• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.1072-1073
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• 2023

본 논문은 지진해일로 인한 인명피해를 감소시키고 항만 미관을 증진시킬 수 있는 "항만 지진해일 인명피해 감소 위한 디지털 사이니지 라이프가드"를 제안한다. 본 논문이 제안하는 특징은 다음과 같다. 첫째, 지진 해일 발생 시 라이프가드 내부 공간을 개방해 해일로부터 사람들을 보호한다. 둘째, 라이프가드 외부 디스플레이에 항만 홍보, 작업 정보, 지진해일 대피안내, 광고 영상을 재생한다. 셋째, 안전 통합관제센터 SW와 근로자/일반인용 모바일 앱을 통해 라이프가드의 동작 제어, 현황 조회를 수행한다. IoT기술과 연동된 디지털 사이니지 시스템을 통해 일상 안전 정보 제공 및 비상시 인명 보호를 통한 높은 안전 수준을 유지할 것으로 기대된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.328-329
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• 2007

본 논문은 로봇과 같이 외부 음향잡음에 노출되어 있는 상황 하에서, 대면하고 있는 사람이 입술을 움직여 발성하는 경우에만 음성인식 기능이 수행되도록 하기 위한 방안의 일환으로, 입술움직임 영상을 보다 정확히 추적하기 위한 테스트 환경 구현에 관한 것이다. 음성구간 검출과정에서 입술움직임 영상 추적결과의 활용여부는 입술움직임을 얼마나 정확하게 추적할 수 있느냐에 달려있다. 이를 위해 영상 프레임율 동적 제어, 칼라/이진영상 변환, 순간 캡쳐, 녹화 및 재생기능을 구현함으로써, 다각적인 방향에서 입술움직임 영상 추적기능을 확인해 볼 수 있도록 하였다. 음성/영상기능을 연동시킨 결과 약 99.3%의 연동성공율을 보였다.

• Journal of KIISE:Information Networking
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• v.34 no.5
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• pp.379-388
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• 2007

With proliferation of computer and wireless network technology, it is common to access Internet through wireless network using mobile device. Ratio of using streaming media out of many applications through Internet is increasing not only in wired network but also in wireless network. Streaming media is much bigger than other contents and requires more network bandwidth and more computing resources. However mobile devices hate relatively poor computing resource and low network bandwidth. If media streaming service is provided for mobile devices without any consideration about network bandwidth and computing power, it is hard for the client to get high qualify service. Since mobile device is supported with very limited energy from the battery, media streaming should be adjusted to varying energy state of mobile device in realtime to ensure complete playback of streaming media. In this paper, we propose DFRC to provide high qualify service to mobile client through wireless network by controlling the number of frames transmitted to client based on computing resource and energy state of mobile device.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2930-2942
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• 1998

POTS(Plain Old Telephone Service) is the most popular telecommunication service and should be supported in the future BUSDN that is based on the ATM technology. Therefore, the interwoking system between ATM network and PSTN is needed, which provides telephone service between client of ATM network and subscriber of PSTN. In this paper, the interwoking system between ATM network and PSTN is designed and implemented. The interwoking system consists of PSTN I/F module, signaling processing module, voice sampling module, voice regeneration module, transmission module and ATM I/F module. The PSTN I/F module and ATM I/F module are implemented using the existing commercial H/W products. However, the other 4 modules are implemented for the WIN95 environments by software. The test environment is also implemented and the interworking system is operated without problems.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.305-312
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• 2005

In this thesis, Lohmann's algorithm and FFT (fast Fourier transform) are used to synthesize binary-phase holograms. FFT computing is carried out for the calculation of complex wavefronts of $128{\times}128$ sampling points of an object that is numerically specified. Then using the Lohmann's algorithm, the amplitude and the phase of complex wavefronts are encoded in binary holograms on each sampling points. PC (personal computer) and laser printer are used to plot binary-phase holograms and CGH (computer generated holograms) films are obtained from this plot by photographic reduction. Holographic images of numerically specified objects are reconstructed from the He-Ne laser and the inverse Fourier optics system. We estimate the quality of holographic images according to the sampling number, application of random phase, amplitude clipping and bleaching the CGH film. We derive optimized conditions to reconstruct better holographic images and to reduce the speckle noise. FFT and Lohmann's algorithm are implemented with MS Visual BASIC 6.0 for the programming of binary-phase hologram.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.3
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• pp.34-40
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• 2002

In this paper, a new encryption method for a binary image using Phase modulation and Fourier transform is proposed. For decryption we use the characteristics of square law detector. In encryption process, a key image is obtained by phase modulation of 256 level random pattern and its Fourier transformation, and input image is encrypted by Fourier transforming the multiplication of the phase modulated random pattern and phase modulated input image. The encrypted image and key image have only phase information, so they can not be copied or counterfeited and the original image can not be decrypted without the key image. To reconstruct the original image, each phase mask of the key image and the encrypted image must be placed on each path of the Mach-Zehnder interferometry with Fourier transform lens and the output image is obtained in the form of intensity in the CCD(Charge Coupled Device) camera. The real-time decryption is possible in the proposed system by use of a LCD as a phase modulator and a CCD camera as an intensity detector. The proposed method shows a good performance in the computer simulation and optical experiment as an encryption scheme.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.331-336
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• 2011

The three-dimensional complex curvature of the airfoil complicates the manufacture and repair of gas-turbine components. As a result of the developments in computer technology since the early 1990s, CNC-based technologies for machine tools and related programs have been increasingly applied in the gas turbine industry. In particular, fiveaxis simultaneous machines with adaptive functions have proven its excellent flexibility and productivity due to the capability in determining the 3D data from the unknown curvature. A well-organized robot system with eight-axis simultaneous control can lead to powerful standardization and high productivity. We summarize and review CNC technologies and their applications in the gas turbine industry, with a discussion of the manufacture and repair of gas turbine parts.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.2
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• pp.41-48
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• 2018

Until now, various studies on anti-phishing have been conducted. The most typical anti-phishing method is a method of collecting URL information of a phishing site in advance and then detecting phishing by comparing the URL of the visited site with the previously stored information. However, this blacklist-based anti-phishing method can not detect new phishing sites. For this reason, various anti-phishing authentication protocols have been proposed. but these protocols require a public key and a private key. In this paper, we propose a password-based mutual authentication protocol that is safe for phishing attacks. In the proposed protocol, the mutual authentication between the client and the server is performed through the authentication message including the password information. The proposed protocol is safe to eavesdropping attack because the authentication message uses the hash value of the password, not the original password, And it is safe to replay attack because different messages are used every time of authentication. In addition, since mutual authentication is performed, it is safe for man-in-the-middle attack. Finally, the proposed protocol does not require a key issuance process for authentication.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.110.2-110.2
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• 2011

일본 Sanyo 사에 의해서 획기적으로 HIT 태양전지가 개발된 바 있다. 이러한 HIT 태양전지는 기존의 확산-접합 Si 태양전지에 비해서 저비용 고효율의 장점을 갖는다: 22% 이상의 변환효율, $200^{\circ}C$ 이하의 공정온도, 낮은 태양전지 온도 의존도, 높은 개방전압. 한편 Sanyo사의 HIT 태양전지는 n-형 Si 웨이퍼를 이용한 반면에, 최근 미국 National Renewable Energy Laboratory는 p-형 Si 웨이퍼를 이용해서 변환효율 19% 대의 HIT 태양전지를 개발한 바 있다. 그 동안 지속적으로 p-형 Si HIT 태양전지를 고효율화하기(< 22%) 위해서 많은 노력이 진행되어 왔지만 이와 같은 노력에도 불구하고 아직 p-형 HIT는 n-형 HIT 태양전지에 비해서 다소 성능면에서 떨어져 있다. 본 연구는 n- 및 p-형 실리콘 웨이퍼로 구성된 HIT 태양전지의 물리적인 차이점에 초점을 맞추고, 결정 및 비정질 실리콘 층의 역할에 대해서 연구하였다. 특히 태양전지 효율을 향상시키는 요소들로서 결정 실리콘의 불순물 준위(n- 및 p-형) 또는 비저항, 비정질 실리콘으로 구성된 emitter 층, intrinsic 층, 경계면이 고려되었다. 그리고 이러한 요소들이 HIT 태양전지에 미치는 영향을 조사하기 위해서 AMPS-1D 컴퓨터 프로그램을 사용하였고, 이를 통해서 HIT 태양전지의 결정 및 비정질 실리콘 층의 역할을 물리적 정량적으로 분석하였다. 본 연구에 적용되는 HIT는 ITO/a-Si:H(p+)/a-Si:H(i)/c-Si(n)/a-Si:H(i)/a-Si:H(n+) 및 ITO/a-Si:H(n+)/a-Si:H(i)/c-Si(p)/a-Si:H(i)/a-Si:H(p+)의 구조로서 다음과 같은 태양전지 특성을 갖는다: n-형 HIT의 경우, fill factor ~ 0.78, 단락전류밀도 ~ 38.1 $mA/cm^2$, 개방전압 0.74 V, 변환효율 22.3 % (그리고 p-형 HIT의 경우, fill factor ~ 0.76, 단락전류밀도 ~ 36.5 $mA/cm^2$, 개방전압 0.69 V, 변환효율 19.4 %).

• Journal of KIISE:Software and Applications
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• v.29 no.3
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• pp.145-155
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• 2002

In content-based image retrieval (CBIR), most conventional approaches assume a linear relationship between different features and require users themselves to assign the appropriate weights to each feature. However, the linear relationship assumed between the features is too restricted to accurately represent high-level concepts and the intricacies of human perception. In this paper, a neural network-based image retrieval (NNIR) model is proposed. It has been developed based on a human-computer interaction approach to CBIR using a radial basis function network (RBFN). By using the RBFN, this approach determines the nonlinear relationship between features and it allows the user to select an initial query image and search incrementally the target images via relevance feedback so that more accurate similarity comparison between images can be supported. The experiment was performed to calculate the level of recall and precision based on a database that contains 1,015 images and consists of 145 classes. The experimental results showed that the recall and level of the proposed approach were 93.45% and 80.61% respectively, which is superior than precision the existing approaches such as the linearly combining approach, the rank-based method, and the backpropagation algorithm-based method.