3,126 research outputs found
Non-linear convergence in Asian interest rates and inflation rates
We examine the dynamics of convergence of the ASEAN5 plus the big three for nominal interest rates, inflation rates, and real interest rates. We test for convergence relative to the U.S and Japan, using monthly data over the period January 1990 - December 2010, using non-linear unit root tests. The results show strong evidence of stationary inflation and real interest rate differentials in all but China’s inflation differential relative to the U.S., and stationary nominal interest differentials in most of the cases. We interpret these results as convergence in inflation rates and real interest rates in all cases, and as nominal interest convergence in most of the cases. Moreover, examining the impact of the Asian crisis shows less number of convergences before the crisis and more convergences after the crisis. This suggests that convergence has increased after the 1997/98 Asian crisis, and that the crisis has pulled the economies together.interest rates convergence; inflation convergence; nonlinear unit root tests
Non-linearities in the dynamics of oil prices
We utilize non-linear models to examine the stationarity of oil prices (Brent, Dubai, WIT and World) over the period 1973:2-2011:2. Real oil prices are calculated and expressed in the domestic currencies of seven Asian countries (Indonesia, Japan, Korea, Malaysia, the Philippines, Singapore and Thailand) and in the U.S dollar. Applying linear unit root tests with and without structural breaks shows very limited evidence of stationarity. However, applying non-linear models shows evidence of non-linearity in all the cases. In most cases, we find significant evidence of exponential smooth transition autoregression (ESTAR) type non-linearity. Notably, the results for Japan suggest logistic (LSTAR) type non-linearity for the four oil prices. Applying unit root tests, which account for two types of non-linearities (smooth transition and nonlinear deterministic trends), reveals evidence of stationarity in all the cases.oil prices; nonlinear unit root tests; nonlinear deterministic trends; smooth transition autoregression
Electroweak Phase Transition in the U(1)' MSSM
In this work, we have investigated the nature of the electroweak phase
transition in the U(1) extended minimal supersymmetric standard model without
introducing any exotic fields. The effective potential has been estimated
exactly at finite temperature taking into account the whole particle spectrum.
For reasonable values of the lightest Higgs and neutralino, we found that the
electroweak phase transition could be strongly first order due to: (1) the
interactions of the singlet with the doublets in the effective potential, and
(2) the evolution of the wrong vacuum that delays the transition.Comment: substantial changes, references added, 18 pages, 4 figure
Using Agency Theory in Understanding Switching Behavior in B2B Service Industries “I”
Understanding switching behavior is a cornerstone in sustaining customer led marketing efforts especially in services which depend on long-term relationships with the customers and where the switching process is compound and costly for both the customer and the service provider. The issue of understanding the motives and barriers behind agency-brand switching behavior still needs further conceptual support and empirical investigation in service industries context, where the emphasis placed on investigating the actual switching motives without trying to conceptualize the issue, which if done will result in better understanding for the whole switching process. In this paper, the authors attempt to bridge this gap in the literature by examining the criterion validity of the switching behavior model using the agency theory, as the relation between the business company (principle) and an Advertising agency (the agent) could be described as agency relationship. Furthermore, this approach helps in supporting the efforts for retaining the business-to-business customers, strengthening the relationship with them, developing and adopting globally integrated customer led strategies in different countries, a trend which is expected to dominate the marketing field in the future due to the increasing role of the agency brand selection and switching in today’s world markets.Brand switching, agency theory, business to business marketing, service marketing, international advertising research
Acquired aortocameral fistula occurring late after infective endocarditis:An emblematic case and review of 38 reported cases
AIM To delineate the features and current therapeutic option of congenital and acquired aortocameral fistulas (ACF) secondary to iatrogenic or infectious disorders. METHODS From a PubMed search using the term "aortocameral fistula", 30 suitable papers for the current review were retrieved. Reviews, case series and case reports published in English were considered. Abstracts and reports from scientific meetings were not included. A total of 38 reviewed subjects were collected and analyzed. In addition, another case - an adult male who presented with ACF between commissures of the right and noncoronary sinuses and right atrium as a late complication of Staphylococcus aureus infective endocarditis of the AV - is added, the world literature is briefly reviewed. RESULTS A total of thirty-eight subjects producing 39 fistulas were reviewed, analyzed and stratified into either congenital (47%) or acquired (53%) according to their etiology. Of all subjects, 11% were asymptomatic and 89% were symptomatic with dyspnea (21 x) as the most common presentation. Diagnosis was established by a multidiagnostic approach in 23 (60%), single method in 14 (37%) (echocardiography in 12 and catheterization in 2), and at autopsy in 2 (3%) of the subjects. Treatment options included percutaneous transcatheter closure in 12 (30%) with the deployment of the Amplatzer duct or septal occluder and Gianturco coil and surgical correction in 24 (63%). CONCLUSION Acquired ACF is an infrequent entity which may occur late after an episode of endocarditis of the native AV. The management of ACF is generally by surgical correction but non-surgical device intervention has recently been introduced as a safe alternative
A Robust UWSN Handover Prediction System Using Ensemble Learning.
The use of underwater wireless sensor networks (UWSNs) for collaborative monitoring and marine data collection tasks is rapidly increasing. One of the major challenges associated with building these networks is handover prediction; this is because the mobility model of the sensor nodes is different from that of ground-based wireless sensor network (WSN) devices. Therefore, handover prediction is the focus of the present work. There have been limited efforts in addressing the handover prediction problem in UWSNs and in the use of ensemble learning in handover prediction for UWSNs. Hence, we propose the simulation of the sensor node mobility using real marine data collected by the Korea Hydrographic and Oceanographic Agency. These data include the water current speed and direction between data. The proposed simulation consists of a large number of sensor nodes and base stations in a UWSN. Next, we collected the handover events from the simulation, which were utilized as a dataset for the handover prediction task. Finally, we utilized four machine learning prediction algorithms (i.e., gradient boosting, decision tree (DT), Gaussian naive Bayes (GNB), and K-nearest neighbor (KNN)) to predict handover events based on historically collected handover events. The obtained prediction accuracy rates were above 95%. The best prediction accuracy rate achieved by the state-of-the-art method was 56% for any UWSN. Moreover, when the proposed models were evaluated on performance metrics, the measured evolution scores emphasized the high quality of the proposed prediction models. While the ensemble learning model outperformed the GNB and KNN models, the performance of ensemble learning and decision tree models was almost identical
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Mean-Line Design of a Supercritical CO2 Micro Axial Turbine
Supercritical carbon dioxide (sCO 2 ) power cycles are promising candidates for concentrated-solar power and waste-heat recovery applications, having advantages of compact turbomachinery and high cycle efficiencies at heat-source temperature in the range of 400 to 800 ∘ C. However, for distributed-scale systems (0.1–1.0 MW) the choice of turbomachinery type is unclear. Radial turbines are known to be an effective machine for micro-scale applications. Alternatively, feasible single-stage axial turbine designs could be achieved allowing for better heat transfer control and improved bearing life. Thus, the aim of this study is to investigate the design of a single-stage 100 kW sCO 2 axial turbine through the identification of optimal turbine design parameters from both mechanical and aerodynamic performance perspectives. For this purpose, a preliminary design tool has been developed and refined by accounting for passage losses using loss models that are widely used for the design of turbomachinery operating with fluids such as air or steam. The designs were assessed for a turbine that runs at inlet conditions of 923 K, 170 bar, expansion ratio of 3 and shaft speeds of 150k, 200k and 250k RPM respectively. It was found that feasible single-stage designs could be achieved if the turbine is designed with a high loading coefficient and low flow coefficient. Moreover, a turbine with the lowest degree of reaction, over a specified range from 0 to 0.5, was found to achieve the highest efficiency and highest inlet rotor angles
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