On Secrecy Capacity of Fast Fading MIMOME Wiretap Channels With Statistical CSIT

In this paper, we consider secure transmissions in ergodic Rayleigh fast-faded multiple-input multiple-output multiple-antenna-eavesdropper (MIMOME) wiretap channels with only statistical channel state information at the transmitter (CSIT). When the legitimate receiver has more (or equal) antennas than the eavesdropper, we prove the first MIMOME secrecy capacity with partial CSIT by establishing a new secrecy capacity upper-bound. The key step is to form an MIMOME degraded channel by dividing the legitimate receiver's channel matrix into two submatrices, and setting one of the submatrices to be the same as the eavesdropper's channel matrix. Next, under the total power constraint over all transmit antennas, we analytically solve the channel-input covariance matrix optimization problem to fully characterize the MIMOME secrecy capacity. Typically, the MIMOME optimization problems are non-concave. However, thank to the proposed degraded channel, we can transform the stochastic MIMOME optimization problem to be a Schur-concave one and then find its solution. Besides total power constraint, we also investigate the secrecy capacity when the transmitter is subject to the practical per-antenna power constraint. The corresponding optimization problem is even more difficult since it is not Schuar-concave. Under the two power constraints considered, the corresponding MIMOME secrecy capacities can both scale with the signal-to-noise ratios (SNR) when the difference between numbers of antennas at legitimate receiver and eavesdropper are large enough. However, when the legitimate receiver and eavesdropper have a single antenna each, such SNR scalings do not exist for both cases.Comment: submitted to IEEE Transactions on Wireless Communication

Local Taxes and Parental Choice of Education: The Case of Pennsylvania

In this paper, we empirically examine the link between local taxes and education choice. Due to the endogenous relationship, 2SLS estimation is applied to correct for simultaneous equations bias. A total of 500 school districts in the state of Pennsylvania during the school years 1999-2000 to 2001-2002 are selected for a case study. Results indicate that local taxes per student are positively associated with private school enrollment rates, implying that increases in these enrollments greatly benefit public schools through tax support.Local Taxes

Implications of grade inflation: knowledge illusion and economic inefficiency in the knowledge market

In this paper, we adopt the neoclassical model of consumer choice and view students as a utility maximizer to investigate two implied issues caused by grade inflation – knowledge illusion and economic inefficiency in the knowledge market. These issues are important because they negatively impact the quality of higher education and weaken the signaling role of educational credentials in screening workers. More importantly, students eventually suffer a loss in well-being in the knowledge market and become less productive and competitive in the labor market.grade inflation; knowledge illusion; economic inefficiency

Alternative measure for education variable in an empirical economic growth model: Is primary education less important?

In this paper, an alternative measure of the education variable is proposed in an empirical economic growth model. Taiwan from 1964-2000 is selected as a case study. The main innovation of this paper is the weighting of education inputs by schooling level as an additional input into the application of production. Results reveal that primary education carries the greatest credits in Taiwan's economic development, which suggests that educators and policy makers value the importance of the foundation (i.e., primary education).

THE INCIDENCE AND WAGE EFFECTS OF OVEREDUCATION: THE CASE OF TAIWAN

This paper, based on data from Survey of Family Income and Expenditure of Taiwan, shows that the recent trends of job match in Taiwan labor market have been marked by increasing proportion of overeducated workers due to the higher education expansion policy, while the incidence of undereducation continues to decline. Furthermore, workers¡¯ economic position is not completely determined by their educational levels. Working experience also plays an important role in workers¡¯ job placement and their wages. Workers with relatively less working experience are more likely to be overeducated, while workers with relatively more working experience are more likely to be undereducated. Overeducated (Undereducated) workers would earn more (less) than their co-workers with adequate education but less (more) than the workers having the same educational level with adequate education for jobs. However, the rewards (penalties) to adequate education and overeducation (undereducation) decline as more experience accumulated. Evidence also shows effect of bumping down from overeducation on the wages and employment of lower educated workers.Overeducation, Wage, Bumping Down, Labor Market, Taiwan