Twisted Reflection Positivity

Reflection positivity has several applications in both mathematics and physics. For example, reflection positivity induces a duality between group representations. In this thesis, we coin a new definition for a new kind of reflection positivity, namely, twisted reflection positive representation on a vector space. We show that all of the non-compactly causal symmetric spaces give rise to twisted reflection positive representations. We discover examples of twisted reflection positive representations on the sphere and on the Grassmannian manifold which are not unitary, namely, the generalized principle series with the Cosine transform as an intertwining operator. We give a direct proof for the reflection positivity of the Cosine transform on SO(n). On the other hand, we generalize an integrability theorem to the case of non-positive definite distribution. As a result, we give a relation between the non-compactly causal symmetric spaces and the reflection positive distributions. Cocycle conditions are also treated. We construct a general method to generate twisted reflection positive representations and then we apply it to get twisted reflection positive representations on the Euclidean space. Finally, we introduce a reflection positive cyclic distribution vector for the circle case. Then we prove that this distribution vector generates a well known reflection positive function

Janus: An Uncertain Cache Architecture to Cope with Side Channel Attacks

Side channel attacks are a major class of attacks to crypto-systems. Attackers collect and analyze timing behavior, I/O data, or power consumption in these systems to undermine their effectiveness in protecting sensitive information. In this work, we propose a new cache architecture, called Janus, to enable crypto-systems to introduce randomization and uncertainty in their runtime timing behavior and power utilization profile. In the proposed cache architecture, each data block is equipped with an on-off flag to enable/disable the data block. The Janus architecture has two special instructions in its instruction set to support the on-off flag. Beside the analytical evaluation of the proposed cache architecture, we deploy it in an ARM-7 processor core to study its feasibility and practicality. Results show a significant variation in the timing behavior across all the benchmarks. The new secure processor architecture has minimal hardware overhead and significant improvement in protecting against power analysis and timing behavior attacks.Comment: 4 pages, 4 figure

Formulating layered adjustable autonomy for unmanned aerial vehicles

Purpose - In this paper, we propose a Layered Adjustable Autonomy (LAA) as a dynamically adjustable autonomy model for a multi-agent system. It is mainly used to efficiently manage humans and agents share control of autonomous systems and maintain humans’ global control over the agents. Design/Methodology/Approach - We apply the LAA model in an agent-based autonomous Unmanned Arial Vehicle (UAV) system. The UAV system implementation consists of two parts, software, and hardware. The software part represents the controller and the cognitive and the hardware represents the computing machinery and the actuator of the UAV system. The UAV system performs three experimental scenarios of dance, surveillance and search missions. The selected scenarios demonstrate different behaviors in order to create a suitable test plan and ensure significant results. Findings - The results of the UAV system tests prove that segregating the autonomy of a system as multidimensional and adjustable layers enables humans and/or agents to perform actions in a convenient autonomy levels. Hence, reducing the adjustable autonomy drawbacks of constraining the autonomy of the agents, increasing humans’ workload and exposing the system to disturbances. Originality/value - The application of the LAA model in a UAV manifests the significance of implementing dynamic adjustable autonomy. Assessing the autonomy within three phases of agents run cycle (task-selection, actions-selection, actions-execution) is an original idea that aims to direct agents’ autonomy towards performance competency. The agents’ abilities are well exploited when an incompetent agent switches with a more competent on

National Cultures and Stock Prices: Evidence from the Emerging Markets

This report in the field of behavioral finance explores the effect of national culture factors and firm specific factors on the stock prices of publicly traded firms in the 36 countries in the emerging markets. Using linear regression, we tested 13 variables (three of them were Hofstede’s indices for Individualism, Uncertainty Avoidance, and Long-term Orientation) against the stock prices. We found that in the Africa, America, and Europe regions, the cultural factors had no significant effect on stock prices. On the other hand we found that only individualistic behavior had a significant effect on stock prices in businesses in Arab and Asia. Moreover, we found that a firm’s value and investment activities had a significant impact on stock prices in Africa and Asia regions, while a firm’s size had that impact in Latin America and Arab regions

Design of a Mechatronic Interface with Compliant Manipulator for Robot Assisted Echocardiography

Abstract A compliant manipulator with a compound soft actuator is proposed for robot-assisted echocardiography. The target application is devoted to the TOE echo (Trans-oesophageal echocardiography), which is conventionally performed by medical practitioners. The manual manipulation of the echocardiography probe shows significant risks such as human errors, exposure to ionizing radiation, and multitasking complexity. Automation of TOE provides advantages in terms of control, safety, and workload of the operator. This paper proposes a teleoperated robotic system assisting the physician to perform TOE, to be used in cardiac catheterization laboratories as well as hybrid operation theatres. A system containing a holder with master-slave Dynamixel servos and a manipulator with soft actuators has been developed. To alleviate the major lack of the previous designs in conducting the insertion tube, a robotic arm with a soft structure is proposed that has not hazards of conventional robot manipulators. The fundamental equations and relations for quasi-static control of the system are developed in this paper

Steps towards mathematical modeling of microcasting process from mesoscopic point of view

Microcasting is one of the significant technologies for the production of metallic micro parts with high aspect ratio (ratio of flow length to diameter). The aim of this research is to investigate scaling effects on mathematical formulation of fluid flow in micro casting and present governing differential equations. Keywords: microcasting,, microchannel, meso scele, fluid flow, mathematical modeling

Experimental Investigation of the Phase Equilibria in the Mg-Mn-{Ce, Nd} and Ce-Mg-Zn Ternary Systems and Diffusivity Measurements of the Mg-{Ce, Nd, Zn} and Zn-{Ce, Nd} Binary Systems

In this work, the 450°C Mg-Mn-{Ce, Nd} and 300°C Ce-Mg-Zn isothermal sections were established using diffusion couples and key alloys. The phase relationships were determined using XDR, EDS/WDS and metallography. Diffusion couples were also used to measure the interdiffusion coefficients of the Mg-{Ce, Nd, Zn} and Zn-{Ce, Nd} binary systems based on the experimental composition profiles and Boltzmann-Matano method. No ternary compounds were found in the Mg-Mn-{Ce, Nd} isothermal sections at 450°C. Microstructures of the ternary diffusion couples showed stationary Mn grain morphology in most of the diffusion zones. This was attributed to the affinity of Ce and Nd to Mg atoms, which forming several Mg-{Ce, Nd} binary compounds during the diffusion process. However, some of these binary compounds dissolved Mn. The ternary solubility of (γ-Ce)Mg,Mn, (CeMg), (CeMg3), (CeMg12), (α-Nd)Mg,Mn, (MgNd) and (Mg3Nd) was measured at 450°C to be 3.0, 5.1, 3.2, 1.8, 3.0, 13.0 and 3.7 at.% Mn, respectively. In both systems, the phase boundary lines were pointing towards the Mn-rich corner, except for the (α-Nd)Mg,Mn+Mn17Nd2+(MgNd) phase field. Eight ternary compounds were observed in the Ce-Mg-Zn isothermal section at 300°C. These are: τ1 (Ce6Mg3Zn19), τ2 (CeMg29Zn25), τ3 (Ce2Mg3Zn3), τ4 (CeMg3Zn5), τ5 iv (CeMg7Zn12), τ6 (CeMg2.3-xZn12.8+x; 0≤x≤1.1), τ7 (CeMgZn4) and τ8 (Ce(Mg1-yZny)11); 0.096≤y≤0.43). The ternary solubility of Zn in Ce-Mg compounds was found to increase with the decrease in Mg concentration. Accordingly, the ternary solid solubility of Zn in (CeMg12) and (CeMg3) was measured as 5.6 and 28.4 at.% Zn, respectively. Diffusion couples with Boltzmann-Matano analysis were used to calculate the interdiffusion coefficients of the Mg-{Ce, Nd, Zn} and Zn-{Ce, Nd} systems. A systematic annealing procedure was followed to obtain all expected phases in the studied systems. For the available literature data for some of the compounds in the Mg-{Ce, Nd, Zn} systems, the calculated interdiffusion coefficients are in good agreement. The activation energy and the pre-exponential factor for the growth of the Mg-{Ce, Nd, Zn} compounds were determined using Arrhenius equation. The activation energies of the growth of the Mg-Ce compounds showed relatively higher values than those of Mg-Nd and Mg-Zn compounds