16,876 research outputs found
Connecting Neutrino Masses and Dark Matter by High-dimensional Lepton Number Violation Operator
We propose a new model with the Majorana neutrino masses generated at
two-loop level, in which the lepton number violation (LNV) processes, such as
neutrinoless double beta decays, are mainly induced by the dimension-7 LNV
effective operator O_7=\bar l_R^c \gamma^\mu L_L(D_mu \Phi) \Phi \Phi. Note
that it is necessary to impose an Z_2 symmetry in order that O_7 dominates over
the conventional dimension-5 Weinberg operator, which naturally results in a
stable Z_2-odd neutral particle to be the cold dark matter candidate. More
interestingly, due to the non-trivial dependence of the charged lepton masses,
the model predicts the neutrino mass matrix to be in the form of the normal
hierarchy. We also focus on a specific parameter region of great
phenomenological interests, such as electroweak precision tests, dark matter
direct searches along with its relic abundance, and lepton flavor violation
processes.Comment: 19 pages, 5 figure
Rainfall Reliability Evaluation for Stability of Municipal Solid Waste Landfills on Slope
[[abstract]]A method to assess the reliability for the stability of municipal solid waste (MSW) landfills on slope due to rainfall infiltration is proposed. Parameter studies are first done to explore the influence of factors on the stability of MSW. These factors include rainfall intensity, duration, pattern, and the engineering properties of MSW. Then 100 different combinations of parameters are generated and associated stability analyses of MSW on slope are performed assuming that each parameter is uniform distributed around its reason ranges. In the following, the performance of the stability of MSW is interpreted by the artificial neural network (ANN) trained and verified based on the aforementioned 100 analysis results. The reliability for the stability of MSW landfills on slope is then evaluated and explored for different rainfall parameters by the ANN model with first-order reliability method (FORM) and Monte Carlo simulation (MCS).[[incitationindex]]SCI[[booktype]]紙
Why Do Players Stick to a Specific Online Game? The Users and Gratifications Perspective
Driven by the dominant Internet usage and the prospective profits from the game industry, especially from the thriving and robust free-to-play model of online games, there is a need to realize players’ behaviors. Playing online games is experienceoriented but rare studies further explore what reactions of initial (trial) experiences in game playing are and how they will further influence players’ behaviors. Uses and gratification theory can be seen in cases such as online games selection. Players select an online game not only to fit particular interests but also to attempt to show empowerment or other socially conscience motives. This study, therefore, seeks to explore the important antecedents (i.e. gratifications, presence, service mechanisms, and continuance motivation) of stickiness intention on the online game and examine the associated relationships among them. The implications of findings to both researchers and practitioners are also discussed
Enhanced call quality using user-specific voiceprint model
The audio quality of a call conducted using a user device such as a phone can be unsatisfactory due to a variety of reasons. Such reasons include noisy surroundings at the location from which the user conducts a call, position of the phone near the user’s face, users that speak with a soft voice, presence of far-end echoes, etc. This disclosure describes techniques that use a user-specific voiceprint to home into the user’s speech and cut out surrounding disturbances from a voice call. The techniques are implemented with user permission to generate and use the voiceprint
Phenotype-based and Self-learning Inter-individual Sleep Apnea Screening with a Level IV Monitoring System
Purpose: We propose a phenotype-based artificial intelligence system that can
self-learn and is accurate for screening purposes, and test it on a Level IV
monitoring system. Methods: Based on the physiological knowledge, we
hypothesize that the phenotype information will allow us to find subjects from
a well-annotated database that share similar sleep apnea patterns. Therefore,
for a new-arriving subject, we can establish a prediction model from the
existing database that is adaptive to the subject. We test the proposed
algorithm on a database consisting of 62 subjects with the signals recorded
from a Level IV wearable device measuring the thoracic and abdominal movements
and the SpO2. Results: With the leave-one cross validation, the accuracy of the
proposed algorithm to screen subjects with an apnea-hypopnea index greater or
equal to 15 is 93.6%, the positive likelihood ratio is 6.8, and the negative
likelihood ratio is 0.03. Conclusion: The results confirm the hypothesis and
show that the proposed algorithm has great potential to screen patients with
SAS
Development of a 3D Parallel Mechanism Robot Arm with Three Vertical-Axial Pneumatic Actuators Combined with a Stereo Vision System
This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot’s end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H∞ tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to verify the feasibility of the proposed parallel mechanism robot driven by three vertical pneumatic servo actuators, a full-scale test rig of the proposed parallel mechanism pneumatic robot is set up. Thus, simulations and experiments for different complex 3D motion profiles of the robot end-effector can be successfully achieved. The desired, the actual and the calculated 3D position of the end-effector can be compared in the complex 3D motion control
Laser Welding Control
In laser welding of metallic workpieces, the energetic beam is moved over the workpiece surface to form a pool of molten weld metal that quickly solidifies behind the advance of the laser into a weld nugget. The laser beam produces a keyhole of plasma-containing vapor within the molten pool. Weld nugget porosity, due to entrapment of the vapor, is minimized by continually sensing radiation from the molten metal pool to determine pool depth and width and then controlling laser power and speed to continually produce a weld metal pool wide enough for the liquid to fully expel the vapor and solidify into a pore free nugget
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