• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1445-1451
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• 2011

Pneumatic valves are widely used parts that have the ability to control the air supplied to automation systems. However, if failure occurs in a pneumatic valve, it may affect the entire system and could lead to huge losses, depending on the characteristics of the system at the time of failure. Because of this significant risk and the level of consumer demand for reliability, there has been much study on ensuring the reliability of products by predicting valve lifetime distributions and degradation characteristics. In this paper, in order to determine the main factors useful for predicting the lifetime of a pneumatic valve, the scale parameter and $B_{10}$ life time value of the widely used plug-in-type pneumatic manifold valves were measured using complete observational data on the valve lifetimes. And also the property of life distribution has been distribution-suitabilityreviewed by correlation coefficients, the degradation characteristics of valve has been presented by the result of analysis through dynamic response time test and leakage test.

• Membrane Journal
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• v.27 no.2
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• pp.129-137
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• 2017

In this study, we have developed cation-exchange membranes (CEMs) which can efficiently separate heavy-metal ions among the cations contained in a water system. Sulfonated polyetheretherketone (SPEEK) was used as a base polymer and a powdered chelating resin with strong binding ability to heavy-metal ions was added into it. In order to optimize the performance of the CEM, the content of chelating resin powder and the ion exchange capacity of SPEEK have been controlled. As a result, it was confirmed that the removal efficiency of heavy metal ion was improved by more than 20% by applying the CEM to membrane capacitive deionization (MCDI).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.106-112
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• 2005

Modern versions of supersonic jet fighter aircraft have several different weapon loading configuration to support air-to-air combat and air-to-ground delivery of weapon modes. These various aircraft loading conditions could result in asymmetric configurations to the aircraft once delivered. These asymmetric configurations could result in decreased handling qualities for the pilot maneuvering, stability, control issues and aerodynamic performance of the aircraft. In order to eliminate or decrease these adverse impacts on the pilot's ability, development of T-50 flight control law attempts to control the aircraft in both longitudinal and lateral-directional axes. Especially, the design of the lateral-directional roll axis control laws, utilizing a simple roll rate feedback structure and gains such as F-16, is developed for the T-50 aircraft to meet the aircraft's design requirements. Consequently, it is found that the improved control law decreases the roll-off phenomenon in lateral axes during pitch maneuver.

• The Korean Journal of Pain
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• v.28 no.1
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• pp.4-10
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• 2015

Etifoxine (etafenoxine, $Stresam^{(R)}$) is a non-benzodiazepine anxiolytic with an anticonvulsant effect. It was developed in the 1960s for anxiety disorders and is currently being studied for its ability to promote peripheral nerve healing and to treat chemotherapy-induced pain. In addition to being mediated by $GABA_A{\alpha}2$ receptors like benzodiazepines, etifoxine appears to produce anxiolytic effects directly by binding to ${\beta}2$ or ${\beta}3$ subunits of the $GABA_A$ receptor complex. It also modulates $GABA_A$ receptors indirectly via stimulation of neurosteroid production after etifoxine binds to the 18 kDa translocator protein (TSPO) of the outer mitochondrial membrane in the central and peripheral nervous systems, previously known as the peripheral benzodiazepine receptor (PBR). Therefore, the effects of etifoxine are not completely reversed by the benzodiazepine antagonist flumazenil. Etifoxine is used for various emotional and bodily reactions followed by anxiety. It is contraindicated in situations such as shock, severely impaired liver or kidney function, and severe respiratory failure. The average dosage is 150 mg per day for no more than 12 weeks. The most common adverse effect is drowsiness at the initial stage. It does not usually cause any withdrawal syndromes. In conclusion, etifoxine shows less adverse effects of anterograde amnesia, sedation, impaired psychomotor performance, and withdrawal syndromes than those of benzodiazepines. It potentiates $GABA_A$ receptor-function by a direct allosteric effect and by an indirect mechanism involving the activation of TSPO. It seems promising that non-benzodiazepine anxiolytics including etifoxine will replenish shortcomings of benzodiazepines and selective serotonin reuptake inhibitors according to animated studies related to TSPO.

• Journal of Pharmaceutical Investigation
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• v.28 no.2
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• pp.73-80
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• 1998

In order to elucidate the effect of N-demethylation on the in vivo metabolite kinetics, especially hepatic first-pass effect of trimebutine(TMB), the N-demethylation of TMB to N-monodesmethyl trimebutine(N-TMB) was studied in rats. TMB(10 mg/kg) and N-TMB(10 mg/kg) were injected into the femoral and the portal vein, respectively. And the pharmacokinetic parameters were obtained from the plasma concentration-time profiles of TMB and N-TMB determined by the simultaneous analysis using high-performance liquid chromatography. It was supposed that these drugs were almost metabolized in vivo because the urinary and biliary excreated amounts of TMB and N-TMB were lower than 0.1% of the administered dose. According to the hepatic biotransformation model and metabolic pathways of TMB proposed, it was found that the fraction of systemic clearance of TMB which formed N-TMB in liver$(G_{mi})$ was 0.826, that of TMB which furnishes the available N-TMB to the systemic circulation$(F_{mi})$ was 0.083, and the absolute hepatic bioavailability of N-TMB formed trom TMB$(F_{mi.p})$ was 0.1. These results showed that TMB was suspected of the sequential hepatic first-pass metabolism and N-demethylated by 82.6%. Therefore, the residue would be hydrolyzed by the esterase in the liver. That is, the ability of N-demethylation of TMB was 4.75-fold larger than that of hydrolysis by the esterase in rats.

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.322-332
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• 2007

The purposes of this research were to examine the effect of the catering company's dietetic internship program through a self-evaluating ability test about management performance between pre and post internship programs and consequently to suggest improvement in the internship program. In this study, two types of questionnaires were conducted in July and October 2006, targeting 41 dietetic interns who trained in a 6 months internship program. Except the 4 dropped interns, data from 37 interns were collected and used for statistical analysis, using the SPSS Win 11.0 version. The results of this study were as follows: First of all, the analysis on the effect of the internship program according to classified management segments showed significant improvements in the following order: purchase management (p<0.001), computer program management (p<0.001), facilities management (p<0.001), accounting management (p<0.01), personnel management (p<0.01), retention management (p<0.01), sanitation management (p<0.01), service management (p<0.01) and foodservice management (p<0.01). However, there was no significantly improvement in management of clients. Secondly, the result of the analysis on the details of each management segment that were significant improvement and changing score was the top 5 duties were as follows: In the purchase management, the score of weekly and daily order management was increased 1.0 (p<0.001), the score of weekly inventory management was 0.81 (p<0.001). In the computation office management, expenses handling through a computer program was 0.65 (p<0.01). In the personnel management, the score of work schedule management increased 0.81 (p<0.001). In the accounting management, the score of monthly profit and loss account management was 0.65 (p<0.001). Furthermore, qualified educational programs connected with the internship program will have to be systematically developed and continually carried out in order to improve service and management abilities of branch managers.

• Journal of Engineering Education Research
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• v.16 no.2
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• pp.50-57
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• 2013

The study to improve engineering students' performance in studying physics lacked despite of the importance of studying physics in engineering education. The cognitive belief and the motivational belief in studying physics had a strong effect on studying physics. The purpose of this study was to seek the educational way through comparing professors' expectations with students' beliefs about the cognitive belief and the motivational belief in studying physics. The cognitive belief in studying physics was considered as variables like 'knowledge', 'learning' and 'relation'. The motivational belief in studying physics was considered as variables like 'expectancy' and 'value'. It was the 'expectancy' that was the most different dimension between professors' expectations and students' beliefs. It means that students have little confidence in their abilities to study physics, though professors expect their students to be confident. Professor who teaches physics to engineering students recognize these differences, need to have interest in affective domains of beliefs to teach. In addition, there is need to teaching and learning strategies that can lead engineering students' beliefs about ability to perform the task, the purpose, importance, interesting for physics.

• Journal of Sensor Science and Technology
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• v.10 no.5
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• pp.329-336
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• 2001

This paper describes the steering control and geomagnetism cancellation for an autonomous vehicle using an MR sensor. The magneto-resistive (MR) sensor obtains the vector summation of the magnetic fields from embedded magnets and the Earth. The vehicle is controlled by the magnetic fields from embedded magnets. So, geomagnetism is the disturbance in the steering control system. In this paper, we propose a new method of the sensor arrangement in order to remove the geomagnetism and vehicle body interference. The proposed method uses two MR sensors located in a level plane and the steering controller has been developed. The controller has three input variables ($dB_x$, $dB_y$, $dB_z$) using the measured magnetic field difference, and an output variable (the steering angle). A simulation program was developed to acquire the data to teach the neural network, in order to test the ability of a neural network to learn the steering control process. Also, the computer simulation of the vehicle (including vehicle dynamics and steering) was used to verify the steering performance of the vehicle controller using the neural network. From the simulation and field test, good result was obtained and we confirmed the robustness of the neural network controller in a real autonomous vehicle.

• School Mathematics
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• v.9 no.1
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• pp.45-64
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• 2007

The primary purposes of this study were to investigate how sixth graders would react to the types of tasks with regard to the comprehension of graphs and what differences might be among the kinds of graphs, and to raise issues about instructional methods of graphs. A descriptive study through pencil-and-paper tests was conducted. The tests consisted of 48 questions with 4 types of tasks (reading the data, reading between the data, reading beyond the data, and understanding the situations) and 6 kinds of graphs. The conclusions drawn from the results obtained in this study were as follows: First, it is necessary to foster the ability of interpreting the data and understanding the situation in graphs as well as that of reading the data and finding out the relationships in the data. Second, it is informative for teachers to know students' difficulties and thinking processes. Third, in order to develop understanding of graphs, it is important that students solve different types of tasks beyond simple question-answer tasks. Fourth, teachers need to pay attention to teach fundamental factors such as reading the data with regard to line graphs and stem-and-leaf plots Finally, graph type and task type interact to determine graph-comprehension performance. Therefore, both learning all kinds of graphs and being familiar with multiple types of tasks are important.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4357-4378
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• 2017

In cooperative multi-relay networks, the relay nodes which are selected are very important to the system performance. How to choose the best cooperative relay nodes is an optimization problem. In this paper, multi-relay selection schemes which consider either single objective or multi-objective are proposed based on evolutionary algorithms. Firstly, the single objective optimization problems of multi-relay selection considering signal to noise ratio (SNR) or power efficiency maximization are solved based on the quantum bee colony optimization (QBCO). Then the multi-objective optimization problems of multi-relay selection considering SNR maximization and power consumption minimization (two contradictive objectives) or SNR maximization and power efficiency maximization (also two contradictive objectives) are solved based on non-dominated sorting quantum bee colony optimization (NSQBCO), which can obtain the Pareto front solutions considering two contradictive objectives simultaneously. Simulation results show that QBCO based multi-relay selection schemes have the ability to search global optimal solution compared with other multi-relay selection schemes in literature, while NSQBCO based multi-relay selection schemes can obtain the same Pareto front solutions as exhaustive search when the number of relays is not very large. When the number of relays is very large, exhaustive search cannot be used due to complexity but NSQBCO based multi-relay selection schemes can still be used to solve the problems. All simulation results demonstrate the effectiveness of the proposed schemes.