• Journal of KIISE:Computer Systems and Theory
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• v.31 no.3_4
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• pp.213-223
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• 2004

A dynamic thread pool model is one of a multi-thread server programming model that handles many requests from users concurrently. In most cases, bounded thread pool model is used for server programming. Because it reduces a thread overhead by creating a pool of threads in advance, it ran response more quickly to users' requests. But this model always occupies system resource when there are small amount of requests, which prevents other applications from using available resources. In this paper, for the utilization of occupied but unused resources, we proposed and implemented a prediction-based dynamic thread pool scheme using customized exponential average. From the experiments, we show that this scheme outperforms hounded thread pool model and uses small resources.

• Journal of Korean Association for Spatial Structures
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• v.8 no.4
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• pp.73-80
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• 2008

The objective of current study is to develop an optimization technique for the seismic actively controlled building structures using active tendon devices by an efficient solution of LQR control gain. In order to solve the active control system, the Ricatti closed-loop algorithm has been applied, and the state vector has been formulated by the transfer matrix and solved by a numerical technique of the trapezoidal rule. The time-delay problem has been also considered by phase compensation. To optimize the performance index, the ratio of the weighted matrix is the design variable, allowable story drift limits of IBC 2000 and tendon forces have been applied as restraint conditions, and the optimum control program has been developed with the algorithm of the SUMT technique. In examples of the optimization problem of eight stories shear buildings, it is evaluated that the optimum controlled building is more suitable in the control of earthquake response than the uncontrolled system and can reduce the performance index to compare with the controlled system with a constant ratio of the weighted matrix.

• Phonetics and Speech Sciences
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• v.15 no.2
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• pp.1-11
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• 2023

This study investigated the response time and patterns of categorical perception of the wh-scope of an embedded clause with the non-bridge verb, "gung-geum hada 'wonder'," in the matrix verb phrase in Gyeongsang Korean. Using the same procedure as Yun (2022), 72 responses and response times for each stimulus were collected from 24 participants over the course of three trials. The stimuli were recorded readings of 40 speakers (20 male, 20 female). Context was provided to induce a matrix scope interpretation of the embedded wh-phrase in the target sentence. We sorted the 40 stimuli according to the number of matrix scope responses each received, and charted the response times for each stimulus. Although there was considerable overlap for the different types of wh-scope interpretations, there was a clear difference in categorical perception between the matrix and embedded scopes. The 24 participants also differed in their categorical perceptions. The results suggested that response time and wh-scope interpretation were not directly related and that two main weighted factors affected wh-scope interpretation: morpho-syntactic constraints and prosodic structural integrity. The weighting of each of these factors was inversely correlated and varied among subjects.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.199-203
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• 2005

One of the most important hydrological response characteristics is the lag time. It is well known as being under the influence of the morphometric properties of the basin, which could be expressed by catchment shape descriptors. In this paper, the geometric characteristics of an equivalent ellipse proposed by Moussa(2003) is applied for the lag time analysis. The lag time is obtained from the rainfall-runoff observed data by the method of moments suggested by Nash(1960) and the relationships between the basin morphometric properties and the lag time are discussed as applied to 3 catchments in Korea. Additionally, the shapes of equivalent ellipse are examined how they are transformed from upstream area to downstream one. As a result, the relationship between descriptors based on a equivalent ellipse a+b and $a+b+{\epsilon}OM$, and the lag time is shown to be close and the shape of ellipse is presented to approach a circle along the river downwards. Also, the notion of compactness which is used to express the shape of an irregular plan-form is tried to apply.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.3
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• pp.311-319
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• 2003

This paper aims at investigating the exact dynamic response of the system undergoing a exponential impact force from the viewpoints of conservations of momentum and energy. The midpoint method applied in the Newmark's family algorithm is found to be identical to the case of the application of the trapezoidal method which provides conservations of momentum and energy. For the linear impact force the mid point, the trapezoidal and the (n+1) point method exactly meet the conservation characteristics independent of the size of integration interval. On the other hand, constants for the dynamic motion resulting from the nonlinear impact are underestimated or overestimated by these method mentioned above. To overcome this indispensible error, the Simpson 1/3 method as one of multi step methods whose advantages is to use longer time interval with the same number of evaluation functions is adopted for the exact conservations of momentum and energy. Moreover, the suggested method is expected to expand the similar algorithm for the general dynamic motion including finite rotations.

• Journal of the Korean GEO-environmental Society
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• v.19 no.10
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• pp.13-19
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• 2018

Following the 2016 Gyeongju earthquake, the Pohang Earthquake occurred in 2017, and the south-east region in Korea is under the threat of an earthquake. Especially, in the Pohang Earthquake, the liquefaction phenomenon occurred in the sedimentation area of the coast, and preparation of countermeasures is very important. The soil liquefaction can affect the underground facilities directly as well as various structures on the ground. Therefore, it is necessary to identify the liquefaction risk of facilities and the structures against the possible earthquakes and to prepare countermeasures to minimize them. In this study, we investigated the seismic liquefaction risk about the electric power utility tunnels in the southeast area where the earthquake occurred in Korea recently. In the analysis of seismic liquefaction risk, the earthquake with return period 1000 years and liquefaction potential index are used. The liquefaction risk analysis was conducted in two stages. In the first stage, the liquefaction risk was analyzed by calculating the liquefaction potential index using the ground survey data of the location of electric power utility tunnels in the southeast region. At that time, the seismic amplification in soil layer was considered by soil amplification factor according to the soil classification. In the second stage, the liquefaction risk analysis based on the site response analyses inputted 3 earthquake records were performed for the locations determined to be dangerous from the first step analysis, and the final liquefaction potential index was recalculated. In the analysis, the site investigation data were used from the National Geotechnical Information DB Center. Finally, it can be found that the proposed two stage assessments for liquefaction risk that the macro assessment of liquefaction risk for the underground facilities including the electric power utility tunnel in Korea is carried out at the first stage, and the second risk assessment is performed again with site response analysis for the dangerous regions of the first stage assessment is reasonable and effective.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.404-412
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• 2012

The main object of this study is to render a better dental education to mental disabilities, teachers, and their parents. By providing a better dental education to them, mental disabilities would understand the importance of their oral hygiene. The study was held in Seoul at two different locations, named H and E mental welfare facilities. Ninety Three mental disabilities were studied by observing their oral behavior, simple oral hygiene index and plaque index prior and post to dental education. At the end of education, following result were gathered from two mental facilities. First, the level of oral behavior in Class 1,2, and 3 mental disabilities were observed prior and post to the dental education. Overall, there was no significant difference among Class 1 mental disabilities with the dental education. Second, in simple oral hygiene index, the severity of mental illness has affected on their oral behavior (F=6.322, p<.001). Third, in simple oral hygiene index, the frequency of dental education, regardless of severity of mental illness has affected on their oral hygiene (F=5.961, p<.01). Fourth, the plaque index also illustrated that the frequency of dental education, regardless of severity of dental illness has affected on their oral hygiene (F=5.126, p<.05). Finally, the general characteristics of mental disabilities according to changes in oral health awareness to gender, age, disability type, educational level do not statistically significant in all variables. Their simple oral hygiene index and plaque index advanced, although after a while they started to lose focus, which brought back their old habits. Nevertheless, in conclusion I believe that helping mental disabilities more frequently to constant reminder, will not only keep them entertained, but help them realize how important oral hygiene practice is, hopefully increasing and benefiting those with mental disabilities for future reference.

• Journal of Oral Medicine and Pain
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• v.33 no.2
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• pp.147-158
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• 2008

In our study, we investigated self-evaluation of tongue coating, self-rating intensity of oral malodor, habit related to tooth brushing and tongue scraping. Investigation was carried out on 714 Korean college students by method of self-reporting to prepared questionnaire. The obtained data were processed and analyzed with SAS program. The results of this study are as follows. 1. Students who have frequently experienced tongue coating have tendency to have stronger oral malodor than the other students. 2. The self-reporting prevalence rate of oral malodor is 81.1%. 3. Students who brush teeth shortly and irregularly have tendency to have stronger oral malodor than the other students. 4. Students with strong oral malodor have tendency to neglect scraping tongue. 5. Students with low index of tooth brushing or low index of oral hygiene controllability have tendency to have stronger oral malodor than the other students. 6. Mean scales of tooth brushing index(p<.0001), tongue scraping index(p=0.0439) and oral hygiene controllability index(p<.0001) among students in the department of Dental Hygiene and Dental Technology are significantly higher than those among general students.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.265-274
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• 2013

The purpose of this study was to investigate the dietary habits of the relevant factors according to the obesity status of children and adolescents. Services research studies conducted in the Ministry of Health, Welfare and Family Affairs of the '2009 Children and Youth Online Games and Family Activity Survey findings utilizing data. Study, the subjects utilized 9,462 elementary school students 2,778 people, 3,385 middle school students, high school students a total of 3,299 people were enrolled in the study. Were grouped according to the BMI of the study subjects. After dinner snack intake 18.5>BMI groups disagree 38.8%, 18.5${\leq}$BMI<23.0 group it was 41.1%, 23.5${\leq}$BMI<25.0 group it was 40.1%, $25{\leq}BMI$ groups disagree 37.4% response was highest(p=0.001). Investigate whether regular exercise every day, results showed that a high BMI index groups do not exercise more. Aggressiveness in time, such as physical education, the survey showed that a low BMI index group more likely to exercise vigorously. BMI index group of people around you and the speed of eating more meals were faster. If you let more to allow time to practice proper education of children and youth, health and enrich lives of the appropriation will be able to Services to live a healthy and happy life than to correct perceptions and lifestyles of children and adolescents. To do this, there is a need to educate parents, children and youth, as well as.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.185-198
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• 2016

In this work, experimental errors from an impact hammer test were investigated to develop a statistic-based technique for updating a finite element model. Digital signal processing was analyzed by using theoretical models and experiments when errors occurred during the experimental procedure. First, the duration time and peak level of the excitation signal, the stiffness and position of elastic springs connecting the specimen as well as the support, position and mass of the accelerometer were considered as error factors during the experiment. Then the picket fence effect, leakage, and exponential window function were considered as candidate error factors during the digital signal processing. Finally, methods to reduce errors are suggested.