scholarly journals Optimal minimax rates against non-smooth alternatives

2021 ◽  
Author(s):  
Kohtaro Hitomi ◽  
Masamune Iwasawa ◽  
Yoshihiko Nishiyama
Keyword(s):  
Alternative Hypothesis ◽  
Error Variance ◽  
Smooth Functions ◽  
Engel Curves ◽  
Minimax Rates ◽  
Instrumental Variable Regression ◽  
Bounded Functions ◽  
The Difference ◽  
Set Up ◽  
Minimax Rate

Abstract This study investigates optimal minimax rates for specification testing when the alternative hypothesis is built on a set of non-smooth functions. The set consists of bounded functions that are not necessarily differentiable with no smoothness constraints imposed on their derivatives. In the instrumental variable regression set up with an unknown error variance structure, we find that the optimal minimax rate is n−1/4, where n is the sample size. The rate is achieved by a simple test based on the difference between non-parametric and parametric variance estimators. Simulation studies illustrate that the test has reasonable power against various non-smooth alternatives. The empirical application to Engel curves specification emphasizes the good applicability of the test.

Experimental Investigation into Driver Behavior along Curved and Parallel Diverging Terminals of Exit Interchange Ramps

2021 ◽  
pp. 036119812199742
Author(s):  
Alberto Portera ◽  
Marco Bassani
Keyword(s):  
Design Stage ◽  
Lane Change ◽  
Age And Gender ◽  
Traffic Conditions ◽  
Current Design ◽  
The Difference ◽  
Safety Countermeasures ◽  
And Gender ◽  
Set Up ◽  
Curve Radius

Current design manuals provide guidance on how to design exit ramps to facilitate driving operations and minimize the incidence of crashes. They also suggest that interchanges should be built along straight roadway sections. These criteria may prove ineffective in situations where there is no alternative to terminals being located along curved motorway segments. The paper investigates driving behavior along parallel deceleration curved terminals, with attention paid to the difference in impact between terminals having a curvature which is the same sign as the motorway segment (i.e., continue design), and those having an opposite curvature (i.e., reverse design). A driving simulation study was set up to collect longitudinal and transversal driver behavioral data in response to experimental factor variations. Forty-eight drivers were stratified on the basis of age and gender, and asked to drive along three randomly assigned circuits with off-ramps obtained by combining experimental factors such as motorway mainline curve radius (2 values), terminal length (3), curve direction (2), and traffic conditions (2). The motorway radius was found to be significant for drivers’ preferred speed when approaching the terminal. Terminal length and traffic volume do not have a significant impact on either longitudinal or transversal driver outputs. However, the effect of curve direction was found to be significant, notably for reverse terminals which do not compel drivers to select appropriate speeds and lane change positions. This terminal type can give rise to critical driving situations that should be considered at the design stage to facilitate the adoption of appropriate safety countermeasures.

Pump Performance Improvement by Restraining Back Flow in Screw-Type Centrifugal Pump

2005 ◽  
Vol 127 (4) ◽  
pp. 755-762 ◽  
Author(s):  
Yasushi Tatebayashi ◽  
Kazuhiro Tanaka ◽  
Toshio Kobayashi
Keyword(s):  
Pressure Fluctuations ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Simple Method ◽  
Back Flow ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Pump Head ◽  
The Difference ◽  
Set Up

The authors have been investigating the various characteristics of screw-type centrifugal pumps, such as pressure fluctuations in impellers, flow patterns in volute casings, and pump performance in air-water two-phase flow conditions. During these investigations, numerical results of our investigations made it clear that three back flow regions existed in this type of pump. Among these, the back flow from the volute casing toward the impeller outlet was the most influential on the pump performance. Thus the most important factor to achieve higher pump performance was to reduce the influence of this back flow. One simple method was proposed to obtain the restraint of back flow and so as to improve the pump performance. This method was to set up a ringlike wall at the suction cover casing between the impeller outlet and the volute casing. Its effects on the flow pattern and the pump performance have been discussed and clarified to compare the calculated results with experimental results done under two conditions, namely, one with and one without this ring-type wall. The influence of wall’s height on the pump head was investigated by numerical simulations. In addition, the difference due to the wall’s effect was clarified to compare its effects on two kinds of volute casing. From the results obtained it can be said that restraining the back flow of such pumps was very important to achieve higher pump performance. Furthermore, another method was suggested to restrain back flow effectively. This method was to attach a wall at the trailing edge of impeller. This method was very useful for avoiding the congestion of solids because this wall was smaller than that used in the first method. The influence of these factors on the pump performance was also discussed by comparing simulated calculations with actual experiments.

Telemedicine in pediatric and perinatal cardiology: Economic evaluation of a service in English hospitals

2007 ◽  
Vol 23 (1) ◽  
pp. 116-125 ◽  
Author(s):  
Robin Dowie ◽  
Hema Mistry ◽  
Tracey A. Young ◽  
Gwyn C. Weatherburn ◽  
Helena M. Gardiner ◽  
...  
Keyword(s):  
Older Children ◽  
Telemedicine Service ◽  
Clinical Events ◽  
District Hospitals ◽  
Nonsignificant Difference ◽  
Patient Groups ◽  
Women And Children ◽  
The Difference ◽  
Set Up ◽  
Mean Cost

Objectives:Pediatric cardiology has an expanding role in fetal and pediatric screening. The aims of this study were to observe how district hospitals use a pediatric telecardiology service, and to compare the costs and outcomes of patients referred to specialists by means of this service or conventionally.Methods:A telemedicine service was set up between a pediatric cardiac center in London and four district hospitals for referrals of second trimester women, newborn babies, and older children. Clinicians in each hospital decided on the role for their service. Clinical events were audited prospectively and costed, and patient surveys were conducted.Results:The hospitals differed in their selection of patient groups for the service. In all, 117 telemedicine patients were compared with 387 patients seen in London or in outreach clinics. Patients selected for telemedicine were generally healthier. For all patients, the mean cost for the initial consultation was £411 for tele-referrals and £277 for conventional referrals, a nonsignificant difference. Teleconsultations for women and children were significantly more expensive because of technology costs, whereas for babies, ambulance transfers were much more costly. After 6-months follow-up, the difference between referral methods for all patients was nonsignificant (telemedicine, £3,350; conventional referrals, £2,172), and nonsignificant within the patient groups.Conclusions:Telemedicine was perceived by cardiologists, district clinicians, and families as reliable and efficient. The equivocal 6-month cost results indicate that investment in the technology is warranted to enhance pediatric and perinatal cardiology services.

Reconfiguration and Unified Kinematics Analysis of a Metamorphic Parallel Mechanism With Bifurcated Motion

2012 ◽  
Author(s):  
Dongming Gan ◽  
Jian S. Dai ◽  
Lakmal D. Seneviratne
Keyword(s):  
Parallel Mechanism ◽  
Geometric Condition ◽  
Translation Vector ◽  
Kinematics Analysis ◽  
Constraint Equations ◽  
Mechanism Modeling ◽  
The Difference ◽  
Two Phases ◽  
Set Up ◽  
Joint Center

This paper introduced a new metamorphic parallel mechanism consisting of four reconfigurable rTPS limbs. Based on the reconfigurability of the reconfigurable Hooke (rT) joint, the rTPS limb has two phases while in one phase the limb has no constraint to the platform, in the other it constrains the spherical joint center to lie on a plane. This results in the mechanism to have ability of reconfiguration between different topologies with variable mobility. Geometric constraint equations of the platform rotation matrix and translation vector are set up based on the point-plane constraint, which reveals the bifurcated motion property in the topology with mobility 2 and the geometric condition with mobility change in altering to other mechanism topologies. Following this, a unified kinematics limb modeling is proposed considering the difference between the two phases of the reconfigurable rTPS limb. This is further applied for the mechanism modeling and both the inverse and forward kinematics is analytically solved by combining phases of the four limbs covering all the mechanism topologies.

scholarly journals Reproducibility of suppression of Pythium wilt of cucumber by compost

2014 ◽  
Vol 23 (3) ◽  
pp. 236-245 ◽  
Author(s):  
Mauritz Vilhelm Vestberg ◽  
Sanna Kukkonen ◽  
Päivi Parikka ◽  
Dan Yu ◽  
Martin Romantschuk
Keyword(s):  
Raw Materials ◽  
Dry Weight ◽  
Shoot Height ◽  
Bacterial Diseases ◽  
Sphagnum Peat ◽  
Shoot Dry Weight ◽  
Suppressive Capacity ◽  
The Difference ◽  
Set Up

There is increasing global interest in using compost to suppress soil-borne fungal and bacterial diseases and nematodes. We studied the reproducibility of compost suppressive capacity (SC) against Pythium wilt of cucumber using nine composts produced by the same composting plant in 2008 and 2009. A bioassay was set up in a greenhouse using cucumber inoculated with two strains of Pythium. The composts were used as 20% mixtures (v:v) of a basic steam-sterilized light Sphagnum peat and sand (3:1, v:v). Shoot height was measured weekly during the 5-week experiment. At harvest, the SC was calculated as the % difference in shoot dry weight (DW) between non-inoculated and inoculated cucumbers. The SC was not affected by year of production (2008 or 2009), indicating reproducibility of SC when the raw materials and the composting method are not changed. Differences in shoot height were not as pronounced as those for shoot DW. The results were encouraging, but further studies are still needed for producing compost with guaranteed suppressiveness properties.

scholarly journals Experimental tests for characterization of GPR antenna patterns

1994 ◽  
Vol 37 (5 Sup.) ◽  
Author(s):  
E. Pettinelli ◽  
N. Pierdicca ◽  
S. Piro ◽  
L. Versino
Keyword(s):  
Radiation Pattern ◽  
National Research Council ◽  
Experimental Tests ◽  
Radar Signal ◽  
Antenna Radiation ◽  
Buried Structures ◽  
Antenna Radiation Pattern ◽  
The Difference ◽  
Set Up

Detection and location of buried structures using the electromagnetic impulsive methodologies (GPR) require the study of the spatial distribution of energy irradiated by an antenna into the ground and the mechanisms of wave propagation and scattering from relevant targets. Evaluation of the difference in wave field distribution in the ground with respect to free space can provide some useful indications on the propagation of the Geo-radar signal in the ground and the spatial resolution capability of the GPR method. For this reason, a research group, involving “La Sapienza” University, Rome and the National Research Council began, during 1992, to perform studies on antenna radiation pattern, the propagation and scattering phenomena of GPR. This paper presents the experimental set up and the obtained results on the antenna radiation pattern.

scholarly journals THE EFFECT OF BLINDFOLD GAME ON STUDENTS’ VOCABULARY ACHIEVEMENT AT SMP NEGERI 13 KENDARI

2020 ◽  
Vol 5 (3) ◽  
pp. 200
Author(s):  
Andi An-Nisaa Arfin ◽  
Kamaluddin Kamaluddin ◽  
Wa Ode Fatmawati
Keyword(s):  
Junior High School ◽  
Alternative Hypothesis ◽  
First Grade ◽  
First Year ◽  
First Year Students ◽  
Comparison Research ◽  
Significant Difference ◽  
Post Test ◽  
The Difference ◽  
Vocabulary Achievement

The purpose of conducting this research is to examine the difference NGain scores between students who learn vocabulary with Blindfold Game and students who learn vocabulary without Blindfold Game at the first year students of SMP Negeri 13 Kendari. The samples of this research are the first grade four (VII-4) and the first grade three (VII-3) which consists of 27 students for each class. This research is conducted in comparison research design that consists of experimental class (VII-4) and controll class (VII-3). The data of this research are collected by giving pre-test and post-test in two classes (VII-4 & VII-3). The result shows that there is an improvement of the students’ vocabulary achievement. Independent samples t-test shows that, there is a significant difference in the Ngain scores for experimental class ( M = 60.08,  SD = 9.36 ) and controll class ( M = 20.41, SD = 14.56 ), t (52) = 11.904, p (0.000) < 0.05. Therefore, it can be concluded that the value of Sig (2 tailed) is lower than the significance α value (0.000 < 0.05). In other words, alternative hypothesis (H1) is accepted and the null hypothesis (H0) is rejected. It means that the Blindfold game can enrich students’ vocabulary achievement for Junior High School Student.

Pump Performance Improvement by Restraining Back Flow in Screw-Type Centrifugal Pump

2005 ◽  
Author(s):  
Yasushi Tatebayashi ◽  
Kazuhiro Tanaka ◽  
Toshio Kobayashi
Keyword(s):  
Pressure Fluctuations ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Simple Method ◽  
Back Flow ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Pump Head ◽  
The Difference ◽  
Set Up

The authors have been investigating the various characteristics of screw-type centrifugal pumps, such as pressure fluctuations in impellers, flow patterns in volute casings, and pump performance in air-water two-phase flow conditions. During these investigations, numerical results of our investigations made it clear that three back flow regions existed in this type of pump. Among these, the back flow from the volute casing toward the impeller outlet was the most influential on the pump performance. Thus the most important factor to achieve higher pump performance was to reduce the influence of this back flow. One simple method was proposed to obtain the restraint of back flow and so as to improve the pump performance. This method was to set up a Ring-like wall at the suction cover casing between the impeller outlet and the volute casing. Its effects on the flow pattern and the pump performance have been discussed and clarified to compare the calculated results with experimental results done under two conditions — namely, one with and one without this Ring-type wall. The influence of wall’s height on the pump head was investigated by numerical simulations. In addition, the difference due to the wall’s effect was clarified to compare its effects on two kinds of volute casing. From the results obtained it can be said that restraining the back flow of such pumps was very important to achieve higher pump performance. Furthermore, another method was suggested to restrain back-flow effectively. This method was to attach a wall at the trailing edge of impeller. This method was very useful for avoiding the congestion of solids because this wall was smaller than that used in the first method. The influence of these factors on the pump performance was also discussed by comparing simulated calculations with actual experiments.

scholarly journals Marginal Sea Overflows and the Upper Ocean Interaction

2009 ◽  
Vol 39 (2) ◽  
pp. 387-403 ◽  
Author(s):  
Shinichiro Kida ◽  
Jiayan Yang ◽  
James F. Price
Keyword(s):  
Ocean Circulation ◽  
Potential Vorticity ◽  
Baroclinic Instability ◽  
Upper Ocean ◽  
Marginal Sea ◽  
The Mediterranean ◽  
The Difference ◽  
Set Up ◽  
Numerical Model Experiments ◽  
Gyre Circulation

Abstract Marginal sea overflows and the overlying upper ocean are coupled in the vertical by two distinct mechanisms—by an interfacial mass flux from the upper ocean to the overflow layer that accompanies entrainment and by a divergent eddy flux associated with baroclinic instability. Because both mechanisms tend to be localized in space, the resulting upper ocean circulation can be characterized as a β plume for which the relevant background potential vorticity is set by the slope of the topography, that is, a topographic β plume. The entrainment-driven topographic β plume consists of a single gyre that is aligned along isobaths. The circulation is cyclonic within the upper ocean (water columns are stretched). The transport within one branch of the topographic β plume may exceed the entrainment flux by a factor of 2 or more. Overflows are likely to be baroclinically unstable, especially near the strait. This creates eddy variability in both the upper ocean and overflow layers and a flux of momentum and energy in the vertical. In the time mean, the eddies accompanying baroclinic instability set up a double-gyre circulation in the upper ocean, an eddy-driven topographic β plume. In regions where baroclinic instability is growing, the momentum flux from the overflow into the upper ocean acts as a drag on the overflow and causes the overflow to descend the slope at a steeper angle than what would arise from bottom friction alone. Numerical model experiments suggest that the Faroe Bank Channel overflow should be the most prominent example of an eddy-driven topographic β plume and that the resulting upper-layer transport should be comparable to that of the overflow. The overflow-layer eddies that accompany baroclinic instability are analogous to those observed in moored array data. In contrast, the upper layer of the Mediterranean overflow is likely to be dominated more by an entrainment-driven topographic β plume. The difference arises because entrainment occurs at a much shallower location for the Mediterranean case and the background potential vorticity gradient of the upper ocean is much larger.

The EU’s engagement with foreign powers on human rights

2020 ◽  
pp. 265-292
Author(s):  
Francisca Costa Reis ◽  
Weiyuan Gao ◽  
Vineet Hegde
Keyword(s):  
Human Rights ◽  
Lisbon Treaty ◽  
The European Union ◽  
Human Rights Protection ◽  
Rights Protection ◽  
Cohesive Group ◽  
The Difference ◽  
Economic Partnership ◽  
Set Up ◽  
The Eu

With a mandate under the Lisbon Treaty, the European Union (EU) has been engaging with foreign powers like Brazil, Russia, India, China, and South Africa (BRICS) nations on human rights issues. Despite the common and shared goals, the BRICS set-up is not institutionalised, which prompts the EU to engage with each country on a bilateral basis. Such collaborations have occurred in bilateral dialogues, multilateral fora, through developmental assistance, and negotiations in economic partnership agreements. The scope and content of the discussions and cooperation vary due to the difference in the political structures of the countries. While the EU and the BRICS may share some common goals politically and economically, pursuing shared objectives related to democracy and human rights promotion remains challenging. These countries may believe in human rights protection, but the understandings and the approaches vary drastically, as visible when issues of sovereignty and non-intervention are raised to resist comprehensive discussions. Although the BRICS are emerging as an interconnected group and have begun to cooperate more closely in multilateral fora, the EU may also have to consider dealing with it in its institutional capacity. It could be more challenging to fulfill the mandate of the Lisbon Treaty for the EU while dealing with this cohesive group that has different understandings on human rights protection within their own states.

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