• Journal of the Chungcheong Mathematical Society
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• v.28 no.4
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• pp.537-543
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• 2015

In [9], the authors determine an infinite class of non-unimodal Gorenstein sequence, which includes the example $$\bar{h}_1\text{ = (1, 125, 95, 77, 71, 77, 95, 125, 1)}$$. They raise a question whether there is a Gorenstein algebra with Hilbert function $$\bar{h}_2\text{= (1, 125, 95, 77, 70, 77, 95, 125, 1)}$$, which has remained an open question. In this paper, we prove that there is no Gorenstein algebra with Hilbert function $\bar{h}_2$.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.116-122
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• 2014

This study proposes a system reliability analysis of rack storage facilities subjected to forklift colliding events. The proposed system reliability analysis consists of two steps: the first step is to identify dominant failure modes that most contribute to the failure of the whole rack facilities, and the second step is to evaluate the system failure probability. In the first step, dominant failure modes are identified by using a simulation-based selective searching technique where the contribution of a failure mode to the system failure is roughly estimated based on the distance from the origin in the space of the random variables. In the second step, the multi-scale system reliability method is used to compute the system reliability where the first-order reliability method (FORM) is initially used to evaluate the component failure probability (failure probability of one member), and then the probabilities of the identified failure modes and their statistical dependence are evaluated, which is called as the lower-scale reliability analysis. Since the system failure probability is comprised of the probabilities of the failure modes, a higher-scale reliability analysis is performed again based on the results of the lower-scale analyses, and the system failure probability is finally evaluated. The illustrative example demonstrates the results of the system reliability analysis of the rack storage facilities subjected to forklift impact loadings. The numerical efficiency and accuracy of the approach are compared with the Monte Carlo simulations. The results show that the proposed two-step approach is able to provide accurate reliability assessment as well as significant saving of computational time. The results of the identified failure modes additionally let us know the most-critical members and their failure sequence under the complicated configuration of the member connections.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.265-270
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• 2011

This paper describes a reliability/durability test of the remanufactured steering gear units. There used to be government restrictions to remanufacture certain types of automotive components regarding safety of passengers. Nevertheless, scientific approach to sustainability and remanufacturing process provided solid evidence of highly beneficial sides of reusing the products. Failure mode analysis of the steering gear unit is performed and main failure is found out. The unit is remanufactured by fixing the failure and its quality is assessed through designing a new sequence of loading events. Oil leakage is witnessed as a possible failure and its volume is measured. Conclusions based on laboratory condition durability test are given at the end.

• Communications for Statistical Applications and Methods
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• v.29 no.4
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• pp.403-411
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• 2022

This article presents an independence test between pairs of interval censored failure times. The Mantel-Haenszel test is commonly applied to test the independence between two categorical variables accompanied with a strata variable. Hsu and Prentice (1996) applied a Mantel-Haenszel test to the sequence of 2 × 2 tables formed at the grids which are composed of failure times. In this article, due to unknown failure times, the suitable grid points should be determined and the status of failure and at risk are estimated at those grid points. We also consider a weighted test statistic to bring a more powerful test. Simulation studies are performed to evaluate the power of test statistics under finite samples. The method is applied to analyze two real data sets, mastitis data from milk cows and an age-related eye disease study.

• Advances in materials Research
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• v.13 no.4
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• pp.299-319
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• 2024

Due to higher strength-to-weight ratio of composite laminates, they find uses in many weight-sensitive applications like aerospace, automobile and marine structures. From a reliability point of view, accurate prediction of failure of these structures is important. Due to the complexities in the manufacturing processes of composite laminates, there is a variation in the material properties and geometric parameters. Hence stochastic aspects are important while designing the composite laminates. Many existing works of composite laminate failure analysis are based on the deterministic approach but it is important to consider the randomness in the material properties, geometry and loading to predict accurate failure loads. In this paper the statistics of the ultimate failure load of the [0/θ]_s laminated composite plate (LCP) containing the edge crack and voids subjected to the tensile loading are presented in terms of the mean and coefficient of variance (COV). The objective is to better the efficacy of laminate failure by predicting the statistics of the ultimate failure load of LCP with random material, geometric and loading parameters. The stochastic analysis is done by using the extended finite element method (XFEM) combined with the second-order perturbation technique (SOPT). The ultimate failure load of the LCP is obtained by ply-by-ply failure analysis using the ply discount method combined with the Tsai-Wu failure criterion. The aim is to know the effect of the stacking sequence, crack length, crack angle, location of voids and number of voids on the mean and corresponding COV of the ultimate failure load of LCP is investigated. The results of the ultimate failure load obtained by the present method are in good agreement with the existing experimental and numerical results. It is observed that [0/θ]_s LCPs are very sensitive to the randomness in the crack length, applied load, transverse tensile strength of the laminate and modulus of elasticity of the material, so precise control of these parameters is important. The novelty of the present study is, the stochastic implementation in XFEM for the failure prediction of LCPs containing crack and voids.

• Parasites, Hosts and Diseases
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• v.54 no.1
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• pp.21-29
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• 2016

The sodium hydrogen exchanger 1 (NHE1), which functions in maintaining the ratio of $Na^+$ and $H^+$ ions, is widely distributed in cell plasma membranes. It plays a prominent role in pH balancing, cell proliferation, differentiation, adhesion, and migration. However, its exact subcellular location and biological functions in Toxoplasma gondii are largely unclear. In this study, we cloned the C-terminal sequence of T. gondii NHE1 (TgNHE1) incorporating the C-terminal peptide of NHE1 (C-NHE1) into the pGEX4T-1 expression plasmid. The peptide sequence was predicted to have good antigenicity based on the information obtained from an immune epitope database. After induction of heterologous gene expression with isopropyl-b-D-thiogalactoside, the recombinant C-NHE1 protein successfully expressed in a soluble form was purified by glutathione sepharose beads as an immunogen for production of a rabbit polyclonal antiserum. The specificity of this antiserum was confirmed by western blotting and immunofluorescence. The antiserum could reduce T. gondii invasion into host cells, indicated by the decreased TgNHE1 expression in T. gondii parasites that were pre-incubated with antiserum in the process of cell entry. Furthermore, the antiserum reduced the virulence of T. gondii parasites to host cells in vitro, possibly by blocking the release of $Ca^{2+}$. In this regard, this antiserum has potential to be a valuable tool for further studies of TgNHE1.

• Journal of Microbiology
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• v.33 no.4
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• pp.350-354
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• 1995

Saccharomyces cervisiae has a highly ordered ring of filaments that lies just inside the cytoplasmic membrane in the region of the mother-bud neck. Mutants defective in any one of the our cell division cycle genes (CDC3, CDC10, CDC11, CDC12) fail to form these filaments and exhibit a pleiotropic phenotype that includes failure to complete cytokinesis and abnormal bud growth. However, the role of the filament is not clear. In order to find out the role of filament, the similar gene in S pombe (called cdc103$\^$+) to the CDC3 was cloned and sequenced. Here I report the sequence analysis of the cdc103$\^$+/ ) to the CDC3 was cloned and sequenced. Here I report the sequence analysis of the cdc103$\^$+/. Comparison of the predicted amino acid sequences of cdc103$\^$+/ and CDC3 revealed that they share significant similarity (43% identity and 56% identity or similarity) to each other.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.341-350
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• 2000

This study was conducted to develop a control unit for a tying device of a variable chamber round baler. The work process of the tying device was thoroughly analyzed and the control sequence was established according to the work process. Based on this control sequence, a control unit using an 8 bit microprocessor AT 89C52 as a CPU was developed. The driving circuit to control the actuator motion was developed and the PWM method was used to regulate the velocity of the actuator. On the front panel of the control unit, indicators were also installed to show the operations being conducted. A prototype of the developed control unit was manufactured and tested. A total of 50 complete cycles of the control sequence was repeated and no failure was observed. It was evaluated that the developed control unit has an excellent performance and can be used practically for variable chamber round balers.

• Nuclear Engineering and Technology
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• v.28 no.3
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• pp.247-256
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• 1996

This paper presents a new approach for assessing accident management strategies using containment event trees (CETs) developed during an individual plant examination (IPE) for a reference plant (CE type, 950 MWe PWR). Various accident management strategies to reduce risk have been proposed through IPE. Three strategies for the station blackout sequence are used as an example : 1) reactor cavity flooding only, 2) primary system depressurization only, and 3) doing both. These strategies are assumed to be initiated at about the time of core uncovery. The station blackout (SBO) sequence is selected in this paper since it is identified as one of the most threatening sequences to safety of the reference plant. The effectiveness and adverse effects of each accident management strategy are considered synthetically in the CETs. A best estimate assessment for the developed CETs using data obtained from NUREG-1150, other PRA results, and the MAAP code calculations is performed. The strategies are ranked with respect to minimizing the frequencies of Various containment failure modes. The proposed approach is demonstrated to be very flexible in that it can be applied to any kind of accident management strategy for any sequence.

• Advances in pediatric surgery
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• v.6 no.1
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• pp.10-18
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• 2000

Multisystem organ failure resulting from gram negative bacterial sepsis is associated with high morbidity and mortality in surgical neonates. There are differences in the clinical characteristics of organ failure in neonates and adults. The purpose of this study is to identify the differences and determine the order of organ failure between baby rats and adult rats after induction of gram negative sepsis. Fifty baby rats less than 30-day-old and another 50 adult rats more than 2-month-old were divided into control group (G1) and experimental group (G2). The G1 consisted of 10 baby- and 10 adult-rats, and the G2 consisted of 40 babies and 40 adults. E. coli ($10^8/mL$ per 100g of body weight) were injected into the peritoneal cavity in G2 and same amount of saline was injected in G 1. Blood samples were obtained before injection, 24 hour, 48 hour, 72 hour and after death. WEC, platelet, $PaO_2$, $PaCO_2$, total bilirubin, BUN, creatinine, albumin and abdominal wall thickness were measured to evaluate the sequence of organ failure. The mortality was 55.0 % in G2-babies and 32.5 % in G2-adults. In baby rats, microvascular, hematologic and renal failure appeared within 24 hours after injection and pulmonary failure followed. Pulmonary, renal and liver failure developed within 24-48 hours in adult rats; however, microvascular failure did not appear until they were moribund. Thrombocytopenia, hypoalbuminemia, increased BUN and generalized edema was the earlist sign of sepsis in baby rats.