Compton cloud） decreases, i.e. the area of the Compton cloud decreases by a factor of ～23 during the transition from the hard state to the soft state. Combining the new radio and quasi-periodic oscillation studies, the model of total flux in the 2–100 keV energy range, the jet emission and the timing analysis during the state transition, we suggest a possible geometry and evolution for the （jet＋corona＋disk） system, like that proposed by Kalemci et al. based on enhanced lags and peak frequency shift during the transition.展开更多
In this work,we investigate a possible conceptual link between torus-shaped black hole solutions of the vacuum gravitational field equations in(1+3)-dimensional general relativity and mitochondrial DNA(mtDNA).We propo...In this work,we investigate a possible conceptual link between torus-shaped black hole solutions of the vacuum gravitational field equations in(1+3)-dimensional general relativity and mitochondrial DNA(mtDNA).We propose that this analogy could serve as a framework for transferring insights and methodologies between the study of mtDNA and toroidal black hole geometries.By establishing this connection,we aim to provide novel perspectives that could contribute to advancements in both theoretical physics and molecular biology,offering new tools for understanding complex structures in these disciplines.展开更多
A disformal rotating black-hole solution is a black-hole solution in quadratic degenerate higher-order scalar-tensor theories.It breaks the circular condition of spacetime different from the case of the usual Kerr spa...A disformal rotating black-hole solution is a black-hole solution in quadratic degenerate higher-order scalar-tensor theories.It breaks the circular condition of spacetime different from the case of the usual Kerr spacetime.This study investigated the dynamic behaviors of the motion of timelike particles in such disformal black-hole spacetime with an extra deformation parameter.Results showed that the characteristics of the particle’s motion depend on the sign of the deformation parameter.For the positive deformation parameter,the motion is regular and orderly.For the negative one,as the deformation parameter changes,the motion of the particles undergoes a series of transitions between the chaotic motion and the regular motion and falls into the horizon or escapes to spatial infinity.This means that the dynamic behavior of timelike particles in the disformal Kerr black-hole spacetime with noncircularity becomes richer than that in the usual Kerr black-hole case.展开更多
文摘In terms of security and privacy,mobile ad-hoc network(MANET)continues to be in demand for additional debate and development.As more MANET applications become data-oriented,implementing a secure and reliable data transfer protocol becomes a major concern in the architecture.However,MANET’s lack of infrastructure,unpredictable topology,and restricted resources,as well as the lack of a previously permitted trust relationship among connected nodes,contribute to the attack detection burden.A novel detection approach is presented in this paper to classify passive and active black-hole attacks.The proposed approach is based on the dipper throated optimization(DTO)algorithm,which presents a plausible path out of multiple paths for statistics transmission to boost MANETs’quality of service.A group of selected packet features will then be weighed by the DTO-based multi-layer perceptron(DTO-MLP),and these features are collected from nodes using the Low Energy Adaptive Clustering Hierarchical(LEACH)clustering technique.MLP is a powerful classifier and the DTO weight optimization method has a significant impact on improving the classification process by strengthening the weights of key features while suppressing the weights ofminor features.This hybridmethod is primarily designed to combat active black-hole assaults.Using the LEACH clustering phase,however,can also detect passive black-hole attacks.The effect of mobility variation on detection error and routing overhead is explored and evaluated using the suggested approach.For diverse mobility situations,the results demonstrate up to 97%detection accuracy and faster execution time.Furthermore,the suggested approach uses an adjustable threshold value to make a correct conclusion regarding whether a node is malicious or benign.
文摘The Network Layer in wireless mesh networks is responsible for routing packets making it a prime target for intruders and hackers. Black-hole attack is a type of denial-of-service attack which when carried out can disrupt the services of this layer. This paper takes a look at some important detection and mitigation techniques and presents the drawbacks. After analysis of current mechanisms, the paper proposes RID-AODV, a security solution for multiple black-hole attack in wireless mesh networks. Based on the backbone of AODV, RID-AODV combines the ability of route skipping of IDSAODV and route failure correction using reverse route establishment of RAODV. The enhanced protocol RID-AODV, AODV, IDSAODV, and RAODV are implemented in a simulated environment using ns-2.35 simulator. The networks for each protocol are bombarded with up to ten black-hole nodes starting from zero. The results obtained are then analyzed and compared and a discussion is presented.
基金partially supported by the Grant-in-Aid for Scientific Research on Priority Areas (Grant No. 14079101)financial supports from the National Natural Science Foundation of China (Grant No. 10778702)+1 种基金the National Basic Research Program of China (973 Program, Grant No. 2009CB824800)the Policy Research Program of Chinese Academy of Sciences (KJCX2-YWT24)
文摘We present the results of the spectral fits made to 59 Rossi X-ray Timing Explorer （RXTE） observations of the Galactic X-Ray Black-Hole Candidate XTE J1650–500 covering the first 30d of its 2001/2002 outburst when the source was in a transition from the hard state to the soft state. The photon spectra can be well fit- ted with a phenomenological model of a power-law/cutoff power-law and a physical model of bulk-motion Comptonization. The spectral properties smoothly evolve away from the hard state and then stay in the soft state. The fitting results of the physical model reveal the peak of the burst had a flux of 2.90 × 10-8 erg cm-2 s-1 in the 2–100 keV energy range and was observed on 2001 Sep. 9; it transitioned to the hard state. The total flux decays by a factor of ～3 as it evolves into the soft state. The photon index Γ increases from ～1.5 in the hard state and stays at ～2.5 in the soft state. We found that the effective area of the high-energy X-ray emission region （the Compton cloud） decreases, i.e. the area of the Compton cloud decreases by a factor of ～23 during the transition from the hard state to the soft state. Combining the new radio and quasi-periodic oscillation studies, the model of total flux in the 2–100 keV energy range, the jet emission and the timing analysis during the state transition, we suggest a possible geometry and evolution for the （jet＋corona＋disk） system, like that proposed by Kalemci et al. based on enhanced lags and peak frequency shift during the transition.
文摘In this work,we investigate a possible conceptual link between torus-shaped black hole solutions of the vacuum gravitational field equations in(1+3)-dimensional general relativity and mitochondrial DNA(mtDNA).We propose that this analogy could serve as a framework for transferring insights and methodologies between the study of mtDNA and toroidal black hole geometries.By establishing this connection,we aim to provide novel perspectives that could contribute to advancements in both theoretical physics and molecular biology,offering new tools for understanding complex structures in these disciplines.
基金supported by the National Natural Science Foundation of China(Grant Nos.11875026,11875025,12035005,and2020YFC2201403)。
文摘A disformal rotating black-hole solution is a black-hole solution in quadratic degenerate higher-order scalar-tensor theories.It breaks the circular condition of spacetime different from the case of the usual Kerr spacetime.This study investigated the dynamic behaviors of the motion of timelike particles in such disformal black-hole spacetime with an extra deformation parameter.Results showed that the characteristics of the particle’s motion depend on the sign of the deformation parameter.For the positive deformation parameter,the motion is regular and orderly.For the negative one,as the deformation parameter changes,the motion of the particles undergoes a series of transitions between the chaotic motion and the regular motion and falls into the horizon or escapes to spatial infinity.This means that the dynamic behavior of timelike particles in the disformal Kerr black-hole spacetime with noncircularity becomes richer than that in the usual Kerr black-hole case.
文摘声学黑洞结构因其优异的波能聚集特性在振动控制中受到广泛关注,但传统设计多基于低阻尼材料构建,其在高阻尼体系中的适用性仍缺乏验证。针对装备基座结构的振动抑制需求,提出一种基于阻尼材料本体构建的对称波导声学黑洞(symmetric waveguide acoustic black hole,SWABH)结构,并重点研究其在高阻尼条件下的能量聚集与耗散能力。仿真结果表明,SWABH结构在低频与宽频段内依然具备明显的波能汇聚特性,能有效提高能量耗散效率,并显著削弱基座结构的响应幅值。研究验证了该结构在高阻尼环境中应用于基座振动控制的可行性与有效性,为实现轻质宽频减振提供了新思路。
