1,454 research outputs found
Re-examining Symmetry of Shocks for East Asia: Results Using a VAR with Sign Restrictions
I revisit the hotly debated topic regarding the possibility of introducing a common currency for East Asia from the point of view of shock symmetry. I first point out a serious problem of the existing studies which use the VAR method with long-run restrictions developed by Blanchard and Quah (1989) in that the signs of the impulse response functions to the same structural shock are not necessarily consistent across the countries. This means that the high (low) correlations of structural shocks do not necessarily imply low (high) costs of a common currency area. To overcome this problem, I apply the VAR method with sign restrictions developed by Uhlig (2005). I used the AD-AS model to impose sign restrictions on the responses of GDP and CPI to demand and supply shocks. One main finding is that demand shocks are significantly positively correlated among almost all East Asian countries. But overall, East Asia as a whole is not suitable for a common currency because correlations of supply shocks are low.Structural VAR, Long run restriction, Sign restriction, Symmetry of Shocks, Common Currency, East Asia
Harmonic Allocation to Major Loads in Transmission Systems
A few decades ago, harmonic levels in electricity transmission networks were relatively low due to limited harmonic loads (such as renewable generation), low emissions from bulk supply points, high levels of synchronous generation and absorption from connected loads. Various international publications have forecasted that by 2030 many power systems around the world would have as high as 30% of renewable generation, e.g. solar and wind plants, which produce significant harmonics, and more than 60% increase in other harmonic producing loads (industrial, farming and residential equipment). This is coupled with the expected retirement of a large number of fossil-fuelled synchronous generators. Accordingly, growth in harmonic levels in the transmission network is anticipated.
The Australian power system landscape has already changed and will continue to move rapidly towards having more renewable energy sources and power electronic loads. Recently, state governments throughout Australia have confirmed their support for the development of Renewable Energy Zones (REZ), i.e. areas with high concentrations of renewable energy sources. In August 2020, the Australian Energy Market Operator (AEMO) published the Integrated System Plan (ISP), which provides a 20-year roadmap for the National Electricity Market (NEM) through the energy transition period to 2040. The ISP includes a 63% reduction in coal-fired synchronous generation, a 200% increase in Distributed Energy Resources and a 75% increase in solar and wind plants. These new technologies bring with them a wide range of harmonic issues; however, there has been no significant updates in the harmonic management of Australian transmission systems. In particular, the latest version of the Australian National Electricity Rules (NER), as of 17 September 2020, still referenced the 20 years old Australian and New Zealand Standard, i.e. AS/NZS 61000.3.6:2001. Transmission System Operators (TSOs) rely heavily on existing standards and guidelines, which have increasingly become less relevant and less effective for modern power systems. Urgent review and improvement of existing standards and guidelines are needed to avoid unnecessary impediment to the transition plan of power systems towards modern loads and higher renewable penetration platforms
A Cost Efficiency Analysis for Private Vehicles: Determinants for Households’ Choices of Vehicles Using a Household-Level Commute Data Approach
In attempts to evaluate the different levels of fuel efficiencies across different types of vehicles, this paper uses a household-level commute dataset to look at the different determinants for a household owning an efficient vehicle. Employing both an OLS and a Probit model, the empirical results illustrate that the current number of vehicles and the vehicle’s purchasing price are the attributes that most significantly affect the household’s probability to own an efficient vehicle. A similar analysis is adopted for the case of electric vehicles as well. A further analysis includes calculations for different total costs of owning vehicles with different fuel economies. The results of these calculations suggest that while the more efficient vehicle is more expensive to own at first, its benefits will outweigh its costs as the vehicle is utilized more
Context-aware CNNs for person head detection
Person detection is a key problem for many computer vision tasks. While face
detection has reached maturity, detecting people under a full variation of
camera view-points, human poses, lighting conditions and occlusions is still a
difficult challenge. In this work we focus on detecting human heads in natural
scenes. Starting from the recent local R-CNN object detector, we extend it with
two types of contextual cues. First, we leverage person-scene relations and
propose a Global CNN model trained to predict positions and scales of heads
directly from the full image. Second, we explicitly model pairwise relations
among objects and train a Pairwise CNN model using a structured-output
surrogate loss. The Local, Global and Pairwise models are combined into a joint
CNN framework. To train and test our full model, we introduce a large dataset
composed of 369,846 human heads annotated in 224,740 movie frames. We evaluate
our method and demonstrate improvements of person head detection against
several recent baselines in three datasets. We also show improvements of the
detection speed provided by our model.Comment: To appear in International Conference on Computer Vision (ICCV), 201
Inverse Problem for Fractional Diffusion Equation
MSC 2010: 26A33, 33E12, 34K29, 34L15, 35K57, 35R30We prove that by taking suitable initial distributions only finitely many measurements on the boundary are required to recover uniquely the diffusion coefficient of a one dimensional fractional diffusion equation. If a lower bound on the diffusion coefficient is known a priori then even only two measurements are sufficient. The technique is based on possibility of extracting the full boundary spectral data from special lateral measurements
A 60 GHz CMOS Power Amplifier for Wireless Communications
This paper presents a 60 GHz power amplifier (PA) suitable for wireless communications. The two-stage wideband PA is fabricated in 55 nm CMOS. Measurement results show that the PA obtains a peak gain of 16 dB over a -3 dB bandwidth from 57 GHz to 67 GHz. It archives an output 1 dB compression point (OP1dB) of 4 dbm and a peak power added efficiency (PAE) of 12.6%. The PA consumes a total DC power of 38.3 mW from a 1.2 V supply voltage while its core occupies a chip area of 0.45 mm2
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