• Restorative Dentistry and Endodontics
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• v.34 no.2
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• pp.145-153
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• 2009

The purpose of this study was to evaluate the effect of instrument compliance on the polymerization shrinkage stress measurements of dental composites. The contraction strain and stress of composites during light curing were measured by a custom made stress-strain analyzer, which consisted of a displacement sensor, a cantilever load cell and a negative feedback mechanism. The instrument can measure the polymerization stress by two modes: with compliance mode in which the instrument compliance is allowed, or without compliance mode in which the instrument compliance is not allowed. A flowable (Filtek Flow: FF) and two universal hybrid (Z100: Z1 and Z250: Z2) composites were studied. A silane treated metal rod with a diameter of 3.0 mm was fixed at free end of the load cell, and other metal rod was fixed on the base plate. Composite of 1.0 mm thickness was placed between the two rods and light cured. The axial shrinkage strain and stress of the composite were recorded for 10 minutes during polymerization. and the tensile modulus of the materials was also determined with the instrument. The statistical analysis was conducted by ANOVA. paired t-test and Tukey's test (${\alpha}<0.05$). There were significant differences between the two measurement modes and among materials. With compliance mode, the contraction stress of FF was the highest: 3.11 (0.13). followed by Z1: 2.91 (0.10) and Z2: 1.94 (0.09) MPa. When the instrument compliance is not allowed, the contraction stress of Z1 was the highest: 17.08 (0.89), followed by FF: 10.11 (0.29) and Z2: 9.46 (1.63) MPa. The tensile modulus for Z1, Z2 and FF was 2.31 (0.18), 2.05 (0.20), 1.41 (0.11) GPa, respectively. With compliance mode. the measured stress correlated with the axial shrinkage strain of composite: while without compliance the elastic modulus of materials played a significant role in the stress measurement.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.2
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• pp.157-166
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• 2015

Purpose : Cyber-Knife tumor tracking system, based on the correlation relationship between the position of a tumor which moves in response to the real time respiratory cycle signal and respiration was obtained by the LED marker attached to the outside of the patient, the location of the tumor to predict in advance, the movement of the tumor in synchronization with the therapeutic device to track real-time tumor, is a system for treating. The purpose of this study, in the cyber knife tumor tracking radiation therapy, trying to evaluate the accuracy of tumor tracking radiation therapy system due to the change in the form of unpredictable sudden breathing due to cough and sleep. Materials and Methods : Breathing Log files that were used in the study, based on the Respiratory gating radiotherapy and Cyber-knife tracking radiosurgery breathing Log files of patients who received herein, measured using the Log files in the form of a Sinusoidal pattern and Sudden change pattern. it has been reconstituted as possible. Enter the reconstructed respiratory Log file cyber knife dynamic chest Phantom, so that it is possible to implement a motion due to respiration, add manufacturing the driving apparatus of the existing dynamic chest Phantom, Phantom the form of respiration we have developed a program that can be applied to. Movement of the phantom inside the target (Ball cube target) was driven by the displacement of three sizes of according to the size of the respiratory vertical (Superior-Inferior) direction to the 5 mm, 10 mm, 20 mm. Insert crosses two EBT3 films in phantom inside the target in response to changes in the target movement, the End-to-End (E2E) test provided in Cyber-Knife manufacturer depending on the form of the breathing five times each. It was determined by carrying. Accuracy of tumor tracking system is indicated by the target error by analyzing the inserted film, additional E2E test is analyzed by measuring the correlation error while being advanced. Results : If the target error is a sine curve breathing form, the size of the target of the movement is in response to the 5 mm, 10 mm, 20 mm, respectively, of the average $1.14{\pm}0.13mm$, $1.05{\pm}0.20mm$, with $2.37{\pm}0.17mm$, suddenly for it is variations in breathing, respective average $1.87{\pm}0.19mm$, $2.15{\pm}0.21mm$, and analyzed with $2.44{\pm}0.26mm$. If the correlation error can be defined by the length of the displacement vector in the target track is a sinusoidal breathing mode, the size of the target of the movement in response to 5 mm, 10 mm, 20 mm, respective average $0.84{\pm}0.01mm$, $0.70{\pm}0.13mm$, with $1.63{\pm}0.10mm$, if it is a variant of sudden breathing respective average $0.97{\pm}0.06mm$, $1.44{\pm}0.11mm$, and analyzed with $1.98{\pm}0.10mm$. The larger the correlation error values in both the both the respiratory form, the target error value is large. If the motion size of the target of the sine curve breathing form is greater than or equal to 20 mm, was measured at 1.5 mm or more is a recommendation value of both cyber knife manufacturer of both error value. Conclusion : There is a tendency that the correlation error value between about target error value magnitude of the target motion is large is increased, the error value becomes large in variation of rapid respiration than breathing the form of a sine curve. The more the shape of the breathing large movements regular shape of sine curves target accuracy of the tumor tracking system can be judged to be reduced. Using the algorithm of Cyber-Knife tumor tracking system, when there is a change in the sudden unpredictable respiratory due patient coughing during treatment enforcement is to stop the treatment, it is assumed to carry out the internal target validation process again, it is necessary to readjust the form of respiration. Patients under treatment is determined to be able to improve the treatment of accuracy to induce the observed form of regular breathing and put like to see the goggles monitor capable of the respiratory form of the person.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.23-29
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• 2017

The packaged optical fiber Bragg grating sensors which were networked by multiplexing the Bragg grating sensors with WDM technology were investigated in application for the structural health monitoring of the marine trestle structure transporting the ship. The optical fiber Bragg grating sensor was packaged in a cylindrical shape made of aluminum tubes. Furthermore, after the packaged optical fiber sensor was inserted in polymeric tube, the epoxy was filled inside the tube so that the sensor has resistance and durability against sea water. The packaged optical fiber sensor component was investigated under 0.2 MPa of hydraulic pressure and was found to be robust. The number and location of Bragg gratings attached at the trestle were determined where the trestle was subject to high displacement obtained by the finite element simulation. Strain of the part in the trestle being subjected to the maximum load was analyzed to be ${\sim}1000{\mu}{\varepsilon}$ and thus shift in Bragg wavelength of the sensor caused by the maximum load of the trestle was found to be ~1,200 pm. According to results of the finite element analysis, the Bragg wavelength spacings of the sensors were determined to have 3~5 nm without overlapping of grating wavelengths between sensors when the trestle was under loads and thus 50 of the grating sensors with each module consisting of 5 sensors could be networked within 150 nm optical window at 1550 nm wavelength of the Bragg wavelength interrogator. Shifts in Bragg wavelength of the 5 packaged optical fiber sensors attached at the mock trestle unit were well interrogated by the grating interrogator which used the optical fiber loop mirror, and the maximum strain rate was measured to be about $235.650{\mu}{\varepsilon}$. The modelling result of the sensor packaging and networking was in good agreements with experimental result each other.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.8-8
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• 1987

This paper describes on the distribution of the vibration and the noise produced on a skipjack pole and line training ship M/S Pusan 403 (243GT, 1,000ps) under the cruising or drifting condition. The vibration and the noise level were measured by use of protable vibration analyzer (B and K 3513) and sound level meter (B and K 2205), and so the vibration level was converted into dB unit. The check points were set through every decks and around important places of the ship. The results obtained can be summarized as follows: 1. The vibration and the noise level 1) On the main deck, both the vibration and the noise level were highest at the vertically above the main engine, whereas the vibration level was the lowest in the bow store and the noise level beneath the bridge. 2) Under cruising condition, the vibration level around the cylinder head of main engine, port side of the engine room, on the shaft tunnel was 80, 67, 65 dB and the noise level 104, 87, 86 dB, respectively. 3) The vibration level on the vertical line passing through the bridge was the highest at the orlop deck with 60 dB and the lowest on the bridge deck with 55 dB, whereas the noise level the highest at the compass deck with 75 dB and the lowest at the orlop deck with 53 dB. 4) The vibration and the noise level on the open decks were the highest with 65 dB and 84 dB on the boat deck, whereas the vibration level was the lowest at the lecture room with 51 dB and the noise level the lowest at the fore castle deck with 57 dB. 5) On the orlop decks, both the vibration and the noise level were the highest at the engine room with 65 dB and 85 dB, and the lowest at bow store with 54 dB and 52 dB, respectively. Comparing with the vibration level and the noise level, the vibration level was higher than the noise level in the bow part and it was contrary in the stern part of the ship. 2. Vibration analysis 1) The vibration displacement and the vibration velocity were the greatest at the cylinder head of main engine with 100μm and 11mm/sec, and were the smallest at the compass deck with 3μm and 0.07mm/sec. They were also attenuated rapidly around the frequency of 100Hz and over. 2) The vibration acceleration was the greatest at the cylinder head with the main frequency of 1KHz and the acceleration of 1.1mm/sec super(2), and the smallest at the compass deck with 30KHz and 0.05mm/sec super(2).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.23 no.2
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• pp.54-60
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• 1987

This paper describes on the distribution of the vibration and the noise produced on a skipjack pole and line training ship M/S Pusan 403 (243GT, 1,000ps) under the cruising or drifting condition. The vibration and the noise level were measured by use of protable vibration analyzer (B and K 3513) and sound level meter (B and K 2205), and so the vibration level was converted into dB unit. The check points were set through every decks and around important places of the ship. The results obtained can be summarized as follows: 1. The vibration and the noise level 1) On the main deck, both the vibration and the noise level were highest at the vertically above the main engine, whereas the vibration level was the lowest in the bow store and the noise level beneath the bridge. 2) Under cruising condition, the vibration level around the cylinder head of main engine, port side of the engine room, on the shaft tunnel was 80, 67, 65 dB and the noise level 104, 87, 86 dB, respectively. 3) The vibration level on the vertical line passing through the bridge was the highest at the orlop deck with 60 dB and the lowest on the bridge deck with 55 dB, whereas the noise level the highest at the compass deck with 75 dB and the lowest at the orlop deck with 53 dB. 4) The vibration and the noise level on the open decks were the highest with 65 dB and 84 dB on the boat deck, whereas the vibration level was the lowest at the lecture room with 51 dB and the noise level the lowest at the fore castle deck with 57 dB. 5) On the orlop decks, both the vibration and the noise level were the highest at the engine room with 65 dB and 85 dB, and the lowest at bow store with 54 dB and 52 dB, respectively. Comparing with the vibration level and the noise level, the vibration level was higher than the noise level in the bow part and it was contrary in the stern part of the ship. 2. Vibration analysis 1) The vibration displacement and the vibration velocity were the greatest at the cylinder head of main engine with 100$\mu$m and 11mm/sec, and were the smallest at the compass deck with 3$\mu$m and 0.07mm/sec. They were also attenuated rapidly around the frequency of 100Hz and over. 2) The vibration acceleration was the greatest at the cylinder head with the main frequency of 1KHz and the acceleration of 1.1mm/sec super(2), and the smallest at the compass deck with 30KHz and 0.05mm/sec super(2).

• Progress in Medical Physics
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• v.23 no.3
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• pp.145-153
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• 2012

In this study, we quantify the residual motion artifact in 4D-CT scan using the dynamic lung phantom which could simulate respiratory target motion and suggest a simple one-dimension theoretical model to explain and characterize the source of motion artifacts in 4DCT scanning. We set-up regular 1D sine motion and adjusted three level of amplitude (10, 20, 30 mm) with fixed period (4s). The 4DCT scans are acquired in helical mode and phase information provided by the belt type respiratory monitoring system. The images were sorted into ten phase bins ranging from 0% to 90%. The reconstructed images were subsequently imported into the Treatment Planning System (CorePLAN, SC&J) for target delineation using a fixed contour window and dimensions of the three targets are measured along the direction of motion. Target dimension of each phase image have same changing trend. The error is minimum at 50% phase in all case (10, 20, 30 mm) and we found that ${\Delta}S$ (target dimension change) of 10, 20 and 30 mm amplitude were 0 (0%), 0.1 (5%), 0.1 (5%) cm respectively compare to the static image of target diameter (2 cm). while the error is maximum at 30% and 80% phase ${\Delta}S$ of 10, 20 and 30 mm amplitude were 0.2 (10%), 0.7 (35%), 0.9 (45%) cm respectively. Based on these result, we try to analysis the residual motion artifact in 4D-CT scan using a simple one-dimension theoretical model and also we developed a simulation program. Our results explain the effect of residual motion on each phase target displacement and also shown that residual motion artifact was affected that the target velocity at each phase. In this study, we focus on provides a more intuitive understanding about the residual motion artifact and try to explain the relationship motion parameters of the scanner, treatment couch and tumor. In conclusion, our results could help to decide the appropriate reconstruction phase and CT parameters which reduce the residual motion artifact in 4DCT.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.3
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• pp.199-212
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• 2007

If a type IP-2 transport package were to be subjected to a free drop test and a penetration test under the normal conditions of transport, it should prevent a loss or dispersal of the radioactive contents and a more than 20% increase in the maximum radiation level at any external surface of the package. In this paper, we suggested the analytic method to evaluate the structural safety of a type IP-2 transport package using a thick steel plate for a structure part and a bolt for tying a bolt. Using an analysis a loss or dispersal of the radioactive contents and a loss of shielding integrity were confirmed for two kinds of type IP-2 transport packages to transport radioactive waste drums from a waste facility to a temporary storage site in a nuclear power plant. Under the free drop condition the maximum average stress at the bolts and the maximum opening displacement of a lid were compared with the tensile stress of a bolt and the steps in a lid, which were made to avoid a streaming radiation in the shielding path, to evaluate a loss or dispersal of radioactive waste contents. Also a loss of shielding integrity was evaluated using the maximum decrease in a shielding thickness. To verify the impact dynamic analysis for free drop test condition and evaluate experimentally the safety of two kinds of type IP-2 transport packages, free drop tests were conducted with various drop directions. For the tests we examined the failure of bolts and the deformation of flange to evaluate a loss or dispersal of radioactive material and measured the shielding thickness using a ultrasonic thickness gauge to assess a loss of shielding integrity. The strains and accelerations acquired from tests were compared with those by analyses to verify the impact dynamic analysis. The analytic results were larger than the those of test so that the analysis showed the conservative results. Finally, we evaluated the safety of the type IP-2 transport package under the stacking test condition using a finite element analysis. Under the stacking test condition, the maximum Tresca stress of the shielding material was 1/3 of the yielding stress. Two kinds of a type IP-2 transport package were safe for the free drop test condition and the stacking test condition.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.1
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• pp.25-32
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• 2010

Purpose: In radiotherapy that takes into account respiration using a RPM (Real time Position Management, Varian, USA) system, which can treat in consideration of the movement of tumor, infrared reflective markers supplied by manufacturers cannot obtain respiratory signal if the couch rotates at a certain angle or larger. In order to solve this problem, the author developed the 3D infrared reflective marker named 'Kw-marker' that can obtain respiratory signal at any angle, and evaluate its usefulness. Materials and Methods: In order to measure the stability of respiratory signal, we put the infrared reflective marker on the 3D moving phantom that can reproduce respiratory movement and acquired respiratory signal for 3 minutes under each of 3 conditions (A: $couch\;0^{\circ}$, a manufacturer's infrared reflective marker B: $couch\;0^{\circ}$, Kw-marker C: $couch\;90^{\circ}$, Kw-marker). By analyzing the respiratory signal using a breath analysis program (Labview Ver. 7.0), we obtained the peak value, valley value, standard deviation, variation value, and amplitude value. In order to examine the rotation error and moving range of the target, we placed a B.B phantom on the 3D moving phantom, and obtained images at a couch angle of $0^{\circ}$ and $90^{\circ}$ using OBI, and then acquired the X, Y and Z values (mm) of the ball bearing at the center of the B.B phantom. Results: According to the results of analyzing the respiratory signal, the standard deviation at the peak value was A: 0.002, B: 0.002 and C: 0.003, and the stability of respiration for amplitude was A: 0.15%, B: 0.14% and C:0.13%, showing that we could get respiratory signal stably by using the Kw-marker. When the couch rotated $couch\;90^{\circ}$, the mean rotation error of the ball bearing, namely, the target was X: -1.25 mm, Y: -0.45 mm and Z: +0.1 mm, which were within 1.3 mm on the average in all directions, and the difference in the moving range of the target was within 0.3 mm. Conclusion: When we obtained respiratory signal using the Kw-marker in non-coplanar treatment where the couch rotated, we could acquire respiratory signal stably and the Kw-marker was effective enough to substitute for the manufacturer's infrared reflective marker. When the rotation error and moving range of the target were measured, there was little difference, indicating that the displacement of the reflector movement in couch rotation is the cause of change in the scale and amplitude of respiratory signal. If the converted value of amplitude height according to couch angle is studied further and applied, it may be possible to perform non-coplanar phase-based gating treatment.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.85-93
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• 2012

Purpose: It is essential to minimize the respiratory-induced motion of involved organs in the Tomotherapy for tumor located in the chest and abdominal region. However, the application of breathing control system to Tomotherapy is limited. This study was aimed to investigate the possible application of the ABCHES system and its efficacy as a means of breathing control in the tomotherapy treatment. Materials and Methods: Five subjects who were treated with a Hi-Art Tomotherapy system for lung, liver, gallbladder and pancreatic tumors. All patients undertook trained on two breathing methodes using an ABCHES, free breathing methode and shallow breathing methode. When the patients could carry out the breathing control, 4D-CT scan was a total of 10 4D tomographic images were acquired. A radiologist resident manually drew the tumor region, including surrounding nomal organs, on each of CT images at the inhalation phase, the exhalation phase and the 40% phase (mid-inhalation) and average CT image. Those CT images were then exported to the Tomotherapy planning station. Data exported from the Tomotherapy planning station was analyzed to quantify characteristics of dose-volume histograms and motion of tumors. Organ motions under free breathing and shallow breathing were examined six directions, respectively. Radiation exposure to the surrounding organs were also measured and compared. Results: Organ motion is in the six directions with more than a 5 mm displacement. A total of 12 Organ motions occurred during free breathing while organ motions decreased to 2 times during shallow breathing under the use of Abches. Based on the quantitative analysis of the dose-volume histograms shallow breathing showed lower resulting values, compared to free breathing, in every measure. That is, treatment volume, the dose of radiation to the tumor and two surrounding normal organs (mean doses), the volume of healthy tissue exposed to radiation were lower at the shallow breathing state. Conclusion: This study proposes that the use of ABCHES is effective for the Tomotherapy treatment as it makes shortness of breathing easy for patients. Respiratory-induced tumor motion is minimized, and radiation exposure to surrounding normal tissues is also reduced as a result.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.2
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• pp.102-108
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• 2009

Purpose: The purpose of this study is to report a result of the technique that reconstruct posterior cruciate ligament (PCL) and posterolateral corner (PLC) simultaneously using a fresh-frozen Achilles tendon allograft. Materials and Methods: Forty two patients (45 legs) underwent PCL and PLC reconstruction were included. There were 38 males and 4 females. Mean age was 39 years. Used graft was a fresh frozen Achilles tendon allograft, which was divided by two size, larger one (${\emptyset}$ 10 mm) for PCL reconstruction and smaller one (${\emptyset}$ 8 mm) for PLC reconstruction. Arthroscopic reconstruction of the PCL was performed using transtibial, single incision, and single bundle technique with 10mm fresh frozen Achilles allograft tendon first. After PCL reconstruction, reconstruction procedure for posterolateral instability was performed using modified figure of "8" technique using smaller gtaft. For clinical evaluation, range of motion, posterior drawer test, varus stress test, prone external rotation (dial) test, Lysholm score, Tegner activity scale and posterior stress radiograph were used. Mean follow up period was 25 months. Results: Preoperatively posterior drawer test was 5 cases in grade II and 40 cases in grade III posterior instability. At final follow-up 22 cases returned within normal condition, 18 cases grade I and 5 cases grade II posterior instability. Though all patients showed positive result over 10 degrees in dial and varus stress test preoperatively, but only 9 cases showed positive both test at final follow-up. The range of motion deficit over $10^{\circ}$ flexion was 3 cases. Lysholm score was improved from mean 50 preoperatively to mean 83(p<0.05) and Tegner activity scale improved from mean 2.1 preoperatively to mean 4.6(p<0.05). In posterior stress radiographs, posterior displacement was improve from mean 16mm preoperatively to 4.1mm after treatment(p<0.05). All patients had improved compared to their pre-operative status as measured by physical examination such as posterior drawer test, varus stress test, dial test. Conclusion: We had successful results by combined reconstruction of the PCL & PLC with a fresh frozen Achilles tendon allograft in patients with PCL and posterolateral rotatory instability at a time.