• Science of Emotion and Sensibility
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• v.20 no.3
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• pp.141-150
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• 2017

The purpose of this study was to analyze the effect of the shape and attached position of E-textile-based stretchable sensors on motion-sensing performance and to investigate the requirements for the optimal structure of clothes for sensing limb motions. An experimental garment was prepared with different sensor shapes, and attachment positions. A child subject, wearing the experimental garment, performed arm and leg bending and extension motions at $60^{\circ}$, $90^{\circ}$ and $120^{\circ}$ motion angles, at a rate of 60 deg/sec. The changes in voltage triggered by the stretching and contracting of the fabric-sensor were measured, and an acceleration sensor was utilized to verify that the experimental motions were correctly performed. Dummy arms and legs of a child were manufactured to perform an identical test, in order to compare the dummy results with the actual human body experiment results. The analysis showed that the reproducibility and reliability of the rectangular sensor, showing uniform and stable were higher than those of the boat-shaped sensor, in both the dummy and the human body experiments. The attachment position of the sensor was more reproducible and reliable when placed on 4 cm below the elbow and knee joints in the dummy test, when placed in the joints of the elbow and knee, in children experiment. The appropriate shapes and attached positions of the sensor for sensing the motions were analyzed, and the results proved that motion-sensing of the human body is possible by utilizing flexible fabric-sensors integrated into clothes.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.1-7
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• 2006

3-dimensional(3-D) simulations of ideal double-gate bulk FinFET were performed extensively and the electrical characteristics. were analyzed. In 3-D device simulation, we changed gate length($L_g$), height($H_g$), and channel doping concentration($N_b$) to see the behaviors of the threshold voltage($V_{th}$), DIBL(drain induced barrier lowering), and SS(subthreshold swing) with source/drain junction depth($X_{jSDE}$). When the $H_g$ is changed from 30 nm to 45nm, the variation gives a little change in $V_{th}$(less than 20 mV). The DIBL and SS were degraded rapidly as the $X_{jSDE}$ is deeper than $H_g$ at low fin body doping($1{\times}10^{16}cm^{-3}{\sim}1{\times}10^{17}cm^{-3}$). By adopting local doping at ${\sim}10nm$ under the $H_g$, the degradation could be suppressed significantly. The local doping also alleviated $V_{th}$ lowering by the shallower $X_{jSDE}\;than\;H_g$ at low fin body doping.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.280-288
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• 2008

Purpose: To identify the inter-fractional shift pattern and to assess an adequate treatment margin in the radiotherapy of a liver tumor using mega-voltage computed tomography (MVCT) of a tomotherapy unit. Materials and Methods: Twenty-six patients were treated for liver tumors by tomotherapy from April 2006 to August 2007. The MVCT images of each patient were analyzed from the $1^{st}$ to the $10^{th}$ fraction for the assessment of the daily liver shift by four groups based on Couinard's proposal. Daily setup errors were corrected by bony landmarks as a prerequisite. Subsequently, the anterior-, posterior-, right-, and left shifts of the liver edges were measured by maximum linear discrepancies between the kilo-voltage computed tomography (KVCT) image and MVCT image. All data were set in the 2-dimensional right angle coordinate system of the transverse section of each patient's body. Results: The liver boundary shift had different patterns for each group. In group II (segment 2, 3, and 4), the anterior mean shift was $2.80{\pm}1.73\;mm$ outwards, while the left mean shift was $2.23{\pm}1.37\;mm$ inwards. In group IV (segment 7 and 8), the anterior-, posterior-, right-, and left mean shifts were $0.15{\pm}3.93\;mm$ inwards, $3.15{\pm}6.58\;mm$ inwards, $0.60{\pm}3.58\;mm$ inwards, and $4.50{\pm}5.35\;mm$ inwards, respectively. The reduced volume in group II after MVCT reassessment might be a consequence of stomach toxicity. Conclusion: Inter-fractional liver shifts of each group based on Couinard's proposal were somewhat systematic despite certain variations observed in each patient. The geometrical deformation of the liver by respiratory movement can cause shrinkage in the left margins of liver. We recommend a more sophisticated approach in free-breathing mode when irradiating the left lobe of liver in order to avoid stomach toxicity.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.1
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• pp.17-24
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• 2019

Purpose: The present study aims to assess the level of coherency and the accuracy of Point dose of the Isocenter of VERO, a linear accelerator developed for the purpose of the Stereotactic Body Radiation Therapy(SBRT). Materials and Method: The study was conducted randomly with 10 treatment plans among SBRT patients in Kyungpook National University Chilgok Hospital, using VERO, a linear accelerator between June and December, 2018. In order to assess the equipment's power stability level, we measured the output constancy by using PTW-LinaCheck, an output detector. We also attempted to measure the level of accuracy of the equipment's Laser, kV(Kilo Voltage) imaging System, and MV(Mega Voltage) Beam by using Tofu Phantom(BrainLab, Germany) to assess the accuracy level of geometrical Isocenter. We conducted a comparative analysis to assess the accuracy level of the dose by using an acrylic Phantom($30{\times}30{\times}20cm$), a calibrated ion chamber CC-01(IBA Dosimetry), and an Electrometer(IBA, Dosimetry). Results: The output uniformity of VERO was calculated to be 0.66 %. As for geometrical Isocenter accuracy, we analyzed the error values of ball Isocenter of inner Phantom, and the results showed a maximum of 0.4 mm, a minimum of 0.0 mm, and an average of 0.28 mm on X-axis, and a maximum of -0.4 mm, a minimum of 0.0 mm, and an average of -0.24 mm on Y-axis. A comparison and evaluation of the treatment plan dose with the actual measured dose resulted in a maximum of 0.97 % and a minimum of 0.08 %. Conclusion: The equipment's average output dose was calculated to be 0.66 %, meeting the ${\pm}3%$ tolerance, which was considered as a much uniform fashion. As for the accuracy assessment of the geometric Isocenter, the results met the recommended criteria of ${\pm}1mm$ tolerance, affirming a high level of reproducibility of the patient's posture. The difference between the treatment plan dose and the actual measurement dose was calculated to be 0.52 % on average, significantly less than the 3 % tolerance, confirming that it obtained predicted does. The current study suggested that VERO equipment is suitable for SBRT, and would result in notable therapeutic effect.

• Applied Microscopy
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• v.36 no.2
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• pp.73-82
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• 2006

Major contributions has been made in cellular ultrastructure studies with the use of high voltage electron microscopy (HVEM) and tomography. Applications of HVEM, accompanied by appropriate image processing, have provided great improvements in the analysis of three-dimensional cellular structures. In the present study, structural patterns of the crystalline bodies that are distinguished in mesophyll plastids of CAM-performing Sedum rotundifolium L., have been investigated using HVEM and tomography. Tilting, and diffraction pattern analysis were performed during the investigation. The titlting was performed at ${\pm}60^{\circ}\;with\;2^{\circ}$ increments while examining serial sections ranging from 0.125 to $1{\mu}m$ in thickness. The young plastids exhibited crystalline inclusion bodies that revealed a peculiar structural pattern. They were irregular in shape and also variable in size. Their structural attributes affected the plastid morphology. The body consisted of a large number of tubular elements, often reaching up to several thousand in number. The tubular elements typically aggregated to form a fluster The elements demonstrated either a parallel or lattice arrangement depending on the sectioning angle. The distance between the elements was approximately 20nm as demonstrated by the diffraction analysis. HVEM examination of the serial sections revealed an occasional fusion or branching of elements within the inclusion bodies. Finally, a three-dimensional reconstruction of the plastid crystalline bodies has been attempted using two different image processing methods.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.987-994
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• 2019

Low energy x-rays that occur in the low tube voltage radiography of general radiography are absorbed strongly in the body and do not aid image quality enhancement. This study maintains titer in general radiography while using tube current that are proportional to density and the tube voltage 15% principle according to density to reduce patient exposure doses, and area doses and entrance surface doses were measured to compare patient exposure doses. In hand, knee, abdomen, and skull radiography, kVp was increased to 115% and mAs was decreased to 50% and kVp was decreased to 85% while mAs was increased to 200% and area doses and entrance surface doses were measured to compare relative doses. Also, 5 places in each image were set, density was measured, and Kruskal wallis H test was conducted to observe significance probabilities between groups. To fix density, kVp was increased to 115% and mAs was decreased to 50% and after measurements of mean area doses and entrance surface doses were made by each part, each decreased to 58.68% and 59.85% when standard doses were set to 100%, and each increased to 147.28% and 159.9% when kVp was decreased to 85% and mAs was increased to 200%. Comparisons of density changes showed that hand, knee, abdomen, and skull radiography all displayed significance probabilities>0.05, showing no changes in concentration. Radiography that increases kVp and lowers mAs through reasonable calculations within ranges that don't affect resolution and contrast seems to be a simple way to decrease patient exposure doses.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.698-706
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• 2019

Over the last few decades, there have been a lot of efforts to develop soft actuators, which can be external stimuli-responsive and applied to the human body. In order to fabricate medical soft actuators with a dynamic precision control, the 3D crosslinked poly(acrylic acid) (PAAc)/poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogels were synthesized in this study by using a radiation technique without noxious chemical additives or initiators. After irradiation, all hydrogels showed high gel fraction over 75% and the ATR-FTIR spectra indicated that PAAc/PVA/PEG hydrogels were successfully synthesized. In addition, the gel fraction, equilibrium water content, and compressive strength were measured to determine the change in physical properties of PAAc/PVA/PEG hydrogels according to the irradiation dose and content ratio of constituents. As the irradiation dose and amount of poly(ethylene glycol) diacrylate (PEGDA) increased, the PAAc/PVA/PEG hydrogels showed a high crosslinking density and mechanical strength. It was also confirmed that PAAc/PVA/PEG hydrogels responded to electrical stimulation even at a low voltage of 3 V. The bending behavior of hydrogels under an electric field can be controlled by changing the crosslinking density, ionic group content, applied voltage, and ionic strength of swelling solution.

• Applied Microscopy
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• v.36 no.3
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• pp.217-226
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• 2006

Image processing by ultra high voltage electron microscopy (UHVEM) and tomography has offered major contributions to research in the field of cellular ultrastructure. Furthermore, such advancements also have enabled the improved analysis of three-dimensional cellular structures in botany. In the present study. using UHVEM and tomography, we attempted to reconstruct the three-dimensional images of plastid inclusions that probably differentiate during photosynthesis. The foliar tissues were studied Primarily with the TEM and further examined with UHVEM. The spatial relationship between tubular elements and the thylakoidal membrane and/or starch grains within plastids mainly have been investigated in CAM-performing Sedum as well as in $C_4$ Salsola species. The inclusion bodies were found to occur only in early development in the former, while they were found only in mesophyll cells in the latter. The specimens were tilted every two degrees to obtain two-dimensional images with UHVEM and subsequently comparison has been made between the two types. Digital image processing was performed on the elements of the inclusion body using tilting, tomography, and IMOD program to generate and reconstruct three-dimensional images on the cellular level. In Sedum plastids, the inclusion bodies consisted of tubular elements exhibiting about 20 nm distance between elements. However, in Salsola, plastid inclusion bodies demonstrated quite different element structure, displaying pattern, and origin relative to those of the Sedum. The inclusion bodies had an integrative relationship with the starch grains in both species.

• Journal of Biomedical Engineering Research
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• v.23 no.4
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• pp.269-279
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• 2002

When we inject a current into an electrically conducting subject such as a human body, voltage and current density distributions are formed inside the subject. The current density within the subject and injection current in the lead wires generate a magnetic field. This magnetic flux density within the subject distorts phase of spin-echo magnetic resonance images. In Magnetic Resonance Current Density Imaging (MRCDI) technique, we obtain internal magnetic flux density images and produce current density images from $\bigtriangledown{\times}B/\mu_\theta$. This internal information is used in Magnetic Resonance Electrical Impedance Tomography (MREIT) where we try to reconstruct a cross-sectional resistivity image of a subject. This paper describes numerical techniques of computing voltage. current density, and magnetic flux density within a subject due to an injection current. We use the Finite Element Method (FEM) and Biot-Savart law to calculate these variables from three-dimensional models with different internal resistivity distributions. The numerical analysis techniques described in this paper are used in the design of MRCDI experiments and also image reconstruction a1gorithms for MREIT.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.80-85
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• 2011

This paper presents the design of the power-assisted controller for the in-wheel type smart wheelchair by using torque estimation that is predicted by relationship between input voltage and output wheel angular velocity. Nowadays, interest of the moving assistant aids is increased according to the increase in population of the elderly and the handicapped person. However some of the moving assistant aids have problems. For example, manual wheelchair has difficulty moving at the slope, because users lack the muscular strength of their arm. In electric wheelchair case, users should be weak by being decreased muscles of upper body. To overcome these problems, power-assisted electric wheelchair are proposed. Most of the power-assisted electric wheelchair have the special rims that can measure the user's power. In here, the rims have to be designed to install the sensors to measure user's power. In this paper, we don't design the rim to measure the man power. To predict the man power, we propose a control algorithm of the in-wheeled electric wheelchair by using torque estimation from the wheel. First, we measure the wheel velocity and voltage at the in-wheel electric wheelchair. And then we extract driving will forces by using proposed mathematical model. Also they are applied at the controller as the control input, we verify to be able to control in-wheel type smart wheelchair by using simulation.