• Journal of KIBIM
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• v.10 no.4
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• pp.89-97
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• 2020

The purpose of this study is to identify the problems of the currently used 3D spatial information utilization system to realize a more accurate landscape and to establish a user-oriented environment to improve the utilization plan for future landscape evaluation. As citizens' interest in urban landscapes with strong public characteristics increases and the speed of urban development also increases, more suitable simulation methods for landscape management are required. Nevertheless, there are many cases of inconvenient correction according to development changes along with many errors in various steps for creating landscape simulation. Therefore, in performing landscape deliberation according to development, it is necessary to create more accurate and efficient landscape simulation, and if changes occur after the initial deliberation, a process that can quickly and conveniently correct and supplement data is needed. In addition, it is necessary to create landscape simulation so that the created modeling source can be used by being compatible with other application programs. In this study, a method of constructing a more accurate and efficient simulation at the time of initial deliberation and a method of creating a landscape simulation model for rapid response to a plan that is changed at the time of re-deliberation are described.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.222-232
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• 1993

In this paper, we present two sets of fuzzy algorithms for the steam generator level control ; one for the high power operations where the flow error is available and the other for the low power operations where the flow error is not available. These are converted to a PID type controller for the high power case and to a quadratic function form of a controller for the low power case. These controllers are implemented on the Compact Nuclear Simulator at Korea Atomic Energy Research Institute and tested by a set of four simulation experiments for each. For both cases, the results show that the total variation of the level error and of the flow error are about 50% of those by the PI controllers with about one half of the control action. For the high power case, this is mainly due to the fact that a combination of two PD type controllers in the velocity algorithm form rather than a combination of two PI type controllers in the position algorithm form is used. For the low power case, the controller is essentially a PID type with a very small integral component where the average values for the derivative component input and for the controller output are used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1916-1923
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• 2007

We have studied to obtain the SAW filter for the passband was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and thin we performed computer-simulated by simulator. We cm fabricate that the block weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulation. Also, we have performed to obtain the properly design conditions about phase shift of the SAW filter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are $5000\;{\AA}$ and $3.6{\mu}m$ respectively. And we have employed that the distances from the hot electrode to the reflector are $2.0{\mu}m$, $2.4{\mu}m$ and the distance from the hot electrode to the ground is $1.5{\mu}m$ respectively. Frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 7,8MHz. And we could obtain that return loss is less then -18dB, ripple characteristics is probably 3dB and triple transit echo is less then -25dB after when we have matched impedance.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.649-656
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• 2006

The purpose of study is to measure soil erosion quantity for elapsed four years from the fire on forest fired sites of Dong-gu, Daegu. This study was conducted to investigate the characteristics of soil erosion by fire occurrence influencing on the soil erosion were. Also analysis result follows that the relations between soil erosion quantity and rainfall intensity, the slope and elapsed year. The results analysed were as follows: 1. Soil erosion by year of occurrence of forest fire was increased 1.9 to 5.7 times as rainfall intensity was increased by 30 m/hr, and 1.4 to 14.2% as degree of slope was increased by $10^{\circ}$. 2. In the first year of forest fire occurrence, soil erosion was fairly heavy for 10 minutes of initial rainfall of which rainfall intensity was 80 m/hr and degree of slope was $30^{\circ}$. The amount of soil erosion was gradually reduced as elapsed time. From two years after fire, the amount of soil erosion by rainfall intensity and degree of slope was nearly constant. 3. The amount of soil erosion by rainfall intensity and slope in accordance with elapsed time after fire was reduced 28.9 to 94.1% in three years after occurrence of forest fire as compared to the first year of fire. Soil erosion was fairly heavy by rainfall intensity and slope in the first year of fire, but it was gradually reduced from two years after fire. 4. In the analysis on influences of each factors on the amount of soil erosion on forest fired sites, the amount of soil erosion was significant differences in major impacts of each rainfall intensity, degree of slope and elapsed year after fire and interaction of rainfall intensity${\times}$degree of slope and rainfall intensity${\times}$elapsed year after fire, but no differences were observed in interaction of degree of slope${\times}$elapsed year after fire and rainfall intensity${\times}$degree of slope${\times}$elapsed year after fire. Rainfall intensity was the most affecting factor on the amount of soil erosion and followed by degree of slope and elapsed year after fire. 5. For correlation between soil erosion and affecting three factors, soil erosion showed significant positive relation with rainfall intensity and degree of slope at I % level, and significant negative relation with elapsed year after fire at 1 % level. 6. As a result of regression of affecting three factors on soil erosion. rainfall intensity was most significant impact factor in explaining the amount of soil erosion on forest fired sites, followed by degree of slope and elapsed year after forest fire. 7. The formula for estimating soil erosion using rainfall intensity, degree of slope and elapsed year after forest fire occurrence was made. S.E = 0.092R.I + 0.211D.S - 0.942E.Y(S.E : Soil erosion, R.I : Rainfall intensity, D.S : Degree of slope, E.Y : Elapsed year after forest fire occurrence)

• Journal of the Korea Society for Simulation
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• v.15 no.3
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• pp.87-91
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• 2006

With the growth of the internet, the number of wireless internet users has increased continuously up to date. However, mobile communications could not support high speed transmission rate with cheap communication fee and wireless LAN has problems in providing terminal mobility and wide area connectivity, respectively. So the WMAN standard has been newly designed to make up for these limits. The initial 802.16 specification effectively offers a solution for providing fixed users with high speed wireless communication but it does not offer terminal mobility. So the 802.16d and 802.16e have been developed as the next generation solution that can support various PHY layer (SC, SCa, OFDM, OFDMA) and offer the terminal mobility. In this paper, we propose an effective uplink scheduling algorithm for VoIP with using UGS, and we show that our proposed algorithm is superior in view of average delay and management of uplink bandwidth to conventional rtPS algorithm and the scheme in reference, with using NS-2 network simulator.

• Journal of the Korea Society for Simulation
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• v.26 no.4
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• pp.43-49
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• 2017

With the advances in and expansion of the semiconductor and display businesses in Korea the demand of the engineers in such fields is increasing. Keeping pace with the trend, the semiconductor courses in undergraduate not only include the newest technologies in addition to the fundamental theories but fabrication related technologies as well in order to produce engineers with practical knowledge. However, since semiconductor fabrication requires expensive equipment and materials in a clean room, laboratory class can't be provided in undergraduate. To overcome this limitation actual fabrication processes are recorded in video and played in class. In addition, 3D visualization of fabrication processes can be used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.772-779
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• 2015

In this paper,a reconfigurable multi-band mobile antenna with switching line for LTE band 13, GSM, K-PCS, WCDMA band. The proposed antenna is planar strip line design and composed of stub shorted to the ground plane and two switching line for proposed band operation. To obtain the optimized parameters, we used the simulator, Using the obtained parameters is fabricated. The numerical and experiment results demonstrated that the proposed antenna satisfied the -6 dB impedance bandwidth requirement while simultaneously covering when the state of sw1 and sw2 on for LTE band 13, the state of sw1 off and sw2 on for GSM, K-PCS, the state of sw1 off and sw2 off for WCDMA. Respectively and characteristics of gain and radiation patterns are determined for a reconfigurable multi-band mobile terminal.

• Fashion & Textile Research Journal
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• v.18 no.4
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• pp.520-530
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• 2016

This research aims to propose an ergonomic design process for hip protector based on previous studies, existing products, multidisciplinary experts opinion, and wearing test. The elderly are more likely to suffer a hip fracture when they fall due to their physical changes in skeletal form, muscle quantity, bone density, and joint movement. A hip protector is an effective product to prevent hip fractures in the elderly but it also has a problem in that it is uncomfortable. Therefore there is a high chance that it won't be able to prevent hip fractures properly. Since the comfort of a hip protector is one of the most critical elements in preventing a hip fracture, we need to keep improving the hip protector for mobility and usability. Based on the previous studies and limitations of current hip protector products, we need to come up with an optimal design for the Korean elderly. First, knowledge has to be built relating to the ergonomic design of the hip protector considering body shape and size analysis using 3D-scan data, and biomechanical analysis on hip fracture. Second, we need to develop a design process including hip protector pattern design, and wearing evaluation with virtual system. Third, we suggest to reevaluate and verify the design procedure from impact evaluation using testing simulator, virtual evaluation of impact, to wearing comfort and usability evaluation. This design process presented in this study would be expected to contribute to the development of ergonomic hip protector which is suitable for the Korean elderly.

• Korean Journal of Optics and Photonics
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• v.18 no.4
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• pp.235-240
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• 2007

A ceramic stem based TO package incorporating a coplanar waveguide feed-line has been proposed allowing for 10 Gbps grade data transmission. The frequency response of a cylindrical feed-line fer a conventional metal based TO package was first analyzed, and compared with that of the CPW feed-line used for a ceramic based package such as a butterfly package. For the case where a DFB LD chip is packaged to an LD module, the measured 3 dB frequency bandwidths for the conventional and proposed packages were 3.5 GHz and 7.8 GHz respectively, which agree well with the theoretical results obtained from the modeling based on the small signal equivalent circuits. Consequently, we proposed a novel ceramic based TO package with a CPW feed-line in ceramic material as a stem to improve the frequency characteristics of the conventional one. And, its performance was theoretically observed to confirm that the proposed package provides even wider frequency bandwidth compared to the conventional one.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.4
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• pp.350-357
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• 2016

In this paper, a small mu-zero zeroth order resonance(ZOR) antenna based on meta structure is proposed using parasitic patch at 5.8 GHz. The mu-zero ZOR antenna is designed by utilizing the resonance of series inductance and capacitance of mu-negative transmission line and its size can be further reduced by a simple parasitic patch. The parasitic patch can increase series capacitance of mu-negative transmission line related to a resonant frequency. We have simulated and optimized dimension of the parasitic patch using Ansys commercial simulator(HFSS). As a result, the antenna has the following characteristics: kr of 0.59, efficiency of 92 %, and gain of 6.57 dBi. Also, its size is reduced by 24 % compared to a conventional mu-zero ZOR antenna. The measured results are in good agreement with the simulated results.