U(1) flux tube profiles from Hamiltonian lattice gauge theory using a random walk ground-state projector

We use a self-guided random walk to solve the ground-state problem of Hamiltonian U(1) pure gauge theory in 2+1 dimensions in the string sector. By making use of the electric-field representation, we argue that the spatial distribution of the electric field can be more easily measured than in ordinary Monte Carlo simulations.Comment: 3 pages, contribution to Lattice 94, uuencoded compressed Postscrip

Backhaul-Aware Caching Placement for Wireless Networks

As the capacity demand of mobile applications keeps increasing, the backhaul network is becoming a bottleneck to support high quality of experience (QoE) in next-generation wireless networks. Content caching at base stations (BSs) is a promising approach to alleviate the backhaul burden and reduce user-perceived latency. In this paper, we consider a wireless caching network where all the BSs are connected to a central controller via backhaul links. In such a network, users can obtain the required data from candidate BSs if the data are pre-cached. Otherwise, the user data need to be first retrieved from the central controller to local BSs, which introduces extra delay over the backhaul. In order to reduce the download delay, the caching placement strategy needs to be optimized. We formulate such a design problem as the minimization of the average download delay over user requests, subject to the caching capacity constraint of each BS. Different from existing works, our model takes BS cooperation in the radio access into consideration and is fully aware of the propagation delay on the backhaul links. The design problem is a mixed integer programming problem and is highly complicated, and thus we relax the problem and propose a low-complexity algorithm. Simulation results will show that the proposed algorithm can effectively determine the near-optimal caching placement and provide significant performance gains over conventional caching placement strategies.Comment: 6 pages, 3 figures, accepted to IEEE Globecom, San Diego, CA, Dec. 201

Carbon Emission Trading Scheme and the Aviation Sector: An experimental analysis on allocation of allowances

The European Union has proposed a Directive to include aviation activities in the Emission Trading Scheme (ETS) in 2012. The allowance allocation method which will be put in place is relatively easy to implement with low administration cost. However, careful scrutiny suggests that the allocation method does not favor airlines with high energy efficiency. This study proposes an alternative allowance allocation method which is fairer in that it rewards energy efficient airlines. Further, the new method is easy to implement with low administrative cost. The Cournot model serves as the theoretical foundation upon which the experiments are designed to simulate the aviation industry under the ETS. The equilibrium is calculated for each allowance allocation method. Results from experiments suggest consistency with theoretical outcomes.

A Novel Three-Point Modulation Technique for Fractional-N Frequency Synthesizer Applications

This paper presents a novel three-point modulation technique for fractional-N frequency synthesizer applications. Convention modulated fractional-N frequency synthesizers suffer from quantization noise, which degrades not only the phase noise performance but also the modulation quality. To solve this problem, this work proposes a three-point modulation technique, which not only cancels the quantization noise, but also markedly boosts the channel switching speed. Measurements reveal that the implemented 2.4 GHz fractional-N frequency synthesizer using three-point modulation can achieve a 2.5 Mbps GFSK data rate with an FSK error rate of only 1.4 %. The phase noise is approximately -98 dBc/Hz at a frequency offset of 100 kHz. The channel switching time is only 1.1 μs with a frequency step of 80 MHz. Comparing with conventional two-point modulation, the proposed three-point modulation greatly improves the FSK error rate, phase noise and channel switching time by about 10 %, 30 dB and 126 μs, respectively

Voice Conversion Based on Cross-Domain Features Using Variational Auto Encoders

An effective approach to non-parallel voice conversion (VC) is to utilize deep neural networks (DNNs), specifically variational auto encoders (VAEs), to model the latent structure of speech in an unsupervised manner. A previous study has confirmed the ef- fectiveness of VAE using the STRAIGHT spectra for VC. How- ever, VAE using other types of spectral features such as mel- cepstral coefficients (MCCs), which are related to human per- ception and have been widely used in VC, have not been prop- erly investigated. Instead of using one specific type of spectral feature, it is expected that VAE may benefit from using multi- ple types of spectral features simultaneously, thereby improving the capability of VAE for VC. To this end, we propose a novel VAE framework (called cross-domain VAE, CDVAE) for VC. Specifically, the proposed framework utilizes both STRAIGHT spectra and MCCs by explicitly regularizing multiple objectives in order to constrain the behavior of the learned encoder and de- coder. Experimental results demonstrate that the proposed CD- VAE framework outperforms the conventional VAE framework in terms of subjective tests.Comment: Accepted to ISCSLP 201

Precise Frequency Measurement of the 21^{1}S0_{0}-31^{1}D2_{2} Two-Photon Transition in atomic 4^{4}He

We present the first precise frequency measurement of the 2$^{1}$S$_{0}$-3$^{1}$D$_{2}$ two-photon transition in $^{4}$He at 1009 nm. The laser source at 1009 nm is stabilized on an optical frequency comb to perform the absolute frequency measurement. The absolute frequency of 2$^{1}$S$_{0}$-3$^{1}$D$_{2}$ transition is experimentally determined to be 594 414 291 803(13) kHz with a relative uncertainty of 1.6 $\times$ 10$^{-11}$ which is more precise than previous determination by a factor of 25. Combined with the theoretical ionization energy of the 3$^{1}$D$_{2}$ state, the ionization energy of the 2$^{1}$S$_{0}$ state is determined to be 960 332 040 866(24) kHz. In addition, the deduced 2$^{1}$S$_{0}$ and 2$^{3}$S$_{1}$ Lamb shifts are 2806.817(24) and 4058.8(24) MHz respectively which are 1.6 times better than previous determinations.Comment: 5 pages, 6 figure

An evaluation of two new inference control methods

[[abstract]]An evaluation method is developed to measure the cost-effectiveness of two inference methods. The factors of the evaluation function consist of: preparation cost for the control method; query complexity; and security level under various attacks. The first control method is based on restriction, and the second on perturbation. Simulation results indicate that both methods have higher preparation cost, better security, and faster response time than L.H. Cox's method (1980) and L.L. Beck's method (1980). Finally, these two methods are compared to each other. In general, the control methods based on restriction have higher preparation cost and better security, and the control methods based on perturbation have fast response time for a query, but more information leak[[fileno]]2030204010032[[department]]資訊工程學

Determinants of left ventricular hypertrophy among elderly hypertensive in Malaysia

Left ventricular hypertrophy (LVH) has high prognostic value on cardiovascular mortality and morbidity. However, echocardiography is not routinely performed among elderly hypertensives in the primary-care setting due to limited resources. The aim of this study was to determine the prevalence of LVH and its associated risk factors in a multi- ethnic elderly hypertensive population in a primary-care clinic in Malaysia. This study was a sub-analysis of a cross-sectional study of 359 patients with hypertension in a primary-care clinic. All test subjects recruited for the study were hypertensive patients aged 60 and above. Blood pressure, height and weight were measured. All patients underwent an echocardiogram examination for diagnosis of LVH. One hundred and ninety-nine patients were studied for the analysis. The mean age and duration of hypertension was 64.8 (SD 2.9) and 10.4 (SD 7.7) years, respectively. The study found that 44.7% of respondents achieved target blood pressure. The prevalence of LVH was 23.6%. Using multiple logistic regression, factors associated with LVH among elderly patients with hypertension were diabetes (odds ratio [OR] 3.346, 95% confidence interval [CI] 1.458-7.676), higher diastolic blood pressure (OR: 1.088; 95% CI: 1.024-1.156), higher body mass index (OR: 1.113; 95% CI: 1.031-1.203) and poorer blood pressure control was 23.6%. Using multiple logistic regression, factors associated with LVH among elderly patients with hypertension were diabetes (odds ratio [OR] 3.346, 95% confidence interval [CI] 1.458-7.676), higher diastolic blood pressure (OR: 1.088; 95% CI: 1.024-1.156), higher body mass index (OR: 1.113; 95% CI: 1.031-1.203) and poorer blood pressure control (OR: 2.924; 95% CI: 1.180-7.258). Poor hypertension control, higher diastolic blood pressure, presence of diabetes and obesity are the predictors for the development of LVH in elderly hypertensive