• Toxicological Research
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• v.33 no.2
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• pp.107-118
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• 2017

Although alternative test methods based on the 3Rs (Replacement, Reduction, Refinement) are being developed to replace animal testing in reproductive and developmental toxicology, they are still in an early stage. Consequently, we aimed to develop alternative test methods in male animals using mouse spermatogonial stem cells (mSSCs). Here, we modified the OECD TG 489 and optimized the in vitro comet assay in our previous study. This study aimed to verify the validity of in vitro tests involving mSSCs by comparing their results with those of in vivo tests using C57BL/6 mice by gavage. We selected hydroxyurea (HU), which is known to chemically induce male reproductive toxicity. The 50% inhibitory concentration ($IC_{50}$) value of HU was 0.9 mM, as determined by the MTT assay. In the in vitro comet assay, % tail DNA and Olive tail moment (OTM) after HU administration increased significantly, compared to the control. Annexin V, PI staining and TUNEL assays showed that HU caused apoptosis in mSSCs. In order to compare in vitro tests with in vivo tests, the same substances were administered to male C57BL/6 mice. Reproductive toxicity was observed at 25, 50, 100, and 200 mg/kg/day as measured by clinical measures of reduction in sperm motility and testicular weight. The comet assay, DCFH-DA assay, H&E staining, and TUNEL assay were also performed. The results of the test with C57BL/6 mice were similar to those with mSSCs for HU treatment. Finally, linear regression analysis showed a strong positive correlation between results of in vitro tests and those of in vivo. In conclusion, the present study is the first to demonstrate the effect of HU-induced DNA damage, ROS formation, and apoptosis in mSSCs. Further, the results of the current study suggest that mSSCs could be a useful model to predict male reproductive toxicity.

• International Journal of Reliability and Applications
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• v.6 no.1
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• pp.1-12
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• 2005

A new test for testing that a life distribution is exponential against the alternative that it is harmonic new better (worse) than used in expectation upper tail HNBUET (HNWUET), but not exponential is presented based on the highly popular 'Kernel methods' of curve fitting. This new procedure is competitive with old one in the sense of Pitman's asymptotic relative efficiency, easy to compute and does not depend on the choice of either the band width or kernel. It also enjoys good power.

• Journal of Information Technology Applications and Management
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• v.16 no.3
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• pp.17-28
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• 2009

This paper presents a novel method for evaluating the usefulness of online product recommendation. Previous studies on evaluating recommendation systems have mostly relied on two methods : testing the accuracy of estimating user preferences by recommendation systems, or empirically testing the effectiveness with lab experiments involving human participants. The former does not measure the usefulness directly and hence can be misleading; the latter is expensive in that it requires a working online store System and test participants. In order to address the problems, the proposed approach uses simulation to imitate customer behavior and evaluate the usefulness of recommendation. Models for user behavior and an abstract Internet store are developed for simulation. Actual simulation experiments are performed to illustrate the use of the approach.

• Toxicological Research
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• v.25 no.1
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• pp.9-15
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• 2009

Historically, research in toxicology has utilized non-human mammalian species, particularly rats and mice, to study in vivo the effects of toxic exposure on physiology and behavior. However, ethical considerations and the overwhelming increase in the number of chemicals to be screened has led to a shift away from in vivo work. The decline in in vivo experimentation has been accompanied by an increase in alternative methods for detecting and predicting detrimental effects: in vitro experimentation and in silico modeling. Yet, these new methodologies can not replace the need for in vivo work on animal physiology and behavior. The development of new, non-mammalian model systems shows great promise in restoring our ability to use behavioral endpoints in toxicological testing. Of these systems, the zebrafish, Danio rerio, is the model organism for which we are accumulating enough knowledge in vivo, in vitro, and in silico to enable us to develop a comprehensive, high-throughput toxicology screening system.

• Analytical Science and Technology
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• v.27 no.4
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• pp.196-200
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• 2014

Currently nonaqueous titration method for the assay method using the hazardous reagent, mercury acetate for difemerine hydrochloride has been used in Korean Pharmaceutical Codex. We developed an alternative titration assay method by substituting the use of the hazardous reagent, mercury acetate to the use of less toxic ones like ethyl alcohol. The linearity of the calibration curves in the desired concentration range was good (r>0.999). Precision was less than 0.64%. Accuracy was obtained with recoveries in range of 99.10% and 99.71%. The developed assay could be expected to become valuable tools for revising the Korean Pharmaceutical Codex.

• The Korean Journal of Emergency Medical Services
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• v.25 no.2
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• pp.7-18
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• 2021

Purpose: This study aimed to present the learning items of indirect practice as an alternative means of ambulance riding practice. Methods: Twelve on-site professionals participated in testing the effectiveness of learning items of utility value in indirect experience practice among the recommended learning objectives of ambulance ride practice using the modified Delphi technique. To validate the learning objectives, the Delphi technique was used to check content validity, and analytic hierarchy process (AHP) analysis was used to analyze the weighting value. Results: As the learning goal of indirect experience practice replaced the ambulance riding practice, four items were derived in consideration of practicality. These items were consistent with the Delphi panel's consistency index, convergence, and agreement. The first learning item to consider was 'Prevention of infection and risk of infection.' Conclusion: The results of this study are meaningful in that they propose the learning items that can achieve the minimum educational goal through indirect experience practice as an alternative means of ambulance training.

• Journal of Information Technology Services
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• v.17 no.3
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• pp.63-75
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• 2018

In this paper, we propose a testing method of the quality of device application effectively reflecting the necessity of increasing mobile device application quality test, and designed and developed it as a web system. We have studied traditional software testing methods for designing and developing a system. We have developed a next-generation alternative technology that can analyze and compensate for the weaknesses of the web and weaknesses of the Android in order to realize the access system and the responsive web system. As an example applied to the system, we analyzed the requirements of the system implementation and expressed the functions of the system through the use case diagram. The test scenarios were conducted by connecting 5,000 devices to each system using the existing HTTP polling method and the proposed web socket method. After setting the comparative group, the result of the proposed web management system was observed and compared through repeated tests. The research shows that the proposed web socket system has better performance than HTTP polling. The more the number of simultaneous processing of the devices, the lower the server stability but the better the time efficiency. In conclusion, the more the number of devices to be tested is, the more the number of devices can be effectively tested using the proposed web management system.

• Journal of Animal Science and Technology
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• v.56 no.8
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• pp.32.1-32.4
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• 2014

Though many alternative methods to tuberculin skin testing (TST) have been established and evaluated in recent years, sensitivities and specificities of most methods could not meet the requirements of golden standards. In this study, we sought to identify whether repeated TSTs could affect the immune responses in experimental monkeys. Nine natural tuberculosis (TB) monkeys receiving repeated TSTs biweekly were used to demonstrate the effect on TST responsiveness. Two healthy monkeys were administrated with repeated TSTs to analyze the immune response profiling. Intrapalpebral reactions in TB infections gradually weakened or presented intermittent positive reactions. The leukocyte counts, cytokine responses, and antibody responses to all antigens except Old tuberculin (OT) and MPT64L showed no specific changes for TB in healthy monkeys. Positive antibody responses to OT and MPT64L emerged during the first half experimental period, which may cause by their cross-reactivity with mycobacterial species. Results showed that repeated TSTs had no significant effects on immune responses in healthy monkeys but a progressive reduction in TST responsiveness in TB infections.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1110-1122
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• 2018

This paper proposes an alternative method to evaluate the effect of wind power to the power system stability with small disturbance. Alternatively, available techniques for stability analysis of a power system based on deterministic methods are less accurate for high penetration of wind power. Numerical simulations of random behaviors are computationally expensive. A stochastic stability index (SSI) is proposed for the power system stability evaluation based on the theory of stochastic stability and energy function, specifically the stochastic derivative of the relative well-defined energy function and the critical energy. The SSI is implemented on the modified nine-bus system including wind turbines under different conditions. A doubly-fed induction generator (DFIG) wind turbine is characterized and modeled using measured wind data from several sites in Thailand. Each of the obtained wind power data is analyzed. The wind power effect is modeled considering the aggregated effect of wind turbines. With the proposed method, the system behavior is properly predicted and the stability is quantitatively evaluated with less computational effort compared with conventional numerical simulation methods.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.11
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• pp.1091-1097
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• 2017

Sales of commercial-type cooling fans intended for application in military electronics are often discontinued during equipment production. This results in requirements for alternative fan selection as well as equipment performance and reliability tests, such as high-temperature operation testing. This study deals with alternative fan selection and verification methods that can be used during the production process. First, an alternative fan was selected by calculating the flow and pressure required to effectively cool the equipment, then the feasibility of the selected fan was verified using a reliable CFD heat dissipation analysis model. Following this, a high-temperature operation test was performed using the alternative fan in the equipment. Results demonstrated that the equipment satisfied its required function in a high-temperature environment, and the main parts as well as internal air temperature were found to be thermally stable.