• 호남수학학술지
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• 제45권2호
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• pp.231-247
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• 2023

In this study, we mean that timelike q-helices are curves whose q-frame fields make a constant angle with a non-zero fixed axis. We present the necessary and sufficient conditions for timelike curves via the q-frame to be q-helices in Lorentz-Minkowski 3-space. Then we find some results of the relations between q-helices and Darboux q-helices. Furthermore, we portray Darboux q-helices as special curves whose Darboux vector makes a constant angle with a non-zero fixed axis by choosing the curve as one of the types of q-helices, and also the general case.

• Journal of information and communication convergence engineering
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• 제8권1호
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• pp.45-50
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• 2010

EPCglobal Class-1 Gen-2 standard proposed Q-algorithm to select a frame size for the next query round. Q-algorithm calculates the frame size without estimating the number of tags. Therefore, the Q-algorithm has advantage that the reader's algorithm is simpler than other algorithms. However, it is impossible to allocate the optimized frame size. Also. the conventional Q-algorithm does not define an optimized parameter value C for adjusting the frame size. In this paper, we propose a modified Q-algorithm with the tag number estimation scheme, and evaluate the performance with computer simulations.

• Journal of information and communication convergence engineering
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• 제8권3호
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• pp.307-311
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• 2010

EPCglobal Class-1 Gen-2 protocol has been proposed for UHF-band RFID systems. In Gen-2 standard, Q-algorithm was proposed to select a frame size for the next query round without estimating the number of tags. Therefore, the Q-algorithm has advantage that the reader's algorithm is simpler than other algorithms. However, it is impossible to allocate the optimized frame size. Also, the original Q-algorithm did not define an optimized parameter C for adjusting the frame size. In this paper, we propose an adaptive Q-algorithm with the different parameter $C_c$ and $C_i$ in accordance with the status of reply slot. Simulation results show that the proposed adaptive Q-algorithm outperforms the original Gen-2 Q-algorithm.

• 한국정보통신학회논문지
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• 제14권5호
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• pp.1133-1138
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• 2010

EPCglobal Class-1 Gen-2 충돌방지 기법에서는 Q-알고리즘을 통하여 질의 라운드의 프레임 크기를 결정한다. Q-알고리즘은 리더의 식별영역 내에 있는 태그의 수를 추정하지 않고 슬롯의 상태만을 이용하여 질의 라운드의 프레임 크기를 계산하므로 알고리즘에 비하여 리더의 알고리즘이 단순한 장점이 있다. 반면, 실제 태그의 수를 반영한 최적화된 프레임 크기를 할당할 수 없는 단점이 있다. 또한, 기존의 Q-알고리즘에서는 프레임 크기를 조절하기 위한 매개변수인 C값이 정해져 있지 않다. 따라서 본 논문에서는 매 질의 라운드마다 태그의 수를 추정하여 Q-알고리즘의 매개변수 C값을 결정하는 기법을 제안하고, 이에 대한 성능분석을 한다.

• 한국정보통신학회논문지
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• 제13권12호
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• pp.2541-2546
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• 2009

EPCglobal Class-1 Gen-2 충돌방지 기법에서는 Q-알고리즘을 통하여 질의 라운드의 프레임 크기를 결정한다. Q-알고리즘은 리더의 식별영역 내에 있는 태그의 수를 추정하지 않고 슬롯의 상태만을 이용하여 질의 라운드의 프레임 크기를 계산하므로 다른 DFSA 알고리즘에 비하여 리더의 알고리즘이 단순한 장점이 있다. 반면, Q-알고리즘에서는 프레임 크기를 조절하기 위한 매개변수의 최적화 된 값은 정의하지 않고 있다. 따라서 본 논문에서는 시뮬레이션을 통하여 최소의 식별시간을 얻을 수 있는 최적의 매개변수 값을 제안하였다.

• Journal of Power Electronics
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• 제8권1호
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• pp.91-100
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• 2008

The d-q harmonic detecting algorithms are dominant methods to generate current references for active power filters (APF). They are often implemented in the synchronous frame and time domain. This paper researches the frequency characteristics of d-q synchronous transformations, which are closely related to the analysis and design issues of control system. Intuitively, the synchronous transformation is explained with amplitude modulation (AM) in this paper. Then, the synchronous filter is proven to be a time-invariant and linear system, and its transfer function matrix is derived in the stationary frames. These frequency-domain models imply that the synchronous transformation has an equivalent effect of frequency transformation. It is because of this feature, the d-q method achieves band-pass characteristics with the low pass filters in the synchronous frame at run time. To simplify these analytical models, an instantaneous positive-negative sequence frame is proposed as expansion of traditional symmetrical components theory. Furthermore, the synchronous filter is compared with the traditional bind-pass filters based on these frequency-domain analytical models. The d-q harmonic detection methods are also improved to eliminate the inherent coupling effect of synchronous transformation. Typical examples are given to verify previous analysis and comparison. Simulation and experimental results are also provided for verification.

• Journal of information and communication convergence engineering
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• 제7권4호
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• pp.469-474
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• 2009

Q-algorithm is proposed at EPC global Class-1 Generation-2 RFID systems to determine the frame size of next query round. In Q-algorithm, the reader calculates the frame size without estimating the number of tags. But, it uses only the slot conditions: empty, success, or collision. Therefore, it wastes less computational cost and is simpler than other algorithms. However, the constant parameter C value, which is used for calculating the next frame size, is not optimized. In this paper, we propose the optimized C values of Q-algorithm according to the number of tags within the identification range of reader through a lot of computer simulations.

• 한국전자통신학회논문지
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• 제8권9호
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• pp.1325-1332
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• 2013

비디오 코딩에서 GOP의 첫 번째 프레임인 I 프레임은 많은 비트를 발생시키는 인트라 모드로 압축되고 다음 프레임의 인터 모드 압축에 사용되기 때문에 I 프레임을 위한 초기 QP 값은 I 프레임뿐만 아니라 이후 프레임에도 영향을 주게 된다. 이전 연구에서 정확한 초기 QP 계산을 위해 I 프레임의 압축 후 비트량을 분석하였고, GOP의 PSNR을 최대로 하는 I 프레임의 비트량이 GOP에 상관없이 일정한 값을 가짐을 보였다. 본 논문에서는 기존 방법을 이용하여 최적의 I 프레임 비트량을 계산한 후 이 값을 이용하여 초기 QP를 계산할 수 있는 R-Q 모델을 제안한다. 제안하는 모델은 간단하면서도 적응적으로 모델 파라미터를 수정하기 때문에 실시간 응용에 적합하다. 실험 결과는 제안하는 모델이 초기 QP 계산에 필요한 트래픽 특성을 잘 반영하고 있으며 또한 실시간으로 모델 파라미터를 구하는 방법도 효과적으로 작동함을 보여준다.

• 복식
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• 제63권4호
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• pp.118-131
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• 2013

The purpose of this study is to take a look at the fashion frame of Korean women in their twenties and thirties to sort the actual fashion image and the ideal fashion image according to the fashion frame of Korean women in their twenties and thirties, and also to find out the standards and features that divide such a classification. For this study, we used the Q method, which is valued as an effective way to assess subjectivity. This helps to objectively classify the perception the fashion images of and the response to them as well. The analyzed materials were divided into two actual fashion frames and two ideal fashion frames, and classified them into 12 fashion image types in total, that is, six actual fashion images and six ideal fashion images, and we named each type of the fashion images and analyzed the features of each fashion image type through the in-depth Q workshop in which 14 professionals participated. The results of this study are as follows: First, the actual fashion frames of Korean women in their twenties and thirties was largely divided into 'Fashion Gold Girl', the fashion frame of mainstream and 'Indi-idol', the fashion frame of subcultures, and this was further divided into six fashion image types: 'Basic Casual', 'Vintage Performer', 'Easy Chic', 'Ladies' Look', 'City Office Girl' and 'Club Mania'. Second, the ideal fashion frame of Korean women in their twenties and thirties was divided into 'Urban Refinement', the fashion frame of the mainstream and 'Mismatched Style', the fashion frame of subcultures. It was also divided into six fashion image types: Power Fashion', 'Fashion Conservative', 'Semi-culture', 'Fashion Otaku', 'Sweet Darling' and 'Fashion Panic'. Third, The characteristics of the fashion images' colors are recognizable according to the type of fashion images.

• Kyungpook Mathematical Journal
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• 제47권3호
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• pp.381-392
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• 2007

In 1906, da Rios, a student of Leivi-Civita, wrote a master's thesis modeling the motion of a vortex in a viscous fluid by the motion of a curve propagating in $R^3$, in the direction of its binormal with a speed equal to its curvature. Much later, in 1971 Hasimoto showed the equivalence of this system with the non-linear Schr$\ddot{o}$dinger equation (NLS) $$q_t=i(q_{ss}+\frac{1}{2}{\mid}q{\mid}^2q$$. In this paper, we use the same idea as Terng used in her lecture notes but different technique to extend the above relation to the case of $R^3$, and obtained an analogous equation that $$q_t=i[q_{ss}+(\frac{1}{2}{\mid}q{\mid}^2+1)q]$$.