• Nuclear Engineering and Technology
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• v.13 no.3
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• pp.121-129
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• 1981

Three most outstanding maximum flow rate formulas are identified from many existing models. Outlines of the three limiting mass flow rate models are given along with computational procedures to estimate approximate amount of fission products released from a containment to environment for a given characteristic hole size for containment-isolation failure and containment pressure and temperature under a loss of coolant accident. Sample calculations are performed using the critical ideal gas flow rate model and the Moody's graphs for the maximum two-phase flow rates, and the results are compared with the values obtained from the mass leakage rate formula of CONTEMPT-LT code for converging nozzle and sonic flow. It is shown that the critical ideal gas flow rate formula gives almost comparable results as one can obtain from the Moody's model. It is also found that a more conservative approach to estimate leakage rate from a containment under a LOCA is to use the maximum ideal gas flow rate equation rather than tile mass leakage rate formula of CONTEMPT-LT.

• Transactions of Materials Processing
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• v.10 no.1
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• pp.3-14
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• 2001

Hydroforming is the technology using hydraulic pressure and forming sheet or tube metals to desired shape in a die cavity. lt can be characterized as tube hydroforming and sheet hydroforming depending on the shape of used blank. Due to its prcess-related benefits, this production technology has been remarkably noticed for great potential for feasible applications and recently gained great attraction from many industrials including automotive and non-automotive. This Paper analyzed the tube and the welded blank hydroforming process and compared formability of the processes for automotive engine mount bracket. The mathematical analysis was performed by using the dynamic explicit finite element code, PAM-STAMP. In tube hydroforming, bending, springback, and forming analysis were carried out and the effect of mandrel and axial feeding were examined. In welded blank hydroforming, pressure curve history is determined and the results of forming analysis were evaluated by the comparison of experimental results in the aspects of deformed shape and thickness distribution.

• Korean Journal of Clinical Pharmacy
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• v.31 no.2
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• pp.153-159
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• 2021

Background: With increasing economic evaluation studies on the treatment of or screening tools for liver diseases that cause hepatocellular carcinoma (HCC), interest in the analysis of the medical utilization and costs of HCC treatment is increasing. Therefore, we aimed to estimate the medical utilization and costs of HCC patients, and calculate the cost of main procedures for HCC treatment, including liver transplant (LT), hepatic resection (HR), radiofrequency ablation (RFA), and transarterial chemoembolization (TACE). Methods: We analyzed claim data from January to December 2018 from the Health Insurance and Review and Assessment Service-National Patient Sample (HIRA-NPS-2018) dataset, including data of patients diagnosed with HCC (Korean Standard Classification of Diseases code C22.0) who had at least one inpatient claim for HCC. Results: A total of 715 HCC patients were identified. In 2018, the yearly average medical cost per HCC patient was ₩18,460K (thousand), of which ₩14,870K was attributed to HCC. Among the total medical costs of HCC patients, the inpatient cost accounted for the largest portion of both the total medical and HCC-related costs. The major procedures of HCC treatment occurred most frequently in the order of TACE, RFA, HR, and LT. The average medical cost per treatment episode was the highest for LT (₩87,280K), followed by HR (₩10,026K), TACE (₩4,047K), and RFA (₩2,927K). Conclusion: By identifying the medical costs of HCC patients and the costs of the main procedures of HCC treatment, our results provide basic information that could be utilized for cost estimation in liver disease-related economic evaluation studies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.1
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• pp.62-77
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• 2010

Emerging applications with high data rates will need to transport bulk data reliably in wireless sensor networks. ARQ (Automatic Repeat request) or Forward Error Correction (FEC) code schemes can be used to provide reliable transmission in a sensor network. However, the naive ARQ approach drops the whole frame, even though there is a bit error in the frame and the FEC at the bit level scheme may require a highly complex method to adjust the amount of FEC redundancy. We propose a bulk data transmission scheme based on erasure-resilient code in this paper to overcome these inefficiencies. The sender fragments bulk data into many small blocks, encodes the blocks with LT codes and packages several such blocks into a frame. The receiver only drops the corrupted blocks (compared to the entire frame) and the original data can be reconstructed if sufficient error-free blocks are received. An incidental benefit is that the frame error rate (FER) becomes irrelevant to frame size (error recovery). A frame can therefore be sufficiently large to provide high utilization of the wireless channel bandwidth without sacrificing the effectiveness of error recovery. The scheme has been implemented as a new data link layer in TinyOS, and evaluated through experiments in a testbed of Zigbex motes. Results show single hop transmission throughput can be improved by at least 20% under typical wireless channel conditions. It also reduces the transmission time of a reasonable range of size files by more than 30%, compared to a frame ARQ scheme. The total number of bytes sent by all nodes in the multi-hop communication is reduced by more than 60% compared to the frame ARQ scheme.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.22-28
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• 2008

This paper designed a efficient 8-bit CMOS analog-to-digital converter(ADC) for an SOC(System On Chip) application. The architecture consists of two modified 4-bit full-flash ADCs, it has been designed using a more efficient architecture. This is to predict roughly the range in which input signal residers and can be placed in the proximity of input signal based on initial prediction. The prediction of input signal is made available by introducing a voltage estimator. For 4-bit resolution, the modified full-flash ADC need only 6 comparators. So a 8-bit ADC require only 12 comparators and 32 resistors. The speed of this ADC is almost similar to conventional full-flash ADC, but the die area consumption is much less due to reduce numbers of comparators and registors. This architecture uses even fewer comparator than half-flash ADC. The circuits which are implemented in this paper is simulated with LT SPICE tool of computer.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.462-468
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• 2017

In this paper IoT/WSN(Internet of Things/Wireless Sensor Network) has been modeled with a random geometric graph. And a performance of the decentralized code for the efficient storage of data which is generated from WSN has been analyzed. WSN with n=100 or 200 has been modeled as a random geometric graph and has been simulated for their performance analysis. When the number of the total nodes of WSN is n=100 or 200, the successful decoding probability as decoding ratio ${\eta}$ depends more on the number of source nodes k rather than the number of nodes n. Especially, from the simulation results we can see that the successful decoding rate depends greatly on k value than n value and the successful decoding rate was above 70% when $${\eta}{\leq_-}2.0$$. We showed that the number of operations of BP(belief propagation) decoding scheme increased exponentially with k value from the simulation of the number of operations as a ${\eta}$. This is probably because the length of the LT code becomes longer as the number of source nodes increases and thus the decoding computation amount increases greatly.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.838-849
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• 2017

This paper proposes penalty factor equations that take into consideration the weld strength over-match given in the classified form similar to the revised equations presented in the Code Case N-779 via cyclic elastic-plastic finite element analysis. It was found that the $K_e$ analysis data reflecting elastic follow-up can be consolidated by normalizing the primary-plus-secondary stress intensity ranges excluding the nonlinear thermal stress intensity component, $S_n$ to over-match degree of yield strength, $M_F$. For the effect of over-match on $K_n{\times}K_{\nu}$, dispersion of the $K_n{\times}K_{\nu}$ analysis data can be sharply reduced by dividing total stress intensity range, excluding local thermal stresses, $S_{p-lt}$ by $M_F$. Finally, the proposed equations were applied to the weld between the safe end and the piping of a pressurizer surge nozzle in pressurized water reactors in order to calculate a cumulative usage factor. The cumulative usage factor was then compared with those derived by the previous $K_e$ factor equations. The result shows that application of the proposed equations can significantly reduce conservatism of fatigue assessment using the previous $K_e$ factor equations.

• Advances in Computational Design
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• v.3 no.1
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• pp.49-69
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• 2018

This paper shows an optimal design for reinforced concrete rectangular combined footings based on a criterion of minimum cost. The classical design method for reinforced concrete rectangular combined footings is: First, a dimension is proposed that should comply with the allowable stresses (Minimum stress should be equal or greater than zero, and maximum stress must be equal or less than the allowable capacity withstand by the soil); subsequently, the effective depth is obtained due to the maximum moment and this effective depth is checked against the bending shear and the punching shear until, it complies with these conditions, and then the steel reinforcement is obtained, but this is not guaranteed that obtained cost is a minimum cost. A numerical experimentation shows the model capability to estimate the minimum cost design of the materials used for a rectangular combined footing that supports two columns under an axial load and moments in two directions at each column in accordance to the building code requirements for structural concrete and commentary (ACI 318S-14). Numerical experimentation is developed by modifying the values of the rectangular combined footing to from "d" (Effective depth), "b" (Short dimension), "a" (Greater dimension), "${\rho}_{P1}$" (Ratio of reinforcement steel under column 1), "${\rho}_{P2}$" (Ratio of reinforcement steel under column 2), "${\rho}_{yLB}$" (Ratio of longitudinal reinforcement steel in the bottom), "${\rho}_{yLT}$" (Ratio of longitudinal reinforcement steel at the top). Results show that the optimal design is more economical and more precise with respect to the classical design. Therefore, the optimal design presented in this paper should be used to obtain the minimum cost design for reinforced concrete rectangular combined footings.

• Journal of Intelligence and Information Systems
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• v.24 no.3
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• pp.221-241
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• 2018

As we enter the knowledge society, the importance of information as a new form of capital is being emphasized. The importance of information classification is also increasing for efficient management of digital information produced exponentially. In this study, we tried to automatically classify and provide tailored information that can help companies decide to make technology commercialization. Therefore, we propose a method to classify information based on Korea Standard Industry Classification (KSIC), which indicates the business characteristics of enterprises. The classification of information or documents has been largely based on machine learning, but there is not enough training data categorized on the basis of KSIC. Therefore, this study applied the method of calculating similarity between documents. Specifically, a method and a model for presenting the most appropriate KSIC code are proposed by collecting explanatory texts of each code of KSIC and calculating the similarity with the classification object document using the vector space model. The IPC data were collected and classified by KSIC. And then verified the methodology by comparing it with the KSIC-IPC concordance table provided by the Korean Intellectual Property Office. As a result of the verification, the highest agreement was obtained when the LT method, which is a kind of TF-IDF calculation formula, was applied. At this time, the degree of match of the first rank matching KSIC was 53% and the cumulative match of the fifth ranking was 76%. Through this, it can be confirmed that KSIC classification of technology, industry, and market information that SMEs need more quantitatively and objectively is possible. In addition, it is considered that the methods and results provided in this study can be used as a basic data to help the qualitative judgment of experts in creating a linkage table between heterogeneous classification systems.

• Journal of the Korean Geosynthetics Society
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• v.22 no.3
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• pp.1-10
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• 2023

Recently, numerous structures have been constructed near the Nakdong river estuary, with pile foundations embedded in sand and gravel layers. In this study, the side resistance for six drilled shafts embedded in that region was evaluated based on the results of bi-directional and static axial compressive pile load tests. Subsequently, these results were compared with the side resistance calculated using domestic and foreign design codes such as FHWA (1999), KDS (2021), and AIJ (2004). Based on the test results, the evaluated side resistances ranged from 120 to 444kPa. However, the estimated values obtained from the design codes ranged from 69.3 to 170kPa, which were less than 50% of the evaluated values. It was observed that the empirical methods and correlations used in design codes provide a conservative estimation of the side resistance for drilled shafts embedded in sand and gravel layers. It implies that a suitable domestic approach should be developed to accurately estimate the side resistance of pile in sandy gravel and gravel layers near the Nakdong river estuary.