Strategic Defense and Attack for Series and Parallel Reliability Systems: Comment

The contest-theoretic literature on the attack and defense of networks of targets focuses primarily on pure-strategy Nash equilibria. Hausken\u27s 2008 European Journal of Operational Research article typifies this approach, and many of the models in this literature either build upon this model or utilize similar techniques. We show that Hausken\u27s characterization of Nash equilibrium is invalid for much of the parameter space examined and provides necessary conditions for his solution to hold. The complete characterization of mixed-strategy equilibria remains an open problem, although there exist solutions in the literature for special prominent cases

Aggressive Signaling in New World Warblers

In many animal species, communication can enable individuals to resolve conflict without the high potential costs involved in direct fighting. During contests, animals may exchange information about their aggressive motivational state. A central question throughout the study of animal communication research has been whether animal signals convey reliable information, and this question has been particularly relevant to communication during conflicts where the evolutionary interests of competitors directly oppose. Deceptive signaling of aggressive motivation would be highly favored by natural selection because it could allow individuals to gain access to resources they might not gain through direct combat. However, selection should also favor signal recipients to respond only to informative signals, and therefore only reliable signals are expected to be maintained over evolutionary time. Due to methodological limitations, there has been a lack of empirical research that has appropriately assessed the reliability of aggressive signals. In my dissertation, I seek to identify animal signals with potentially aggressive content, and to assess whether such signals do indeed reliably convey information about aggressive motivation. To do this, I combined both observational and experimental approaches focusing on vocal signaling in a clade of songbirds, the New World warblers, and in particular the black-throated blue warbler (Setophaga caerulescens). First, I asked how black-throated blue warblers use their vocal repertoires across different social contexts, and especially across contexts that vary in intensity of conflict, with the goal of identifying potentially important vocal signal features involved in aggressive escalation. I found that black-throated blue warbler songs fall into two acoustically distinct categories of song types, called type I and type II songs. The use of type II songs relative to type I songs increased with increasing intensity of agonistic interactions, especially during early stages of aggressive escalation. I also found that low-amplitude versions of songs (soft songs) were strongly associated with close range vocal interactions and were frequently produced just prior to fights. These results suggest that soft songs might convey information about a highly aggressive state, and that type II songs play a role in aggressive escalation. Next, I applied a recently developed experimental approach to ask whether signal features reliably predict subsequent aggressive behavior such as an attack by the signal sender. I conducted experimental trials in which subjects were provoked by playback of rivals’ signals, their vocal responses were documented, and then they were presented with a taxidermic model that could be attacked. I found that the use of soft song was an extremely reliable predictor of whether birds would subsequently attack the model. I then extended this approach to ask whether sequences of signals used during aggressive escalation might convey increasing levels of aggressive motivation. I simulated interactions that gradually increased in intensity by presenting subjects with two sequential and increasing levels of threat. I found that the use of type II song in response to the low threat level predicted later use of soft song in response to the high threat level, and that soft song, in turn, predicted attack of the model. These results provide evidence that animal signals not only reliably convey motivation to attack, but can also convey motivation to escalate to more intense stages of signaling. Next, I asked how generally these patterns of aggressive signaling might apply to other warbler species, and how aggressive signals might vary across species in this clade. I conducted experimental trials to identify signals that reliably predict future attack in two additional warbler species, the ovenbird (Seiurus aurocapillus), and the American redstart (Setophaga ruticilla), and compared findings to those obtained for black-throated blue warblers. I found that in all three species, the use of soft song reliably predicted future attack. Additionally, in ovenbirds, use of a non-song call, and in American redstarts the use of shortened songs and postural displays, were also reliable predictors of attack. These findings show an underlying commonality in reliable aggressive signaling among the three species, as well as species-specific diversity, and provide insights into processes of aggressive signal evolution. Finally, I conclude my dissertation by providing evidence that when aggressive interactions in songbirds do escalate to combat, such fighting can be costly and potentially fatal. I describe an observation where a male black-capped chickadee (Poecile atricapillus) appeared to kill another male during a competitive interaction. The two opponents were both high-ranking males, consistent with the prediction that mortal combat is most likely to occur between evenly matched individuals

Electronic voting : 6th International Joint Conference, E-Vote-ID 2021, virtual event, October 5-8, 2021

This book constitutes the proceedings of the 6th International Conference on Electronic Voting, E-Vote-ID 2021, held online -due to COVID -19- in Bregenz, Austria, in October 2021. The 14 full papers presented were carefully reviewed and selected from 55 submissions. The conference collected the most relevant debates on the development of Electronic Voting, from aspects relating to security and usability through to practical experiences and applications of voting systems, as well as legal, social or political aspects

Casanovas are liars : behavioral syndromes, sperm competition risk, and the evolution of deceptive male mating behavior in live-bearing fishes [version 2; referees: 2 approved, 1 approved with reservations]

Male reproductive biology can by characterized through competition over mates as well as mate choice. Multiple mating and male mate choice copying, especially in internally fertilizing species, set the stage for increased sperm competition, i.e., sperm of two or more males can compete for fertilization of the female’s ova. In the internally fertilizing fish Poecilia mexicana, males respond to the presence of rivals with reduced expression of mating preferences (audience effect), thereby lowering the risk of by-standing rivals copying their mate choice. Also, males interact initially more with a non-preferred female when observed by a rival, which has been interpreted in previous studies as a strategy to mislead rivals, again reducing sperm competition risk (SCR). Nevertheless, species might differ consistently in their expression of aggressive and reproductive behaviors, possibly due to varying levels of SCR. In the current study, we present a unique data set comprising ten poeciliid species (in two cases including multiple populations) and ask whether species can be characterized through consistent differences in the expression of aggression, sexual activity and changes in mate choice under increased SCR. We found consistent species-specific differences in aggressive behavior, sexual activity as well as in the level of misleading behavior, while decreased preference expression under increased SCR was a general feature of all but one species examined. Furthermore, mean sexual activity correlated positively with the occurrence of potentially misleading behavior. An alternative explanation for audience effects would be that males attempt to avoid aggressive encounters, which would predict stronger audience effects in more aggressive species. We demonstrate a positive correlation between mean aggressiveness and sexual activity (suggesting a hormonal link as a mechanistic explanation), but did not detect a correlation between aggressiveness and audience effects. Suites of correlated behavioral tendencies are termed behavioral syndromes, and our present study provides correlational evidence for the evolutionary significance of SCR in shaping a behavioral syndrome at the species level across poeciliid taxa

Risk-attitude-based defense strategy considering proactive strike, preventive strike and imperfect false targets

This paper analyzes the optimal strategies for the attacker and the defender in an attack–defense game, considering the risk attitudes of both parties. The defender moves first, allocating its limited resources to three different measures: launching a proactive strike or preventive strike, building false targets, and protecting its genuine object. It is assumed that (a) launching a proactive strike has limited effectiveness on its rival and does not expose the genuine object itself, (b) a false target might be correctly identified as false, and (c) launching a preventive strike consumes less resources than a proactive strike and might expose the genuine object. The attacker moves after observing the defender's movements, allocating its limited resources to three measures: protecting its own base from a proactive strike or preventive strike, building false bases, and attacking the defender's genuine object. For each of the defender's given strategies, the attacker chooses the attack strategy that maximizes its cumulative prospect value, which accounts for the players’ risk attitudes. Similarly, the defender maximizes its cumulative prospect value by anticipating that the attacker will always choose the strategy combination that maximizes its own cumulative prospect value. Backward induction is used to obtain the optimal defense, attack strategies, and their corresponding cumulative prospect values. Our results show that the introduction of risk attitudes leads the game to a lose-lose situation under some circumstances and benefits one party in other cases

Exploitation of Unintentional Information Leakage from Integrated Circuits

Unintentional electromagnetic emissions are used to recognize or verify the identity of a unique integrated circuit (IC) based on fabrication process-induced variations in a manner analogous to biometric human identification. The effectiveness of the technique is demonstrated through an extensive empirical study, with results presented indicating correct device identification success rates of greater than 99:5%, and average verification equal error rates (EERs) of less than 0:05% for 40 near-identical devices. The proposed approach is suitable for security applications involving commodity commercial ICs, with substantial cost and scalability advantages over existing approaches. A systematic leakage mapping methodology is also proposed to comprehensively assess the information leakage of arbitrary block cipher implementations, and to quantitatively bound an arbitrary implementation\u27s resistance to the general class of differential side channel analysis techniques. The framework is demonstrated using the well-known Hamming Weight and Hamming Distance leakage models, and approach\u27s effectiveness is demonstrated through the empirical assessment of two typical unprotected implementations of the Advanced Encryption Standard. The assessment results are empirically validated against correlation-based differential power and electromagnetic analysis attacks

Trade-offs between feeding competition and predation risk in baboons

This study investigates the influence of feeding competition and predation risk on the behaviour and ecology of baboons. Four groups of chacma baboons (Papio cynocephalus ursinus) were habituated and studied over 12 months between 1990-91 in the Pro-Namib desert region of Namibia. Each group differed in size and composition (with 1-6 adult males occupying groups of between 22-55 members), but their ranges overlapped extensively. Additional data were collected describing (1) food quality and availability and (2) biologically relevant measures of predation risk. The results suggest that contest competition for food or safety was minimal both within and between groups in this population. However, scramble competition for food did occur, despite high levels of food availability. Female reproductive state had little influence on feeding or anti-predator behaviour. Females and individuals in small groups were shown to be at the greatest risk of predation, and responded as predicted by exhibiting the highest levels of anti-predator behaviour. Habitat use reflected a trade-off between food availability and the reduction of both diurnal and nocturnal predation risk. Individual spatial position within groups was influenced by male reproductive strategies and predation risk, although social constraints might also have been present. Vigilance in males reflected reproductive strategies while in females vigilance was aimed at predator detection. Trade-offs between foraging and predation risk were suggested in the patterns of home range habitat composition, the use of habitat in the home range, the presence of scramble feeding competition, the choice of feeding site and the choice of diet. In addition, large groups reduced feeding competition at the expense of increased predation risk. Finally, points of special interest included the reduction of predation risk by both (1) the active use of "rest" time and (2) the defensive behaviour of male group members