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We introduce a new genuinely 2N qubit state, known as the “mirror state” with interesting entanglement properties. The well known Bell and the cluster states form a special case of these “mirror states”, for N = 1 and N = 2 respectively. It can be experimentally realized using SWAP and multiply controlled phase shift operations. After establishing the general conditions for a state to be useful for various communicational protocols involving quantum and classical information, it is shown that the present state can optimally implement algorithms for the quantum teleportation of an arbitrary N qubit state and achieve quantum information splitting in all possible ways. With regard to superdense coding, one can send 2N classical bits by sending only N qubits and consuming N ebits of entanglement. Explicit comparison of the mirror state with the rearranged N Bell pairs and the linear cluster states is considered for these quantum protocols. We also show that mirror states are more robust than the rearranged Bell pairs with respect to a certain class of collisional decoherence.

Option backdating practices have resulted in broad regulatory scrutiny, formal inquiries by federal authorities, and internal investigations by companies. In this paper, we investigate stock market reactions to option backdating probe announcements. For the 245 implicated companies, we detect negative abnormal stock returns, which are modest for internal investigation, larger for SEC probes, and the most severe for Department of Justice investigations. We also find that the market reaction is more negative for companies with higher stock price volatility, less effective corporate governance, and lower quality of financial statements. Results suggest that option backdating practices demonstrate weak corporate governance and financial reporting, and regulatory investigations of such practices are value-relevant as reflected in stock prices.

Passwords are used for user authentication by almost every Internet service today, despite a number of wellknown weaknesses. Numerous attempts to replace passwords have failed, in part because changing users’ behavior has proven to be difficult. One approach to strengthening password-based authentication without changing user experience is to classify login attempts into normal and suspicious activity based on a number of parameters such as source IP, geo-location, browser configuration, and time of day. For the suspicious attempts, the service can then require additional verification, e.g., by an additional phone-based authentication step. Systems working along these principles have been deployed by a number of Internet services but have never been studied publicly. In this work, we perform the first public evaluation of a classification system for user authentication. In particular: (i) We develop a statistical framework for identifying suspicious login attempts. (ii) We develop a fully functional prototype implementation that can be evaluated efficiently on large datasets. (iii) We validate our system on a sample of real-life login data from LinkedIn as well as simulated attacks, and demonstrate that a majority of attacks can be prevented by imposing additional verification steps on only a small fraction of users. (iv) We provide a systematic study of possible attackers against such a system, including attackers targeting the classifier itself.

A mobile Adhoc Network (MANET) is a huddle of autonomous mobile nodes which dynamically forms a temporary multi-hoped radio network, without any use of previous infrastructure. Due to its characteristics like limited resources, changing topology and lack of centralized administration, MANET is exposed to various network layer attacks.

Copyright © 2015 ACM. In this work, we propose and evaluate an active learning algorithm in context of CPSGrader, an automatic grading and feedback generation tool for laboratory-based courses in the area of cyber-physical systems. CPSGrader detects the presence of certain classes of mistakes using test benches that are generated in part via machine learning from solutions that have the fault and those that do not (positive and negative examples). We develop a clustering-based active learning technique that selects from a large database of unlabeled solutions, a small number of reference solutions for the expert to label that will be used as training data. The goal is to achieve better accuracy of fault identification with fewer reference solutions as compared to random selection. We demonstrate the effectiveness of our algorithm using data obtained from an on-campus laboratory-based course at UC Berkeley.

Web services are increasingly adopting auxiliary authentication mechanisms to supplement the security provided by conventional password verification. In the domain of social network based web-services, Facebook has pioneered the use of social authentication as an auxiliary authentication mechanism. If Facebook detects a user login under suspicious circumstances, then users are asked to verify information about their friends (in addition to verifying their passwords). However, recent work has shown that Facebook’s social authentication is insecure. In this work-in-progress, we propose to rethink the design of social authentication. Our key insight is that online social network (OSN) operators are privy to large amounts of private data generated by users, including information about users’ online interactions. Based on this insight, we architect a system for social authentication that asks users to verify information about their social contacts and their interactions. Our system leverages information protected by privacy policies of OSNs to resist attacks, such as questions based on private user interactions including exchanging messages and poking social contacts. We implemented our system prototype as a Facebook application, and performed a preliminary user study to evaluate feasibility of the approach. Our initial experiments have been encouraging; we find that users have high rates of recall for information generated in the context of OSN interactions. Overall, our work provides a promising new direction for the secure and usable deployment of social authentication.

Comparison of heat transfer performance of a non-axisymmetric contoured endwall to a planar baseline endwall in presence of leakage flow through stator-rotor rim seal interface and mateface gap is reported in this paper. Heat transfer experiments were performed on a high turning (∼127°) turbine airfoil passage at Virginia Tech’s transonic blow down cascade facility under design conditions (exit isentropic Mach number 0.88 and 0° incidence) for two leakage flow configurations — 1) mateface blowing only, 2) simultaneous coolant injection from the upstream slot as well as mateface gap. Coolant to mainstream mass flow ratios (MFR) were 0.35% for mateface blowing only, whereas for combination blowing, a 1.0% MFR was chosen from upstream slot and 0.35% MFR from mateface. A common source of coolant supply to the upstream slot and mateface plenum made sure the coolant temperatures were identical at both upstream slot and mateface gap at the injection location. The contoured endwall geometry was generated to minimize secondary aerodynamic losses. Transient IR (Infrared) thermography technique was used to measure endwall surface temperature and a linear regression method was developed for simultaneous calculation of heat transfer coefficient (HTC) and adiabatic cooling effectiveness (ETA), assuming a 1D semi-infinite transient conduction. Results indicate reduction in local hot spot regions near suction side as well as area averaged HTC using the contoured endwall compared to baseline endwall for all coolant blowing cases. Contoured geometry also shows better coolant coverage profiles further along the passage. Detailed interpretation of the heat transfer results along with near endwall flow physics has also been discussed.Copyright © 2014 by Siemens Energy, Inc.

The present article investigates mixed out aerodynamic loss coefficient measurements for a high turning, contoured endwall passage under transonic operating conditions in presence of upstream purge slot and mateface gap. The upstream purge slot represents the gap between stator-rotor interface and the mateface gap simulates the assembly feature between adjacent airfoils in an actual high pressure turbine stage. While the performance of the mateface and upstream slot has been studied for lower Mach number, no studies exist in literature for transonic flow conditions. Experiments were performed at the Virginia Tech’s linear, transonic blow down cascade facility. Measurements were carried out at design conditions (isentropic exit Mach number of 0.88, design incidence) without and with coolant blowing. Upstream leakage flow of 1.0% coolant to mainstream mass flow ratio (MFR) was considered with the presence of mateface gap. There was no coolant blowing through the mateface gap itself. Cascade exit pressure measurements were carried out using a 5-hole probe traverse at a plane 1.0-Cax downstream of the trailing edge. Spanwise measurements were performed to complete the entire 2D loss plane from endwall to midspan, which were used to plot pitchwise averaged losses for different span locations and loss contours for the passage. Results reveal significant reduction in aerodynamic losses using the contoured endwall due to the modification of flow physics compared to a non-contoured planar endwall. The heat transfer experiments, designed to find the heat transfer coefficient and the film cooling effectiveness are described in detail in a separate paper [1].Copyright © 2014 by Siemens Energy, Inc.

Modern production system requires a high degree of automation for the feeding and handling of small, individual components, which tends to reduce both the production time and human labour. Mechanized feeders are used to bring components to be fed, from a disorderly state into the required orientation in required quantity for a particular process. Present study has been carried out with regard to the analysis of performance of a Rotary Hook feeder under certain variable factors. For this, the above-mentioned feeder has been developed. A series of experiments were carried out on cylindrical parts, and effect of different input parameters on the feed rate was studied graphically. Experimentation shows that the performance of this feeder depends upon various factors such as part population, number of hooks, speed, part sizes and blind/through-holed parts. However, only the first three parameters have been studied in the present case, and a mathematical model has been formulated. The design of experiments is done using 23 full-factorial method. Significance of individual factors as well as their interactions is examined using Design Experts Software. Analysis of Variance (ANOVA) method is used to predict proficiency of the model. This model also provides optimized feed rate for appropriate process parameters under given constraints.

In this paper, we examine if there are any prior return patterns for sector returns for BRICKS markets from January 1993 to February 2008. For short-term portfolio formation windows (up to 12 months), India and S.Africa report momentum behavior while South Korea reports reversals. For long-term formation windows (up to 60 months), Brazil exhibits momentum patterns which disappear for 60-12-12 strategies. India and Russia momentum patterns continue even for long-term portfolio formation windows South Korea, South Africa and China show weak reversals for long-term portfolio formation windows. We construct a sector factor based on Liu and Zhang (2008) argument that winner sector exhibit higher risk owing to stronger growth potential. We observe that a large part of prior return patterns in stock returns are absorbed by similar patterns in sector returns. Our findings shall be useful for portfolio managers and academicians with better insights about prior return patterns in sector data. The study contributes to the asset pricing and behavioral finance literature for emerging markets.

Momentum strategies have drawn great attention in investment management literature over last two decades. In this paper we examine three important propositions in Indian context (1) Do momentum profits persist for long time periods?, (2) Can these momentum profits be absorbed by risk models?, and (3) Is stock momentum an outcome of sectoral momentum?.We develop 6-6 and 12-12 investment strategies based on past returns as well as company characteristics. We find momentum profits in Indian context for our prior return portfolios which are stronger for 6-6 compared to 12-12 strategies. These momentum profits are larger for some characteristic sorted portfolios. Risk models such as CAPM and Fama French model significantly fail to capture momentum profits. In fact, winner portfolios generally comprise of large firm and high P/B stocks, thus defying the risk story. Some zero investment momentum based trading strategies do provide significant payoffs. We also observe momentum profits in sectoral returns. A part of stock momentum profits is captured by sectoral factor, thus implying that it may mainly be an outcome of sectoral momentum. Our findings are pertinent for portfolio managers and investment analysts who are continuously in pursuit of trading strategies that provide abnormal returns.

"Quantum conversation" is a way in which two parties can communicate classical information with each other using entanglement as a shared resource. We present this scheme using a multipartite entangled state after describing its generation through appropriate circuit diagrams. We make use of a discrimination scheme which allows one to perform a measurement on the system without destroying its entanglement. We later prove that this scheme is secure in a noiseless and a lossless quantum channel., Comment: 6 pages

The pervasiveness of option backdating practices has resulted in broad regulatory scrutiny, formal investigations by federal authorities and internal inquiries by more than 200 implicated companies. Prior studies (Yermack 1997; Aboody and Kasznik 2000; Lie 2005; Heron and Lie 2006) find a pattern of timing of stock option grants to influence stock prices. Option backdating happens when grant dates are managed retroactively to precede a run-up in underlying shares in an attempt to maximize the option value. We investigate capital market reactions to backdating probe announcements for a sample of 180 implicated companies and the link between such reactions and specific firm attributes. We detect, on average, negative abnormal returns for implicated companies. We also find that the market reaction is more negative for companies that have higher stock price volatility, less effective corporate governance resulting in shareholder lawsuits or departure of their executives, and more leverage. These results have implications for public companies, policy makers, regulators, and the investing and academic communities, as more companies are being investigated by federal authorities and their corporate governance, financial reporting and management integrity are being scrutinized.

The pervasiveness of option backdating practices has resulted in broad regulatory scrutiny, formal investigations by federal authorities and internal inquiries by more than 200 implicated companies. Prior studies (Yermack 1997; Aboody and Kasznik 2000; Lie 2005; Heron and Lie 2006) find a pattern of timing of stock option grants to influence stock prices. Option backdating happens when the actual grant dates are days, weeks, or months before or after their stated date. We investigate capital market reactions to backdating probe announcements for a sample of 180 implicated companies. We detect, on average, negative abnormal returns for implicated companies. We also find that the market reaction is more negative for companies that have higher stock price volatility, less effective corporate governance resulting in shareholder lawsuits or departure of their executives, and more leverage. These results have implications for public companies, policy makers, regulators, and the investing and academic communities, as more companies are being investigated by federal authorities and their corporate governance, financial reporting and management integrity are being scrutinized.

Constructing good quality fleet schedules is essential for an airline to operate in an effective and efficient way in order to accomplish high levels of consumer satisfaction and to maximise profits. The robustness of an airline schedule is an indicative measure of how good the schedule is because a robust plan allows the airline to cope with the unexpected disturbances which normally occur on a daily basis. This paper describes a method to measure the robustness of schedules for aircraft fleet scheduling within KLM Airlines. The method is based on the “Aircraft on Ground (ACOG)” measure, it employs statistical methods (although alternative methods were also considered) and it is shown to provide a good estimation of the robustness of a given schedule.

This paper covers the basis and design of the Blind audio guidance system. It describes a guidance system for blind and partially sighted people with the aim of coping in the known and unknown internal and external spaces without the assistance of human guides. This represents a significant step forward in the application of innovative techno- logical solutions to increase independence and improve the quality of life for people with disabilities. It describes the technical and functional architecture of the system for orientation and guidance of a blind person using available modern technology. The Blind Audio guidance is systems that will help blind people navigate through buildings. The system is implemented using proximity sensors (IR sensors) that are located at various locations in a particular building (say an organization).