• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.93-98
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• 2021

meta-iodobenzylguanidine is one of the norepinephrine analogs and reuptakes together with norepinephrine with norepinephrine transporter. The radioiodinated ligand, ¹²³I-meta-iodobenzylguanidine, is the most widely used for single photon emission computed tomography imaging to diagnose functional abnormalities and tumors of the sympathetic nervous system. In this study, we performed cellular uptake studies of ¹²³I-meta-iodobenzylguanidine in positive- and negative-norepinephrine transporter cells in vitro to verify the uptake activity for norepinephrine transporter. After ¹²³I-meta-iodobenzylguanidine was injected via a tail vein into normal mice, Single photon emission computed tomography/computed tomography images were acquired at 1 h, 4 h, and 24 h post-injection, and quantified the distribution in each organ including the adrenal medulla as a norepinephrine transporter expressing organ. In vitro cell study showed that ¹²³I-meta-iodobenzylguanidine specifically uptaked via norepinephrine transporter, and significant uptake of ¹²³I-meta-iodobenzylguanidine in the adrenal medulla in vivo single photon emission computed tomography images. These results demonstrated that single photon emission computed tomography imaging with ¹²³I-meta-iodobenzylguanidine were able to quantify the biodistribution in vivo in the adrenal medulla in normal mice.

• Smart Structures and Systems
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• v.31 no.2
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• pp.101-111
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• 2023

Structural health monitoring (SHM) covers a range of damage detection strategies for buildings. In real-time, SHM provides a basis for rapid decision making to optimise the speed and economic efficiency of post-event response. Previous work introduced an SHM method based on identifying structural nonlinear hysteretic parameters and their evolution from structural force-deformation hysteresis loops in real-time. This research extends and generalises this method to investigate the impact of a wide range of flag-shaped or pinching shape nonlinear hysteretic response and its impact on the SHM accuracy. A particular focus is plastic stiffness (K_p), where accurate identification of this parameter enables accurate identification of net and total plastic deformation and plastic energy dissipated, all of which are directly related to damage and infrequently assessed in SHM. A sensitivity study using a realistic seismic case study with known ground truth values investigates the impact of hysteresis loop shape, as well as added noise, on SHM accuracy using a suite of 20 ground motions from the PEER database. Monte Carlo analysis over 22,000 simulations with different hysteresis loops and added noise resulted in absolute percentage identification error (median, (IQR)) in K_p of 1.88% (0.79, 4.94)%. Errors were larger where five events (Earthquakes #1, 6, 9, 14) have very large errors over 100% for resulted K_p as an almost entirely linear response yielded only negligible plastic response, increasing identification error. The sensitivity analysis shows accuracy is reduces to within 3% when plastic drift is induced. This method shows clear potential to provide accurate, real-time metrics of non-linear stiffness and deformation to assist rapid damage assessment and decision making, utilising algorithms significantly simpler than previous non-linear structural model-based parameter identification SHM methods.

• Computers and Concrete
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• v.31 no.5
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• pp.433-442
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• 2023

This study presents the visually observed behavior of fibers embedded in concrete samples that were subjected to a flexural bending test. Three types of fibers such as macro polypropylene, macro polyethylene, and the hybrid of steel and polyvinyl alcohol were mixed with cement by a designated mix ratio to prepare a total of nine specimens of each. The bending test was conducted by following ASTM C1609 with a net deflection of 2, 4, and 7 mm. The X-ray computed tomography (XCT) was carried out for 7 mm-deflection specimens. The original XCT images were post-processed to denoise the beam-hardening effect. Then, fiber, crack, and void were semi-manually segmented. The hybrid specimen showed the highest toughness compared to the other two types. Debonding based on 2D XCT sliced images was commonly observed for all three groups. The cement matrix near the crack surface often involved partially localized breakage in conjunction with debonding. The pullout was predominant for steel fibers that were partially slipped toward the crack. Crack bridging and rupture were not found presumably due to the image resolution and the level of energy dissipation for poly-fibers, while the XCT imaging was advantageous in evaluating the distribution and behavior of various fibers upon bending for fiber-reinforced concrete beam elements.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.209-209
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• 2022

Reservoirs play a key role in the carbon cycle between terrestrial and marine systems and are pathways that release greenhouse gases(GHGs), CO₂, CH₄, and N₂O, into the atmosphere by decomposing organic matters. Developed countries have been actively conducting research on carbon emission assessment of dam reservoirs for over 10 years under the leadership of UNESCO/IHA, but associated research is very rare in Korea. In particular, the GHGs footprint evaluation, which calculates the change in net carbon emission considering the watershed environment between pre- and post- impoundment, is very important in evaluating the carbon emission of hydroelectric dams. The objective of this study was to estimate the GHG emissions and footprints in Daecheong Reservoir using the G-res Tool, an online platform developed by UNESCO/IHA. The G-res Tool estimates CO₂ and CH₄ emissions in consideration of diverse pathway fluxes of GHGs from the reservoir and characterizes changes in GHG fluxes over 100 years based on the expected lifetime of the dam. The input required to use the G-res Tool include data related to watersheds, reservoirs, and dams, and most were collected through the government's public portal. As a result of the study, the GHG footprint of Daecheong Reservoir was estimated to be 93 gCO₂eq/m²/yr, which is similar to that of other reservoirs around the world in the same climate zone. After impoundment, the CH₄ diffusion emission from the reservoir was 73 gCO₂eq/m²/yr, also similar to those of the overseas reservoirs, but the CH₄ bubbling emission, degassing emission, and CO₂ diffusion emissions were 44, 34, 252 gCO₂eq/m²/yr, respectively, showing a rather high tendency. Since the dam reservoir carbon footprint evaluation is essential for the Clean Development Mechanism evaluation of hydroelectric power generation, continuous research is needed in the future. In particular, experimental studies that can replace the emission factors obtained from the overseas dam reservoirs currently used in the G-res Tool should be promoted.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.11
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• pp.2924-2944
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• 2023

Alzheimer's disease (AD) is a neurological condition that is recognized as one of the primary causes of memory loss. AD currently has no cure. Therefore, the need to develop an efficient model with high precision for timely detection of the disease is very essential. When AD is detected early, treatment would be most likely successful. The most often utilized indicators for AD identification are the Mini-mental state examination (MMSE), and the clinical dementia. However, the use of these indicators as ground truth marking could be imprecise for AD detection. Researchers have proposed several computer-aided frameworks and lately, the supervised model is mostly used. In this study, we propose a novel 3D Convolutional Neural Network Multilayer Perceptron (3D CNN-MLP) based model for AD classification. The model uses Attention Mechanism to automatically extract relevant features from Magnetic Resonance Images (MRI) to generate probability maps which serves as input for the MLP classifier. Three MRI scan categories were considered, thus AD dementia patients, Mild Cognitive Impairment patients (MCI), and Normal Control (NC) or healthy patients. The performance of the model is assessed by comparing basic CNN, VGG16, DenseNet models, and other state of the art works. The models were adjusted to fit the 3D images before the comparison was done. Our model exhibited excellent classification performance, with an accuracy of 91.27% for AD and NC, 80.85% for MCI and NC, and 87.34% for AD and MCI.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1225-1233
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• 2024

Level 3 probabilistic safety assessment (PSA) is performed to calculate radionuclide concentrations and exposure dose resulting from nuclear power plant accidents. To calculate the external exposure dose from the released radioactive materials, the radionuclide concentrations are multiplied by two factors of dose coefficient and a finite cloud dose correction factor (FCDCF), and the obtained values are summed. This indicates that a standard set of FCDCFs is required for external exposure dose calculations. To calculate a standard set of FCDCFs, the effective distance from the release point to the receptor along the wind direction should be predetermined. The TID-24190 document published in 1968 provides equations to calculate FCDCFs and the resultant standard set of FCDCFs. However, it does not provide any explanation on the effective distance required to calculate the standard set of FCDCFs. In 2021, Sandia National Laboratories (SNLs) proposed a method to predetermine finite effective distances depending on the atmospheric stability classes A to F, which results in six standard sets of FCDCFs. Meanwhile, independently of the SNLs, the authors of this paper discovered that an infinite effective distance assumption is a very reasonable approach to calculate one standard set of FCDCFs, and they implemented it into the multi-unit radiological consequence calculator (MURCC) code, which is a post-processor of the level 3 PSA codes. This paper calculates and compares short- and long-range FCDCFs calculated using the TID-24190, SNLs method, and MURCC method, and explains the strength of the MURCC method over the SNLs method. Although six standard sets of FCDCFs are required by the SNLs method, one standard sets of FCDCFs are sufficient by the MURCC method. Additionally, the use of the MURCC method and its resultant FCDCFs for level 3 PSA was strongly recommended.

• Journal of Korean Home Economics Education Association
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• v.20 no.4
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• pp.19-42
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• 2008

The purpose of this study was to develop practical problem-based home economics teaching.learning process plans about a unit 'the youth and consumer life' of middle school eighth-grade Technology and Home Economics by applying blended learning(BL) strategy. According to ADDIE instructional design model, this study was conducted in the following procedure: analysis, design/development, implementation, and evaluation. In the stage of design and development, the selected unit was converted into a practical problem-based unit, and practical problem-based teaching. learning process plans were designed in detail by using BL strategy. An online study room for practical problem-based home economics instruction grounded in BL strategy was prepared by using Edunet(http://community.edunet4u.net/${\sim}$consumer2). Eight-session lesson plans were mapped out, and study aids for students and materials for teachers were prepared. In the implementation stage, the first-session teaching plans that dealt with a minor question 'what preparations should be made to become a wise consumer' were utilized when instruction was provided to 115 eighth graders who were in three different province, and the other one was in a middle school in the city of Daejeon. The experimental teaching was implemented for two weeks in the following procedure: preliminary program, pre-online learning, main instruction and post- online learning. The preliminary program was carried out in a session in the classroom, and pre-online learning was provided before the main instruction was given in a session in the classroom. After the main instruction was completed, post-online learning was offered. In the evaluation stage, a survey was conducted on all the learners and teachers to find out their opinions and suggestions.

• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.655-676
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• 2009

The first-ever integral effect test for simulating a guillotine break of a DVI (Direct Vessel Injection) line of the APR1400 was carried out with the ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation) from the same prototypic pressure and temperature conditions as those of the APR1400. The major thermal hydraulic behaviors during a DVI line break accident were identified and investigated experimentally. A method for estimating the break flow based on a balance between the change in RCS inventory and the injection flow is proposed to overcome a direct break low measurement deficiency. A post-test calculation was performed with a best-estimate safety analysis code MARS 3.1 to examine its prediction capability and to identify any code deficiencies for the thermal hydraulic phenomena occurring during the DVI line break accidents. On the whole, the prediction of the MARS code shows a good agreement with the measured data. However, the code predicted a higher core level than did the data just before a loop seal clearing occurs, leading to no increase in the peak cladding temperature. The code also produced a more rapid decrease in the downcomer water level than was predicted by the data. These observable disagreements are thought to be caused by uncertainties in predicting countercurrent flow or condensation phenomena in a downcomer region. The present integral effect test data will be used to support the present conservative safety analysis methodology and to develop a new best-estimate safety analysis methodology for DVI line break accidents of the APR1400.

• Journal of the Korea Concrete Institute
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• v.24 no.6
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• pp.727-735
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• 2012

Recently, a high-strength strand of 2400 MPa was developed using domestic technologies. In 2011, KS D 7002 was revised to cover the newly developed high-strength strands to support their practical usage. Presently, however, discussions and evaluations are not sufficient on the mechanical properties of the strands and their performance in structural members. Also, there were no detailed reviews on the need to revise the current design code for practical use of the high-strength strands. In this study, flexural behavior of a member with the high-strength strands was estimated through sectional analysis and a review and comparison of the domestic and foreign design codes were conducted considering the analysis results. Also, the need for the revision of the design code was discussed. Such discussion especially focused on the estimation of the stress in strand, which related with various issues such as determination methods for yield point of strands, time-dependent loss of prestressing force, estimation of stress in strand at member failure, and net strain limit for ductile failure of member. The discussion revealed that some parts in the design code need a revision and the further studies are required.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.11
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• pp.1588-1596
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• 2006

An experiment was conducted to study the effect of different dietary protein levels on the performance, nutrient balances, blood biochemical parameters and thyroid hormones of crossbred calves. Thirty crossbred (Bos taurus${\times}$Bos indicus) calves aged 3-5 months were divided into 3 equal groups of 10 each and fed graded levels of crude protein, namely 100 (NP), 75 (LP) and 125 (HP) percent of the Kearl recommendations for 105 d. The calves had access to ad libitum oat hay as the basal roughage. A metabolism trial of 6 d duration was conducted at 90 d of the study. Blood collection and its analysis for various hematological and biochemical parameters as well as thyroid hormones was done both during the pre- and post-experimental periods. The fortnightly body weight changes and the net gain did not differ significantly due to dietary variation. The average daily gain was $367{\pm}21.6$, $347{\pm}22.9$ and $337{\pm}26.4g$ in calves fed NP, LP and HP diets, respectively. Averaged across the feeding trial, oat hay intake was higher (p<0.05) in NP animals than HP or LP fed groups. The dry matter (DM) intake showed no significant difference between the 3 groups but the DM digestibility was higher (p<0.05) in the HP fed animals. The digestibility of crude protein, organic matter, crude fiber and nitrogen-free extract was significantly higher (p<0.05) on HP diets compared to LP or NP diets. The calves on all 3 diets were in positive nitrogen (N) balance, however the N retention was higher (p<0.05) in HP than in LP fed calves. The intake and retention of calcium and phosphorus were similar between the treatments. The blood biochemical profile revealed no significant influence of the dietary treatments on hemoglobin, packed cell volume as well as serum levels of glucose, total protein, albumin, globulin, Ca, P, and alkaline phosphatase. Serum levels of the circulating thyroid hormones ($T_3$ and $T_4$) tended to be lower (p>0.05) on feeding of the LP diet besides showing an increasing trend with the advancement of age. Considering the similar performance and metabolic profile, it could be concluded that crossbred calves can be satisfactorily reared on 25% lower protein level as recommended by Kearl for developing countries, which would not only economize the cost of production but also help to reduce environmental pollution attributable to livestock production.