• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1676-1685
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• 2021

We develop a new high-fidelity multiphysics model to simulate boron chemistry in the porous Chalk River Unidentified Deposit (CRUD) deposits. Heat transfer, capillary flow, solute transport, and chemical reactions are fully coupled. The evaporation of coolant in the deposits is included in governing equations modified by the volume-averaged assumption of wick boiling. The axial offset anomaly (AOA) of the Seabrook nuclear power plant is simulated. The new model reasonably predicts the distributions of temperature, pressure, velocity, volumetric boiling heat density, and chemical concentrations. In the thicker CRUD regions, 60% of the total heat is removed by evaporative heat transfer, causing boron species accumulation. The new model successfully shows the quantitative effect of coolant evaporation on the local distributions of boron. The total amount of boron in the CRUD layer increases by a factor of 1.21 when an evaporation-driven increase of soluble and precipitated boron concentrations is reflected. In addition, the concentrations of B(OH)₃ and LiBO₂ are estimated according to various conditions such as different CRUD thickness and porosity. At the end of the cycle in the AOA case, the total mass of boron incorporated in CRUD deposits of a reference single fuel rod is estimated to be about 0.5 mg.

• Structural Engineering and Mechanics
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• v.81 no.5
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• pp.565-574
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• 2022

The infrastructures such as offshore, bridges, power plant, oil and gas piping and aircraft operate in a harsh environment during their service life. Structural integrity of engineering components used in these industries is paramount for the reliability and economics of operation. Two regression models based on the concept of Gaussian process regression (GPR) and Minimax probability machine regression (MPMR) were developed to predict stress intensity factor range (𝚫K). Both GPR and MPMR are in the frame work of probability distribution. Models were developed by using the fatigue crack growth data in MATLAB by appropriately modifying the tools. Fatigue crack growth experiments were carried out on Eccentrically-loaded Single Edge notch Tension (ESE(T)) specimens made of API 5L X65 Grade steel in inert and corrosive environments (2.0% and 3.5% NaCl). The experiments were carried out under constant amplitude cyclic loading with a stress ratio of 0.1 and 5.0 Hz frequency (inert environment), 0.5 Hz frequency (corrosive environment). Crack growth rate (da/dN) and stress intensity factor range (𝚫K) values were evaluated at incremental values of loading cycle and crack length. About 70 to 75% of the data has been used for training and the remaining for validation of the models. It is observed that the predicted SIF range is in good agreement with the corresponding experimental observations. Further, the performance of the models was assessed with several statistical parameters, namely, Root Mean Square Error (RMSE), Mean Absolute Error (MAE), Coefficient of Efficiency (E), Root Mean Square Error to Observation's Standard Deviation Ratio (RSR), Normalized Mean Bias Error (NMBE), Performance Index (ρ) and Variance Account Factor (VAF).

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.1-10
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• 2009

Precise branch predictor has a profound impact on system performance in modern processor architectures. Recent works show that prediction latency as well as prediction accuracy has a critical impact on overall system performance as well. However, prediction latency tends to be overlooked. In this paper, we propose Branch Pre-Prediction policy to tolerate branch prediction latency. The proposed solution allows that branch predictor can proceed its prediction without any information from the fetch engine, separating the prediction engine from fetch stage. In addition, we propose newly modified BTE structure to support our solution. The simulation result shows that proposed solution can hide most prediction latency with still providing the same level of prediction accuracy. Furthermore, the proposed solution shows even better performance than the ideal case, that is the predictor which always takes a single cycle prediction latency. In our experiments, IPC improvement is up to 11.92% and 5.15% in average, compared to conventional predictor system.

• The Korean Journal of Archival Studies
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• no.77
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• pp.109-150
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• 2023

Prior researchers interpreted the records of criminal cases involving the Progressive Party from a historical perspective. In marked contrast to existing trends, this study examines the Progressive Party case records through the lens of archival science. This study dissects the Progressive Party case records as a single and complete record group and at each stage of their life cycle from police investigation through criminal prosecution to trial. This approach enables a holistic analysis of archival characteristics of the records. This study begins with an appraisal of the nature and types of case records generated and maintained by the various agencies in light of the investigatory authorities delegated to each institution. This study then dissects the police, prosecution, and Counter Intelligence Corps records leading up to the indictment of Progressive Party members as well as the court records of the trial that followed. In particular, this study reveals the insufficiency and illegality of the evidence against the defendants in the Progressive Party case from an archival standpoint. Setting aside the admissibility or strength of the evidence under criminal law, the present study demonstrates that the records lack reliability, authenticity, and integrity-the fundamental attributes required for evidentiary efficacy of records from an archival standpoint.

• Tribology and Lubricants
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• v.39 no.5
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• pp.203-211
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• 2023

This study experimentally investigates the effects of angular acceleration on the friction and wear performances of a gas foil thrust bearing (GFTB) using a typical GFTB with six pads. The outer radius of the bearing is 31.5 mm, the total bearing area is 2,041 mm² , and the bump foil and incline (ramp) height are both 500 ㎛. The newly developed GFTB test rig for measuring the friction torque and coefficient measures the axial load, drag torque, lift-off speed, and touch-down speed. The experiment is conducted for angular accelerations of 78.5, 314.2, and 328.3 rad/s² at axial loads of 5, 10, and 15 N, respectively. The test shows that the start-up friction coefficient increases with increasing axial load at the same angular acceleration, and the friction coefficient decreases with increasing angular acceleration under the same axial load. As the angular acceleration increases, the lift-off speed at the motor start-up increases, and the touch-down speed at the motor stop decreases. The wear distance of the GFTB for a single on/off cycle increases with increasing axial load at the same angular acceleration and decreases nonlinearly with increasing angular acceleration under the same axial load. The test results suggest that adjusting the rotational angular acceleration helps reduce bearing friction and wear.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.21 no.1
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• pp.15-21
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• 2021

Purpose: Urea cycle disorder (UCD) is an inherited inborn error of metabolism, acting on each step of urea cycle that cause various phenotypes. The purpose of the study was to investigate the long-term clinical consequences in different groups of UCD to characterize it. Methods: Twenty-two patients with UCD genetically confirmed were enrolled at Pusan National University Children's hospital and reviewed clinical features, biochemical and genetic features retrospectively. Results: UCD diagnosed in the present study included ornithine transcarbamylase deficiency (OTCD) (n=10, 45.5%), argininosuccinate synthase 1 deficiency (ASSD) (n=6, 27.3%), carbamoyl-phosphate synthetase 1 deficiency (CPS1D) (n=3, 13.6%), hyperornithinemia-hyperammonemia-homocitrullinuria syndrome (HHHS) (n=2, 9.1%), and arginase-1 deficiency (ARG1D) (n=1, 4.5%). The age at the diagnosis was 32.7±66.2 months old (range 0.1 to 228.0 months). Eight (36.4%) patients with UCD displayed short stature. Neurologic sequelae were observed in eleven (50%) patients with UCD. Molecular analysis identified 37 different mutation types (14 missense, 6 nonsense, 6 deletion, 6 splicing, 3 delins, 1 insertion, and 1 duplication) including 14 novel variants. Progressive growth impairment and poor neurological outcomes were associated with plasma isoleucine and leucine concentrations, respectively. Conclusion: Although combinations of treatments such as nutritional restriction of proteins and use of alternative pathways for discarding excessive nitrogen are extensively employed, the prognosis of UCD remains unsatisfactory. Prospective clinical trials are necessary to evaluate whether supplementation with BCAAs might improve growth or neurological outcomes and decrease metabolic crisis episodes in patients with UCD.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.163-170
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• 1999

Objectives: The aims of this study are 1) to determine if GAST is a better indicator in predicting ovarian response to COH compared with patient's age or basal FSH level and 2) to evaluate its role in detecting abnormal ovarian response. Design: Prospective study in 118 patients undergoing IVF-ET using GnRH-a short protocol during May-September 1995. Materials and Methods: After blood sampling for basal FSH and estradiol $(E_2)$ on cycle day two, 0.5ml (0.525mg) GnRH agonist ($Suprefact^{(r)}$, Hoechst) was injected subcutaneously. Serum $E_2$ was measured 24 hours later. Initial $E_2$ difference $({\Delta}E_2)$ was defined as the change in $E_2$ on day 3 over the baseline day 2 value. Sixteen patients with ovarian cyst or single ovary or incorrect blood collection time were excluded from the analysis. The patients were divided into three groups by ${\Delta}E_2$; group A (n=30):${\Delta}E_2$<40 pg/ml, group B (n=52): 40 pg/ml${\leq}{\Delta}E_2$<100 pg/ml, group C (n=20): ${\Delta}E_2{\leq}100$ pg/ml. COH was done by GnRH agonist/HMG/hCG and IVF-ET was followed. Ratio of $E_2$ on day of hCG injection over the number of ampules of gonadotropins used ($E_2hCGday$/Amp) was regarded as ovarian responsiveness. Poor ovarian response and overstimulation were defined as $E_2$ hCGday less than 600 pg/ml and greater than 5000 pg/ml, respectively. Results: Mean age $({\pm}SEM)$ in group A, B and C were $33.7{\pm}0.8^*,\;31.5{\pm}0.6\;and\;30.6{\pm}0.5^*$, respectively ($^*$: p<0.05). Mean basal FSH level of group $A(11.1{\pm}1.1mlU/ml)$ was significantly higher than those of $B(7.4{\pm}0.2mIU/ml)$ and C $(6.8{\pm}0.4mIU/ml)$ (p<0.001). Mean $E_2hCGday$ of group A was significantly lower than those of group B or C, i.e., $1402.1{\pm}187.7pg/ml,\;3153.2{\pm}240.0pg/ml,\;4078.8{\pm}306.4pg/ml$ respectively (p<0.0001). The number of ampules of gonadotropins used in group A was significantly greater than those in group B or C: $38.6{\pm}2.3,\;24.2{\pm}1.1\;and\;18.5{\pm}1.0$ (p<0.0001). The number of oocytes retrieved in group A was significantly smaller than those in group B or C: $6.4{\pm}1.1,\;15.5{\pm}1.1\;and\;18.6{\pm}1.6$, respectively (p<0.0001). By stepwise multiple regression, only ${\Delta}E_2$ showed a significant correlation (r=0.68, p<0.0001) with $E_2HCGday$/Amp, while age or basal FSH level were not significant. Likewise, only ${\Delta}E_2$ correlated significantly with the number of oocytes retrieved (r=0.57, p<0.001). All four patients whose COH was canceled due to poor ovarian response belonged to group A only (Fisher's exact test, p<0.01). Whereas none of 30 patients in group A (0%) had overstimulation, 14 patients among 72 patients (19.4%) in group B and C had overstimulation (Fisher's exact test, p<0.01). Conclusions: These data suggest that initial $E_2$ difference after GAST may be a better prognostic indicator of ovarian response to COH than age or basal FSH level. Since initial $E_2$ difference demonstrates significant association with abnormal ovarian response such as poor ovarian response necessitating cycle cancellation or overstimulation, GAST may be helpful in monitoring and consultation of patients during COH in IVF-ET cycle.

• Korean Journal of Remote Sensing
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• v.33 no.5_2
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• pp.621-630
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• 2017

In this paper, a study on classification targeting a main production area of garlic and onion was carried out in order to figure out the applicability of multi-temporal high-resolution satellite imagery for field crop classification. After collecting satellite imagery in accordance with the growth cycle of garlic and onion, classifications using each sing date imagery and various combinations of multi-temporal dataset were conducted. In the case of single date imagery, high classification accuracy was obtained in December when the planting was completed and March when garlic and onion started to grow vigorously. Meanwhile, higher classification accuracy was obtained when using multi-temporal dataset rather than single date imagery. However, more images did not guarantee higher classification accuracy. Rather, the imagery at the planting season or right after planting reduced classification accuracy. The highest classification accuracy was obtained when using the combination of March, April and May data corresponding the growth season of garlic and onion. Therefore, it is recommended to secure imagery at main growth season in order to classify garlic and onion field using multi-temporal satellite imagery.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.137-148
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• 2006

The purpose of this study was to compare muscle activity in the lower extremity during walking wearing jogging and roller shoes. Twelve male middle school students (age: 15.0 yrs, height 173.7 cm, weight 587.7 N) who have no known musculoskeletal disorders were recruited as the subjects. Seven pairs of surface electrodes (QEMG8, Laxtha Korea, gain = 1,000, input impedance >$1012{\Omega}$, CMMR >100 dB) were attached to the right-hand side of the body to monitor the rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), tibialis anterior (TA), and medial (GM) and lateral gastrocnemius (GL) while subjects walked wearing roller and jogging shoes in random order at a speed of 1.1 m/s. An event sync unit with a bright LED light was used to synchronize the video and EMG recordings. EMG data were filtered using a 10 Hz to 350 Hz Butterworth band-passdigital filter and further normalized to the respective maximum voluntary isometric contraction EMG levels. For each trial being analyzed, five critical instants and four phases were identified from the recording. Averaged IEMG and peak IEMG were determined for each trial. For each dependent variable, paired t-test was performed to test if significant difference existed between shoe conditions (p<.05). The VM, TA, BF, and GM activities during the initial double limb stance and the initial single limb stance reduced significantly when going from jogging shoe to roller shoe condition. The decrease in EMG levels in those muscles indicated that the subjects locked the ankle and knee joints in an awkward fashion to compensate for the imbalance. Muscle activity in the GM for the roller shoe condition was significantly greater than the corresponding value for the jogging shoe condition during the terminal double limb stance and the terminal single limb stance. Because the subjects tried to keep their upper body weight in front of the hip to prevent falling backward, the GM activity for the roller shoe condition increased. It seems that there are differences in muscle activity between roller shoe and jogging shoe conditions. The differences in EMG pattern may be caused primarily by the altered position of ankle, knee, and center of mass throughout the walking cycle. Future studies should examine joint kinematics during walking with roller shoes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.3
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• pp.257-264
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• 2017

For the safe disposal of intermediate level radioactive waste according to the Nuclear Safety and Security Commission's notice and KORAD's management plan for low and intermediate level radioactive waste, the disposal concentration limit was derived based on the IAEA methodology. The evaluation of the derived disposal concentration limit revealed that it is not suitable as a practical limit for intermediate level radioactive waste. This is because the disposal concentration limit according to the IAEA methodology is derived using a single value of radioactive waste density and the disposal facility's volume. The IAEA methodology is suitable for setting the concentration limit for vault type disposal, which consists of a single type of waste, whereas an underground silo type disposal facility is composed of several types of radioactive waste, and thus the IAEA methodology has limitations in determining the disposal concentration limit. It is necessary to develop and apply an improved method to derive the disposal concentration limit for intermediate level radioactive waste by considering the radioactivity of various types of radioactive waste, the corresponding scenario evaluation results, and the regulatory limit.