• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.535-542
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• 2006

In this study, removals of 1-naphthol by oxidative-coupling reaction using birnessite, one of natural Mn oxides present in soil, was investigated in various experimental conditions(reaction time, Mn oxide loadings, pH, etc). Removal efficiency of 1-naphthol by birnessite was high in all the experimental conditions, and UV-vis. and mass spectrometric analyses on the supernatant after reaction confirmed that the reaction products were oligomers formed by oxidative-coupling reaction. Pseudo-first order rate constants, f, for the oxidative transformation of 1-naphthol by birnessite was derived from the kinetic experiments under various amount of birnessite loadings, and using the observed pseudo-first order rate constants with respect to birnessite loadings, surface area-normalized specific rate constant, $k_{surf}$ was also determined to be $9.31{\times}10^{-4}(L/m^2{\cdot}min)$ for 1-naphthol. In addition, the oxidative transformation of 1-naphthol was found to be dependent on solution pH, and the pseudo-first order rate constants were increased from 0.129 at pH 10 to 0.187 at pH 4.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1701-1705
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• 2006

본 연구에서는 일차원 수리학적 하도추적모형인 FLDWAV 모형을 이용하여 낙동강 유역에 대해서 댐하류유역의 하도망을 구성하여 모형을 수행함으로서 댐 방류에 따른 안동댐에서 하구둑까지의 수리학적 흐름특성을 분석하였다. 대상구간은 안동댐${\sim}$하구둑까지의 본류구간과 임하댐직하${\sim}$반변천합류점, 합천댐직하${\sim}$황강합류점, 남강댐직하${\sim}$남강합류점까지의 단면을 적용하였으며, 하천정비기본계획상에 나타난 실측하상단면자료를 FLDWAV모형에 적합하게 변환하였다. 본 연구에서 적용된 모형은 1차원 부정류 해석모형으로서 단일하도 뿐만 아니라 지류와 연계된 하도망의 해석도 성공적으로 수행하게 된다. 모형에 의해 산정된 유량 및 수위의 값들은 당시의 실측값과 비교하여 유사한 형태를 가지며 정량적, 정성적인 부분에서 모형의 적합성을 증명하였다. 본 연구를 통하여 대상구간의 전체하도에 대한 적용절차 및 분석기법 등을 참조하여 다른 수계로의 확장이 가능하게 된다. 단면변환 및 경계조건 산정방법, 모형의 수행 및 결과 분석 과정 등이 댐방류 또는 지류의 유입을 고려한 합리적인 하천관리를 위한 방향을 제시하게 될 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.73-80
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• 2015

An investigation on the removals of tetracycline (TTC), which is a family of antibiotics widely founded in the environment, from the aqueous solution by birnessite(${\delta}-MnO_2$)-mediated oxidative transformation was described. This study also examined the potential effect of the naturally occurring substances, humic acid (HA) on the oxidative transformation. The experiment was carried out in various conditions (reaction time, Mn oxide loadings, pH) and in the presence of HA as a batch test. The removals of TTC followed pseudo-first order reactions, and rate constants (k, $hr^{-1}$) for the removals of TTC were constantly increased with decreasing pH from 0.98 (pH 9) to 2.97 (pH 3). The rate constants also increased about 1.3 times when the birnessite loading increased from 1 to 2 g/L. Presence of HA (5 mg-C/L, at $pH{\geq}6$) caused some enhancement in the removals of TTC as compared to the control, and also showed the removal efficiencies of TTC in the birnessite mediated systems (TTC=0.25 mM, ${\delta}-MnO_2=2.0g/L$, pH 6) increased with increasing HA concentrations (1~10 mg-C/L). The results obtained from the oxidative transformation of TTC and the effect of HA were discussed in terms of reaction characteristics and mechanism.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.78-83
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• 2014

This paper suggest an effective idea to implement an low area multi-mode one dimension transform block of HEVC(High Efficiency Video Coding). The time consuming multiplier path is designed to operate on low frequency. Normal multipliers dealing with variable operands are replaced with smaller constant multipliers which do the product with constant coefficient and variable only using shifters and adders. This scheme increases total multiplier counts but entire areas are reduced owing to smaller area of constant multiplier. Idle cycles caused by doubled multipliers enable to use multi-cycle paths on the cycle eating multiplier data path. Operating frequency is lowered by multi-cycle path but total throughput is maintained. This structure is implemented with TSMC 0.18 CMOS process library, and operated on 186MHz frequency to process a 4k($3840{\times}2160$) image. Max operating frequency is 300MHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.10-19
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• 2009

In this paper, an efficient optical watermark method using multiple phase wrapping and real-valued decoding key is proposed. In the embedding process, two zero-padded original images placed in two quadrants on input plane are multiplied with two statistically independent random phase patterns and are Fourier transformed, respectively. Two encoded images are obtained by taking the real-valued data from these Fourier transformed images. And then two phase-encoded patterns, used as a hidden image and a decoding key, are generated by the use of multiple phase wrapping from each of the encoded images. A transmitted image is made from the linear superposition of the weighted hidden images and a cover image. In reconstruction process, the mirror reconstructed images can be obtained at all quadrants by the inverse-Fourier transform of the product of the transmitted image and the decoding key. Computer simulation and optical experiment are demonstrated in order to confirm the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.417-425
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• 2006

This Paper Proposes a method of building a panoramic video from several videos captured from adjacent cameras. The panoramic image which constructed from adjacent and overlapped images is used for photogrammetry, satellite photo or many computer graphic applications. The perspective transformation, which is estimated from the appropriate corresponding pairs of images, can be used to construct the panoramic image without unwarranted distortion and its quality is decided by how to find the features needed for transform estimation. We used the corner points for the corresponding features, and morphological structures were utilized for fast and robust corner detection. We used the criterion of the corner strength, which guarantees the robust detection of the corner in most situations. For the transformation, 8 parameters were estimated from perspective equations which use matched points of adjacent images, and bilinear color blending was used to construct a soapless panoramic video. The experiments showed that the proposed method yields fast results with good quality under various conditions.

• Journal of Korea Game Society
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• v.7 no.4
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• pp.63-70
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• 2007

Since the fisheye lens has a wide field of view, it can capture the scene and illumination from all directions from far less number of omnidirectional images. Due to these advantages of the omnidirectional camera, it is widely used in surveillance and reconstruction of 3D structure of the scene In this paper, we present a new self-calibration algorithm of omnidirectional camera from uncalibrated images by considering the inlier distribution. First, one parametric non-linear projection model of omnidirectional camera is estimated with the known rotation and translation parameters. After deriving projection model, we can compute an essential matrix of the camera with unknown motions, and then determine the camera information: rotation and translations. The standard deviations are used as a quantitative measure to select a proper inlier set. The experimental results showed that we can achieve a precise estimation of the omnidirectional camera model and extrinsic parameters including rotation and translation.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.418-420
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• 2001

본 논문에서는 뉴스 비디오의 정지 영상에서 뉴스 자막과 배경 문자를 추출하기 위한 새로운 방법을 제안한다. 본 논문에서는 일차적으로 입력 컬러 영상을 그레이 영상으로 변환한 후 입력 영상의 명암 대비를 강화시키기 위해 명암 대비 스트레칭을 적용한다. 이후 명암 대비 스트레칭된 영상의 분할을 위해 적응적 임계값을 적용하고 다음 단계에서 문자와 유사한 영역들을 적당한 크기 의 structuring element를 이용하여 제거하는 1차 하부 단계와 모폴로지 녹임(erosion)을 적용한 영상과 모폴로지(열림닫힘[OpenClose]+닫힘열림[CloseOpen])/2가 적용된 영상 사이의 차이 영상을 구하는 2차 하부 단계를 적용시킨다. 마지막 단계에서 각 후보 영역들 중 실제 자막 영역을 추출해내기 위해, 후보 문자 영역의 화소수 비율과 외곽선의 화소수의 비율, 그리고 장축과 단축간의 비율 등에 대해 필터링을 적용한다. 본 논문에서는 임의의 300개의 뉴스영상을 입력 값으로 실험한 결과 93.6%의 우수한 인식률을 얻을 수 있었다. 또한 본 논문에서 제안한 방법은 structuring element의 크기 조절을 통해 크기가 다른 다양한 이미지에서도 좋은 성능을 거둘 수 있다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.2
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• pp.1-6
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• 1982

This paper reviews and describes some applications of perturbation theory in the practical analysis of linear systems which involve random parameters. Statistical measures of the system outputs are derived in terms of statistical measures of the system parameters and inputs (i.e., in the way of perturbed linear operator equations). Perturbed state transition matrix is also derived. With simple first-order and second-order linear system models, we compare the accuracy of perturbation results with the exact ones. And the convergence of perturbation series is also investigated.

• Journal of IKEEE
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• v.17 no.3
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• pp.248-253
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• 2013

Frequency detector is a circuit that converts the frequency to a digital representation and finds its application in various fields such as modulator and synchronization circuitry. In this paper, a couple of first-order and second-order frequency discriminator structures are modeled and analyzed with their quantization noise sources. Also a delta-sigma frequency detector architecture is proposed. Through theoretical analysis and derived equations, the output noise is obtained, which is validated by simulation. The proposed all-digital frequency discriminator may be applied in the feedback path of the all-digital phase-locked loop.