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Assistant Professor |
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Visiting Researcher |
Prof. Wei ’s research activity in AY 2009 was focused on modeling and computer simulation of ECG and advanced algorithms for ECG and EEG data processing. AY 2009 was the starting year for the Grants-In-Aid for Scientific Research No. 21500297 of Japan Society for the Promotion of Science, where Prof. Wei is the research representative, with cooperators of Prof. Zhu from the same Lab, and Dr. Okazaki from the International Medical Center of Japan. In this year, two of Prof. Wei’s patent applications have been filed in US and in China, respectively. One of Prof. Wei’s Ph.D. student, Mr. Motoki Sakai, got a Ph.D. in this year, and find a job (assistant professor) in the next year in the National Fukushima University. Prof. We hosted a visiting professor, Xiangjian He from University of Technology, Sydney, Australia. Prof. Chen ’s research activities were specifically emphasized on the ICT-based healthcare domain which aims to provide an individualized total solution through utilizing the latest ICT technologies to enhance health promotion, disease prevention, as well as the whole care cycle. In AY2009, Prof. Chen participated in several projects funded by Ministry of Internal Affairs and Communications, Ministry of Education, Culture, Sports, Science and Technology (MEXT) Grants-In-Aid for Scientific Research, and Prefectural Industrial-Academic-Government Innovation. These projects are heading towards developing a series of instrumentations for continuous and persistent monitoring of vital signs without any inconvenience in daily life environment, and applying various data mining mathematics to allow objective characterization of an individual health state, finally building a scalable healthcare integrated platform “ SHIP ” for lifelong health management. Prof. Zhu’s researches were focused on cardiac modeling and simulation, biomedical signal processing, and healthcare systems. In 2009, he was in charge of the lectures and exercise of biomedical information technology course with Prof. Wei and Chen, and the exercise of computer graphics course.
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Refereed Journal Papers
| [dm-wei-01:2009] |
Motoki Sakai, Daming Wei, Wanzeng Kong, Guojun Dai, and Hua H.
Detection of Change in Alpha Wave following Eye Closure Based on KM2OLangevin
Equation. International Journal of Bioelectromagnetism, 12(2):89
–93, 2010. |
|
Electroencephalogram (EEG)-based brain-computer interfaces (BCI) is the technique
used for controlling devices only by thinking. Some BCI systems switch devices
on and off by detecting the change in the alpha wave caused by eye closure. Among
several methods to detect the change in the alpha wave, it is reported that a power
spectrum-based method is particularly effective. However, the power spectrum-based
method has a drawback with respect to thresholding. In this study, the KM2OLangevin
equation is adopted for the detection of changes in the alpha wave, expecting
that the detection of the changes in the alpha wave is accomplished by finding the
aberrations in the weakly stationary region of an EEG signal with KM2O-Langevin
equation. For the evaluation, switching time, sensitivity, and specificity were used.
The sensitivity and specificity were 93.4% and 86.4%, respectively, and the switching
time was 4.2 s on an average. In contrast to the power spectrum-based method,
the switching time was slightly slower, but the sensitivity and specificity were more
accurate. |
|
| [dm-wei-02:2009] |
Weijia Lu, Cuiwei Yang, Zuxiang Fang, Xingpeng Liu, Xin Zhu, and
Daming Wei. Implementation of a novel interpolating method to epicardial
potential mapping for atrial fibrillation study. Computers in Biology and
Medicine, 40:456463, 2010. |
| Epicardial potential mapping is an efficient way to visualize the potential distribution
on the epicardial surface. We found in our previous study, that the traditional
linear interpolation used for the epicardial mapping may cause errors and distortions
in reconstruction of the electric activities on the epicardial surface especially during
the atrial fibrillation. In this study, we devoted on the implementation of a 3D interpolating
method, and verified it in comparison with another interpolating method as
well as studying of the mechanism of vagal atrial fibrillation (AF). In case studying,
we analyzed the epicardial data from seven canine cardiac models using this method
and found the macro-re-entry during the sustainable AF is more likely due to the
dispersion of refractoriness in the myocardium and does not demonstrated the focal
patterns at the beginning of AF. This indicated that the electrophysiological characteristics
of myocardium might have been changed during the paroxysmal atrial
fibrillation (PAF).
|
|
| [dm-wei-03:2009,wenxi-01:2009, zhuxin-01:2009] |
Xin Zhu, Wenxi Chen, Tetsu Nemoto,
Kei ichiro Kitamura, and Daming Wei. Long-Term Monitoring of Heart Rate,
Respiration Rhythm, and Body Movement During Sleep Based upon a Network.
Telemedicine and e-healthe, 16(2):244–253, 2010. |
|
A method for accurately recording heart rate (HR), respiration rhythm (RR), and
body movement (BM) during sleep using a network based system is proposed in this
article. Its application to the longterm monitoring of HR, RR, and BM during sleep
was examined. HR, RR, and BM were detected by pressure variations corresponding to changes in the heartbeat and respiratory motion, which were measured by a
sensor unit placed beneath a pillow during sleep under completely unconstrained
conditions. The pressure signals were digitized and transmitted to a remote database
server using transmission control protocol=IP via a netbox. In the server, the data
were processed to obtain HR, RR, and BM. The overall performance of the system
was examined using data collected over a 13-month period from a female subject.
Besides the long-term profiles of HR, RR, and the periods during which the HR
and RR were undetectable owing to BMs during sleep, the average frequency of BM
in a day varied from 4.4 to 22.4=h, and the mean frequency over 332 nights was
8.3=h with a standard deviation of 2.2=h. Periodic biorhythms can also be assessed
using the profiles of the average HR and certain frequency domain parameters of HR
variability. The rhythmic property of these profiles was confirmed to coincide with
the subject’s menstrual cycle. The results of this 13-month trial operation show that
this system can be installed in the home environment; used to monitor HR, RR,
and BM during sleep; and analyze various physiological rhythms in humans over
prolonged periods.
|
|
| [dm-wei-04:2009] |
Daming Wei, Shin Hasegawa, Kunio Takahashi, Elena Ryzhii, and Xin
Zhu. A Virtual Reality for Catheter-based EPS based on Whole-heart Model.
International Journal of Bioelectromagnetism, 11(1):2–6, 2009. |
| This paper presents an introductory description of a development of virtual reality
for computer simulation of catheter-based electrophysiology study (EPS). We first
summarize a state-ofthe- art model of the heart and computer simulation of body
surface electrocardiograms (ECG), giving a latest example in simulation of Brugada
syndrome.We summarize the extension of the whole-heart model in order to compute
intracardiac electrograms for simulation of catheter-based EPS. We then introduce
a development of virtual reality, called virtual EP Lab, which links the heart model
to input device through a computer graphics interface. The virtual EP Lab may be
useful for the purposes of medical training in learning catheter operation and clinical
EPS. |
|
| [dm-wei-05:2009] |
Zhang Bofeng, Zhang Jingru, Yan Ke, Jiang Susu, and Wei Daming.
Research on Gait Feature Extracting Methods Based on Human Walking
Model. Computer Application and Software (in Chinese), 26(5):198–201,
2009. |
| Gait analysis and evaluation is one of important focuses in human health and rehabilitation,
kinematics analysis method is the most effective,accurate and direct way in
gait analysis,so it has been used extensively.Gait feature extracting is the key technology
of kinematics analysis method,and also is the foundation to further gait analysis.
In this paper it firstly presents a three-dimension model of human walking,and
then provides a set of gait feature extracting methods based on the data of kinematics,
including gait cycle feature and footprint feature extracting methods.Finally,the
kinematics data of 44 individuals,20-60 age old,are analyzed.The experimental results
show that these methods are of high accuracy and practicality. |
|
| [dm-wei-06:2009] |
Motoki Sakai and Daming Wei. Separation of Electrocardiographic
and Encephalographic Components based on Signal Averaging and Wavelet Shrinkage Techniques. Computers in Biology and Medicine, 39(7):620–639,
2009. |
| During ambulatory monitoring, it is often required to record the electroencephalogram
(EEG) and the electrocardiogram (ECG) simultaneously. It would be ideal if
both EEG and ECG can be obtained with one measurement. We introduce an algorithm
combining the wavelet shrinkage and signal averaging techniques to extract
the EEG and ECG components from an EEG lead signal to a noncephalic reference
(NCR). The evaluation using simulation data and measured data showed that the
normalized power spectrum unvaried in all frequency bands for the EEG components,
and the sensitivity and specificity of R-wave detection for the ECG component were
nearly 100%. |
|
| [dm-wei-07:2009] |
Elena Ryzhii and Daming Wei. Computer Simulation of Atypical Brugada
Syndrome. Journal of Electrocardiology, 42(4):319–327, 2009. |
| Recently, the so-called atypical Brugada syndrome (BS) has been reported in few
cases in literature. The typical BS is characterized by ST-segment elevation in the
right precordial leads, whereas atypical forms of the disease are distinguished by
electrocardiogram abnormalities of the J wave, and ST-segment elevation appeared in
the inferior and lateral leads. In this work, we report a simulation of atypical BS based
on a 3-dimensional whole-heart model. By setting the action potentials of Brugada
model cells in different epicardial regions, we calculated 12-lead electrocardiogram
and body surface potentials that are in good agreement with clinical data. Applying
additional electrical stimuli, we obtained the induction of ventricular fibrillation in
both typical and atypical BS forms. The calculated results confirm possibility of
similar electrophysiological basis in both cases and suggest that BS can also be
observed in inferior and lateral precordial leads. |
|
| [wenxi-02:2009] |
Wenxi Chen, Masumi Kitazawa, and Tatsuo Togawa. Estimation of the
Biphasic Property in a Female’s Menstrual Cycle from Cutaneous Temperature
Measured during Sleep. Annals of Biomedical Engineering, 37(9):1827–
1838, 2009. |
| This paper proposes a method to estimate a woman’s Menstrual cycle based on the
hidden Markov model (HMM). A tiny device was developed that attaches around the
abdominal region to measure cutaneous temperature at 10-minute intervals during
sleep. The measured temperature data were encoded as a two-dimensional image (QR
code, i.e., Quick Response code) and displayed in the LCD window of the device. A
mobile phone captured the QR code image, decoded the information and transmitted
the data to a database server. The collected data were analyzed by three steps to
estimate the biphasic temperature property in a menstrual cycle. The key step was
an HMM-based step between preprocessing and postprocessing. A discrete Markov
model, with two hidden states, was assumed to represent high- and low-temperature
phases during a menstrual cycle. The proposed method was verified by the data collected
from 30 female participants, aged from 14 to 46, over six consecutive months.
By comparing the estimated results with individual records from the participants,
71.6% of 190 menstrual cycles were correctly estimated. The sensitivity and positive
predictability were 91.8% and 96.6%, respectively. This objective evaluation provides
a promising approach for managing premenstrual syndrome and birth control. |
|
| [wenxi-03:2009] |
Kei-ichiro Kitamura, Tetsu Nemoto, Nobutoshi Sate, and Wenxi Chen.
Development of a new accelerometer-based physical activity monitoring
system using high-frequency sampling rate. Biological Sciences in Space,
23(2):77–83, 2009. |
| It is known that physical activity enhances the mechanical competence of weightbearing
bones and is also effective in prevention of osteoporosis. However, informations
about the optimum exercise and intensity of load to weight-bearing bones, and
about the precise intensity monitoring system of physical activities are not known.
To measure the precise intensities of exercise as a first step, this study is to evaluate
the sampling conditions of data acquisition and develop an accelerometer-based
physical activity monitoring and its intensity analysis system. We found that 1k Hz
of sampling rate is possible to achieve the measurement error less than 2% through
the simulation experiment. With the optimum sampling rate of 1k Hz, we developed
an accelerometer-based activity monitoring system. Then, we assessed the magnitude
of acceleration at the shank, knee and waist in the healthy subjects (n=19),
using activity of going down the stairs. Correlation analysis of the precise acceleration
values at three portions along the body showed that our system was able to
provide clarification of the shock absorptive function of lower extremities. Therefore,
we strongly believe that our system, with the optimum sampling rate of 1k Hz,
enabled accurate measurement of loads acting on weight-bearing bones. |
|
| [wenxi-04:2009, zhuxin-02:2009] |
Kei-Ichiro Kitamura, Xin Zhu, Wenxi Chen, and Tetsu
Nemoto. Development of a new method for the noninvasive measurement of
the core body temperature without a heater. Medical Engineering & Physics,
32(1):1–6, 2010. |
| The conventional zero-heat-flow thermometer, which measures the core body temperature
from the skin surface, is widely used at present. However, this thermometer
requires considerable electricity to power the electric heater that compensates for
heat loss from the probe; thus, AC power is indispensable for its use. Therefore, this
conventional thermometer is inconvenient for portable use. We have developed a new
dual-heat-flux method that can measure the core body temperature from the skin
surface without a heater. Our method is convenient for portable use and long-term
measurement because the instrument is driven by a battery and its design promotes
energy conservation. Its probe consists of dual-heat-flow channels with different thermal
resistances, and each heat-flow-channel has a pair of IC sensors attached on its
top and bottom. The average core temperature measurements taken using both the
dual-heat-flux and then the zero-heat-flow thermometers from the foreheads of 17
healthy subjects were 37:08◦C and 37:02◦C, respectively. In addition, the correlation
coefficient between the values obtained by the 2 methods was 0.970 (p<0.001). These
results show that our method can be used for monitoring the core body temperature
as accurately as the conventional method, and it overcomes the disadvantage of the
necessity of AC power supply. |
Refereed Proceeding Papers
| [dm-wei-08:2009] |
K. Endo, K. Takahashi, and D. Wei. Estimation of Electrode Position from CT Images of Torso for Simulation of Electrocardiogram. In 43th
Japanese Society for Medical and Biological Engineering Tohoku Paper
collection, page 29, Fukushima, November 2009. JSMBE Tohoku, University
of Fukushima. |
|
The six position of chest read is needed to simulate the 12-lead ECG with human
model. This research proposes a way of estimating the electrode position for chest
lead from CT images.In this research, the 12-lead ECG is simulated with estimated
position and human model constructed from CT images. The simulation result
showed that this method is effective.(in Japanese) |
|
| [dm-wei-09:2009] |
Yuki Yoshida and Daming Wei. Biometric Authentication Using Electrocardiogram
- Temporal Effect Investigated with Long-term ECG Data.
In Tsunetoyo Namba and Tohru Ohe, editors, The 25th annual meeting
of Japanese Society for Computerized Electrocardiology(JSCE), page 24,
Hyogo, 10 2009. Japanese Society for Computerized Electrocardiology, The
25th annual meeting of Japanese Society for Computerized Electrocardiology. |
|
Biometric authentication using ECG was suggested for a new approach. Previous
studies were shown high accuracy using healthy subject data. They had a serious
issue. It is important for authentication to remain unchanged data. However, they
did not consider the passage of time. Therefore, we investigated effect on authentication
using long-term ECG data. Additionally, new analysis method was tried to
classify with SVM. Authentication rate was compared SVM and not using SVM.
ECG data was measured for three years. It was from 2005 to 2007. Authentication
rate was investigated using it. First step was feature selection with Jolliffe B2 and
B4. Second step was classification with PCA and SVM. Last step was discriminant
with Mahalanobis Distance. As a result, it was not suitable for classification with
SVM. On the other hand, authentication rate was 80 - 90% not using SVM. Longterm
ECG data tend to have a high dispersion. We indicated that more features
resulted in better authentication rate.(in Japanese) |
|
| [dm-wei-10:2009] |
Mao Yuxiang and Daming Wei. Weight Balanced Linear Programming
SVM on Skewed Distribution and Its Evaluation. In 8th IEEE/ACIS International
Conference on Computer and Information Science, pages 430–435.
IEEE ACIS, IEEE Press, 2009. |
| Support Vector Machines (SVM) have been shown to have strong classification
capability and good generalization results. Among SVM’s, linear-programming
SVM’s (LPSVM) have been shown to have better ability to adapt to large data
sets with more efficiency. However, there have been several variations of LPSVM’s,
and their ability to tackle with skewed distributions are not investigated yet. In
this research, we compared 4 LPSVM formulations and suggested one of them as
the candidate for classifying skewed distributions. We also suggested a novel formula
for evaluation of correctness of classification results, which is more suitable in
multicategory cases. We also introduced a new concept of output balancing, which
can be useful in recovering lost classes in k-SVM applications. Through the experiments,
we showed that weight balancing approach is effective in multicategory
classification. |
|
| [dm-wei-11:2009] |
Shizhong Yuan, Daming Wei, Weimin Xu, and Wenfeng Shen. Web-
Based Sharing of Electrocardiograms: Privacy and Access Control,. In Proceedings
of the 2009 International Conference on Web Information Systems
and Mining, pages 82–86, Shanghai China, November 2009. |
| Health information exchange (HIE) across multiple organizations via the Internet
is a current trend in medicine and healthcare. Protection of the sensitive data
contained in health information from disclosure to unauthorized persons is challenging.
In this paper, we present an access control architecture based on XACML
and SAML to address privacy and security issues in our HIE application, Webbased
sharing of electrocardiograms (ECGs). We also introduce a prototypical
implementation of this access control architecture and a use case scenario for the
experiment. It shows that the access control architecture can protect the ECGs
shared among organizations from disclosure to both the individuals who have no
job-related need to access them and the individuals who have been denied the
privilege to access them by a patient’s privacy consent. |
|
| [dm-wei-12:2009] |
Shizhong Yuan, DamingWei, Weimin Xu, andWenfeng Shen. A Metadata
Registry to Facilitate the Search and Retrieval of Electrocardiograms,.
In Proceedings of the IEEE 9th International Conference on Computer and
Information Technology, pages 269–273, Xiamen China, October 2009. |
| Sequential electrocardiograms (ECGs) are very useful for personalized diagnosis.
It is therefore very useful to search various electrocardiographs or ECG management
systems connected to the Internet for a particular patient’s ECGs. This is
an interesting but not completely solved problem. In this paper, we present an
experimental study of our metadata registry aimed at facilitating the search for
and retrieval of a patient’s ECGs via the Internet. The metadata registry was developed
based on the ebXML registry methodology and Web service technique.
An assessment test in an experimental scenario shows that it is feasible to apply
the metadata registry to discovering and retrieving a patient’s ECGs resident
in a number of emulated electrocardiographs placed in the Internet. This study
demonstrates a useful framework for ECG sharing through the Internet. |
|
| [dm-wei-13:2009] |
Shizhong Yuan, Daming Wei, Weimin Xu, and Wenfeng Shen. Web-
Based Sharing of Electrocardiogram: A Framework for Information Publishing,.
In Proceedings of the 31st Annual International Conference of the
IEEE Engineering in Medicine and Biology Society, pages 1671–1674, Minneapolis
Minnesota USA, September 2009. |
| Network-based data sharing is a current trend in medicine and healthcare. The
search and retrieval architecture (SRA) we previously proposed for web-based sharing
of electrocardiogram (ECG) facilitates the search and retrieval of ECG across
hospitals via the Internet. The SRA has a triangle-like configuration including an
ECG metadata registry, an ECG provider and an ECG querist. In this paper, we
present a framework for ECG information publishing of an ECG provider. We also
introduce a prototype of this framework, which was developed for an experimental
scenario for assessment test based on MFER, an IEEE standard proposed from
Japan. The assessment shows that the prototype of the framework can effectively
publish the ECGs in a group of emulated MFER-conformant electrocardiographs, and the published ECGs can be successfully discovered and retrieved via the Internet. |
|
| [dm-wei-14:2009,zhuxin-04:2009] |
Wenfeng Shen, DamingWei, Weimin Xu, Xin Zhu, and
Shizhong Yuan. GPU-Based Parallelization for Computer Simulation of
Electrocardiogram. In Proceedings of the IEEE 9th International Conference
on Computer and Information Technology, pages 280–284, Xiamen
China, October 2009. |
| This paper presents a parallel algorithm using GPU for computer simulation of
Electrocardiogram (ECG) based on a 3-dimensional (3D) whole-heart model. The
computer heart model includes approximately 50,000 discrete elements (model
cells) inside a torso model represented by 344 nodal points with 684 triangular
meshes. After the excitation propagation is simulated in the heart model, the
Poisson question is applied to the volume conductor for computing ECG, which
involves a maximum of about 50,000 electric current dipole sources and four boundaries
including the torso surface and three surfaces of heart model. The parallel
algorithm was designed to solve this problem based on GPU. It accelerates the
speed of calculation of ECG to 2.74 times with very low relative error compared
with the serial algorithm. This study demonstrates a potential method using GPU
for parallel computing in biomedical simulation study. |
|
| [dm-wei-15:2009,zhuxin-03:2009] |
Wenfeng Shen, Weijia Lu, Daming Wei, Weimin Xu,
Xin Zhu, and Shizhong Yuan. A Parallel Algorithm for Computer Simulation
of Electrocardiogram Based on MPI,. In Proceedings of the 2009
Eigth IEEE/ACIS International Conference on Computer and Information
Science, pages 120–123, June 2009. |
| This paper presents a parallel algorithm for computer simulation of Electrocardiogram
(ECG) based on a 3-dimensional (3D) whole-heart model. The computer
heart model includes approximately 50,000 discrete elements (model cells) inside
a torso model represented by 344 nodal points with 684 triangle meshes. The Poison
question is applied to the volume conductor problem for simulation of ECG,
which involves a maximum of about 50,000 electric current dipole sources and four
boundaries including the torso surface and three surfaces of heart. A parallel algorithm
was introduced to solve this problem based on Message Passing Interface
(MPI). An implementation is conducted with a cluster computer system consisting
of up to eight PCs, each of which has a dualcore processor. It was shown that the
speedup is close to 2 in one PC and close to 8 with 8 processors, as compared to
the serial algorithm. This study demonstrates a useful way of parallel computing
in biomedical simulation study. |
|
| [dm-wei-16:2009] |
Hsien Che Hung and Daming Wei. Muscle Noise Cancellation in Four-
Lead ECG System for Ubiquitous Healthcare,. In Second International
Conference on Ubi-media Computing (U-Media 2009), pages 115–118, Taiwan,
December 2009. |
| The electrocardiogram (ECG) is one of the most frequently used vital sign in
ubiquitous healthcare. In many applications, the standard 12-lead ECG is desirable
for monitoring both arrhythmia and acute coronary syndrome. Wei et al [1, 2] has developed a method for deriving standard 12-lead ECG from four-lead ECG so
that the 12-lead ECG can be monitored in a ubiquitous environment. However, in
multi-lead ECG recording, the noise due to body movement is the main problem
(even for a 4-lead ECG system). In this paper, we introduce an implementation that
applies a low distortion filter method originally aimed at a 12-lead ECG system to
a four 4-lead ECG system. The algorithm is improved for 4-lead ECG application,
and validation is performed with both simulated and clinical ECG signals. The
results show that the effect of the filter method for a 4-lead ECG system is as
good as for a 12-lead ECG system so as to be feasible to ubiquitous healthcare
applications. |
|
| [dm-wei-17:2009] |
Bofeng Zhang, Ke Yan, Susu Jiang, Yuxiang Mao, and Daming Wei.
Feature Selection Methods in Walking Stability Analysise,. In 9th IEEE
International Conference on Computer and Information Technology (CIT
2009), pages 258–262, Xiamen China, October 2009. |
| Walking stability is the main reason for leading to falls for people, especially for
elders. But there are much more features related with walking so that we cannot
understand which features are more important than others to contribute the walking
stability. Almost all of researches focused on some specific features but didn’t
present any reasons for that. Therefore, the Dynamic Time Warping (DTW) is
employed to calculate walking stability, an adaptive Genetic Algorithm (GA) to
search the best contributing and representative features, and an improved Support
Vector Machine (SVM) to assess the fitness of specific feature combination according
to age classification information. After studying walking patterns of 51 healthy
male subjects ranging from 21 years old to 66 years old, the 32 most contributing
features are acquired. The experiments show that these feature selection methods
can improve the discrimination power of walking stability effectively. This research
not only supports more convenient data acquisition equipments, but also helps us
understand walking stability better. |
|
| [dm-wei-18:2009] |
Susu Jiang, Bofeng Zhang, Ke Yan, and Daming Wei. Primery Exploration
on the Symmetry of Human Walking,. In 9th IEEE International
Conference on Computer and Information Technology (CIT 2009), pages
263–268, Xiamen China, October 2009. |
| Normal walking has often been assumed to be symmetric. A few papers have discussed
the kinematic symmetry in healthy adults using statistical and mathematic
calculations, but no consensus exists on the methodology. In this paper, we try to
define what walking symmetry is and determine mathematical symmetry indices.
We have investigated walking symmetry among healthy subjects from 20 to 69
years old by using Fourteen-Linkage (FL) model. In the case of bilateral dynamic
gait data, we make use of a dynamic time warping algorithm to calculate the similarity
between them. The result shows this method has a good application on
describing walking symmetry. The paper analyzes three kinds of symmetry, but
here mainly mentions dynamic symmetry. |
|
| [dm-wei-19:2009] |
Damith J. Mudugamuwa, Xiangjian He, Daming Wei, and Chung Hyun Ahn. Super-Resolution by Prediction Based Sub-pel Motion Estimation,. In Proceedings of Image and Vision Computing New Zealand 2009
(IVCNZ2009), pages 282–287, New Zealand, 2009. |
| Super-resolution reconstruction produces high-resolution images from a set of lowresolution
images of the same scene. In the last two and a half decades, many
super-resolution algorithms have been proposed. These algorithms are usually very
sensitive to their assumed models of data and noise, and also computationally
expensive for many practical applications. In this paper we adopt computationally
efficient prediction based sub-pel motion estimation to produce a fast superresolution
reconstruction that can also accommodate generic motion patterns. The
proposed algorithm adaptively exploits the available high frequency content in adjacent
video frames to generate high resolution video frames. Initial experiments
showed promising results of around 2 dB, PSNR improvement, over single frame
bi-linear interpolation. |
|
| [dm-wei-20:2009] |
Ruo Du, Qiang Wu, Xiangjian He, Wenjing Jia, and Daming Wei.
Facial Expression Recognition Using Histogram Variances Faces,. In IEEE
Workshop on Applications of Computer Vision (WACV2009, ARC Tier A),
pages 341–347, 2009. |
| In human’s expression recognition, the representation of expression features is
essential for the recognition accuracy. In this work we propose a novel approach
for extracting expression dynamic features from facial expression videos. Rather
than utilising statistical models e.g. Hidden Markov Model (HMM), our approach
integrates expression dynamic features into a static image, the Histogram Variances
Face (HVF), by fusing histogram variances among the frames in a video. The HVFs
can be automatically obtained from videos with different frame rates and immune
to illumination interference. In our experiments, for the videos picturing the same
facial expression, e.g., surprise, happy and sadness etc., their corresponding HVFs
are similar, even though the pupperformers and frame rates are different. Therefore
the static facial recognition approaches can be utilised for the dynamic expression
recognition. We have applied this approach on the well-known Cohn-Kanade AUCoded
Facial Expression database then classified HVFs using PCA and Support
Vector Machine (SVMs), and found the accuracy of HVFs classification is very
encouraging. |
|
| [dm-wei-21:2009] |
Xiangjian He, Jianmin Li, Daming Wei, Wenjing Jia, and Qiang Wu.
Canny edge detection on a virtual hexagonal image structure,. In Canny
edge detection on a virtual hexagonal image structure, Pervasive Computing
(JCPC), pages 167 – 172, 2009. |
| The Canny edge detector is the most popular tool for edge detection, and has
many applications in the areas of image processing, multimedia and computer vision.
Traditionally, the Canny algorithm, like other image processing algorithms,
operates on the square-pixel structure. A hexagonal structure is an alternative
image representation, which is inspired from anatomical considerations of the primate’s
vision and has many advantages for image processing. In this paper, a brand
new approach that performs Canny edge detection completely on a real hexagonal
structure is proposed. We define various commonly used edge operators on the
hexagonal structure and, for the first time, prove that these operators for gradient computation result in exact the same edge results on the hexagonal structure. To
greatly increase the computation speed, a 1-D approach for Gaussian filtering on
the hexagonal structure is presented. To compare our results with those performed
on the square structure using square-pixel represented images, simple and fast algorithms
are developed for conversions of images between the hexagonal structure
and the square structure. Experiments show that edge detection on the hexagonal
structure is not only better (i.e., more accurate) but also faster to process than on
the square structure. The proposed algorithm provides researchers with an option
for accurate and real-time edge detection. |
|
| [dm-wei-22:2009] |
E. Ryzhii, M. Ryzhii, and D. Wei. Computer simulation study of
gender differences in cardiac repolarization: normal case and Brugada syndrome,.
In 13th Congress of International Society for Holter and Noninvasive
Electrocardiology (ISHNE 2009, Yokohama, June 2009. |
| Gender differences in electrocardiographic (ECG) manifestations affect on the arrhythmia
susceptibility, notably in Brugada syndrome frequently diagnosed in
males (8:1 ratio male:female), but the underlying mechanisms are still unknown.
We included gender differences in the ten Tusscher human ventricular cell model
adjusting densities of the L-type Ca current (ICal), transient outward K (Ito),
and rapid delayed rectifier K current (IKr) according to experimental data. The
simulated action potentials for male and female cases were inputted into a state-ofthe-
art 3D whole-heart model and corresponding ECG waveforms were calculated.
The obtained results demonstrate that in female case cardiac cells have longer action
potential duration and the surface ECG is characterized by longer QT interval.
Male cardiac cells have prominent phase-1 repolarization, and are more susceptible
to all-or-none repolarization, which facilitate the appearance of the Brugada syndrome
manifestations on the surface ECG. These results are supported by previous
clinical findings. |
|
| [dm-wei-23:2009] |
E. Ryzhii, M. Ryzhii, and D. Wei. Extension of whole-heart model by
coupling with human ventricular cell model,. In Progress in Electromagnetics
Research Symposium (PIERS 2009), Russia, August 2009. |
| The experimental possibilities for studying cardiac arrhythmias in human ventricular
myocardium are very limited. Thus, the utilization of computer simulation is
an important alternative method. In this work, we extend 3D whole-heart model
by coupling with ion channel human ventricular cell model developed by ten Tusscher
et al. We adopted the model of the action potential of human ventricular
cells to simulate sex differences in accordance to experimental data for male and
female hearts of different species. Using the extended model the surface 12-lead
Electro-cardiogram (ECG) waveforms were simulated. The obtained results conform
adequately to the available clinical reports. The developed extended model
can reproduce a variety of electrophysiological behaviors and provides a good basis
for understanding the genesis of ECG under normal and abnormal conditions. |
|
| [wenxi-05:2009] |
X. Zhu W. Chen and T. Nemoto. A New Sensory Device and Optimal
Position for Monitoring HR/RR during Sleep. In Proc. of the World
Congress on Medical Physics and Biomedical Engineering (WC2009), pages
126–129, 2009. |
| This study developed a sensory board and investigated the optimal position to
monitor heart rate and respiration rate during sleep. The sensory board was devised
using a circular piezoelectric cell which is sandwiched between two acrylic
boards. Four identical boards were installed in different positions simultaneously
during sleep to detect changes of applied pressure due to heart beating and breathing.
One board was set beneath the pillow; the other three boards were set under
the mattress close to the back, hip and calf level positions. Data were collected
from five healthy university students during a 2-hour ’s nap individually. At the
same time, Lead I ECG and nasal thermistor signals were recorded as heart rate
and respiration rate references, respectively. These rates were detected by applying
the same algorithm on the data collected from different positions. Detection performance
was evaluated by sensitivity and positive predictivity. The results showed
that nearly all positions could be used to detect the above two parameters but
performance was different slightly in positions. Heart rate could be detected in
all positions, and both sensitivity and positive predictivity were over 97% among
all five persons. Sensitivity and positive predictivity in respiration rate detection
could be found the highest performance in the back position; both performance
indexes were over 97% on average and close to the heart rate detection. |
|
| [wenxi-06:2009] |
Keiichiro Kitamura Wenxi Chen Tetsu Nemoto, Kazuhiro Oogai. Development
of vibration measurement equipment of each body part under
the sleep. In Proc. of the 48th Annual Conference of Japanese Society for
Medical and Biological Engineering, 2009. |
| This study developed a sensor board to detect body vibration during sleep. A
piezoelectric element was sandwiched by two plastic plates and metal pressure
transmission nut. Experiment was conducted in 10 adult male and female subjects.
Vibration sensor board was deployed in head position under the pillow, the
abdomen position and the lower leg position beneath mattress during sleep. At
the same time, ECG, thermistors, accelerometers of abdomen and lower leg positions
were also measured. These signals were used as references for heart rate,
respiration rate and body movement, respectively, in order to evaluate the results
obtained from vibration sensor board. (in Japanese) |
|
| [wenxi-07:2009] |
Tetsu Nemoto Wenxi Chen, Xin Zhu and Daming Wei. Estimation of
female menstrual cycles from heart rate measured during sleep. In Proc. of
the 48th Annual Conference of Japanese Society for Medical and Biological
Engineering, 2009. |
| Instead of conventional method of using the basal body temperature, this study
measures heart rate during sleep continuously and unconstrainedly, and uses cosinor
analysis method to estimate menstrual cycle of women from the heart rate data.
Finally, the usefulness and accuracy of the method is evaluated. (in Japanese) |
|
| [wenxi-08:2009] |
HirooWatanabe andWenxi Chen. Detection of Biorhythm Change from
Heart Rate Measured during Sleep. In Proc. of the 48th Annual Conference
of Japanese Society for Medical and Biological Engineering, 2009. |
| A convenient monitoring system was developed to monitor SpO2 and pulse rate
during sleep on daily basis using a finger type pulse oximeter (4100 Nonin Inc.,USA). Measured vital data were transmitted to a home PC via Bluetooth connection
and then to a network database server via the HTTP communication. On
the server side, after removing the noise by a median filter and a LMS filter, a
daily profile of heart rate variability was created. Changes in daily rhythms of
sleep were detected by DTW (Dynamic Time Warping) method. DTW values represent
the similarity of two patterns, smaller value presents higher similarity. This
method was validated using data collected from a healthy person for two months.
(in Japanese) |
|
| [zhuxin-05:2009] |
Daming Wei Xiaolin Zhou, Xin Zhu. Measurement and Evaluation
of QT Interval Prolongation Based on simulated Electrocardiogram Using
Continuous Wavelet Transform. In Dssel and W.C. Schlegel, editors, WC
2009 Proceedings, 2009. |
| The measurement of QT interval prolongation is an important test for evaluating
the proarrhythmic risk associated with drug interactions. Although algorithms for
QT interval detection are well studied, there is no much attention on QT interval
changes. On the other hand, for evaluation of QT interval measurement algorithms,
pathological or experimental Electrocardiograms (ECGs) corresponding to
QT changes are not usually available. In this study, we developed a continuous
wavelet-based algorithm specially aimed at the measurement of QT interval prolongation.
For evaluation, we conducted computer simulation based a whole-heart
model to develop ECGs before and after QT interval prolongation, and used these
data as gold standard to evaluate our algorithm. The simulated ECGs were artificially
mixed with three types of noise under various signal-to-noise ratio (SNR)
of white Gaussian noise. Six cases with different compositions of these noises were
used for the evaluation. For all of the six cases, the standard deviation of the measurement
error tends to decrease as the SNR increases, and the average standard
deviation of measurement errors were less than 1 ms. |
Unrefereed Papers
| [wenxi-09:2009] |
Wenxi Chen. A Long Journey to Health Begins from Yourself and Now!
Glorious Road of Future Fukushima, ISSN 0288-0954(320):37–40, April 2009. |
Chapters in Book
| [wenxi-10:2009] |
Wenxi Chen. Discovery of Biorhythmic Stories behind Daily Vital Signs
and Its Application, pages 453–492. Recent Advances in Biomedical Engineering.
IN-TECH, Vienna, Austria, 2009. |
Grants
| [dm-wei-24:2009] |
Daming Wei, Osamu Okazaki, and Xin Zhu. Ministry of Education
Scientific Research Fund (c) - Development of New Diagnosis Method for the
Brugada Syndrome using Synthesized ECG Technique, 2009-2011. |
| [wenxi-11:2009] |
Wenxi Chen. Fukushima Industry-University-Government Cooperation
Promotion Program, 2009. |
| [wenxi-12:2009] |
Wenxi Chen. JSPS Grants-In-Aid for Scientific Research (20500601),
2009. |
| [zhuxin-06:2009] |
Daming Wei, Xin Zhu, and Osamu Okazaki. Study on Novel Assistant
Diagnosis Method for Brugada Syndrome based on derivation of additional
leads, Japan Society for the Promotion of Science under Grants-In-Aid for
Scientific Research (no. 21500297), 2009-2011. |
Academic Activities
| [dm-wei-25:2009] |
Daming Wei, October 2009. Steering Committee Chair, IEEE 9th International Conference on Computer and Information Technology |
| [dm-wei-26:2009] |
Daming Wei, 2009. Member of IEEE EMBS Technical Committee on Cardiopulmonary Systems |
| [dm-wei-27:2009] |
Daming Wei, June 2009. Council member of 13th Congress of International Society for Holter and Noninvasive Electrocardiology (ISHNE 2009) |
| [dm-wei-28:2009] |
Daming Wei, February 2009. PC member of Third International Workshop on Intelligent Informatics in Biology and Medicine (IIBM 2010) |
| [dm-wei-29:2009] |
Daming Wei. Council member of International Society of Bioelectromegnetism |
| [dm-wei-30:2009] |
Daming Wei. Council member and 2010 Chair of Japan Society of Computerized Electrocardiology |
| [dm-wei-31:2009] |
Daming Wei. Council member of Japan Society of Medical and Biological Engineering Tohoku Branch |
| [wenxi-14:2009] |
Wenxi Chen, 2009. Referee for 9th International Conference on Computer and Information Technology( CIT 2009) |
Patents
| [dm-wei-32:2009] |
D. Wei. Method and apparatus to derived ECG on additional leads,
April 2009. |
| [dm-wei-33:2009] |
Wei D. and Sakai Yoshio. Method for deriving standard 12-lead electrocardiogram
and monitoring apparatus using the same, Nov. 2009. |
Ph.D, Master and Graduation Theses
| [dm-wei-34:2009] |
Kousuke Takano. Graduation Thesis: Study on Separation of Electrocardiogram
and Encephalogram Components Based on Nonlinear State-Space
Projections, University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-35:2009] |
Yukari Tsunoda. Graduation Thesis: Effects of Alcohol Ingestion on
Application to Electrocardiogram Authentication, University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-36:2009] |
Kenshi Hiramatsu. Graduation Thesis: Stress Evaluation Using EEG
and ECG, University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-37:2009] |
Mai Watanabe. Graduation Thesis: Drowsiness Evaluation During
Driving Using Electrocardiogram, University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-38:2009] |
Kazuki Endo. Master Thesis: Estimation of the heart dipole from
12-lead electrocardiogram (ECG), University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-39:2009] |
Akira Oyamada. Master Thesis: Software Development of Digital
Pen-based Input System for Dental visiting Service, University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-40:2009] |
Shuji Sato. Master Thesis: Development of Algorithm for Converting
Paper ECG into Digital ECG, University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-41:2009] |
Junya Shinjo. Master Thesis: Spatial positioning using Augmented
Reality techniques for computer simulation of Endoscopic Surgery, University
of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-42:2009] |
Yuki Yoshida. Master Thesis: Derived Electrocardiogram on Additional
Leads using Least Squares Method, University of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-43:2009] |
Motoki Sakai. Doctoral Thesis: Signal Processing for Brain-Computer
Interfaces Based on Electroencephalogram and Electrocardiogram, University
of Aizu, 2009. Thesis Advisor: Daming Wei |
| [dm-wei-44:2009] |
Takahiro Watanabe. Graduation Thesis: Graduation Thesis:”Human
Identification Using Electrocardiogram Analysis for Car Applications”, University
of Aizu, 2009. Thesis Advisor: Daming Wei |
| [wenxi-15:2009] |
Yukiya Nakagawa. Graduation Thesis: Android-Based Portable Vital
Sign Monitor for Bluetooth-Enabled Pulse Oximeter, UoA, 2009. Thesis Advisor: Wenxi Chen |
| [wenxi-16:2009] |
Takeshi Yoshida. Graduation Thesis: Evaluation of the Correlation
between Heart Rate Variability and Mental Stress, UoA, 2009. Thesis Advisor: Wenxi Chen |
| [wenxi-17:2009] |
Shunosuke Watanabe. Graduation Thesis: Evaluation of Stress State
by Time Domain Parameters of Heart Rate Variability, UoA, 2009. Thesis Advisor: Wenxi Chen |
| [wenxi-18:2009] |
Yuma Saito. Graduation Thesis: Influence of Alcohol on Pulse Rate
During Sleep, UoA, 2009. Thesis Advisor: Wenxi Chen |
| [wenxi-19:2009] |
Jun Yamaguchi. Graduation Thesis: Evaluation of Stress State by
Frequency Domain Analysis of Heart Rate Variability, UoA, 2009. Thesis Advisor: Wenxi Chen |
| [wenxi-20:2009] |
Yu Naruse. Graduation Thesis: The Effect of Favorite Music on Heart
Rate Variability, UoA, 2009. Thesis Advisor: Wenxi Chen |
| [zhuxin-07:2009] |
Ryo Yugawa. Graduation Thesis: Study on Parallelization of Medical
Image Processing Based on GPGPU, School of Computer Science and Engineering,
2009. Thesis Advisor: Xin Zhu |
