• 한국정보과학회논문지:소프트웨어및응용
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• 제32권3호
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• pp.141-152
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• 2005

본 논문에서는 새로운 감성기반 영상검색방법을 제안한다. 서로 다른 색상, 명도, 도트크기를 나타내는 30개의 랜덤 패턴이 제시될 때 인간이 느끼는13가지 감성("like", "beautiful", "natural", "dynamic", "warm", "gay", "cheerful", "unstable", "light", "strong", "gaudy", "hard", "heavy") 평가 데이타로부터 질의 칼라코드와 질의 그레이코드로 명명한 질의 감성 표시자를 설계한다. 감성영상검색을 위해서 질의 감성을 선택하면 질의를 표현하는 칼라코드와 그레이코드가 선택되고 데이타베이스의 영상의 색상 정보를 나타내는 DB 칼라코드와 명도와 도트크기 정보를 나타내는 DB그레이코드값을 추출하여, 칼라코드간의 매칭과 그레이 코드간의 매칭을 통해 유사도를 판단한다. 또한 검색과정에 사용자의 의도를 반영하여 질의 칼라코드와 질의 그레이코드사이의 가중치와 칼라코드내의 가중치를 자동적으로 갱신하는 새로운 유사도 피드백 방법을 제안한다. 430개의 영상에 대해 실험한 결과 최초 질의에 대해 적합한 영상이 부적합한 영상보다 많았으며 유사도 피드백을 사용함에 따라 적합한 영상의 개수가 증가하였다.

• 감성과학
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• 제5권4호
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• pp.45-49
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• 2002

가상환경시스템은 매우 현실감 있는 정보를 제공할 수 있다는 점에서 산업, 의료, 교육훈련 등에 널리 사용되고 있다. 그러나 아직 많은 가상환경 시스템에서 부정적 요인으로 멀미, 시각피로, 방향감각 상실로 대표되는 cybersickness중세를 수반하고 있어 그 사용과 확산에 제약이 되고 있다. 이러한 cybersickness문제에 대응하기 위해서는 우선 이것을 객관적으로 측정, 평가할 수 있는 방법의 개발이 필요하다. 이러한 방법들 중의 하나로 신체동요의 정도를 평가 지표로 사용할 수 있다. 이번 연구에서는 45 명의 피실험자들을 대상으로 가상현실 운전시뮬레이터를 운전하기 전과 후의 신체동요 정도를 힘판(force platform)을 이용해 측정하였다. 특히 본 실험에 사용된 가상현실 운전시뮬레이터는 피실험자에게 운동판(motion platform)을 이용해 운동감을 제공할 수 있었고, 피실험자의 멀미 현상이 검지되면, 시야각을 1/3로 줄여주는 멀미 완화 피드백(feedback) 시스템이 연결되어 있었다. 그래서 motion의 제공여부와 feedback의 제공 여부도 실험의 독립변수로 추가하였다. 실험 결과, 가상현실 체험 후 유의한 차이는 아니나 피실험자들의 신체동요가 약간 증가하는 것이 관측되었다. motion과 feedback에 대한 분석에서는, 유일하게 motion을 제공하는 것이 제공 안할 때에 비해 좌우 방향의 신체동요가 더 적어지는 것으로 나타났다. 신체동요를cybersickness의 지표로 사용하기 위해서는 추후연구가 더 요청된다.

• 한국운동역학회지
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• 제27권1호
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• pp.75-81
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• 2017

Objective: The purpose of this study was to compare and analyze the kinematic variables and electromyography (EMG) findings that change with varying characteristics of crouch start and feedback provision, and to provide the fundamental data for record improvement in 400 mH. Method: Four short-distance runners participated in the experiment. The analyzed variables were elapsed time per interval, stride length, and muscle activities in three lower limb muscles. These variables were analyzed by using Kwon3d XP and Noraxon Myoresearch. The participants were subjected to three conditions, including two conditions that relate to the thrusting foot on the rear block and another condition pertinent to feedback provision. Results: In terms of a one-step interval, the elapsed time in condition A was longer than that in condition B, and the one after the feedback was the longest. The stride length of a one-step interval was the longest in condition A. The stride length of a two-step interval was the shortest in condition A. The muscle activity during a one-step interval showed differences in vastus medialis and medial gastrocnemius, with condition A being the highest. Conclusion: When the non-dominant left foot was located at the back, negative results were observed in terms of elapsed time and stride length. Moreover, an imbalance in muscle activity was observed between the left and right feet when the left foot was placed at the back. As a result, significant differences in elapsed time, stride length, and muscle activity were observed depending on the foot placed on the rear block. In conclusion, we identified the characteristics of crouch start in 400 mH, and a specialized program must be suggested.

• Molecules and Cells
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• 제39권4호
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• pp.299-309
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• 2016

We have previously reported the role of miR-217 in anti-cancer drug-resistance. miRNA array and miRNA hybridization analysis predicted miR-30a-3p as a target of miR-217. miR-30a-3p and miR-217 formed a negative feedback loop and regulated the expression of each other. Ago1 immunoprecipitation and co-localization analysis revealed a possible interaction between miR-30a-3p and miR-217. miR-30a-3p conferred resistance to anti-cancer drugs and enhanced the invasion, migration, angiogenic, tumorigenic, and metastatic potential of cancer cells in CAGE-dependent manner. CAGE increased the expression of miR-30a-3p by binding to the promoter sequences of miR-30a-3p, suggesting a positive feedback loop between CAGE and miR-30a-3p. miR-30a-3p decreased the expression of p53, which showed the binding to the promoter sequences of miR-30a-3p and CAGE in anti-cancer drug-sensitive cancer cells. Luciferase activity assays showed that p53 serves as a target of miR-30a. Thus, the miR-30a-3p-CAGE-p53 feedback loop serves as a target for overcoming resistance to anti-cancer drugs.

• Smart Structures and Systems
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• 제32권5호
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• pp.281-295
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• 2023

The purpose of this study is to demonstrate and verify the application of phase-control absolute-acceleration-feedback active tuned mass dampers (PCA-ATMD) to multiple-degree-of-freedom (MDOF) building structures. In addition, servo speed control technique has been developed as a replacement for force control in order to mitigate the negative effects caused by friction and inertia. The essence of the proposed PCA-ATMD is to achieve a 90° phase lag for a structure by implementing the desired control force so that the PCA-ATMD can receive the maximum power flow with which to effectively mitigate the structural vibration. An MDOF building structure with a PCA-ATMD and a real-time filter forming a complete system is modeled using a state-space representation and is presented in detail. The feedback measurement for the phase control algorithm of the MDOF structure is compact, with only the absolute acceleration of one structural floor and ATMD's velocity relative to the structure required. A discrete-time direct output-feedback optimization method is introduced to the PCA-ATMD to ensure that the control system is optimized and stable. Numerical simulation and shaking table experiments are conducted on a three-story steel shear building structure to verify the performance of the PCA-ATMD. The results indicate that the absolute acceleration of the structure is well suppressed whether considering peak or root-mean-square responses. The experiment also demonstrates that the control of the PCA-ATMD can be decentralized, so that it is convenient to apply and maintain to real high-rise building structures.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.1233-1236
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• 2003

This paper proposes a phase-locked loop (PLL) that achieves one-cycle lock acquisition by employing the lock-acquisition circuit (LAC). The LAC produces the initial analog voltage ( v$_{c}$ ) that corresponds to the input frequency. When the transfer curve of the LAC matches that of the voltage-controlled oscillator (VCO), one-cycle locking can be possible. By HSPICE simulations, the proposed LAC is proved to be applicable to any kinds of PLL [1][2][3].].

• 한국정밀공학회지
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• 제2권3호
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• pp.13-19
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• 1985

Servo의 안정성: Servo는 정상상태, 과도상태의 특성을 문제삼기에 앞서 먼저 안정하지 않으면 안된다. 제어량과 제어편차와 같이 제어 loop 속의 신호가 일정치에 수검하지 않는 현상을 불안정이라 한다. 제어량의 feedback을 정(positive)으로 하며 일반 목표치에는 수검하지 않고 제어편차는 단조롭게 정, 또는 부(negative)의 방향으로 발산한다. 이것은 접속 잘못에 의한 이상현상에 속한다. 이것에 대해서, 부 feeeback으로 하여도 제어 량이 목표치에 수검하지 않고 지속적으로 진동하는 불안현상도 있다. 이들은 선형발진과 비선형발진으로 구분할 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.967-970
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• 1999

A novel linear transconductor for low-voltage low-power signal processing is proposed. The transconductor consists of a pnp differential-pair and a npn differential-pair which are biased by local negative feedback. The simulation results show that the transcondcutor with transconductance of 50 $mutextrm{s}$ has a linearity error of 0.05% and the power dissipation is 2.44 ㎽ over an input linear range from -2V to +2V at supply voltage $\pm$3V.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (2)
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• pp.327-329
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• 1998

Up-Propagation is an algorithm for inverting and learning neural network generative models. Sensory input is processed by inverting a model that generates patterns from hidden variables using top-down connections. The inversion process is iterative, utilizing a negative feedback loop that depends on an error signal propagated by bottom-up connections. The error signal is also used to learn the generative model from examples. the algorithm is benchmarked against principal component analysis in experiments on images of handwritten digits.

• 대한전기학회논문지
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• 제31권7호
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• pp.18-24
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• 1982

We derived an optimal control of the Stochastic Bilinear Systems. For that we, firstly, formulated stochastic bilinear system and estimated its state when the system state is not directly observable. Optimal control problem of this system is reviewed on the line of three optimization techniques. An optimal control is derived using Hamilton-Jacobi-Bellman equation via dynamic programming method. It consists of combination of linear and quadratic form in the state. This negative feedback control, also, makes the system stable as far as value function is chosen to be a Lyapunov function. Several other properties of this control are discussed.