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Hong Qi Zhang - One of the best experts on this subject based on the ideXlab platform.
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Optimal Strategy selection approach to moving target defense based on Markov robust game
Computers & Security, 2019Co-Authors: Hong Qi Zhang, Yu-qiao ChengAbstract:Abstract Moving target defense, as a “game-changing” security technique for network warfare, thwarts the apparent certainty of attackers by transforming the network resource vulnerabilities. In order to enhance the defense of unknown security threats, a novel of Optimal Strategy selection approach to moving target defense based on Markov robust game is first proposed in this paper. Firstly, moving target defense model based on moving attack and exploration surfaces is defined. Thus, the random emerging of vulnerabilities is described, as well as the cognitive and behavioral difference of offensive and defensive sides caused by defensive transformation. Based on it, Markov robust game model is constructed to depict the multistage and multistate features of moving target defense confrontation, in which the unknown prior information in incomplete information assumption are illustrated by combining Markov decision process with robust game theory. Further, the existence of Optimal Strategy of Markov robust game is proved. Additionally, by equivalent converting Optimal Strategy selection into a nonlinear programming problem, an efficient Optimal defensive Strategy selection algorithm is designed. Finally, simulation and deduction of the proposed approach are given in the case study so as to demonstrate the feasibility of constructed game model and effectiveness of the proposed approach.
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Incomplete information Markov game theoretic approach to Strategy generation for moving target defense
Computer Communications, 2018Co-Authors: Cheng Lei, Hong Qi Zhang, Li-ming Wan, Lu LiuAbstract:Abstract With the extensively study on moving target defense, Optimal Strategy generation has become one of the key problems in current research. A novel of incomplete information Markov game theoretic approach to Strategy generation for moving target defense is proposed to solve the existing problems. On the one hand, traditional matrix game structure and complete information assumption often fail to describe moving target defense confrontation accurately. To deal with this inaccuracy, moving target defense game model based on incomplete information Markov game theory is constructed by introducing moving attack surface and moving exploration surface concept, extending Optimal Strategy selection of moving target defense with incomplete information from mono-state or mono-phase to multi-stated and multi-phased. On the other hand, traditional models care little about defense cost in the process of Optimal Strategy generation. After comprehensively analyzing the impact of defensive cost and defensive benefit on Strategy generation, an Optimal Strategy generation algorithm is designed to prevent the deviation of the selected strategies from actual network conditions, thus ensuring the correctness of Optimal Strategy generation. Finally, simulation and deduction experiments have been performed in a case study so as to confirm the feasibility and the effectiveness of the proposed approach.
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Optimal Strategy Selection for Moving Target Defense Based on Markov Game
IEEE Access, 2017Co-Authors: Hong Qi ZhangAbstract:With the evolution of the research on network moving target defense (MTD), the selection of Optimal Strategy has become one of the key problems in current research. Directed to the problem of the improper defensive Strategy selection caused by inaccurately characterizing the attack and defense game in MTD, Optimal Strategy selection for MTD based on Markov game (MG) is proposed to balance the hopping defensive revenue and network service quality. On the one hand, traditional matrix game structure often fails to describe MTD confrontation accurately. To deal with this inaccuracy, MTD based on MG is constructed. Markov decision process is used to characterize the transition among network multi-states. Dynamic game is used to characterize the multi-phases of attack and defense in MTD circumstances. Besides, it converts all the attack and defense actions into the changes in attack surface or the ones in exploration surface, thus improving the universality of the proposed model. On the other hand, traditional models care little about defense cost in the process of Optimal Strategy selection. After comprehensively analyzing the impact of defense cost and defense benefit on the Strategy selection, an Optimal Strategy selection algorithm is designed to prevent the deviation of the selected strategies from actual network conditions, thus ensuring the correctness of Optimal Strategy selection. Finally, the simulation and the deduction of the proposed approach are given in case study so as to demonstrate the feasibility and effectiveness of the proposed Strategy Optimal selection approach.
Ricardas Zitikis - One of the best experts on this subject based on the ideXlab platform.
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an Optimal Strategy for maximizing the expected real estate selling price accept or reject an offer
Journal of statistical theory and practice, 2013Co-Authors: Martin Egozcue, Luis Fuentes Garcia, Ricardas ZitikisAbstract:Motivated by a real-life situation, we put forward a model and then derive an Optimal Strategy that maximizes the expected real-estate selling price when one of the only two remaining buyers has already made an offer but the other one has yet to make an offer. Since the seller is not sure whether the other buyer would make a lower or higher offer, and given no recall, the seller needs a Strategy to decide whether to accept or reject the first-come offer. The herein derived Optimal seller's Strategy, which maximizes the expected selling price, is illustrated under several scenarios, such as independent and dependent offers by the two buyers, and for several parametric price distributions.
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an Optimal Strategy for maximizing the expected real estate selling price accept or reject an offer
MPRA Paper, 2012Co-Authors: Martin Egozcue, Luis Fuentes Garcia, Ricardas ZitikisAbstract:Motivated by a real-life situation, we put forward a model and then derive an Optimal Strategy that maximizes the expected real-estate selling price when one of the only two remaining buyers has already made an offer but the other one is yet to make. Since the seller is not sure whether the other buyer would make a lower or higher offer, and given no recall, the seller needs a Strategy to decide whether to accept or reject the first-come offer. The herein derived Optimal seller's Strategy, which maximizes the expected selling price, is illustrated under several scenarios, such as independent and dependent offers by the two buyers, and for several parametric price distributions.
Hyeoncheol Gwon - One of the best experts on this subject based on the ideXlab platform.
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Optimal Strategy for provisional side branch intervention in coronary bifurcation lesions 3 year outcomes of the smart Strategy randomized trial
Jacc-cardiovascular Interventions, 2016Co-Authors: Young Bin Song, Taek Kyu Park, Jooyong Hahn, Jeong Hoon Yang, Jinho Choi, Seunghyuk Choi, Sang Hoon Lee, Hyeoncheol GwonAbstract:Abstract Objectives This study compared the long-term follow-up results of conservative versus aggressive strategies for provisional side branch (SB) intervention in coronary bifurcation lesions. Background The appropriate criteria for provisional SB ballooning or stenting have not been established. Methods A total of 258 patients with a large bifurcation lesion were randomized to a conservative or aggressive SB intervention Strategy. Different criteria applied for the initiation of SB intervention after main vessel stenting in the conservative and aggressive groups were Thrombolysis In Myocardial Infarction flow grade lower than 3 versus a stenosis diameter >75% for non–left main bifurcations, and a stenosis diameter >75% versus a stenosis diameter >50% for left main bifurcations. The primary endpoint was target vessel failure (TVF), defined as a composite of cardiac death, spontaneous myocardial infarction, or target vessel revascularization at 3 years. Results At 3 years, TVF occurred in 11.7% of the conservative group versus 20.8% of the aggressive group (p = 0.049). Although no significant differences were observed in the incidence of TVF between groups at 1 year (9.4% vs. 9.2%; p = 0.97), landmark analysis between 1 and 3 years showed significantly less TVF in patients assigned to the conservative Strategy (2.6% vs. 12.7%; p = 0.004). The crossover to the 2-stent technique was an independent predictor of TVF (hazard ratio: 5.42, 95% confidence interval: 2.03 to 14.5; p Conclusions A conservative Strategy compared with an aggressive Strategy for provisional SB intervention is associated with long-term benefits for patients with a large bifurcation lesion. (Optimal Strategy for Side Branch Stenting in Coronary Bifurcation Lesion; NCT00794014 )
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randomized comparison of conservative versus aggressive Strategy for provisional side branch intervention in coronary bifurcation lesions results from the smart Strategy smart angioplasty research team Optimal Strategy for side branch intervention in
Jacc-cardiovascular Interventions, 2012Co-Authors: Young Bin Song, Jooyong Hahn, Jeong Hoon Yang, Jinho Choi, Seunghyuk Choi, Sang Hoon Lee, Pilsang Song, Hyeoncheol GwonAbstract:Objectives The authors sought to compare conservative and aggressive strategies for provisional side branch (SB) intervention in coronary bifurcation lesions. Background The Optimal provisional approach for coronary bifurcation lesions has not been established. Methods In this prospective randomized trial, 258 patients with a coronary bifurcation lesion treated with drug-eluting stents were randomized to a conservative (n = 128) or aggressive (n = 130) SB intervention Strategy. The criteria for SB intervention after main vessel stenting differed between the conservative and aggressive groups; Thrombolysis In Myocardial Infarction flow grade 75% for non–left main bifurcations and diameter stenosis >75% versus diameter stenosis >50% for left main bifurcations. The primary endpoint was target vessel failure (cardiac death, myocardial infarction, or target vessel revascularization) at 12 months. Results Left main bifurcation lesions were noted in 114 patients (44%) and true bifurcation lesions in 171 patients (66%). SB ballooning after main vessel stenting and SB stenting after SB ballooning were performed less frequently in the conservative group than in the aggressive group (25.8% vs. 68.5%, p Conclusions Compared with the aggressive Strategy, the conservative Strategy for provisional SB intervention was associated with similar long-term clinical outcomes and a lower incidence of procedure-related myocardial necrosis. (Optimal Strategy for Side Branch Stenting in Coronary Bifurcation Lesions [SMART-Strategy]; NCT00794014 )
Huikyoung Jeon - One of the best experts on this subject based on the ideXlab platform.
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a randomized comparison of platinum chromium based everolimus eluting stents versus cobalt chromium based zotarolimus eluting stents in all comers receiving percutaneous coronary intervention host assure harmonizing Optimal Strategy for treatment of coronary artery stenosis safety effectiveness of drug eluting stents anti platelet regimen a randomized controlled noninferiority trial
Journal of the American College of Cardiology, 2014Co-Authors: Kyung Woo Park, Bonkwon Koo, Sihyuck Kang, Hyun Jae Kang, Byoungeun Park, Kwang Soo Cha, Jay Young Rhew, Huikyoung Jeon, Eunseok Shin, Myung Ho JeongAbstract:Objectives This study sought to test whether the newly developed platinum chromium (PtCr)-based everolimus-eluting stent (EES) is noninferior to the cobalt chromium (CoCr)-based zotarolimus-eluting stent (ZES) in all-comers receiving percutaneous coronary intervention (PCI). Background PtCr provides improved radial strength, conformability, and visibility compared with the CoCr alloy, but PtCr-based stents have not been tested in a wide range of patients receiving PCI. Also, recent case series have raised the issue of longitudinal stent deformation (LSD) with newer drug-eluting stents. Methods We randomly assigned 3,755 all-comers receiving PCI to PtCr-EES or CoCr-ZES. The primary outcome was target lesion failure (TLF) at 1-year post-PCI, defined as the composite of cardiac death, nonfatal target vessel–related myocardial infarction, and ischemia-driven target lesion revascularization. Post-hoc angiographic analysis was performed to qualitatively and quantitatively analyze LSD. Results At 1 year, TLF occurred in 2.9% and 2.9% of the population in the PtCr-EES and CoCr-ZES groups, respectively (superiority p = 0.98, noninferiority p = 0.0247). There were no significant differences in the individual components of TLF as well as the patient-oriented clinical outcome. Of 5,010 stents analyzed, LSD occurred in 0.2% and 0% in the PtCr-EES and CoCr-ZES groups, respectively (p = 0.104). There was no significant difference in post-deployment stent length ratio between the 2 stents (p = 0.352). Conclusions At 1 year, PtCr-EES was noninferior to CoCr-ZES in all-comers receiving PCI. Although LSD was observed only in PtCr-EES, both the stent length ratio and the frequency of LSD were not significantly different between the 2 stent types, and PtCr-EES was not associated with adverse clinical outcomes. (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis–SAfety & EffectiveneSS of Drug-ElUting Stents & Anti-platelet REgimen [HOST–ASSURE]; NCT01267734 )
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adjunctive cilostazol versus double dose clopidogrel after drug eluting stent implantation the host assure randomized trial harmonizing Optimal Strategy for treatment of coronary artery stenosis safety effectiveness of drug eluting stents anti platel
Jacc-cardiovascular Interventions, 2013Co-Authors: Kyung Woo Park, Bonkwon Koo, Sihyuck Kang, Jin Joo Park, Hanmo Yang, Hyun Jae Kang, Byoungeun Park, Kwang Soo Cha, Jay Young Rhew, Huikyoung JeonAbstract:Objectives This study sought to test the noninferiority of triple antiplatelet therapy (TAT) versus double-dose clopidogrel dual antiplatelet therapy (DDAT) in patients undergoing percutaneous coronary intervention (PCI). Background Antiplatelet regimen is an integral component of medical therapy after PCI. A 1-week duration of doubling the dose of clopidogrel was shown to improve outcome at 1 month compared with the conventional dose in patients with acute coronary syndrome undergoing PCI. Yet in Asia, the addition of cilostazol is used more commonly than DDAT in high-risk patients. Methods We randomly assigned 3,755 all-comers undergoing PCI to either TAT or DDAT, which was continued for 1 month, to test the noninferiority of TAT versus DDAT. The primary outcome was the cumulative incidence of net clinical outcome at 1 month post-PCI defined as the composite of cardiac death, nonfatal myocardial infarction, stent thrombosis, stroke, and PLATO (Platelet Inhibition and Patient Outcomes) major bleeding. Results TAT was noninferior to DDAT with respect to the primary outcome, which occurred in 1.2% and 1.4% of patients, respectively (−0.22% absolute difference, 0.34% 1-sided 97.5% confidence interval, p = 0.0007 for noninferiority; hazard ratio: 0.85; 95% confidence interval: 0.49 to 1.48; p = 0.558 for superiority). The individual risks of cardiac death, nonfatal myocardial infarction, stent thrombosis, stroke, and PLATO major bleeding did not differ significantly between the 2 groups. There were no significant between-group differences in the treatment effect with regard to the rate of the primary outcome. Conclusions The adjunctive use of cilostazol was noninferior to doubling the dose of clopidogrel for 1 month in all-comers undergoing PCI with exclusively drug-eluting stents. (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis–SAfety & EffectiveneSS of Drug-ElUting Stents & Anti-platelet REgimen [HOST-ASSURE]; NCT01267734 )
Kyung Woo Park - One of the best experts on this subject based on the ideXlab platform.
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a randomized comparison of platinum chromium based everolimus eluting stents versus cobalt chromium based zotarolimus eluting stents in all comers receiving percutaneous coronary intervention host assure harmonizing Optimal Strategy for treatment of coronary artery stenosis safety effectiveness of drug eluting stents anti platelet regimen a randomized controlled noninferiority trial
Journal of the American College of Cardiology, 2014Co-Authors: Kyung Woo Park, Bonkwon Koo, Sihyuck Kang, Hyun Jae Kang, Byoungeun Park, Kwang Soo Cha, Jay Young Rhew, Huikyoung Jeon, Eunseok Shin, Myung Ho JeongAbstract:Objectives This study sought to test whether the newly developed platinum chromium (PtCr)-based everolimus-eluting stent (EES) is noninferior to the cobalt chromium (CoCr)-based zotarolimus-eluting stent (ZES) in all-comers receiving percutaneous coronary intervention (PCI). Background PtCr provides improved radial strength, conformability, and visibility compared with the CoCr alloy, but PtCr-based stents have not been tested in a wide range of patients receiving PCI. Also, recent case series have raised the issue of longitudinal stent deformation (LSD) with newer drug-eluting stents. Methods We randomly assigned 3,755 all-comers receiving PCI to PtCr-EES or CoCr-ZES. The primary outcome was target lesion failure (TLF) at 1-year post-PCI, defined as the composite of cardiac death, nonfatal target vessel–related myocardial infarction, and ischemia-driven target lesion revascularization. Post-hoc angiographic analysis was performed to qualitatively and quantitatively analyze LSD. Results At 1 year, TLF occurred in 2.9% and 2.9% of the population in the PtCr-EES and CoCr-ZES groups, respectively (superiority p = 0.98, noninferiority p = 0.0247). There were no significant differences in the individual components of TLF as well as the patient-oriented clinical outcome. Of 5,010 stents analyzed, LSD occurred in 0.2% and 0% in the PtCr-EES and CoCr-ZES groups, respectively (p = 0.104). There was no significant difference in post-deployment stent length ratio between the 2 stents (p = 0.352). Conclusions At 1 year, PtCr-EES was noninferior to CoCr-ZES in all-comers receiving PCI. Although LSD was observed only in PtCr-EES, both the stent length ratio and the frequency of LSD were not significantly different between the 2 stent types, and PtCr-EES was not associated with adverse clinical outcomes. (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis–SAfety & EffectiveneSS of Drug-ElUting Stents & Anti-platelet REgimen [HOST–ASSURE]; NCT01267734 )
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adjunctive cilostazol versus double dose clopidogrel after drug eluting stent implantation the host assure randomized trial harmonizing Optimal Strategy for treatment of coronary artery stenosis safety effectiveness of drug eluting stents anti platel
Jacc-cardiovascular Interventions, 2013Co-Authors: Kyung Woo Park, Bonkwon Koo, Sihyuck Kang, Jin Joo Park, Hanmo Yang, Hyun Jae Kang, Byoungeun Park, Kwang Soo Cha, Jay Young Rhew, Huikyoung JeonAbstract:Objectives This study sought to test the noninferiority of triple antiplatelet therapy (TAT) versus double-dose clopidogrel dual antiplatelet therapy (DDAT) in patients undergoing percutaneous coronary intervention (PCI). Background Antiplatelet regimen is an integral component of medical therapy after PCI. A 1-week duration of doubling the dose of clopidogrel was shown to improve outcome at 1 month compared with the conventional dose in patients with acute coronary syndrome undergoing PCI. Yet in Asia, the addition of cilostazol is used more commonly than DDAT in high-risk patients. Methods We randomly assigned 3,755 all-comers undergoing PCI to either TAT or DDAT, which was continued for 1 month, to test the noninferiority of TAT versus DDAT. The primary outcome was the cumulative incidence of net clinical outcome at 1 month post-PCI defined as the composite of cardiac death, nonfatal myocardial infarction, stent thrombosis, stroke, and PLATO (Platelet Inhibition and Patient Outcomes) major bleeding. Results TAT was noninferior to DDAT with respect to the primary outcome, which occurred in 1.2% and 1.4% of patients, respectively (−0.22% absolute difference, 0.34% 1-sided 97.5% confidence interval, p = 0.0007 for noninferiority; hazard ratio: 0.85; 95% confidence interval: 0.49 to 1.48; p = 0.558 for superiority). The individual risks of cardiac death, nonfatal myocardial infarction, stent thrombosis, stroke, and PLATO major bleeding did not differ significantly between the 2 groups. There were no significant between-group differences in the treatment effect with regard to the rate of the primary outcome. Conclusions The adjunctive use of cilostazol was noninferior to doubling the dose of clopidogrel for 1 month in all-comers undergoing PCI with exclusively drug-eluting stents. (Harmonizing Optimal Strategy for Treatment of Coronary Artery Stenosis–SAfety & EffectiveneSS of Drug-ElUting Stents & Anti-platelet REgimen [HOST-ASSURE]; NCT01267734 )
