Abstract: In this paper, a double balanced radio frequency multiplier
is presented which is customized for transmitted reference
ultra wideband (UWB) receivers. The multiplier uses 90nm model
parameters and exploits compensating transistors to provide controllable
gain for a Gilbert core. After performing periodic and quasiperiodic
non linear analyses the RF mixer (multiplier) achieves a
voltage conversion gain of 16 dB and a DSB noise figure of 8.253
dB with very low power consumption. A high degree of LO to RF
isolation (in the range of -94dB), RF to IF isolation (in the range of
-95dB) and LO to IF isolation (in the range of -143dB) is expected
for this design with an input-referred IP3 point of -1.93 dBm and an
input referred 1 dB compression point of -10.67dBm. The amount of
noise at the output is 7.7 nV/√Hz when the LO input is driven by
a 10dBm signal. The mixer manifests better results when compared
with other reported multiplier circuits and its Zero-IF performance
ensures its applicability as TR-UWB multipliers.
Abstract: Many medical devices are driven by motor pumps. Some researchers reported that the vibration mainly affected medical devices using a motor pump. The purpose of this study was to examine the effect of stiffness and damping coefficient in a 3-dimensional (3D) model of a motor pump and spring. In the present paper, experimental and mathematical tests for the moments of inertia of the 3D model and the material properties were investigated by an INSTRON machine. The response surfaces could be generated by using 3D multi-body analysis and the design of experiment method. It showed that differences in contours of the response surface were clearly found for the particular area. Displacement of the center of the motor pump was decreased at K≈2000 N/M, C≈12.5 N-sec/M. However, the frequency was increased at K≈2000 N/M, C≈15 N-sec/M. In this study, this study suggested experimental technique for vibration reduction for a motor pump in medical device. The combined method suggested in this study will greatly contribute to design of medical devices concerning vibration and noise intervention.
Abstract: This paper proposes view-point insensitive human
pose recognition system using neural network. Recognition system
consists of silhouette image capturing module, data driven database,
and neural network. The advantages of our system are first, it is
possible to capture multiple view-point silhouette images of 3D human
model automatically. This automatic capture module is helpful to
reduce time consuming task of database construction. Second, we
develop huge feature database to offer view-point insensitivity at pose
recognition. Third, we use neural network to recognize human pose
from multiple-view because every pose from each model have similar
feature patterns, even though each model has different appearance and
view-point. To construct database, we need to create 3D human model
using 3D manipulate tools. Contour shape is used to convert silhouette
image to feature vector of 12 degree. This extraction task is processed
semi-automatically, which benefits in that capturing images and
converting to silhouette images from the real capturing environment is
needless. We demonstrate the effectiveness of our approach with
experiments on virtual environment.
Abstract: This paper presents the design and implementation of a fully integrated transimpedance amplifier (TIA) as the analog frontend receiver for Capacitive Micromachined Ultrasound Transducers (CMUTs) for ultrasound biomicroscope imaging application. The amplifier is designed to amplify the received signals from 17.5MHz to 52.5MHz with a center frequency of 35MHz. The TIA was fabricated in GF 0.18μm 1P6M 30V high voltage process. The measurement results show that the designed amplifier can reach a transimpedance gain of 61.08dBΩ and operating frequency from 17.5MHz to 100MHz with 1VP-P output voltage under 6V power supply.
Abstract: There are many researches to detect collision between real object and virtual object in 3D space. In general, these techniques are need to huge computing power. So, many research and study are constructed by using cloud computing, network computing, and distribute computing. As a reason of these, this paper proposed a novel fast 3D collision detection algorithm between real and virtual object using 2D intersection area. Proposed algorithm uses 4 multiple cameras and coarse-and-fine method to improve accuracy and speed performance of collision detection. In the coarse step, this system examines the intersection area between real and virtual object silhouettes from all camera views. The result of this step is the index of virtual sensors which has a possibility of collision in 3D space. To decide collision accurately, at the fine step, this system examines the collision detection in 3D space by using the visual hull algorithm. Performance of the algorithm is verified by comparing with existing algorithm. We believe proposed algorithm help many other research, study and application fields such as HCI, augmented reality, intelligent space, and so on.
Abstract: Dielectric sheet perturbation to the dominant TE111
mode resonant frequency of a circular cavity is studied and presented
in this paper. The dielectric sheet, placed at the middle of the airfilled
cavity, introduces discontinuities and disturbs the configuration
of electromagnetic fields in the cavity. For fixed dimensions of cavity
and fixed thickness of the loading dielectric, the dominant resonant
frequency varies quite linearly with the permittivity of the dielectric.
This quasi-linear relationship is plotted using Maple software and
verified using 3D electromagnetic simulations. Two probes are used
in the simulation for wave excitation into and from the cavity. The
best length of probe is found to be 3 mm, giving the closest resonant
frequency to the one calculated using Maple. A total of fourteen
different dielectrics of permittivity ranging from 1 to 12.9 are tested
one by one in the simulation. The works show very close agreement
between the results from Maple and the simulation. A constant
difference of 0.04 GHz is found between the resonant frequencies
collected during simulation and the ones from Maple. The success of
this project may lead to the possibility of using the middle loaded
cavity at TE111 mode as a microwave non-destructive testing of solid
materials.
Abstract: In this paper, we propose an improved 3D star skeleton
technique, which is a suitable skeletonization for human posture representation
and reflects the 3D information of human posture.
Moreover, the proposed technique is simple and then can be performed
in real-time. The existing skeleton construction techniques, such as
distance transformation, Voronoi diagram, and thinning, focus on the
precision of skeleton information. Therefore, those techniques are not
applicable to real-time posture recognition since they are computationally
expensive and highly susceptible to noise of boundary. Although
a 2D star skeleton was proposed to complement these problems,
it also has some limitations to describe the 3D information of the
posture. To represent human posture effectively, the constructed skeleton
should consider the 3D information of posture. The proposed 3D
star skeleton contains 3D data of human, and focuses on human action
and posture recognition. Our 3D star skeleton uses the 8 projection
maps which have 2D silhouette information and depth data of human
surface. And the extremal points can be extracted as the features of 3D
star skeleton, without searching whole boundary of object. Therefore,
on execution time, our 3D star skeleton is faster than the “greedy" 3D
star skeleton using the whole boundary points on the surface. Moreover,
our method can offer more accurate skeleton of posture than the
existing star skeleton since the 3D data for the object is concerned.
Additionally, we make a codebook, a collection of representative 3D
star skeletons about 7 postures, to recognize what posture of constructed
skeleton is.
Abstract: A talking head system (THS) is presented to animate
the face of a speaking 3D avatar in such a way that it realistically
pronounces the given Korean text. The proposed system consists of
SAPI compliant text-to-speech (TTS) engine and MPEG-4 compliant
face animation generator. The input to the THS is a unicode text that is
to be spoken with synchronized lip shape. The TTS engine generates a
phoneme sequence with their duration and audio data. The TTS
applies the coarticulation rules to the phoneme sequence and sends a
mouth animation sequence to the face modeler. The proposed THS can
make more natural lip sync and facial expression by using the face
animation generator than those using the conventional visemes only.
The experimental results show that our system has great potential for
the implementation of talking head for Korean text.
Abstract: The paper discusses a 3D numerical solution of the inverse boundary problem for a continuous casting process of alloy. The main goal of the analysis presented within the paper was to estimate heat fluxes along the external surface of the ingot. The verified information on these fluxes was crucial for a good design of a mould, effective cooling system and generally the whole caster. In the study an enthalpy-porosity technique implemented in Fluent package was used for modeling the solidification process. In this method, the phase change interface was determined on the basis of the liquid fraction approach. In inverse procedure the sensitivity analysis was applied for retrieving boundary conditions. A comparison of the measured and retrieved values showed a high accuracy of the computations. Additionally, the influence of the accuracy of measurements on the estimated heat fluxes was also investigated.
Abstract: In this study, the precision heading process of
spur gears has been investigated by means of numerical
analysis. The effect of some parameters such as teeth number
and module on the forming force and material flow were
presented. The simulation works were performed rigid-plastic
finite element method using DEFORM 3D software. In order
to validate the estimated numerical results, they were
compared with those obtained experimentally during heading
of spur gear using lead as a model material. Results showed
that the optimum number of gear teeth is between 10 to 20,
that is because of being the specific pressure in its minimum
value.
Abstract: Laser Metal Deposition (LMD) is an additive manufacturing process with capabilities that include: producing new
part directly from 3 Dimensional Computer Aided Design (3D CAD)
model, building new part on the existing old component and repairing an existing high valued component parts that would have
been discarded in the past. With all these capabilities and its advantages over other additive manufacturing techniques, the
underlying physics of the LMD process is yet to be fully understood probably because of high interaction between the processing
parameters and studying many parameters at the same time makes it
further complex to understand. In this study, the effect of laser power
and powder flow rate on physical properties (deposition height and
deposition width), metallurgical property (microstructure) and
mechanical (microhardness) properties on laser deposited most
widely used aerospace alloy are studied. Also, because the Ti6Al4V
is very expensive, and LMD is capable of reducing buy-to-fly ratio
of aerospace parts, the material utilization efficiency is also studied.
Four sets of experiments were performed and repeated to establish repeatability using laser power of 1.8 kW and 3.0 kW, powder flow
rate of 2.88 g/min and 5.67 g/min, and keeping the gas flow rate and
scanning speed constant at 2 l/min and 0.005 m/s respectively. The
deposition height / width are found to increase with increase in laser
power and increase in powder flow rate. The material utilization is favoured by higher power while higher powder flow rate reduces
material utilization. The results are presented and fully discussed.
Abstract: With the increasing number of on-chip components and the critical requirement for processing power, Chip Multiprocessor (CMP) has gained wide acceptance in both academia and industry during the last decade. However, the conventional bus-based onchip communication schemes suffer from very high communication delay and low scalability in large scale systems. Network-on-Chip (NoC) has been proposed to solve the bottleneck of parallel onchip communications by applying different network topologies which separate the communication phase from the computation phase. Observing that the memory bandwidth of the communication between on-chip components and off-chip memory has become a critical problem even in NoC based systems, in this paper, we propose a novel 3D NoC with on-chip Dynamic Random Access Memory (DRAM) in which different layers are dedicated to different functionalities such as processors, cache or memory. Results show that, by using our proposed architecture, average link utilization has reduced by 10.25% for SPLASH-2 workloads. Our proposed design costs 1.12% less execution cycles than the traditional design on average.
Abstract: For the communication between human and computer
in an interactive computing environment, the gesture recognition is
studied vigorously. Therefore, a lot of studies have proposed efficient
methods about the recognition algorithm using 2D camera captured
images. However, there is a limitation to these methods, such as the
extracted features cannot fully represent the object in real world.
Although many studies used 3D features instead of 2D features for
more accurate gesture recognition, the problem, such as the processing
time to generate 3D objects, is still unsolved in related researches.
Therefore we propose a method to extract the 3D features combined
with the 3D object reconstruction. This method uses the modified
GPU-based visual hull generation algorithm which disables unnecessary
processes, such as the texture calculation to generate three kinds
of 3D projection maps as the 3D feature: a nearest boundary, a farthest
boundary, and a thickness of the object projected on the base-plane. In
the section of experimental results, we present results of proposed
method on eight human postures: T shape, both hands up, right hand
up, left hand up, hands front, stand, sit and bend, and compare the
computational time of the proposed method with that of the previous
methods.
Abstract: It is hard to percept the interaction process with machines when visual information is not available. In this paper, we have addressed this issue to provide interaction through visual techniques. Posture recognition is done for American Sign Language to recognize static alphabets and numbers. 3D information is exploited to obtain segmentation of hands and face using normal Gaussian distribution and depth information. Features for posture recognition are computed using statistical and geometrical properties which are translation, rotation and scale invariant. Hu-Moment as statistical features and; circularity and rectangularity as geometrical features are incorporated to build the feature vectors. These feature vectors are used to train SVM for classification that recognizes static alphabets and numbers. For the alphabets, curvature analysis is carried out to reduce the misclassifications. The experimental results show that proposed system recognizes posture symbols by achieving recognition rate of 98.65% and 98.6% for ASL alphabets and numbers respectively.
Abstract: In modern human computer interaction systems
(HCI), emotion recognition is becoming an imperative characteristic.
The quest for effective and reliable emotion recognition in HCI has
resulted in a need for better face detection, feature extraction and
classification. In this paper we present results of feature space analysis
after briefly explaining our fully automatic vision based emotion
recognition method. We demonstrate the compactness of the feature
space and show how the 2d/3d based method achieves superior features
for the purpose of emotion classification. Also it is exposed that
through feature normalization a widely person independent feature
space is created. As a consequence, the classifier architecture has
only a minor influence on the classification result. This is particularly
elucidated with the help of confusion matrices. For this purpose
advanced classification algorithms, such as Support Vector Machines
and Artificial Neural Networks are employed, as well as the simple k-
Nearest Neighbor classifier.
Abstract: In this paper, a new method of information fusion – DSmT (Dezert and Smarandache Theory) is introduced to apply to managing and dealing with the uncertain information from robot map building. Here we build grid map form sonar sensors and laser range finder (LRF). The uncertainty mainly comes from sonar sensors and LRF. Aiming to the uncertainty in static environment, we propose Classic DSm (DSmC) model for sonar sensors and laser range finder, and construct the general basic belief assignment function (gbbaf) respectively. Generally speaking, the evidence sources are unreliable in physical system, so we must consider the discounting theory before we apply DSmT. At last, Pioneer II mobile robot serves as a simulation experimental platform. We build 3D grid map of belief layout, then mainly compare the effect of building map using DSmT and DST. Through this simulation experiment, it proves that DSmT is very successful and valid, especially in dealing with highly conflicting information. In short, this study not only finds a new method for building map under static environment, but also supplies with a theory foundation for us to further apply Hybrid DSmT (DSmH) to dynamic unknown environment and multi-robots- building map together.
Abstract: A novel nanofinishing process using improved ball
end magnetorheological (MR) finishing tool was developed for finishing of flat as well as 3D surfaces of ferromagnetic and non ferromagnetic workpieces. In this process a magnetically controlled
ball end of smart MR polishing fluid is generated at the tip surface of
the tool which is used as a finishing medium and it is guided to
follow the surface to be finished through computer controlled 3-axes
motion controller. The experiments were performed on ferromagnetic
workpiece surface in the developed MR finishing setup to study the effect of finishing time on final surface roughness. The performance
of present finishing process on final finished surface roughness was studied. The surface morphology was observed under scanning
electron microscopy and atomic force microscope. The final surface finish was obtained as low as 19.7 nm from the initial surface
roughness of 142.9 nm. The outcome of newly developed finishing process can be found useful in its applications in aerospace,
automotive, dies and molds manufacturing industries, semiconductor and optics machining etc.
Abstract: In this paper, we explore the applicability of the Sinc-
Collocation method to a three-dimensional (3D) oceanography model.
The model describes a wind-driven current with depth-dependent
eddy viscosity in the complex-velocity system. In general, the
Sinc-based methods excel over other traditional numerical methods
due to their exponentially decaying errors, rapid convergence and
handling problems in the presence of singularities in end-points.
Together with these advantages, the Sinc-Collocation approach that
we utilize exploits first derivative interpolation, whose integration
is much less sensitive to numerical errors. We bring up several
model problems to prove the accuracy, stability, and computational
efficiency of the method. The approximate solutions determined by
the Sinc-Collocation technique are compared to exact solutions and
those obtained by the Sinc-Galerkin approach in earlier studies. Our
findings indicate that the Sinc-Collocation method outperforms other
Sinc-based methods in past studies.
Abstract: In this paper, the differential quadrature method is applied to simulate natural convection in an inclined cubic cavity using velocity-vorticity formulation. The numerical capability of the present algorithm is demonstrated by application to natural convection in an inclined cubic cavity. The velocity Poisson equations, the vorticity transport equations and the energy equation are all solved as a coupled system of equations for the seven field variables consisting of three velocities, three vorticities and temperature. The coupled equations are simultaneously solved by imposing the vorticity definition at boundary without requiring the explicit specification of the vorticity boundary conditions. Test results obtained for an inclined cubic cavity with different angle of inclinations for Rayleigh number equal to 103, 104, 105 and 106 indicate that the present coupled solution algorithm could predict the benchmark results for temperature and flow fields. Thus, it is convinced that the present formulation is capable of solving coupled Navier-Stokes equations effectively and accurately.
Abstract: The motivation of this work was to find a suitable 3D
scanner for human body parts digitalization in the field of prosthetics
and orthotics. The main project objective is to compare the three
hand-held portable scanners (two optical and one laser) and two
optical tripod scanners. The comparison was made with respect of
scanning detail, simplicity of operation and ability to scan directly on
the human body. Testing was carried out on a plaster cast of the
upper limb and directly on a few volunteers. The objective monitored
parameters were time of digitizing and post-processing of 3D data
and resulting visual data quality. Subjectively, it was considered level
of usage and handling of the scanner. The new tripod was developed
to improve the face scanning conditions. The results provide an
overview of the suitability of different types of scanners.