• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.11-18
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• 2010

Fuzzy c-means (FCM) is a simple but efficient clustering algorithm using the concept of a fuzzy set that has been proved to be useful in many areas. There are, however, several well known problems with FCM, such as sensitivity to initialization, sensitivity to outliers, and limitation to convex clusters. In this paper, global fuzzy c-means (G-FCM) and kernel fuzzy c-means (K-FCM) are combined to form a non-linear variant of G-FCM, called kernel global fuzzy c-means (KG-FCM). G-FCM is a variant of FCM that uses an incremental seed selection method and is effective in alleviating sensitivity to initialization. There are several approaches to reduce the influence of noise and accommodate non-convex clusters, and K-FCM is one of them. K-FCM is used in this paper because it can easily be extended with different kernels. By combining G-FCM and K-FCM, KG-FCM can resolve the shortcomings mentioned above. The usefulness of the proposed method is demonstrated by experiments using artificial and real world data sets.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.167-180
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• 1996

In the scalar processing oriented machine scalar operations must be performed for the vector processing as many as the number of vector components. So called a vector processing mechanism by the von Neumann operational principle. Accessing vector data hasto beperformed by theevery pointing ofthe instruction or by the address calculation of the ALU, because there is only a program counter(PC) for the sequential counting of the instructions as a memory accessing device. It should be here proposed that an access unit dimensionally to address components has to be designed for the compensation of the organizational hardware defect of the conventional concept. The necessity for the vector structuring has to be implemented in the instruction set and be performed in the mid of the accessing data memory overlapped externally to the data processing unit at the same time.

• Journal of IKEEE
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• v.24 no.4
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• pp.991-997
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• 2020

Reinforcement learning has been applied mainly in sequential decision-making problems. Especially in recent years, reinforcement learning combined with neural networks has brought successful results in previously unsolved fields. However, reinforcement learning using deep neural networks has the disadvantage that it is too complex for immediate use in the field. In this paper, we implemented path planning algorithm for mobile robots using Q-learning, one of the easy-to-learn reinforcement learning algorithms. We used real-time Q-learning to update the Q-table in real-time since the Q-learning method of generating Q-tables in advance has obvious limitations. By adjusting the exploration strategy, we were able to obtain the learning speed required for real-time Q-learning. Finally, we compared the performance of real-time Q-learning and DQN.

• Journal of the Korean Geographical Society
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• v.38 no.4
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• pp.575-590
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• 2003

It was the landscape phase that social relations were extended by production of landscapes during the 16C～17C. Core lineage groups in study area had extended socio-spatial nexus through making of the landscape of ‘authority-ostentation’(권력-과시형 경관) and of ‘kindness-civilization’(시혜ㆍ교화형 경관). Therefore they could gain a result that their power and authority took root in community perfectly. In the case of the Kims of Kwangsan(광산김씨), the first landscape of ‘kindness-civilization’ was Jungheodang(the learning room Jungheo), and next it was built Yangsungdang(the learning room Yangsung), and Imlijung(the pavilion Imli). Through this landscape production, the consciousness of scholastic genealogy was born, and this genealogy consciousness could be deepened and extended in regional scale. One more important feature in this phase is the point that the Kims of Kwangsan in Yeonsan area and the Songs of Unjin(은진송씨) in Hoiduk area could unite socially by the landscape production of ‘kindness-civilization type’ becoming intermediation. And these social union, that is to say, it do connote enlargement of the territoriality. It tells that community of ‘regional’ scale was formed by of core lineage groups of ‘local’ uniting each other.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1079-1086
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• 2012

In this paper, X-band 60 W Solid-State Power Amplifier with sequential control circuit and pulse width variation circuit for improve bias of SSPA module was designed. The sequential control circuit operate in regular sequence drain bias switching of GaAs FET. The distortion and efficiency of output signals due to SSPA nonlinear degradation is increased by making operate in regular sequence the drain bias wider than that of RF input signals pulse width if only input signal using pulsed width variation. The GaAs FETs are used for the 60 W SSPA module which is consists of 3-stage modules, pre-amplifier stage, driver-amplifier stage and main-power amplifier stage. The main power amplifier stage is implemented with the power combiner, as a balanced amplifier structure, to obtain the power greater than 60 W. The designed SSPA modules has 50 dB gain, pulse period 1 msec, pulse width 100 us, 10 % duty cycle and 60 watts output power in the frequency range of 9.2~9.6 GHz and it can be applied to solid-state pulse compression radar using pulse SSPA.

• Annual Conference on Human and Language Technology
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• 2017.10a
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• pp.333-337
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• 2017

본 논문에서는 개체명 인식과 언어 모델의 다중 학습을 이용한 한국어 개체명 인식 방법을 제안한다. 다중 학습은 1 개의 모델에서 2 개 이상의 작업을 동시에 분석하여 성능 향상을 기대할 수 있는 방법이지만, 이를 적용하기 위해서 말뭉치에 각 작업에 해당하는 태그가 부착되어야 하는 문제가 있다. 본 논문에서는 추가적인 태그 부착 없이 정보를 획득할 수 있는 언어 모델을 개체명 인식 작업과 결합하여 성능 향상을 이루고자 한다. 또한 단순한 형태소 입력의 한계를 극복하기 위해 입력 표상을 자소 및 형태소 품사의 임베딩으로 확장하였다. 기계 학습 방법은 순차적 레이블링에서 높은 성능을 제공하는 Bi-directional LSTM CRF 모델을 사용하였고, 실험 결과 언어 모델이 개체명 인식의 오류를 효과적으로 개선함을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.10C
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• pp.1010-1018
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• 2007

In this paper, we propose a companding scheme to effectively reduce PAPR (Peak-to-Average Power Ratio) of the OFDM (Orthogonal frequency Division Multiplexing) signals. The proposed scheme is basically based on the companding scheme to consider both complexity and Bit Error Rate (BER) performance, and composed of the clipping followed by the companding scheme. In the first step of the proposed scheme, some of peak signals which do not influence the BER even without them, are clipped. In the second step, the proposed scheme utilizes the ${\mu}-law$ companding to effectively reduce the PAPR. Simulation results show that the proposed clipped companding scheme can provide more PAPR reduction without degradation of the BER performance, as compare to the conventional ${\mu}-law$ companding.

• Restorative Dentistry and Endodontics
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• v.29 no.1
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• pp.13-22
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• 2004

본 연구는 치수강 상아질 부위 및 상아질 접착제 종류에 따른 결합 강도를 측정하고 이들 사이의 상관관계를 구명하고자 시행되었다 45개의 대구치를 포매 후, 대조군에서는 교합면 법랑질 제거 후 ＃600 SiC paper까지 순차연마하여 상아질을 노출시켰고, 실험군에서는 치수강 개방 후 1시간동안 NaOCl에 보관 후 axial wall과 pulpal floor를 노출시켰다. 노출된 상아질 면에 상아질 접착제를 적용한 후 Z-100을 충전한 다음 40초간 광중합하였다. 사용된 상아질 접착제는 Scotchbond Multi-Purpose와 Single Bond, Clearfil SE Bond였다. $37^{\circ}C$ 증류수에 24시간 보관 후, 저속 diamond saw를 이용하여 0.7mm 두께로 수직절단하고 고속 diamond point(#104)로 단면적 $1{mm}^2$가 되도록 시편을 제작하고, Universal testing machine에서 미세인장 결합강도를 측정하였다. 1. 모든 상아질 접착제의 미세인장강도는 대조군, axial wall군, pulpal floor군 순으로 감소하는 경향을 보였다. 2. 대조군에서 SM과 BB는 SE에 비해 유의성 있게 높은 결합강도를 나타내었다(p<0.05). 3. SM과 SB는 대조군에 비해 axial wall군과 pulpal floor군에서 유의성있게 낮은 결합강도를 보였으나, SE에서는 pulpal floor군만이 유의성 있게 낮은 결합강도를 보였다(p<0.05). 4. Axial wall군과 pulpal floor군에서는 상아질 접착제의 종류에 따른 유의차를 보이지 않았다. 5. 전자현미경 소견에서는 대조군에 비해 axial wall군과 pulpal floor군이 더 부드러운 접착 계면을 나타내었다. 혼성층의 두께는 결합강도의 감소와는 관련이 없었다.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.1-7
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• 2014

Site-specific incorporation of unnatural amino acids (SSIUA) into protein can be achieved in vivo by coexpression of an orthogonal pair of suppressor tRNA and engineered aminoacyl-tRNA synthetase (ARS) that specifically ligates an unnatural amino acid to the suppressor tRNA. As a step to develop the SSIUA technique in Escherichia coli, here we established a new 2-step screening system that can be used for selecting an ARS variant(s) that ligates an unnatural amino acid to a suppressor tRNA. A positive selection system consists of chloramphenicol acetyl transferase gene containing an amber mutation at the $27^{th}$ residue, and efficiently concentrated amber suppressible ARS with a maximum enrichment factor of $9.0{\times}10^5$. On the other hand, a negative selection system was constructed by adding multiple amber codons in front of a lethal gene encoding the control of cell death B toxin (ccdB) which acts as an inhibitory protein of bacterial topoisomerase II. Amber suppression of ccdB by an orthogonal pair of Saccharomyces cerevisiae tyrosyl-tRNA synthetase (TyrRS) and an amber suppressor tRNA significantly inhibits bacterial growth. This selection system was also able to efficiently remove amber suppressible ARS which could ligate natural amino acids to the suppressor tRNA. Thus, sequential combination of these two selection systems might be able to function as a powerful tool for selecting an ARS variant that specifically ligates an unnatural amino acid to the suppressor tRNA from an ARS mutant pool.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.748-754
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• 2000

A novel single feed wide band CP stacked microstrip antenna using crossed slots has been designed, fabricated and measured. For the single rediating element the designed 10dB return loss bandwidth is 34.5%99.45~13.54 GHz), 3dB axial ratio bandwidth is 18.7%(11.17~13.39GHz), and 6 dB gain bandwidth is 29%(10.21~13.64GHz). For the 2$\times$2 array designed using a sequential rotation method, the 10dB return loss bandwidth is 35.9%(9.69~13.94GHz), 3dB axial ratio bandwidth is 34.6GHz (9.93~14.03GHz), and 6dB gain bandwidth is 27.4%(10.35~13.6GHz). For the fabricated 8$\times$8 array antenna, the 10dB return loss bandwidth is 27.3%(10.17~13.41GHz), 3dB axial ratio bandwidth is 27.9GHz(10.1~13.4GHz), and the radiation pattern is good agreement with theory. This antenna can be used for broadband applications for communications or broadcasting in Ku band.