• Journal of the Korea Society for Simulation
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• v.10 no.4
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• pp.21-30
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• 2001

In this paper, EMI measurement, the STGU simulation being conducted, filter design, its characteristics, and its implementation to the PCB, and finally test results are discussed. When the low pass filter was implemented within the STGU, the power of EMI decreased more than 20dBm. Finally, when TE and MTIE, two important quality measure in synchronous reference clock, was assessed, ITU-T G813 requirement was satisfied. EMI(Electromagnetic Interface) is a measure of electomagnetic radiation from equipment in the range of 10KHz to 3GHz, and can cause unexpected reactions of electronics/electrical equipment. In this study, for safe and stable communication operation, a STGU (System Timing Generation Unit), which is a 2.5G SDH System and a major EMI source, was employed to simulate electromagnetic interface. Using Open-Site test, the power of fundamental frequency of EMI of interest and its harmonics were measured. Also, a low pass filter at cut-off frequency of 2GHz was specifically designed for this study to minimize the effect of EMI between electronic components.

• Journal of Sensor Science and Technology
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• v.18 no.3
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• pp.210-216
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• 2009

In this paper the tactile sensor system based on the bending loss of optical fiber sensor is presented. The sensor array was designed with fabric structure. The optical measuring system was composed of LED for light source and CCD camera for the signal light detector. Performance of this tactile sensor system was evaluated in various environments and compared with Harmon's design criteria. The result shows that load range is 3 g$\sim$100 g, resolution is 1.5 g, hysteresis error is 1.5%. The response linearity is good and flexibility of sensor array is excellent.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.55-55
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• 2018

본 연구는 상추 '피델'을 이용한 완전제어형 식물공장에서의 재배를 하기 위해 기존의 배양액에 생육 촉진용 AMG의 농도를 구명하고 그에 맞는 매뉴얼을 확립하기 위해 실시하였다. 실험은 기존 배양액에 AMG(고활성 칼슘용액+복합 활성 미네랄)를 추가하였으며 '피델'의 생육에 적합한 AMG의 농도는 0, 0.05, 0.1, 0.2%를 양액에 추가하여 5반복 4처리로 진행하였다. 생육 조사 항목은 초폭, 초장, 엽장, 엽폭, 엽록소, 생체중을 조사하였다. '피델'의 생장에서 초폭, 엽폭, 엽장은 3주차부터 생장량이 급증하였으며 AMG 4처리구 5주차 조사에서는 초폭 평균 335g, 357g, 369g, 381g을 나타냈으며 엽폭은 평균 168g, 191g, 202g, 208g, 엽장 평균 129g, 134g, 144g, 144g으로 조사되었다. AMG 농도 0.1~0.2%는 통계적으로 생장 촉진 효과가 나타났으나 유의차가 크지 않아 0.1% AMG가 적정한 것으로 판단되었다. 엽록소 함량의 경우 정식 2주차 이후서부터는 SPAD 평균 29~32로 기록되어 엽록소함량은 크게 변화하지 않았다. 또한 엽수의 증가폭에 비해 생체중의 증가폭이 컸으며 생체중의 경우 정식 3주부터 5주 사이에 생체중이 5배 이상 급증하는 생장 패턴을 나타내었다. 5주차 생체중에서는 0% AMG의 경우 평균 82g, 0.05% AMG는 평균 85g, 0.1% AMG는 평균 115g, 그리고 0.2% AMG는 평균 114g으로 조사되었다. 따라서 0.1~0.2% AMG에서는 차이가 없게 나타남에 따라 생장촉진을 위해서는 0.1% AMG를 추가하는 것이 적정하다고 판단되었다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.04a
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• pp.57-57
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• 2018

본 연구는 상추 '피델'을 이용한 완전제어형 식물공장에서의 재배를 하기 위해 기존의 배양액에 생육 촉진용 AMG의 농도를 구명하고 그에 맞는 매뉴얼을 확립하기 위해 실시하였다. 실험은 기존 배양액에 AMG(고활성 칼슘용액+복합 활성 미네랄)를 추가하였으며 '피델'의 생육에 적합한 AMG의 농도는 0, 0.05, 0.1, 0.2%를 양액에 추가하여 5반복 4처리로 진행하였다. 생육 조사 항목은 초폭, 초장, 엽장, 엽폭, 엽록소, 생체중을 조사하였다. '피델'의 생장에서 초폭, 엽폭, 엽장은 3주차부터 생장량이 급증하였으며 AMG 4처리구 5주차 조사에서는 초폭 평균 335g, 357g, 369g, 381g을 나타냈으며 엽폭은 평균 168g, 191g, 202g, 208g, 엽장 평균 129g, 134g, 144g, 144g으로 조사되었다. AMG 농도 0.1~0.2%는 통계적으로 생장 촉진 효과가 나타났으나 유의차가 크지 않아 0.1% AMG가 적정한 것으로 판단되었다. 엽록소함량의 경우 정식 2주차 이후서부터는 SPAD 평균 29~32로 기록되어 엽록소함량은 크게 변화하지 않았다. 또한 엽수의 증가폭에 비해 생체중의 증가폭이 컸으며 생체중의 경우 정식 3주부터 5주 사이에 생체중이 5배 이상 급증하는 생장 패턴을 나타내었다. 5주차 생체중에서는 0% AMG의 경우 평균 82g, 0.05% AMG는 평균 85g, 0.1% AMG는 평균 115g, 그리고 0.2% AMG는 평균 114g으로 조사되었다. 따라서 0.1~0.2% AMG에서는 차이가 없게 나타남에 따라 생장촉진을 위해서는 0.1% AMG를 추가하는 것이 적정하다고 판단되었다.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.23-29
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• 2022

To improve spectrum and energy efficiency in the fifth generation (5G) wireless channels, intelligent reflecting surface (IRS) transmissions have been envisioned, possibly towards the sixth generation (6G) networks. In this paper, we analyze the bit-error rate (BER) performance of intelligent reflecting surface (IRS) assisted non-orthogonal multiple access (NOMA) systems. First, we derive a closed-form expression of the BER in terms of Q functions. Then we analyze the BER improvement of the IRS NOMA system over the conventional NOMA system with respect to the power allocation. Furthermore, we also demonstrate numerically the BER improvement of the IRS NOMA network over the conventional NOMA network in respect of the number of reflecting devices.

• Journal of Aquaculture
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• v.16 no.3
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• pp.142-150
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• 2003

Performance of a biological filter, the rotating biological contactor (RBC), is affected by rotational speed and hydraulic residence time (HRT). A RBC with a disc diameter of 62 cm, total surface area of 48.28 $m^2$, volume of 0.34 ㎥, and submergence ratio of 35.4% was tested for the combinations of five rotational speeds (1, 2, 3, 4 & 5 rpm) and three HRT (0.5, 1.0 & 2.0 hr) to find out the maximum removal efficiencies of total ammonia nitrogen (TAN) and nitrite nitrogen of a simulated recirculating aquaculture system. Ammonia loading rate in the system was 25 g of TAN/ ㎥. day. Removal efficiencies were checked when TAN concentrations in the system stabilized for 3 days in each treatment. The concentration of TAN in the system decreased with increasing rotational speed of the RBC up to 4 rpm in all HRT (P<0.05). At the rotational speed of 5 rpm, the efficiencies decreased in all HRT (P<0.05). When the rotational speeds were 1, 2, 3, 4, and 5 rpm, TAN concentrations in the system were 1.35, 0.94, 0.69, 0.66, and 0.76 mg/L at the 0.5 hr HRT, 2.86, 1.18, 0.96, 0.87, and 1.11 mg/L at the 1.0 hr HRT, and 5.30, 2.44, 1.99, 1.77, and 2.01 mg/L at the 2.0 hr HRT, respectively. The TAN removal efficiencies of the RBC at the rotational speeds of 1, 2, 3, 4, and 5 rpm were 32.9, 49.5, 65.1, 72.9, and 62.9% in 0.5 hr HRT,33.1, 74.1, 87.1, 95.8, and 78.5% in 1.0 hr HRT, and 35.5, 76.7, 89.6, 97.0, and 85.5% in 2.0 hr HRT, respectively. TAN removal efficiency of RBC per pass increased with increasing HRT. However, TAN concentration in the system also increased. The best operating condition among the treatments was obtained at the treatment of 0.5 hr HRT and 4 rpm (P<0.05). The TAN concentration was 0.66 mg/L. Concentrations of nitrite nitrogen (NO$_2$$^{[-10]}$ -N) in the system decreased with increasing rotational speed in all HRT while that in the system increased with increasing HRT in all rotational speeds. The ranges of NO$_2$$^{[-10]}$ -N concentrations at HRT of 0.5, 1.0, and 2.0 hr in the system were 0.26~0.32, 0.31~0.56, and 0.43~l.45 mg/L, respectively. The ranges of daily removal rates of TAN in this system were 20.03~23.0 g TAN/㎥ㆍday and those of nitrite nitrogen were 19.65~30.25 g NO$_2$$^{[-10]}$ -N/㎥ㆍday.

• The korean journal of orthodontics
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• v.49 no.2
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• pp.73-80
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• 2019

Objective: The purpose of this study was to compare the static (SFF) and kinetic frictional forces (KFF) of a computer-aided design and computer-aided manufacturing lingual bracket (CAD/CAM-LB) with those of conventional LB (Con-LB) and Con-LB with narrow bracket width (Con-LB-NBW) under 3 tooth displacement conditions. Methods: The samples were divided into 9 groups according to combinations of 3 LB types (CAD/CAM-LB [Incognito], Con-LB [7th Generation, 7G], and Con-LB-NBW [STb]) with 3 displacement conditions (no displacement [control], maxillary right lateral incisor with 1-mm palatal displacement [MXLI-PD], and maxillary right canine with 1-mm gingival displacement [MXC-GD]; n = 6/group). While drawing a 0.016-inch copper or super-elastic nickel-titanium archwire with 0.5 mm/min for 5 minutes in a chamber maintained at $36.5^{\circ}C$, SFF and KFF were measured. The Kruskal-Wallis method with Bonferroni correction was performed. Results: The Incognito group demonstrated the highest SFF, followed by the 7G and STb groups ([STb-control, STb-MXLI-PD, Stb-MXC-GD] < [7G-MXC-GD, 7G-MXLI-PD, 7G-control] < [Incognito-MXLI-PD, Incognito-control, Incognito-MXC-GD]; p < 0.001). However, there were no significant differences in SFF among the 3 displacement conditions within each bracket group. Within each displacement condition, the Incognito group demonstrated the highest KFF, followed by the 7G and STb groups ([STb-control, STb-MXLI-PD] < Stb-MXC-GD < 7G-MXLI-PD < [7G-control, 7G-MXC-GD] < [7G-MXC-GD, Incognito-MXLI-PD, Incognito-control] < [Incognito-control, Incognito-MXC-GD]; p < 0.001). MXC-GD exhibited higher KFFs than MXLI-PD in the same bracket group. Conclusions: The slot design and ligation method of the CAD/CAM-LB system should be modified to reduce SFF and KFF during the leveling/alignment stage.

• Journal of Power System Engineering
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• v.14 no.5
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• pp.10-16
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• 2010

The main object of this study is to investigate the collection characteristics of multi-layer multi-stage porous plate system experimentally. The experiment is carried out to analyze the characteristics of pressure drop and collection efficiency for the present system with the experimental parameters such as inlet velocity, tube diameter, inlet concentration, and stage number, etc. In results, the pressure drop becomes 22 to $115mmH_2O$ with increment of stage number (1 to 5) of porous plate system at tube velocity 15 m/s and tube diameter ${\Phi}8$. In case of fly ash and 5 stage, the collection efficiency becomes 90.5 to 95.7% increasing the tube velocity 12 to 15 m/s at inlet concentration $3g/m^3$ and tube diameter ${\Phi}8$. Additionally, it is estimated that the collection efficiencies of 5 stage are 94.3, 95.6 and 99.1% for fly ash, steel dust and based power, respectively (${\Phi}8$ tube, $V_t$ = 12m/s, inlet concentration $3g/m^3$).

• Journal of Digital Convergence
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• v.18 no.10
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• pp.225-232
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• 2020

The underlaying communication scheme in 5G cellular network is a very promising resource sharing scheme, and it is an effective scheme for improving service performance of 5G and reducing communication load between a cellular link and a device to device (D2D) link. This paper proposes the algorithm to minimize the resource interference that occurs when performing 5G-based multi-class service on gNB(gNodeB) and the cooperative priority-based resource allocation scheduling scheme (CPRAS) to maximize 5G communication service according to the analyzed control conditions of interference. The proposed CPRAS optimizes communication resources for each device, and it optimizes resource allocation according to the service request required for 5G communication and the current state of the network. In addition, the proposed scheme provides a function to guarantee giga-class service by minimizing resource interference between a cellular link and a D2D link in gNB. The simulation results show that the proposed scheme is better system performance than the Pure cellular and Force cellular schemes. In particular, the higher the priority and the higher the cooperative relationship between UE(User Equipment), the proposed scheme shows the more effective control of the resource interference.

• ETRI Journal
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• v.43 no.2
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• pp.209-220
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• 2021

The filtered orthogonal frequency division multiplexing (F-OFDM) system has been recommended as a waveform candidate for fifth-generation (5G) communications. The suppression of out-of-band emission (OOBE) and asynchronous transmission are the distinctive features of the filtering-based waveform frameworks. Meanwhile, the high peak-to-average power ratio (PAPR) is still a challenge for the new waveform candidates. Partial transmit sequence (PTS) is an effective technique for mitigating the trend of high PAPR in multicarrier systems. In this study, the PTS technique is employed to reduce the high PAPR value of an F-OFDM system. Then, this system is compared with the OFDM system. In addition, the other related parameters such as frequency localization, bit error rate (BER), and computational complexity are evaluated and analyzed for both systems with and without PTS. The simulation results indicate that the F-OFDM based on PTS achieves higher levels of PAPR, BER, and OOBE performances compared with OFDM. Moreover, the BER performance of F-OFDM is uninfluenced by the use of the PTS technique.