• Resources Recycling
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• v.29 no.5
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• pp.64-72
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• 2020

When the multi-stage combustion process is applied to the cement kiln to reduce nitrogen oxide emissions in the cement industry, oxidation/reduction section that can increase combustion efficiency by reducing NO_x to NO and completely burning unburned materials is essential In this study, when applied the oxidation/reduction system of the cement kiln preheater and calciner, the optimal oxidation/reduction calcination crisis that can secure the quality stability of the final product, cement clinker, was to be observed macroscopically, and the mass change of raw materials according to the burning conditions, decarbonation rate, and calcination rate were investigated. The results showed that the thermal decomposition of raw materials tends to be promoted in the oxidation condition rather than in the reduction condition, and that the thermal decomposition of limestone, which has a relatively high CaO content, is carried out later than that of cement raw meal, which is thought to be caused by the CO₂ fractionation in the kiln. The thermal decomposition properties of raw materials according to oxidation/reducing burning condition showed a relatively large difference in temperature range lower than normal limestone themal decomposition temperature, which is thought to be expected to improve the thermal efficiency of raw materials according to the formation of oxidation condition in the section 750℃ of burning temperature. However, for this study, lab scale. Because there is a difference from the field process as a scale study, it is deemed necessary to verify the actual test results of the pilot scale.

• Women's Health Nursing
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• v.6 no.1
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• pp.117-128
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• 2000

The purpose of this study was to examine the effect of low back pain relieving program on back muscle strength, intensity of pain, low back disability level in elementary school teachers who have low back pain. subjects were elementary school women teachers who worked at eight elementary school located in Seoul. Intended subjects size were seventy consist of thirty-four experimental group(three schools) and thirty-six control group(five schools), but actual subjects size was forty-four. Among the forty-four patients subjects, twenty-three were experimental group receiving health education about right postures, etiologies of low back pain, diagnosis of low back pain and exercise program composed of muscle strengthening exercise, stretching exercises and twenty-one were control group. During the 8 weeks program, the subjects were received two times education and six times group exercise practices in 1st week and three times per week group exercise practices, two times education in other 7 weeks. This study as carried out from April 1, 1999 to June 30, 1999. Back muscle strength was measured by back muscle strength measuring machine and the intensity of pain were measured by the Visual Analogue Scale(VAS), and level of disability was measured by Oswestry low back pain disability scale. Study measurements were taken before and after 8 week exercise program. Data were analyzed using paired t-test, and ANCOVA. The results were summarized as follows. 1. After low back relieving program, back muscle strength was increased significantly(p=0.000) and there was significant difference in back muscle strength change between experimental group and control group(p=0.002). 2. After low back pain relieving program, pain on anterior bending, pain on posterior bending were decreased significantly than measurements before the program(p=0.000 p=0.000) and there was significant difference in pain on anterior bending and posterior bending change between experimental group and control group(p=0.000, p=0.000). 3. After low back pain relieving program, Oswestry disability scale scores were decreased significantly(p=0.000, p=0.000) but there was no significant difference in Oswestry disability score change between experimental group and control group.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.25-36
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• 2005

In this study, we suggested a new approach method forecasting distribution demand of urban rail transit usign fuzzy control, with intend to reflect irregularity and various functional relationship between trip length and distribution demand. To establish fuzzy control model and test this model, the actual trip volume(production, attraction and distribution volume) and trip length (space distance between a departure and arrival station) of Daegu subway line 1 were used. Firstly, usign these data we established a fuzzy control model, nd the estimation accuracy of the model was examined and compared with that of generalized gravity model. The results showed that the fuzzy control model was superior to gravity model in accuracy of estimation. Therefore, wwe found that fuzzy control was able to be applied as a effective method to predict the distribution demand of urban rail transit. Finally, to increase the estimation precision of the model, we expect studies that define membership functions and set up fuzzy rules organized with neural networks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.108-111
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• 2009

In this paper, the development of unmanned vehicle systems to analysis applicable communications and alternative IEEE 802.11a. IEEE 802.11b/g uses the 2.4GHz. So, using the 5GHz OFDM in IEEE 802.11a interference phenomenon better. IEEE 802.11a has a maximum speed of 54Mbps. Indoors and apartment parking on experiment to soft roaming, hard roaming. Test equipments are AP four units(RSU), reliable results for the AP one unit Bridge, Switch one unit, one server notebook, one notebook(OBU), one car. Use Softwares are Wireshark, Jperf, Ping and million second transfer was used to develop the program. So the actual car was similar to the environment. With the results of the experiment for the unmanned vehicle systems will provide the best method.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.311-319
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• 2017

The primary suspension system of a railway vehicle restrains the wheelset and the bogie, which greatly affects the dynamic characteristics of the vehicle depending on the stiffness in each direction. In order to improve the dynamic characteristics, different stiffness in each direction is required. However, designing different stiffness in each direction is difficult in the case of a general suspension device. To address this, in this paper, an optimization technique is applied to design different stiffness in each direction by using a conical rubber spring. The optimization is performed by using target and analysis RMS values. Lastly, the final model is proposed by complementing the shape of the weak part of the model. An actual model is developed and the reliability of the optimization model is proved on the basis of a deviation average of about 7.7% compared to the target stiffness through a static load test. In addition, the stiffness value is applied to a multibody dynamics model to analyze the stability and curve performance. The critical speed of the improved model was 190km/h, which was faster than the maximum speed of 110km/h. In addition, the steering performance is improved by 34% compared with the conventional model.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.219-228
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• 2011

In this paper, the design procedure of substructure of the steel-type breakwater was described and the actual foundation design was performed for the test bed. The site investigation was executed at the Osan-port area, in Uljin, Gyeongbuk, where the steeltype detached breakwater is constructed. The foundation mainly depends on the lateral load and uplift force due to the wave force. Since the superstructure is stuck out about 9.0m from the ocean bed, the foundation must resist on the lateral force and bending moment. After considering various factors, the foundation type of this structure was determined by the steel pipe pile(${\varphi}711{\times}t12mm$). On the stability of pile foundation, the safety factors of the pile on the compressive, lateral and uplift forces were grater than the minimum factor of safety. The displacements of pile under the working load were evaluated as the values below the permissible ones. Based on the subgrade reaction method, we evaluated the relationship of subgrade reaction and displacement for the lateral and the vertical directions in the layers. The structural analyses along with the foundation were perfomed and the effect of pile foundations were compared quantitatively.

• Journal of Korean Home Economics Education Association
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• v.33 no.1
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• pp.37-62
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• 2021

The purpose of this study is to develop a project-based teaching-learning instruction to solve the problems in family life. The developed process can be a practical plan to activate environmental education centered on living environment problems curriculum of Home Economic Education[HEE]. In order to achieve the purpose of this study, the curriculum of HEE and environmental education categories were compared and analyzed. The study selected 10 themes and developed a project-based HEE teaching-learning instruction with 8 sessions. The characteristics of the developed teaching-learning instruction are as follows. First, HEE curriculum included environmental knowledge, values and attitudes, competence, and practice and participation in environmental education and related categories in achievement standards and learning elements. Second, since HEE curriculum has a teaching-learning instruction plan based on project-based learning that allows learners to recognize and solve problems themselves was developed based on the real life-centered learning themes related to environmental education. It was also proposed that the subject of HEE has a high correlation with environmental competence and environmental practice, and thus environmental contents that can raise students' interests in society and environment should be added to the HEE curriculum. The teaching-learning instruction developed in this study can be used for classes such as HEE classes or free semeste. A follow up study would need to test the educational effects of this teaching and learning plan by implementing it to the actual class.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.263-268
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• 2021

The purpose of this study was to propose a model which is suitable for the actual delivery system by designing a fetal delivery hospital operation management and fetal health classification model. The number of deaths during childbirth is similar to the number of maternal mortality rate of 295,000 as of 2017. Among those numbers, 94% of deaths are preventable in most cases. Therefore, in this paper, we proposed a model that predicts the health condition of the fetus using data like heart rate of fetuses, fetal movements, uterine contractions, etc. that are extracted from the Cardiotocograms(CTG) test using a random forest. If the redundancy of the data is unbalanced, This proposed model guarantees a stable management of the fetal delivery health management system. To secure the accuracy of the fetal delivery health management system, we remove the outlier which embedded in the system, by setting thresholds for the upper and lower standard deviations. In addition, as the proportion of the sequence class uses the health status of fetus, a small number of classes were replicated by data-resampling to balance the classes. We had the 4~5% improvement and as the result we reached the accuracy of 97.75%. It is expected that the developed model will contribute to prevent death and effective fetal health management, also disease prevention by predicting and managing the fetus'deaths and diseases accurately in advance.

• Journal of Convergence for Information Technology
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• v.11 no.12
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• pp.148-157
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• 2021

This research aims to adapt and evaluate the validity and reliability of the Korean version of the Interdisciplinary Education Perception Scale (K-IEPS). The original IEPS was translated into Korean according to the World Health Organization's guidelines. A total of 302 questionnaires were collected from healthcare professional students at 4 universities in South Korea. The validity and reliability of the scale were measured using Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), Cronbach's alpha, and Intraclass Correlation Coefficient (ICC). As a result of the factor analysis, a ten-item scale with two factors (Competency & Autonomy and Perception of Actual Cooperation) was achieved. Additionally, the Cronbach's alpha coefficient was found to be .87, and test-retest reliability was .83. Our study results show that the Korean version of the IEPS is a valid and reliable instrument. Therefore, the K-IEPS can be used in measuring interdisciplinary perceptions of healthcare professional students between different occupational groups.

• Journal of Navigation and Port Research
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• v.45 no.6
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• pp.352-359
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• 2021

This paper presents the definition and importance of ship-centric direct communication concerning ship safety of maritime autonomous and unmanned ships. It also proposes the concept of MX-S2X communication based on high frequency for wide-bandwidth technology and describes the design and simulation result for the physical layer of MX-S2X. It considered high-speed communication as well as overcoming maritime multi-path fading required to be resolved in the marine environment. The physical layer of MX-S2X communication was designed to overcome the occurrence of error-floor caused by multi-path fading even with receiving sufficient signal strength. To this purpose, a performance analysis was conducted on the physical layer by applying the channel model of the actual maritime communication environment. As a result of the performance analysis of the MX-S2X physical layer, it was confirmed that the BER error-floor observed in the VDE physical layer test was overcome, and it operated within the SNR 2dB degradation range compared to the AWGN channel. It is expected that this will show enough performance suitable for short-distance ship-centered direct communication and can be used for direct communication of maritime autonomous ships, unmanned ships, and group navigation of themshortly.