Delay-Energy lower bound on Two-Way Relay Wireless Network Coding

Network coding is a novel solution that significantly improve the throughput and energy consumed of wireless networks by mixing traffic flows through algebraic operations. In conventional network coding scheme, a packet has to wait for packets from other sources to be coded before transmitting. The wait-and-code scheme will naturally result in packet loss rate in a finite buffer. We will propose Enhanced Network Coding (ENC), an extension to ONC in continuous time domain. In ENC, the relay transmits both coded and uncoded packets to reduce delay. In exchange, more energy is consumed in transmitting uncoded packets. ENC is a practical algorithm to achieve minimal average delay and zero packet-loss rate under given energy constraint. The system model for ENC on a general renewal process queuing is presented. In particular, we will show that there exists a fundamental trade-off between average delay and energy. We will also present the analytic result of lower bound for this trade-off curve, which can be achieved by ENC

Passive network tomography for erroneous networks: A network coding approach

Passive network tomography uses end-to-end observations of network communication to characterize the network, for instance to estimate the network topology and to localize random or adversarial glitches. Under the setting of linear network coding this work provides a comprehensive study of passive network tomography in the presence of network (random or adversarial) glitches. To be concrete, this work is developed along two directions: 1. Tomographic upper and lower bounds (i.e., the most adverse conditions in each problem setting under which network tomography is possible, and corresponding schemes (computationally efficient, if possible) that achieve this performance) are presented for random linear network coding (RLNC). We consider RLNC designed with common randomness, i.e., the receiver knows the random code-books all nodes. (To justify this, we show an upper bound for the problem of topology estimation in networks using RLNC without common randomness.) In this setting we present the first set of algorithms that characterize the network topology exactly. Our algorithm for topology estimation with random network errors has time complexity that is polynomial in network parameters. For the problem of network error localization given the topology information, we present the first computationally tractable algorithm to localize random errors, and prove it is computationally intractable to localize adversarial errors. 2. New network coding schemes are designed that improve the tomographic performance of RLNC while maintaining the desirable low-complexity, throughput-optimal, distributed linear network coding properties of RLNC. In particular, we design network codes based on Reed-Solomon codes so that a maximal number of adversarial errors can be localized in a computationally efficient manner even without the information of network topology.Comment: 40 pages, under submission for IEEE Trans. on Information Theor

Pushing on a String: State-Owned Enterprises and Monetary Policy Transmission in China

This paper studies whether monetary transmission in China is asymmetric. While researchers found an asymmetric transmission in the U.S. and other economies, China offers a specific rationale for asymmetries: the presence of state-owned enterprises (SOEs) enjoying preferential access to financing. To study the consequences of SOEs for policy transmission, we differentiate between expansionary and restrictive policy shocks and argue that SOEs should suffer less from a policy tightening and benefit more from a policy easing. Based on sector-specific macroeconomic time series and a large firm-level data set, we provide evidence of a systematic and sizable asymmetry in the transmission of monetary policy shocks in China. The nature of the asymmetry is consistent with the notion of explicit or implicit government-guarantees of SOEs and has consequences for the adjustment of aggregate variables. In contrast to other central banks, the People’s Bank of China seems to be able to “push on a string”

Leaders’ psychological capital and authentic leadership as predictors of employees’ perceptions of fairness

This research focused on understanding leaders’ psychological capital and authentic leadership as predictors of employees’ perceptions of fairness. In order to achieve this, four research objectives were set.These were: To provide an understanding of psychological capital, authentic leadership and employee perception of fairness, to determine whether there is an impact of a leader’s psychological capital on his/her authentic leadership, to establish the impact of authentic leadership on employee perception of fairness and to make recommendation on how organizational leaders can positively impact employee perception of fairness through authentic leadership. A quantitative research approach was used in addressing these objectives whereby questionnaires were used to collect data from 33 respondents who comprised of managers and employees of different organizations. The collected data was quantitatively analyzed using t the SPSS application, which was instrumental in testing the research hypotheses. Recommendations were also made based on the findings obtained in the researchEsta pesquisa concentrou-se na compreensão do capital psicológico dos líderes e da liderança autêntica como os indicadores para as perceções dos colaboradores sobre a equidade. Para realizar o trabalho, foram estabelecidos quarto objetivos da investigação, nomeadamente, para fornecer uma compreensão sobre o capital psicológico, a liderança autêntica e as perceções dos colaboradores sobre a equidade, para determinar se é existente um impacto do capital psicológico dos líderes em sua liderança autêntica, para estabelecer o impacto da liderança autêntica sobre a perceção dos colaboradores da equidade, e para fazer recomendações sobre como líderes organizacionais podem influenciar a perceção dos colaboradores sobre equidade através da liderança autêntica. Para abordar esses objetivos, utilizou-se abordagem quantitativa da pesquisa através da qual foram utilizados para recolher dados questionários feitos pelos trinta e três entrevistados, formados por gerentes e colaboradores de diferentes organizações. Os dados coletados foram analisados de forma quantitativa através da aplicação SPSS, que foi fundamental para testar as hipóteses de pesquisa. As recomendações também foram feitas com base nos resultados obtidos na pesquisa

Program analysis : termination proofs for Linear Simple Loops

Termination proof synthesis for simple loops, i.e., loops with only conjoined constraints in the loop guard and variable updates in the loop body, is the building block of termination analysis, as well as liveness analysis, for large complex imperative systems. In particular, we consider a subclass of simple loops which contain only linear constraints in the loop guard and linear updates in the loop body. We call them Linear Simple Loops (LSLs). LSLs are particularly interesting because most loops in practice are indeed linear; more importantly, since we allow the update statements to handle nondeterminism, LSLs are expressive enough to serve as a foundational model for non-linear loops as well. Existing techniques can successfully synthesize a linear ranking function for an LSL if there exists one. When a terminating LSL does not have a linear ranking function, these techniques fail. In this dissertation we describe an automatic method that generates proofs of (universal) termination for LSLs based on the synthesis of disjunctive ranking relations. The method repeatedly finds linear ranking functions on parts of the state space and checks whether the transitive closure of the transition relation is included in the union of the ranking relations. We have implemented the method and have shown experimental evidence of the effectiveness of our method

Data exploration by using the monotonicity property

Dealing with different misclassification costs has been a big problem for classification. Some algorithms can predict quite accurately when assuming the misclassification costs for each class are the same, like most rule induction methods. However, when the misclassification costs change, which is a common phenomenon in reality, these algorithms are not capable of adjusting their results. Some other algorithms, like the Bayesian methods, have the ability to yield probabilities of a certain unclassified example belonging to given classes, which is helpful to make modification on the results according to different misclassification costs. The shortcoming of such algorithms is, when the misclassification costs for each class are the same, they do not generate the most accurate results. This thesis attempts to incorporate the merits of both kinds of algorithms into one. That is, to develop a new algorithm which can predict relatively accurately and can adjust to the change of misclassification costs. The strategy of the new algorithm is to create a weighted voting system. A weighted voting system will evaluate the evidence of the new example belonging to each class, calculate the assessment of probabilities for the example, and assign the example to a certain class according to the probabilities as well as the misclassification costs. The main problem of creating a weighted voting system is to decide the optimal weights of the individual votes. To solve this problem, we will mainly refer to the monotonicity property. People have found the monotonicity property does not only exist in pure monotone systems, but also exists in non-monotone systems. Since the study of the monotonicity property has been a huge success on monotone systems, it is only natural to apply the monotonicity property to non-monotone systems too. This thesis deals only with binary systems. Though such systems hardly exist in practice, this treatment provides concrete ideas for the development of general solution algorithms. After the final algorithm has been formulated, it has been tested on a wide range of randomly generated synthetic datasets. It has also been compared with other existing classifiers. The results indicate this algorithm performs both effectively and efficiently

Lockdown Spillovers

Lockdowns imposed to fight the Covid-19 pandemic have cross-border effects. In this paper, we estimate the empirical magnitude of lockdown spillovers in a set of panel local projections. We use daily indicators of economic activity such as stock returns, effective exchange rates, NO2 emissions, mobility and maritime container trade. Lockdown shocks originating in the most important trading partners have a strong and significant adverse effect on economic activity in the home economy. For stock prices and exports, the spillovers can even be larger than the effect of domestic lockdown shocks. The results are robust with respect to alternative country weights used to construct foreign shocks, i.e. weights based on foreign direct investment or the connectedness through value chains. We find that lockdown spillovers have been par-ticularly strong during the first wave of the pandemic. Countries with a higher export share are particularly exposed to lockdown spillovers

Lessons for China from financial liberalization in Scandinavia

This study brings out policy lessons for China today, a financially repressed country, from the financial liberalization process in Denmakr, Finland, Norway and Sweden in the 1980s and early 1990s. This report identifies a set of policy lessons for China today from the experience of financial deregulation, financial crisis and recovery in Scandinavia during the period 1985-2000. Although there are considerable differences between the huge Chinese economy and the small Nordic countries, there are enough similarities to make lesson-drawing a worthwhile exercise. Based on the Scandinavian experience and the added complexity of China's status as a transition economy, financial reforms should strike a proper balance between being gradual (to avoid costly mistakes) and substantive (to secure efficiency gains in the longer term) with due consideration being given to initial conditions concerning regulation, taxes and exchange rate arrangements. A well managed process of financial deregulation requires that policy-makers and market participants fully understand the interlinkages between financial reforms and the rest of the economy. In addition, the supervisory and management systems in the financial sector should move in step with the liberalization process.Financial liberalization,financial crisis,transition,financial regulation,banking,boom-bust,China,Scandinavia,the Nordics