Učinci hiperbaričnog kisika na vidne funkcije u bolesnika s ishemičnom optičkom neuropatijom

The effects of hyperbaric oxygen therapy were studied in nine patients with non-arteritic anterior ischaemic optic neuropathy, who had been unsatisfactorily treated with corticosteroids. In four patients with signs of optic disc atrophy there was no improvement of visual functions after hyperbaric oxygen treatment, whereas in the other five patients, who had no signs of optic disc atrophy, visual acuity and visual field improved. The achieved improvements were maintained al a control examination six months later. Results suggest that hyperbaric oxygen might be a new remedy for the selected cases of non-arteritic ischaemic optic neuropathy and call for a controlled clinical study aiming to acurately assess its efficacy.Ispitivani su učinci tretmana hiperbaričnim kisikom u devet bolesnika s nearteritičinim oblikom prednje ishemične optikoneuropatije, koji su prethodno liječeni kortikosteroidima bez uspjeha. U četiri bolesnika sa znakovima atrofije optičkog diska, nakon tretmana hiperbaričnim kisikom, nije nađeno nikakvo poboljšanje vidnih funkcija, dok je u ostalih pet, bez znakova atrofije optičkog diska, ustanovljeno poboljšanje oštrine vida i vidnog polja. Ova poboljšanja nađena su i na kontrolnom pregledu nakon šest mjeseci. Rezultati ispitivanja sugeriraju hiperbaričnu oksigenaciju kao moguć način liječenja selekcioniranih slučajeva nearteritičnog oblika ishemične optikoneuropatije, kao i kontrolirani klinički pokus, radi egzaktnijeg utvrđivanja efikasnosti hiperbarične oksigenacije u ovih bolesnika

When Eye-Tracking Meets Cognitive Modeling: Applications to Cyber Security Systems

Human cognitive modeling techniques and related software tools have been widely used by researchers and practitioners to evaluate the effectiveness of user interface (UI) designs and related human performance. However, they are rarely used in the cyber security field despite the fact that human factors have been recognized as a key element for cyber security systems. For a cyber security system involving a relatively complicated UI, it could be difficult to build a cognitive model that accurately captures the different cognitive tasks involved in all user interactions. Using a moderately complicated user authentication system as an example system and CogTool as a typical cognitive modeling tool, this paper aims to provide insights into the use of eye-tracking data for facilitating human cognitive modeling of cognitive tasks more effectively and accurately. We used visual scan paths extracted from an eye-tracking user study to facilitate the design of cognitive modeling tasks. This allowed us to reproduce some insecure human behavioral patterns observed in some previous lab-based user studies on the same system, and more importantly, we also found some unexpected new results about human behavior. The comparison between human cognitive models with and without eye-tracking data suggests that eye-tracking data can provide useful information to facilitate the process of human cognitive modeling as well as to achieve a better understanding of security-related human behaviors. In addition, our results demonstrated that cyber security research can benefit from a combination of eye-tracking and cognitive modeling to study human behavior related security problems

An analytic framework for modeling and detecting access layer misbehavior in wireless networks

The widespread deployment of wireless networks and hot spots that employ the IEEE 802.11 technology has forced network designers to put emphasis on the importance of ensuring efficient and fair use of network resources. In this work we propose a novel framework for detection of intelligent adaptive adversaries in the IEEE 802.11 MAC by addressing the problem of detection of the worst-case scenario attacks. Utilizing the nature of this protocol we employ sequential detection methods for detecting greedy behavior and illustrate their performance for detection of least favorable attacks. By using robust statistics in our problem formulation, we attempt to utilize the precision given by parametric tests, while avoiding the specification of the adversarial distribution. This approach establishes the lowest performance bound of a given Intrusion Detection System (IDS) in terms of detection delay and is applicable in online detection systems where users who pay for their services want to obtain the information about the best and the worst case scenarios and performance bounds of the system. This framework is meaningful for studying misbehavior due to the fact that it does not focus on specific adversarial strategies and therefore is applicable to a wide class of adversarial strategies

SAS-Based Authenticated Key Agreement

Abstract. Key agreement protocols are frequently based on the Diffie-Hellman protocol but require authenticating the protocol messages in two ways. This can be made by a cross-authentication protocol. Such protocols, based on the assumption that a channel which can authenticate short strings is available (SAS-based), have been proposed by Vaudenay. In this paper, we survey existing protocols and we propose a new one. Our proposed protocol requires three moves and a single SAS to be authenticated in two ways. It is provably secure in the random oracle model. We can further achieve security with a generic construction (e.g. in the standard model) at the price of an extra move. We discuss applications such as secure peer-to-peer VoIP. 1 The SAS-Based Authenticated Key Agreement Problem Secure communication channels are usually set up by authenticated key agreement protocols. This can be performed by relying on a public-key infrastructure, e.g. based on RSA [RSA78] or the Diffie-Hellman protocol [DH76]. Clearly, this is not well suited to the advent of mobile ad-hoc communications wher

Scheduling and Power Control for Energy-Optimality of Low Duty Cycled Sensor Networks

The main limitation of operating sensor networks autonomously is the finite battery capacity of sensor nodes. Sensors are usually operated at low duty cycle; that is, they remain in active mode for short duration of time, in order to prolong the network lifetime. However, operating at low duty cycle may result in significant performance degradation in system operation. Hence, in this work, we quantitatively investigate the tradeoff between the duty cyle and network performance. Specifically, we address the design of efficient channel access protocol, by developing a scheduling algorithm based on well known Lyapunov optimization framework. Our proposed policy dynamically schedules transmissions of sensor nodes and their sleep cycles by taking into account the time-varying channel state information, traffic arrivals, and energy consumptions due to switching between operational modes. We analytically show that our policy is energy optimal in the sense that it achieves an energy consumption which is arbitrarily close to the global minimum solution. We use simulations to confirm our results