• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2612-2633
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• 2020

Due to the explosive growth of multimedia speech data, how to protect the privacy of speech data and how to efficiently retrieve speech data have become a hot spot for researchers in recent years. In this paper, we proposed an encrypted speech retrieval scheme based on long short-term memory (LSTM) neural network and deep hashing. This scheme not only achieves efficient retrieval of massive speech in cloud environment, but also effectively avoids the risk of sensitive information leakage. Firstly, a novel speech encryption algorithm based on 4D quadratic autonomous hyperchaotic system is proposed to realize the privacy and security of speech data in the cloud. Secondly, the integrated LSTM network model and deep hashing algorithm are used to extract high-level features of speech data. It is used to solve the high dimensional and temporality problems of speech data, and increase the retrieval efficiency and retrieval accuracy of the proposed scheme. Finally, the normalized Hamming distance algorithm is used to achieve matching. Compared with the existing algorithms, the proposed scheme has good discrimination and robustness and it has high recall, precision and retrieval efficiency under various content preserving operations. Meanwhile, the proposed speech encryption algorithm has high key space and can effectively resist exhaustive attacks.

• 정보교육학회논문지
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• 제11권1호
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• pp.29-38
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• 2007

최근 컴퓨터 교육에서 프로그래밍에 대한 관심이 높아지고 있다. 학습에서 논리력과 창의력의 요구가 늘어나고 있는 추세에 힘입어 컴퓨터 교육 분야에서도 프로그래밍 학습을 통한 논리력과 창의력을 함양하려는 다양한 시도가 이루어지고 있다. 프로그램은 알고리즘을 컴퓨터 언어로 구현한 것이므로 문제해결의 핵심은 논리적 해결 방법의 고안 즉, 알고리즘의 고안에 있다. 알고리즘의 중요성을 인식한다면 이제 알고리즘 교육에 대한 방향 정립을 위한 체계적 연구가 필요한 시점에 와 있다고 볼 수 있다. 지금까지 주로 정렬, 탐색과 같은 특정 문제를 중심으로 한 문제 종속적이고 개별적인 알고리즘 학습을 강조해 왔다. 본 논문에서는 문제 독립적, 집단적 성질을 고려하는 문제 해결의 개념적 유형이라는 관점에서 개념적 알고리즘(conceptual algorithm)을 정의한다. 개념적 알고리즘의 유형적 특성을 바탕으로 개별적, 문제 종속적인 기존의 알고리즘 교육과 구분되는 체계적, 문제 독립적, 알고리즘적인 문제 해결력을 지향하는 알고리즘 교육의 새로운 방향을 제안한다.

• 한국군사과학기술학회지
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• 제18권4호
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• pp.451-458
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• 2015

This paper handles self-collision avoidance for a rescue robot with redundant manipulators. In order to detect all available self-collisions in advance, minimum distances between arbitrary robot parts should be monitored in real-time. For the minimum distance estimation, we suggest a modified method from a previous skeleton algorithm which has less computation burden and realize collision avoidance based on a potential function using the proposed algorithm. The resultant command by collision avoidance should not disturb a given primary task, so null-space of joint solution from a CLIK is utilized for collision avoidance by a gradient projection method.

• 제어로봇시스템학회논문지
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• 제15권6호
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• pp.641-648
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• 2009

Currently several kinds of sensor localization methods have been developed for terrestrial wireless sensor networks. This study, in order to extend the field to underwater environments, a localization technique is studied for UWSNs (Underwater Wireless Sensor Networks). In underwater environments, RF (Radio Frequency) signal is not suitable for underwater usage because of extremely limited propagation. Because of that reason UWSNs should be constituted with acoustic modems. But, to realize underwater application, we can borrow many design principles from ongoing research for terrestrial environments. So, in this paper we introduce the modified localization algorithm using ToA method which is based on the terrestrial research. First of all, we study the localization techniques for terrestrial environments where we investigate possible methods to underwater environment. And then the appropriate algorithm is presented in the underwater usage. Finally the proposed underwater based localization algorithm is evaluated by using computer.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.93-94
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• 2010

This paper proposes maximum power point tracking(MPPT) control algorithm of PV system using a novel method. The proposed hybrid method is composed perturb and observe (PO) method and constant voltage(CV) method. PO method is simple to realize and CV method is possible to tracking MPP with low insolation. Response characteristics of proposed algorithm is compared to conventional PO method with insolation variation. This paper proves the validity of proposed algorithm through the analysis result.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1983-1989
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• 2005

Industrial robots are powerful, extremely accurate multi-jointed systems, but they are heavy and highly rigid because of their mechanical structure and motorization. Therefore, sharing the robot working space with its environment is problematic. A novel pneumatic artificial muscle actuator (PAM actuator) has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators. Its main advantages are high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks. The PAM is undoubtedly the most promising artificial muscle for the actuation of new types of industrial robots such as Rubber Actuator and PAM manipulators. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. In addition, the nonlinearities in the PAM manipulator still limit the controllability. Therefore, it is not easy to realize motion with high accuracy and high speed and with respect to various external inertia loads in order to realize a human-friendly therapy robot To overcome these problems a novel controller, which harmonizes a phase plane switching control method with conventional PID controller and the adaptabilities of neural network, is newly proposed. In order to realize satisfactory control performance a variable damper - Magneto-Rheological Brake (MRB) is equipped to the joint of the manipulator. Superb mixture of conventional PID controller and a phase plane switching control using neural network brings us a novel controller. This proposed controller is appropriate for a kind of plants with nonlinearity uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control using neural network and without regard for the changes of external inertia loads.

• 한국콘텐츠학회논문지
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• 제6권8호
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• pp.175-183
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• 2006

컴퓨터 그래픽스 관련 하드웨어의 비약적 발달은 고해상도의 영상을 모니터상에 표현할 수 있게 하였다. 이에 따라 자연 형태의 정밀한 렌더링을 요구하게 되어 높은 수준의 렌더링 알고리즘에 대한 연구가 활발히 진행되고 있다 렌더링 기법에는 사진과 같은 정확한 영상을 구현하는 포토 리얼리스틱 렌더링과, 실시간 빠른 렌더링을 가능케 하는 실시간 렌더링으로 나눌 수 있다. 본 논문에서는 포토 리얼리스틱 렌더링에서 사용되는 여러 기법 중 빛과 재질에 대한 Caustics 표현방법에 대하여 살펴보았다. 먼저 영화 속에서 Caustics가 어떻게 사용되고 표현되었는가를 분석하고 나아가 실제 렌더러를 이용하여 Caustics 효과를 구현한다. 렌더러를 이용한 실증적인 실험을 통하여 사용된 플러그인의 객관적인 기준 및 성능에 대하여 알아보고 구현을 위한 각 변수들의 사용 환경 등을 분석한다. 그 실험결과는 많은 렌더링 작업을 위한 자료로 활용되고 특성 및 성능에 대한 이해를 돕기 위한 데이터로 활용될 수 있을 것이다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.239-244
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• 2002

Even though, tanks are used at the many industry plants, it is very difficult to control the tank level without any overflow and shortage; moreover, cause of its complication of dynamics and nonlinearity, it's impossible to realize the accurate control using the mathematical model which can be applied to the various operation modes. However, the sliding mode controller(SMC) is known as having the robust variable structures for the nonlinear control systems with the parametric perturbations and with the sudden disturbances, but the auto-tuning of parameters was a problem. Therefore, in this paper, a Genetic Algorithm based Sliding Mode Controller (GA-SMC) for the precise control of the coupled tank level was tried. GA optimized the SMCs switching parameters easily and rapidly. The simulation results are shown that the tank level could be satisfactorily controlled with less overshoot and steady-stale error by the proposed GA-SMC.

• Journal of Information Processing Systems
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• 제17권2호
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• pp.411-425
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• 2021

In this paper, a vehicle recognition algorithm based on deep convolutional neural network and compression dictionary is proposed. Firstly, the network structure of fine vehicle recognition based on convolutional neural network is introduced. Then, a vehicle recognition system based on multi-scale pyramid convolutional neural network is constructed. The contribution of different networks to the recognition results is adjusted by the adaptive fusion method that adjusts the network according to the recognition accuracy of a single network. The proportion of output in the network output of the entire multiscale network. Then, the compressed dictionary learning and the data dimension reduction are carried out using the effective block structure method combined with very sparse random projection matrix, which solves the computational complexity caused by high-dimensional features and shortens the dictionary learning time. Finally, the sparse representation classification method is used to realize vehicle type recognition. The experimental results show that the detection effect of the proposed algorithm is stable in sunny, cloudy and rainy weather, and it has strong adaptability to typical application scenarios such as occlusion and blurring, with an average recognition rate of more than 95%.

• Journal of Advanced Marine Engineering and Technology
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• 제24권1호
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• pp.104-111
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• 2000

It is very difficult to maintain the desired tank level without any overflow or any shortage in a dangerous shemical plant and in a cooling one. Futhermore, because its dynamics are very complicate and nonlinear, it is impossible to realize the precise control using the accurate mathematical model which can be applied to the various peration modes. Nonetheless, the sliding mode controller(SMC) is known as having the robust variable structures for the nonlinear control system with the parametric perturbations and with the rapid disturbances. But the adaptive tuning algorithms for their parameters are not satisfactory. Therefore, in this paper, a Real Variable Elitist Genetic Algorithm based Sliding Mode Controller (RVEGA SMC) for the precise control of the coupled tank level was tried. The SMC's switching parameters were optimized easily and rapidly by RVEGA. The simulation results showed that the tank level could be satisfactorily controlled without and overshoot and any steady-state error by the proposed RVEGA SMC.