• Title/Summary/Keyword: College performances

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Performance Analysis of A Hybrid Codebook for LTE Downlink Relay Systems (LTE 하향 링크 중계기 시스템에서 새로운 하이브리드 코드북 성능 분석)

  • Kim, Hyung-Jun;Park, Noe-Yoon;Kim, Young-Ju
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.4
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    • pp.462-469
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    • 2011
  • In this paper, we propose a novel hybrid codebook design method which combines DFT matrix based codebook for Rayleigh fading and LOS codebook for direct path. Link-level performances employing hybrid codebook outperform the ones employing the conventional codebooks when K-factor of Rician distribution is 0.28 to 0.99. Moreover hybrid codebook shows good performances over not only Rayleigh channel but also high K's Rician channels.

An Experimental Study on the Pumping Characteristics of Diffuser/Nozzle Based Piezoelectric Micropumps with Different Geometries and Operating Conditions (압전 구동방식 마이크로 펌프에서 기하학적 형상과 작동조건에 따른 점핑특성에 대한 실험적 연구)

  • Yong, Jung-Kwon;Kim, Chang-Nyung;Kim, Chin-Uck
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.1
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    • pp.33-40
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    • 2009
  • In the present experimental study, the pumping performances of diffuser/nozzle based piezoelectric micropumps are estimated with different operating factors and geometries. Here, the effects of the input voltage and frequency on the pumping performances have been examined together with the influences of the positions of the inlet and outlet. The results show that the flow rate of the micropump is larger with larger input voltage with the largest flow rates for the frequency to be close to 6.0 Hz all through the current experimental study. Also, it has been found that the positions of the inlet and outlet affect much on the performance of the piezoelectric micropumps. Error estimation has been carried out for the evaluation of the pumping performance in association with the uncertainty of the measurement.

The effects of muscle fatigue of knee muscles on balance ability in healthy adults (무릎 근육의 근피로가 정상 성인의 균형에 미치는 영향)

  • Lim, Garin;Chang, Jongsung
    • Journal of Korean Medicine Rehabilitation
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    • v.28 no.2
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    • pp.105-111
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    • 2018
  • Objectives The purpose of this study was to examine the effects muscle fatigue at the knee muscles on balance during standing in healthy adults. Methods Thirty healthy adults were recruited along with their written informed consent. Subjects were randomly assigned to knee extensor group (fatigue on knee extensor, KE), and knee flexor group (fatigue on knee flexor, KF). And subjects performed exercise with each muscle group until muscle fatigue was induced. They were assessed balance ability by functional reaching test (FRT), limit of stability (LOS), and postural sway (one leg standing, normal eye open (NO), normal eye close (NC), pillow with eye open (FO), and pillow with eye close (FC)) before and after fatigue. Results There were significant group differences balance performances in FRT, anterior of limit of stability, one leg standing, and the muscle fatigue of knee muscles were decreased balance performances. The balance performance was affected by visual sense and proprioception. Conclusions These results show that the muscle fatigue of knee muscles decreased balance performance. Therefore, balance exercise program should be trained without muscle fatigue.

Robust PID Controller Tuning Technique and Applicationi to Speed Controller Design for BLDC Motors (견실 PID 제어기 조정기법 및 BLDC 모터의 속도제어기 설계에의 응용)

  • Kim, In-Soo;Lee, Young-Jin;Park, Sung-Jun;Park, Han-Woong;Lee, Man-Hyung
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.8
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    • pp.126-133
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    • 2000
  • This paper is a study on robust PID controller tuning technique using the frequency region model matching method.To design the robust PID controller satisfying disturbance attenuation and robust tracking property for a reference input first an {{{{ETA _$\infty$}}}} controller satisfying given performances is designed using an H$_{\infty}$ control method, And then the parameters(proportional gain integral gain and derivation gain) of the robust PID controller with the performances of the desinged H$_{\infty}$ controller are determined using the model matching method at frequency domain. in this paper this PID controller tuning technique is applied to PID speed controller design for BLDC motors. Consequently simulation results show that the proposed PID speed controller satisfies load torque disturbance attenuation and robust tracking property and this study has usefulness and applicability for the speed control system; design of BLDC motors.

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Algorithms for Classifying the Results at the Baccalaureate Exam-Comparative Analysis of Performances

  • Marcu, Daniela;Danubianu, Mirela;Barila, Adina;Simionescu, Corina
    • International Journal of Computer Science & Network Security
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    • v.21 no.8
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    • pp.35-42
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    • 2021
  • In the current context of digitalization of education, the use of modern methods and techniques of data analysis and processing in order to improve students' school results has a very important role. In our paper, we aimed to perform a comparative study of the classification performances of AdaBoost, SVM, Naive Bayes, Neural Network and kNN algorithms to classify the results obtained at the Baccalaureate by students from a college in Suceava, during 2012-2019. To evaluate the results we used the metrics: AUC, CA, F1, Precision and Recall. The AdaBoost algorithm achieves incredible performance for classifying the results into two categories: promoted / rejected. Next in terms of performance is Naive Bayes with a score of 0.999 for the AUC metric. The Neural Network and kNN algorithms obtain scores of 0.998 and 0.996 for AUC, respectively. SVM shows poorer performance with the score 0.987 for AUC. With the help of the HeatMap and DataTable visualization tools we identified possible correlations between classification results and some characteristics of data.

Seismic demand assessment of semi-rigid steel frames at different performance points

  • Sharma, Vijay;Shrimali, Mahendra K.;Bharti, Shiv D.;Datta, Tushar K.
    • Steel and Composite Structures
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    • v.41 no.5
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    • pp.713-730
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    • 2021
  • The seismic performance of rigid steel frames is widely investigated, but that of semi-rigid (SR) steel frames are not studied extensively, especially for near-field earthquakes. In this paper, the performances of five and ten-story steel SR frames having different degrees of semi-rigidity are evaluated at four performance points in the four different deformation states, namely, the elastic, elasto-plastic, plastic, and near collapse states. The performances of the SR frames are measured by the response parameters including the maximum values of the top floor displacement, base shear, inter-story drift ratio, number of plastic hinges, and SRSS of plastic hinge rotations. These response parameters are obtained by the capacity spectrum method (CSM) using pushover analysis. The validity of the response parameters determined by the CSM is evaluated by the results of the nonlinear time history analysis (NLTHA) for both near and far-field earthquakes at different PGA levels, which are consistent with the performance points. Results of the study show that the plastic hinges of SR frame significantly increase in the range of plastic to near-collapse states for both near and far-field earthquakes. The effect of the degree of semi-rigidity is pronounced only at higher degrees of semi-rigidity. The predictions of the CSM are fairly well in comparison to the NLTHA.

Comparative Analysis of CNN Techniques designed for Rotated Object Classifiation (회전된 객체 분류를 위한 CNN 기법들의 성능 비교 분석)

  • Hee-Il Hahn
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.24 no.1
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    • pp.181-187
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    • 2024
  • There are two kinds of well-known CNN methods, the group equivariant CNN and the CNN using steerable filters, which have excellent classification performances for randomly rotated objects in image space. This paper describes their mathematical structures and introduces implementation methods. We implement them, including the existing CNN, which have the same number of filters, then compare and analyze their performances by simulating them with the randomly rotated MNIST. According to the experimental results, the steerable CNN, which shows a classification improvement over the others, has a relatively small number of parameters to learn, so performance degradation is relatively small even when the size of the training dataset is reduced.

The Effect of Idesolide on Hippocampus-dependent Recognition Memory

  • Lee, Hye-Ryeon;Choi, Jun-Hyeok;Lee, Nuribalhae;Kim, Seung-Hyun;Kim, Young-Choong;Kaang, Bong-Kiun
    • Animal cells and systems
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    • v.12 no.1
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    • pp.11-14
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    • 2008
  • Finding a way to strengthen human cognitive functions, such as learning and memory, has been of great concern since the moment people realized that these functions can be affected and even altered by certain chemicals. Since then, plenty of endeavors have been made to look for safe ways of improving cognitive performances without adverse side-effects. Unfortunately, most of these efforts have turned out to be unsuccessful until now. In this study, we examine the effect of a natural compound, idesolide, on hippocampus-dependent recognition memory. We demonstrate that idesolide is effective in the enhancement of recognition memory, as measured by a novel object recognition task. Thus, idesolide might serve as a novel therapeutic medication for the treatment of memoryrelated brain anomalies such as mild cognitive impairment(MCI) and Alzheimer's disease.

Effect of Choice Feeding on Performance, Gastrointestinal Development and Feed Utilization of Broilers

  • Yao, Junhu;Tian, Xiaoyan;Xi, Haibo;Han, Jincheng;Xu, Ming;Wu, Xiaobing
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.1
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    • pp.91-96
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    • 2006
  • The experiment was conducted to study the effect of choice feeding on growth performance, carcass quality, gastrointestinal development and feed utilization of 22-49 days old broilers. One hundred and forty four 22-day-old broilers were randomly allocated to 3 treatments with 4 replicates per treatment and 12 birds per replicate. Three feeding regimes are complete diet (control), ground corn and protein concentrate (treatment I), and soybean meal and balancer (treatment II). Protein concentrate is the residue part of complete diet without corn, and balancer is the residue part of complete diet without soybean meal. Treatment I and II are designed for the broilers to freely choose the two parts of diet. The results showed that: (1) broilers under choice feeding (treatment I and II) had lower performances compared with the control; (2) gastrointestinal development and the efficiency ratios that broilers converted dietary crude protein and lysine to body weight gain were improved in treatment I (p<0.05); (3) there were no significant differences in the apparent metabolizabilities of dietary dry matter, crude protein and gross energy, and deposition ratios of dietary nitrogen and energy, and carcass quality among three feeding regimes (p>0.05).

Current Limitation by Bi-2223 Bifilar Winding Coils

  • Ahn Min Cheol;Bae Duck Kweon;Park Dong Keun;Yang Seong Eun;Yoon Yong Soo;Ko Tae Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.7 no.2
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    • pp.31-34
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    • 2005
  • There are many kinds of high temperature superconducting (HTS) application using Bi-2223 tape which is the most commercialized HTS material. Also, resistive superconducting fault current limiters (SFCLs) have been developed using many kinds of superconducting material such as YBCO thin film, Bi-2212 bulk and so on. However, SFCL using Bi-2223 tape has never been developed. This paper deals with the feasibility study on SFCL using Bi-2223 wire. The over-current behaviors of Bi-2223 short-length sample were measured. To make the resistive SFCL, two small-scale bifilar winding modules using 7m Bi-2223 wire were fabricated; i.e. solenoid type bifilar coil and pancake type one. The short-circuit tests of the coils were successfully performed up to 16 V$_{rms}$ From these tests, the current limiting capabilities of Bi-2223 bifilar coils were confirmed and current limiting performances between two winding types were compared. In addition, the feasibility of resistive SFCL using another HTS wire, i.e. YBCO coated conductor, was also investigated.