• The Journal of Korea Robotics Society
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• 제19권2호
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• pp.203-212
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• 2024

Simultaneous motion is essential in the activities of daily living (ADL). For motion intention recognition, surface electromyogram (sEMG) and corresponding motion label is necessary. However, this process is time-consuming and it may increase the burden of the user. Therefore, we propose a simultaneous motion recognition framework using data augmentation based on muscle activation model. The model consists of multiple point sources to be optimized while the number of point sources and their initial parameters are automatically determined. From the experimental results, it is shown that the framework has generated the data which are similar to the real one. This aspect is quantified with the following two metrics: structural similarity index measure (SSIM) and mean squared error (MSE). Furthermore, with k-nearest neighbor (k-NN) or support vector machine (SVM), the classification accuracy is also enhanced with the proposed framework. From these results, it can be concluded that the generalization property of the training data is enhanced and the classification accuracy is increased accordingly. We expect that this framework reduces the burden of the user from the excessive and time-consuming data acquisition.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2003년도 봄 학술발표회 논문집
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• pp.291-298
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• 2003

The resonant column testing is a laboratory testing method to determine the shear modulus and the material damping factor of soils. The method has been widely used for many applications and its importance has been increased. Since the establishment of the testing method in 1963, the low-technology electronic devices for testing and data acquisition have limited the measurement to the amplitude of the linear spectrum. The limitations of the testing method were also attributed to the assumption of the linear-elastic material in the theory of the resonant column testing and to the use of the wave equation for the dynamic response of the specimen. For the better theoretical formulation of the resonant column testing, this study derived the equation of motion and provided its solution. This study also proposed the improved data reduction and analysis method for the resonant column testing, based on the advanced data acquisition system and the proposed theoretical solution for the resonant column testing system. For the verification of the proposed data reduction and analysis method, the numerical simulation of the resonant column testing was performed by the finite element analysis. Also, a series of resonant column testing were peformed for Joomunjin sand, which verified the feasibility, of the proposed method and showed the limitations of the conventional data reduction and analysis method.

• Journal of Biomedical Engineering Research
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• 제29권4호
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• pp.295-301
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• 2008

A wireless 3 channel ECG monitoring system was developed so that it could monitor the health and movement state during subject's daily life. The developed system consists of a wireless biomedical signal acquisition device, a personal healthcare server, and a remote medical server. Three experiments were performed to evaluate the accuracy, reliability and operability, applicability during daily life of the developed device. First, ECG signals were measured using the developed device and commercial reference device during sitting and marking time and compared to verify the accuracy of R-R intervals. Second, the reliable data transmission to remote server was verified on two types of simulated emergency event using patient simulator. Third, during five types of motion in daily life, the accuracy of data transmission to remote server using CDMA network was verified on two types of event occurring. By acquiring and comparing subject's biomedical signal and motion signal, the accuracy, reliability and operability, applicability during daily life of the developed device were verified. In addition, PDA-phone based wireless system enabled subject to be monitored without any constraints. Therefore, the developed system is expected to be applicable for monitoring the aged and chronic diseased people and giving first-aid in emergency.

• Journal of Astronomy and Space Sciences
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• 제15권1호
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• pp.183-196
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• 1998

The Synthetic Aperture Radar(SAR) image and the Digital Elevation Model(DEM) of an target area are put into use to generate three dimensional image map. An method of image map generation is explained. The orbit and attitude determination of satellite makes it possible to model signal acquisition configuration precisely, which is a key to mapping image coordinates to geographic coordinates of concerned area. An application is made to RADARSAT in the purpose of testing its validity. To determine the orbit, zero Doppler range is used. And to determine the attitude, Doppler centroid frequency, which is the frequency observed when target is put in the center of antenna's view, is used. Conventional geocoding has been performed on the basis of direct method(mapping image coordinates to geographic coordinates), but in this reserch the inverse method(mapping from geographic coordinates to image coordinates) is taken. This paper shows that precise signal acquisition modeling based on the orbit and attitude determination of satellite as a platform leads to a satellite-centered accurate geocoding process. It also shows how to model relative motion between space-borne radar and target. And the relative motion is described in ECIC(earth-centered-initial coordinates) using Doppler equation and signal acquisition geometry.

• Journal of the Korean Society of Radiology
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• 제14권7호
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• pp.957-964
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• 2020

T2 FLAIR sequence of MRI in Acute Ischemic Stroke patients is meaningful to those who have the diagnosis of cerebral hemorrhage and neurological deficiency, including the detection of cerebral infarction around Cerebrospinal fluid. However, because of the long acquisition time and mutative motion artifacts caused by movement, It is difficult to take the MRI image acquisition for non-cooperative patients who need to apply a rapid image acquisition. In this study, we applied the EPI-FLAIR sequence, which is one of the fastest pulse sequences in use, which is a combination of EPI sequence and T2 FLAIR sequence, to patients with acute ischemic cerebral infarction. Based on the qualitative and quantitative evaluation results of the EPI-FLAIR and T2 FLAIR image, we will evaluate the diagnostic usefulness of the EPI-FLAIR sequence.

• The Journal of the Korea institute of electronic communication sciences
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• 제8권6호
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• pp.831-837
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• 2013

MEMS accelerometer provides a low cost alternative in retrieving the acceleration signal for motion sensing. Theoretically, displacement can be calculated by double integrate the acceleration signal. However, in practical, it could not be done in straight forward manner due to several factors that exist in the real world. This experiment focuses on the processes from practical accelerometer signal acquisition till the result of double integration for low frequency vertical motion.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제35권2호
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• pp.16-20
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• 2012

The purpose of this thesis is to develop a performance rating training tool for the time and motion study. It is widely recognized that rating training tools based on films were made several decades ago and introduced to Korea. However, to the best of our knowledge, those films are not used for rating training in Korea any more. Furthermore, although rating is still important method for the efficient operational management study, it is briefly mentioned without any training or exercise. In this paper, we propose a simple rating training tool based on Excel with VBA. The mottoes of our development are the ease of acquisition and trainees' motivation. Test results show that trainees can obtain the concept of rating and the ability of accurate and consistent rating as they play a computer game sitting in front of the personal computer.

• Journal of the Korean Society for Aviation and Aeronautics
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• 제17권1호
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• pp.1-8
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• 2009

In this paper, reorientation based on angular momentum exchange is applied for a bias momentum stabilized satellite, which is equipped with a spherical fuel tank, and the effect of liquid slosh on the attitude properties such as inertia tensor and angular rate is investigated. In order to represent the slosh motion of liquid an equivalent mechanical model is adopted and full nonlinear equations of motion for three-body system are derived. Computer simulations are performed for several cases, which use the viscosity of liquid and the center location of the tank as input parameters, mainly in order to observe how the viscosity of liquid and the center location of the tank influence the spacecraft’s attitude. The investigation includes observing time-variations of the inertia tensor, especially presence of components of product of inertia during the maneuver.

• Journal of Biomedical Engineering Research
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• 제15권3호
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• pp.289-294
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• 1994

A new type of electrogoniometer to measure the three dimensional motion of the human knee joint was developed. This instrument is composed of six potentiometers: four arranged for two universal joints, one for pin joint, and one for axial rotation measurement. The voltage change in six potentiometers were collected through A/D converter for acquisition, storage and analysis. With a developed instrument, gait analysis was performed. Compared to earlier developed triaxial type goniometer, new instrument shows its convenience in application and accuracy in measurement.

• Journal of Korea Multimedia Society
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• 제12권12호
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• pp.1701-1709
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• 2009

The mobile terminal system plays a key role in medical industries which require in fast and accurate diagnosis from heterogeneous acquisition equipment. The demand for PACS (picture archiving and communication systems) has continued to increase in major hospitals and private clinics. Patient care depends on how fast the medical imaging system provides images and how accurately the images are interpreted by physicians. In this paper, we propose an efficient method to decipher the hundreds of images required by physicians to accurately diagnose patients. By exploring Motion- JPEG (M-JPEG), this paper has demonstrates the possibilities for efficient management of medical images with a newly designed image file format and improvement in imaging diagnoses through the replaying of moving pictures of a patient in a mobile environment.