Dynamic attribute based vehicle authentication

Modern vehicles are proficient in establishing a spontaneous connection over a wireless radio channel, synchronizing actions and information. Security infrastructure is most important in such a sensitive scope of vehicle communication for coordinating actions and avoiding accidents on the road. One of the first security issues that need to be established is authentication via IEEE 1609.2 security infrastructure. According to our preliminary work, vehicle owners are bound to preprocess a certificate from the certificate authority. The certificate carries vehicle static attributes (e.g., licence number, brand and color) certified together with the vehicle public key in a monolithic manner. Nevertheless, a malicious vehicle might clone the static attributes to impersonate a specific vehicle. Therefore, in this paper we consider a resource expensive attack scenario involving multiple malicious vehicles with identical visual static attributes. Apparently, dynamic attributes (e.g., location and direction) can uniquely define a vehicle and can be utilized to resolve the true identity of the vehicle. However, unlike static attributes, dynamic attributes cannot be signed by a trusted authority beforehand. We propose an approach to verify the coupling between non-certified dynamic attributes and certified static attributes on an auxiliary communication channel, for example, a modulated laser beam. Furthermore, we illustrate that the proposed approach can be used to facilitate the usage of existing authentication protocols such as NAXOS, in the new scope of ad-hoc vehicle networks. We use BAN logic to verify the security claims of the protocol against the passive and active interception.     

Optical solution for hard on average #P-complete instances (using exponential space for solving instances of the permanent)

Optical architectures that use exponential space for solving instances of the (non-necessarily-binary) permanent are presented. This is the first work to specifically focus on such hard on average problems. Two architectures are suggested the first is based on programmable masks, and the second on preprepared fixed number of masks.     

Choice coordination with limited failure

The Choice Coordination Problem requiresn asynchronous processes to reach a common choice of one out ofk possible alternatives. Processes communicate viak shared variables. Up tot, t, of the processes may fail to operate by suddenly quitting the protocol. Rabin (1982) presented lower and upper bounds for the extreme caset=n–1. We present deterministic and randomized algorithms for arbitraryt using an alphabet of sizeO(t ²). A semi-synchronous model is also studied. A reduction to a consensus problem proves the necessity to assume some powerful atomic shared-memory operations.     

Mother's insightfulness regarding their infants' internal experience: Relations with maternal sensitivity and infant attachment.

This study examined the associations among mothers' insightfulness into their infants' internal experience, mothers' sensitivity to their infants' signals, and infants' security of attachment to their mothers. The insightfulness of 129 mothers of 12-month-old infants was assessed by showing mothers 3 videotaped segments of observations of their infants and themselves and interviewing them regarding their infants' and their own thoughts and feelings. Interviews were classified into 1 insightful and 3 noninsightful categories. Mothers' sensitivity was assessed during play sessions at home and at the laboratory, and infant-mother attachment was assessed with the Strange Situation. Mothers classified as positively insightful were rated as more sensitive and were more likely to have securely attached children than were mothers not classified as positively insightful. Insightfulness also accounted for variance in attachment beyond the variance explained by maternal sensitivity. These findings add an important dimension to research on caregiving, suggesting that mothers' seeking of explanations for the motives underlying their infants' behavior is related to both maternal sensitivity and infant attachment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The parallel complexity of scheduling with precedence constraints

We study the problem of parallel computation of a schedule for a system of n unit-length tasks on m identical machines, when the tasks are related by a set of precedence constraints. We present NC algorithms for computing an optimal schedule in the case where m, the number of available machines, does not vary with time and the precedence constraints are represented by a collection of outtrees. The algorithms run on an exclusive read, exclusive write (EREW) PRAM. Their complexities are O(log n) and O((log n)²) parallel time using O(n²) and O(n) processors, respectively. The schedule computed by our algorithms is a height-priority schedule. As a complementary result we show that it is very unlikely that computing such a schedule is in NC when any of the above conditions is significantly relaxed. We prove that the problem is P-complete under logspace reductions when the precedence constraints are a collection of intrees and outtrees, or for a collection of outtrees when the number of available machines is allowed to increase with time. The time span of a height-priority schedule for an arbitrary precedence constraints graph is at most 2 − 1/(m − 1) times longer than the optimal (N. E Chen and C. L. Liu, Proc. 1974 Sagamore Computer Conference on Parallel Processing, T. Fend (Ed.), Springer-Verlag, Berlin, 1975, pp. 1–16). Whereas it is P-complete to produce the classical height-priority schedules even for very restricted precedence constraints graphs, we present a simple NC parallel algorithm which produces a different schedule that is only 2 − 1/m times the optimal.     

Psychophysiological detection through the guilty knowledge technique: Effect of mental countermeasures.

The effects of mental countermeasures on the efficiency of psychophysiological detection with the Guilty Knowledge Technique were examined in a mock-crime experiment with 4 groups of participants: innocent participants who were not involved in the mock crime, guilty controls who committed the mock crime but received no countermeasure instructions, guilty participants who received countermeasure instructions, and guilty participants who received countermeasure instructions and were allowed to practice the countermeasures. The countermeasure instructions encouraged participants to recall emotional situations from their past and imagine themselves in these situations during presentation of irrelevant questions. Results revealed a significant reduction in electrodermal detection efficiency under the 2 countermeasure conditions with no differences between them. No countermeasure effects were observed with the respiration line length measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)