• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2689-2708
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• 2016

Multi-camera systems which integrate two or more low-cost digital cameras are adopted to reach higher ground coverage and improve the base-height ratio in low altitude remote sensing. To guarantee accurate multi-camera integration, the geometric relationship among cameras must be determined through platform calibration techniques. This paper proposed a combined two-step platform calibration method. In the first step, the static platform calibration was conducted based on the stable relative orientation constraint and convergent conditions among cameras in static environments. In the second step, a dynamic platform self-calibration approach was proposed based on not only tie points but also straight lines in order to correct the small change of the relative relationship among cameras during dynamic flight. Experiments based on the proposed two-step platform calibration method were carried out with terrestrial and aerial images from a multi-camera system combined with four consumer-grade digital cameras onboard an unmanned aerial vehicle. The experimental results have shown that the proposed platform calibration approach is able to compensate the varied relative relationship during flight, acquiring the mosaicing accuracy of virtual images smaller than 0.5pixel. The proposed approach can be extended for calibrating other low-cost multi-camera system without rigorously mechanical structure.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.597-597
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• 2013

The resistive switching behaviors of Pt nanodisk on Nb-doped SrTiO3 single-crystal have been studied with conductive atomic force microscopy in ultra-high vacuum. The nanometer sizes of Pt disks were formed by using self-assembled patterns of silica nanospheres on Nb-doped SrTiO3 single-crystal semiconductor film using the Langmuir-Blodgett, followed by the metal deposition with e-beam evaporation. The conductance images shows the spatial mapping of the current flowing from the TiN coated AFM probe to Pt nanodisk surface on Nb：STO single-crystal substrate, that was simultaneously obtained with topography. The bipolar resistive switching behaviors of Pt nanodisk on Nb：STO single-crystal junctions was observed. By measuring the current-voltage spectroscopy after the forming process, we found that switching behavior depends on the charging and discharging of interface trap state that exhibit the high resistive state (HRS) and low resistive state (LRS), respectively. The results suggest that the bipolar resistive switching of Pt/Nb:STO single-crystal junctions can be performed without the electrochemical redox reaction between tip and sample with the potential application of nanometer scale resistive switching devices.

• 한국컴퓨터그래픽스학회논문지
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• 제4권2호
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• pp.1-13
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• 1998

캐릭터 애니메이션의 가장 중요한 목표는 효율적으로 캐릭터의 동작을 제어하는 것이다. 지금까지 인간 보행 애니메이션을 위한 많은 기법들이 제안되었고, 파라미터 보간이나 동작 데이터 매핑 을 사용하여 지친 걸음이나 활기찬 걸음과 같은 보행의 감정을 표현하는 기법도 제안되었다. 본 논문은 하나의 다리를 가진 평면 뜀뛰기 모델에 기반한 인간 주행 모델을 제시한다. 본 논문의 기법은 동작 최적화를 위해 유전자 프로그래밍을 사용하며 다양한 캐릭터 모델에 쉽게 적용될 수 있다. 본 논문은 에너지 최소화 기법을 확장하여 감정 표현을 위한 파라미터 설정에 따라 다양한 동작을 생성할 수 있도록 한다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2015년도 하계학술대회
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• pp.75-77
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• 2015

디스플레이 해상도가 지속적으로 고해상화가 되면서, 기존 저해상도 영상을 고해상도 디스플레이 크기에 맞춰 해상도를 키우는 기법인 초해상화(super-resolution, SR) 기법에 많은 관심이 쏟아지고 있으며 이에 대한 많은 초해상화 논문들이 게재되었다. 이 중 현재 최상 품질의 고해상도 영상을 복원하는 한 초해상화 기법은, 입력 받은 저해상도 영상을 자가 예제(self-examples)로 사용하여 선형 매핑(linear mapping)을 통해 점진적으로 여러 레벨(level)를 거쳐 조금씩 키우는 방법이다. 이때 각 레벨마다 기존 저해상도 영상 크기로 반복적으로 줄여 오차를 줄이는 역투영법(back-projection)을 사용하는데, 이 방법은 처리된 영상에 시각적 품질을 낮추는 링 아티팩트(ringing artifacts)를 생산하며, 이는 매 레벨마다 계속 누적이 되어 고해상도 결과 이미지 품질에 악영향을 미치는 단점이 있다. 이를 보완하기 위해, 본 논문에서는 저해상도 정지 영상을 고해상도 정지 영상으로 점진적으로 키울 때 일반적인 역투영법 대신 비국소적 평균법(non-local means, NLM) 기반 역투영법을 사용하는 초해상화 기법을 제안한다. 제안하는 기법은 매 레벨마다 생기는 링 아티팩트를 효과적으로 제거하여 높은 시각적 품질의 고해상도 영상을 복원할 수 있게 한다. 실험을 통해 제안된 초해상화 기법을 사용 시 기존 초해상화 기법보다 향상된 고품질 고해상도 영상 복원이 가능한 것을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제28권8호
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• pp.1299-1312
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• 2004

This paper suggests the simple form of a fuzzy PID controller and describes the design principle, tracking performance, stability analysis and changes of parameters of a suggested fuzzy PID controller. A fuzzy PID controller is derived from the design procedure of fuzzy control. It is well known that a fuzzy PID controller has a simple structure of the conventional PID controller but posses its self-tuning control capability and the gains of a fuzzy PID controller become nonlinear functions of the inputs. Nonlinear calculation during fuzzification, defuzzification and the fuzzy inference require more time in computation. To increase the applicability of a fuzzy PID controller to digital computer, a simple form of a fuzzy PID controller is introduced by the backward difference mapping and the analysis of the fuzzy input space. To guarantee the BIBO stability of a suggested fuzzy PID controller, ‘small gain theorem’ which proves the BIBO stability of a fuzzy PI and a fuzzy PD controller is used. After a detailed stability analysis using ‘small gain theorem’, from which a simple and practical method to decide the parameters of a fuzzy PID controller is derived. Through the computer simulations for the linear and nonlinear plants, the performance of a suggested fuzzy PID controller will be assured and the variation of the gains of a fuzzy PID controller will be investigated.

• Progress in Superconductivity
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• 제8권1호
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• pp.8-15
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• 2006

The size of the superconducting domains and the critical current density inside these domains have to be enhanced for most of cryomagnetic applications of melt-textured YBCO bulks. To enlarge the size of the domains we studied the multi-seeding technique based on a well-established procedure for preparing high quality YBCO monoliths using self-made SmBCO seeds. The distance between the seeds was optimised as a result of the investigation of the effects of various seed distances on the characteristics of the grain boundary Junctions. The influences of a-b plane intersections and c-axis misalignments were researched. Thereby, a small range of tolerance of the misorientations between the seed crystals was found. Field mapping was applied to control the materials quality and the superconductor's grain structure was investigated using polarisation microscopy. YBCO function elements with iou. seeds in a line and an arrangement of making type (100)/(100) and (110)/(110) boundary junctions, respectively, were processed. The trapped field profile in both sample types shows single domain behaviour. To demonstrate the potential of the multi-seeding method a ring-shaped sample was processed by placing sixteen seeds in a way to make both (100)/(100) and (110)/(110) grain junctions at the same time. The results up to now are very promising to prepare large single domain melt-textured YBCO semi-finished products in complex shapes.

• 한국정밀공학회지
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• 제9권4호
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• pp.22-35
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• 1992

In highly automated machining centers, intelligent sensor fddeback systems are indispensable on order to monitor their operations, to ensure efficient metal removal, and to initate remedial action in the event of accident. In this study, an on-line tool wear detection system for thrning operations is developed, and experimentally evaluated. The system employs multiple sensors and the signals from these sensors are processed using a multichannel autoegressive (AR) series model. The resulting output from the signal processing block is then fed to a previously tranied artificial neural network (multiayered perceptron) to make a final decision on the state of the cutting tool. To learn the necessary input/output mapping for tool wear detection, the weithts and thresholds of the network are adjusted according to the back propagation (BP) method during off-line training. The results of experimental evaluation show that the system works well over a wide range of cutting conditions, and the ability of the system to detect tool wear is improved due to the generalization, fault-tolearant and self-ofganizing properties of the neural network.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.740-743
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• 1998

This paper presents an optimization algorithm for a stable Dynamic Neural Network (DNN) using genetic algorithm. Optimized DNN is applied to a problem of controlling nonlinear dynamical systems. DNN is dynamic mapping and is better suited for dynamical systems than static forward neural network. The real time implementation is very important, and thus the neuro controller also needs to be designed such that it converges with a relatively small number of training cycles. SDNN has considerably fewer weights than DNN. The object of proposed algorithm is to the number of self dynamic neuron node and the gradient of activation functions are simultaneously optimized by genetic algorithms. To guarantee convergence, an analytic method based on the Lyapunov function is used to find a stable learning for the SDNN. The ability and effectiveness of identifying and controlling, a nonlinear dynamic system using the proposed optimized SDNN considering stability' is demonstrated by case studies.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(4)
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• pp.101-106
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• 1996

For the application of the neutron flux mapping, an accurate calculation of the sensitivity is required because the sensitivity is proportional to the neutron flux density. Sensitivity is defined as the current per unit length per unit neutron flux and it mainly depends on the depression factor(f), the escape probability from the emitter($\varepsilon$1) and the charge build-up factor of the insulator layer(c). A Monte Carlo simulation was accomplished to calculate the sensitivity of rhodium emitter material and alumina(Al$_2$O$_3$) insulator with a cylindrical geometry, based on the (n,${\beta}$) interaction and on other interaction including the secondary electron generation for the more accurate estimation of the sensitivity. From the simulation results, factors fur the sensitivity were accurately calculated and compared with other theoretical and experimental values. In addition, the sensitivity linearly increases and saturates as the emitter radius increases. The accomplished method is useful in the analysis for the change of SPND sensitivity as a function of burn-up and in the optimum design of SPND.

• 건축역사연구
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• 제8권1호
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• pp.53-62
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• 1999

Modernism in architecture is a very complex and contradictory phenomena. So much so that it has been defined in various ways throughout the history, depending on one's position in the cultural and historical circumstances. It is thus necessary to map out the various concepts of modernism and their relationships in order to have a more comprehensive understanding of modern architecture. This paper attempts to define the various positions as functionalism, formalism and artistic avant-gardism, and to trace their history from the early twentieth century to the present. The change of the concept of modernism from functionalism to artistic avant-gardism seems a logical process in the history of western modem culture. The tendency of contemporary architecture to be more abstract and self referential artistic practice reflects the fragmentation of modern culture and the separation of art and technology. The validity of this position, of course, depends on how one evaluates the role of modern art in the situation of modern culture. It could be viewed either negatively or positively. However, this position is problematic in that it disregards the fundamental differences between architecture and other arts and distanced architecture farther from its material base. Given this historical perspective on the concept of modernism, modernism in Korea should not viewed simply identical to the western modernism, nor should western modernism be imported uncritically. The characteristics of her modernization and their differences from the west should be considered, along with the different status and role of architecture in korean modern society.