• Journal of Computational Design and Engineering
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• v.3 no.4
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• pp.385-397
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• 2016

Scaffolds are essential in bone tissue engineering, as they provide support to cells and growth factors necessary to regenerate tissue. In addition, they meet the mechanical function of the bone while it regenerates. Currently, the multiple methods for designing and manufacturing scaffolds are based on regular structures from a unit cell that repeats in a given domain. However, these methods do not resemble the actual structure of the trabecular bone which may work against osseous tissue regeneration. To explore the design of porous structures with similar mechanical properties to native bone, a geometric generation scheme from a reaction-diffusion model and its manufacturing via a material jetting system is proposed. This article presents the methodology used, the geometric characteristics and the modulus of elasticity of the scaffolds designed and manufactured. The method proposed shows its potential to generate structures that allow to control the basic scaffold properties for bone tissue engineering such as the width of the channels and porosity. The mechanical properties of our scaffolds are similar to trabecular tissue present in vertebrae and tibia bones. Tests on the manufactured scaffolds show that it is necessary to consider the orientation of the object relative to the printing system because the channel geometry, mechanical properties and roughness are heavily influenced by the position of the surface analyzed with respect to the printing axis. A possible line for future work may be the establishment of a set of guidelines to consider the effects of manufacturing processes in designing stages.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.2
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• pp.184-192
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• 2001

In this paper, we analyze the result of the conduced emission and susceptibility tests performed on the KOMPSAT-I ETB Platform. The ETB platform consists of the EM (Engineering Model) boxes developed to perform the electrical functional test. During the conducted emission test, we measured the instant waveform in time domain when each switch was turn on, and spectrum of the noise in the frequency range of 10 Hz up to100 MHz fur the steady state of the ETB. During the conducted susceptibility test, no malfunction and no serious damage of the electronic box were observed when a simulated noise waveform was applied to the DC power bus. The simulated waveform was obtained by adding the 6 dB-system margin to the worst case waveform measured from the conducted emission. This test was performed as co-development of the KOMPSAT-I with TRW in USA.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.2
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• pp.93-98
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• 2024

This paper presents the method to extract the ultrawide-band (UWB) signal and proposes the simple impulse radar system for sensing real-based target within close-range area. The proposed impulse radar system consists of impulse generator, ultrawide-band antennas, function generator, and digital oscilloscope. It is verified by experiment that a differentiated Gaussian pulse is generated with 200ps of pulse width and corresponding spectrum from 0.3 to 4.7 GHz once a sinusoidal wave with 10MHz is excited. The Gaussian doublet is received by identical antennas and it is shown that the UWB pule width of 328ps and its spectrum is from 0.9 to 4.4 GHz. It is confirmed that the UWB pulse is extracted when the real-based targets such as circular target with 4cm radius and corner reflector are placed at the close-range area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1113-1124
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• 2004

In this paper, we proposed a hardware(H/W) structure which can compress and recontruct the input image in real time operation and implemented it into a FPGA platform using VHDL(VHSIC Hardware Description Language). All the image processing element to process both compression and reconstruction in a FPGA were considered each of them was mapped into H/W with the efficient structure for FPGA. We used the DWT(discrete wavelet transform) which transforms the data from spatial domain to the frequency domain, because use considered the motion JPEG2000 as the application. The implemented H/W is separated to both the data path part and the control part. The data path part consisted of the image processing blocks and the data processing blocks. The image processing blocks consisted of the DWT Kernel fur the filtering by DWT, Quantizer/Huffman Encoder, Inverse Adder/Buffer for adding the low frequency coefficient to the high frequency one in the inverse DWT operation, and Huffman Decoder. Also there existed the interface blocks for communicating with the external application environments and the timing blocks for buffering between the internal blocks The global operations of the designed H/W are the image compression and the reconstruction, and it is operated by the unit of a field synchronized with the A/D converter. The implemented H/W used the 69%(16980) LAB(Logic Array Block) and 9%(28352) ESB(Embedded System Block) in the APEX20KC EP20K600CB652-7 FPGA chip of ALTERA, and stably operated in the 70MHz clock frequency. So we verified the real time operation of 60 fields/sec(30 frames/sec).

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.315-315
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• 2017

In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.

• Polymer(Korea)
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• v.35 no.3
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• pp.238-243
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• 2011

Organic/inorganic hybrid materials have a lot of interest in various areas due to their fascinating properties. To control the location and dispersion of inorganic nanoparticles within polymer matrix. thiol-terminated polymeric ligands have been widely used to tune the surface property of nanoparticles. However, the specific binding between the thiol functional group and metal is unstable with increasing temperature. To archive the thermally-stable Au nanoparticles, we previously synthesized various UV-crosslinkable polymeric ligands, which have different compositions of polar, UV-crosslinkable azide unit comparing to non-polar 스티렌 units. After crosslinking the Au nanoparticles, it was found that the nanoparticles had superb stability at high temperature (above $180^{\circ}C$). In this work, we used thermally-stable Au nanoparticles to control the location within the polymer matrix. By changing the amount of polar azide units in the polymeric ligands, we could precisely control the location of nanoparticles from one domain to the interface of block copolymer templates.

• Journal of Science Education
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• v.37 no.1
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• pp.131-141
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• 2013

The purpose of this study was to find out the effect of the science lesson emphasized creativity and character on the creativity and science related attitudes of elementary school students. To conduct this study, 'Unit 1. Weighing', which is a part of content of 4th grade science text book, was analyzed and 11 science lessons emphasized the elements of creativity and character were developed. One experimental group and one control group of 4th grade students were selected to perform a prior investigation. Then the experimental group attended developed science lessons and the control group attended the traditional science lessons based on the text book and teacher's guide. After conducting lessons, a post investigation was performed for each group and the results were analyzed to produce the following conclusions. First, the science lesson emphasized the creativity and character was more effective than traditional one to improve students' creativity. Especially, fluency, originality and abstractness in sub-elements of creativity, were improved meaningfully. Second, the science lesson emphasized the creativity and character was more effective than traditional one to enhance students' science related attitudes. Especially, in sub-domain, the attitude about scientific research and the application of scientific attitude were enhanced meaningfully. Consequently, science lesson emphasized the creativity and character was thought to have a positive effect on improving the creativity and science related attitudes of elementary students.

• Journal of Home Health Care Nursing
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• v.8 no.1
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• pp.5-24
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• 2001

The purpose of this study was to develop a parenting intervention program and determine the efficacy of the program with low-birth weight infants and their mothers. Nine dyads for the experimental group and twelve dyads for the control group discharged from the Neonatal Intensive Care Unit of a University Hospital in Seoul were recruited for the study. For the intervention group, programmed education and support which focused on the maternal sensitivity of the infant's behavior. rearing environment. motherinfant interaction and infant care were given to each subject. Individual counseling and home visits were provided at discharge, one week after discharge. and one and three months of corrected age in every infant. Structured questionaires were administered and feeding interactions were videotaped and coded by a blinded certified observer. A Quasi-experimental design was conducted for this study. Postpartum depression, maternal self esteem. infant care burden, HOME. mother-infant interaction, and infant development were measured. Results were in favor of the intervention versus the control group. On the Beck depression inventory, intervention mothers showed decreasing trends in depressive symptom vs control mothers although, there were statistically no significant differences between the two groups at each time. The mean score of experimental group was 11.55(mild depression state) at discharge and became 8,6(normal state) at 1 month of corrected age. On the other hand, the mean score of the control group was 13.92(mild depression state) at discharge and became 14.0. Maternal self esteem in both groups improved over time. Infant care burden in both groups was also shown to increase over time. There was a significant difference between the two groups in HOME(p=.0340) at 3 months of corrected age. HOME scores of the experimental group and the control's were 31.10 and 25.58, respectively. Mothers' emotional and language responses were significantly high in the intervention group compared with the control group(p=.0155). Intervention group (53.33) showed a significantly high quality of motherinfant interaction compared with the in control group (42.80)(p =.0340). Intervention group mothers appeared have a better quality of mother-infant interaction behaviors. On the other hand, there was no statistical difference in the infant part between groups. Intervention group infants had higher trends in a general developmental quotient: although, there was no statistical difference between groups. The general developmental quotient of intervention infants was 102.56 and control's was 91.28. However, the developmental quotient of the domain of 'individuality-sociality' was higher in the intervention group infants compared with the control's(p=.0155). The concerns identified by parents revealed two domains of an infants' health management -knowledge and skills in caregiving of lowbirthweight-infants, characteristics of lowbirthweight infants, identifying a developmental milestone, coping with emergency situations and relaxation strategies of mothers from the infant care burden. Interview data with the mothers of low-birth weight infants can be used to develop intervention program contents. Limited intervention time and frequency due to time and cost limitations of this study should be modified. The intervention should be continuously implemented when low-birth weight infants become three years old. An NNNS demonstration appeared to be a very effective intervention for the mothers to improve the quality of mother-infant interactions. Therefore intervening in the mothers of low-birth weight infants as early after delivery as possible is desirable. This study has shown that home visit interventions are worthwhile for mothers only beyond the approach as an essential factor in ability of facilitating a growth fostering environment. In conclusion. the intervention program of this study was very effective in enhancing the parenting for the mothers of low-birth weight infants, resulting in health promotion of low-birth weight infants. The home-visit outreach intervention program of this study will contribute to the health delivery system in this country where there is a lack of continuous follow-up programs for low-birth weight infants after discharge from NICU, if it is activated as part of the home visit programs in community health systems.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.611-623
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• 2000

The cooperative learning movement began as parts of the desegregation process in America, aiming at increasing academic achievement and social skills among diverse students. Cooperative learning may be defined as a classroom learning environment in which students work together in small heterogeneous groups. Although many studies have shown the effectiveness of cooperative learning in a variety of subjects, relatively few have focused on biology. In this study, we investigated the effects of cooperative learning on students' achievement and attitude of middle school biology students. For this purpose this study compared three sections. In one section, a cooperative learning strategy was used. Second section was taught in small groups and the third section was instructed in the traditional method. The unit 'Structures and functions of animals' was used. A total of 188 students were included in this study. These classes were treated for 10hours during 10weeks from September 1 to November 28, 1999. The pretests-posttests control group design was applyed. An analysis of covariance(ANCOVA) was used as the data analysis procedure. Significant differences were found in the achievement and the attitude of students using cooperative learning strategy(p<.05) when compared to traditional classroom structure and small group learning. Cooperative learning was more effective in the low-ability and average-ability students than the high-ability students in the science achievement. Cooperative learning is effective in both male and female students. And students in the cooperative group achieved better than those in other groups in affective, behavioral, and intention-cognitive domain of science attitude.

• Journal of Intelligence and Information Systems
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• v.26 no.2
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• pp.131-145
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• 2020

In line with the trend of industrial innovation, IoT technology utilized in a variety of fields is emerging as a key element in creation of new business models and the provision of user-friendly services through the combination of big data. The accumulated data from devices with the Internet-of-Things (IoT) is being used in many ways to build a convenience-based smart system as it can provide customized intelligent systems through user environment and pattern analysis. Recently, it has been applied to innovation in the public domain and has been using it for smart city and smart transportation, such as solving traffic and crime problems using CCTV. In particular, it is necessary to comprehensively consider the easiness of securing real-time service data and the stability of security when planning underground services or establishing movement amount control information system to enhance citizens' or commuters' convenience in circumstances with the congestion of public transportation such as subways, urban railways, etc. However, previous studies that utilize image data have limitations in reducing the performance of object detection under private issue and abnormal conditions. The IoT device-based sensor data used in this study is free from private issue because it does not require identification for individuals, and can be effectively utilized to build intelligent public services for unspecified people. Especially, sensor data stored by the IoT device need not be identified to an individual, and can be effectively utilized for constructing intelligent public services for many and unspecified people as data free form private issue. We utilize the IoT-based infrared sensor devices for an intelligent pedestrian tracking system in metro service which many people use on a daily basis and temperature data measured by sensors are therein transmitted in real time. The experimental environment for collecting data detected in real time from sensors was established for the equally-spaced midpoints of 4×4 upper parts in the ceiling of subway entrances where the actual movement amount of passengers is high, and it measured the temperature change for objects entering and leaving the detection spots. The measured data have gone through a preprocessing in which the reference values for 16 different areas are set and the difference values between the temperatures in 16 distinct areas and their reference values per unit of time are calculated. This corresponds to the methodology that maximizes movement within the detection area. In addition, the size of the data was increased by 10 times in order to more sensitively reflect the difference in temperature by area. For example, if the temperature data collected from the sensor at a given time were 28.5℃, the data analysis was conducted by changing the value to 285. As above, the data collected from sensors have the characteristics of time series data and image data with 4×4 resolution. Reflecting the characteristics of the measured, preprocessed data, we finally propose a hybrid algorithm that combines CNN in superior performance for image classification and LSTM, especially suitable for analyzing time series data, as referred to CNN-LSTM (Convolutional Neural Network-Long Short Term Memory). In the study, the CNN-LSTM algorithm is used to predict the number of passing persons in one of 4×4 detection areas. We verified the validation of the proposed model by taking performance comparison with other artificial intelligence algorithms such as Multi-Layer Perceptron (MLP), Long Short Term Memory (LSTM) and RNN-LSTM (Recurrent Neural Network-Long Short Term Memory). As a result of the experiment, proposed CNN-LSTM hybrid model compared to MLP, LSTM and RNN-LSTM has the best predictive performance. By utilizing the proposed devices and models, it is expected various metro services will be provided with no illegal issue about the personal information such as real-time monitoring of public transport facilities and emergency situation response services on the basis of congestion. However, the data have been collected by selecting one side of the entrances as the subject of analysis, and the data collected for a short period of time have been applied to the prediction. There exists the limitation that the verification of application in other environments needs to be carried out. In the future, it is expected that more reliability will be provided for the proposed model if experimental data is sufficiently collected in various environments or if learning data is further configured by measuring data in other sensors.