• Mycobiology
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• 제37권2호
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• pp.121-127
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• 2009

Purification and characterization of intracellular cellulase produced by A. oryzae ITCC-4857.01 are reported. The enzyme was purified by ion-exchange chromatography using DEAE-cellulose followed by Gel filtration. The purification achieved was 41 fold from the crude extract with yield of 27%. The purified enzyme showed single band on poly acrylamide gel. The molecular weight as determined by SDS-PAGE and gel filtration was 38 KDa and 38.6 KDa respectively and contained only one subunit. The enzyme is glycoprotien as nature and contained 0.67% neutral sugar. The apparent Km value of the enzyme against cellulose was 0.83%. The enzyme showed the highest relative ativities on CMC followed by avicel, salicin and filter paper. The optimum pH of activity was 5.5 and very slight activity was observed at or above pH 7.5 as well as bellow pH 3.5. The optimum tempreture of the activity was $45^{\circ}C$ and the highest activity was exhibited in 35 to $45^{\circ}C$. The enzyme lost their activities almost completely (95${\sim}$100%) at $80^{\circ}C$ or above and as well as bellow $25^{\circ}C$.

• 한국통신학회논문지
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• 제40권2호
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• pp.247-252
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• 2015

영확률을 성능기준으로 하는 적응 알고리듬은 충격성 잡음에 강인함을 나타내며 그 결정 궤환 알고리듬은 심각한 다경로 채널 왜곡을 효과적으로 보상하는 것으로 알려져 있다. 그러나 이러한 결정 궤환 영확률 알고리듬은 각 필터 구역에 대해 매 샘플시간마다 여러 합산 동작을 계산해야하는데 이것이 실제 구현에 장애가 되고 있다. 이 논문에서는 반복적 기울기 추정 방식을 가진 결정 궤환 영확률 알고리듬을 제안하며 이 알고리듬은 기존 계산량 O(N)을 샘플 사이즈 N에 무관한 상수량으로 줄일 수 있음을 보인다. 또한 초기상태와 안정상태의 가중치 갱신이 연속적인 과정으로 이루어져 결정 궤환에서 어떤 기울기 추정 오류 전파도 일으키지 않음을 보인다.

• 한국통신학회논문지
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• 제41권9호
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• pp.995-1000
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• 2016

무작위 발생된 심볼 집합과 최대 상호 코렌트로피 (maximum cross-correntropy) 로 설계된 MCC 알고리듬은 최소자승평균 (MSE) 기반 알고리듬과 달리, 충격성 잡음 하에서 최적 가중치가 동요 없이 안정을 유지하며 그 요인이 오차 전력에 따라 입력의 세기를 조절하는 입력 크기 조정기 (input magnitude controller, IMC)에 있음이 밝혀졌다. 이 논문에서는 스텝사이즈를 정규화한 알고리듬 (normalized MCC, NMCC)를 제안하였으며 여기서 IMC 통과된 신호 전력은 1-pole 저역 통과 필터로 반복적 추정한다. 두 가지 다중경로 채널 모델과 충격성 잡음 환경에서 시행된 시뮬레이션 결과, 정규화된 NMCC알고리듬은 MCC알고리듬에 비해 정상상태 MSE에서 1 dB 정도의 성능 향상을, 수렴 속도에서도 500 샘플 정도 빠른 성능을 나타냈다.

• Journal of Power Electronics
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• 제15권4호
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• pp.939-950
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• 2015

A single-stage AC-AC converter has been designed for a wind energy conversion system (WECS) that eliminates multistage operation and DC-link filter elements, thus resolving size, weight, and reliability issues. A simple switching strategy is used to control the switches that changes the variable-frequency AC output of an electrical generator to a constant-frequency supply to feed into a distributed electrical load/grid. In addition, a modified random sinusoidal pulse width modulation (RSPWM) technique has been developed for the designed converter to make the overall system more efficient by increasing generating power capacity and reducing the effects of inter-harmonics and sub-harmonics generated in the WECS. The technique uses carrier and reference waves of variable switching frequency to calculate the firing angles of the switches of the converter so that the three-phase output voltage of the converter is very close to a sine wave with reduced THD. A comparison of the performance of the proposed RSPWM technique with the conventional SPWM demonstrated that the power generated by a turbine in the proposed approximately increased by 5% to 10% and THD reduces by 40% both in voltage and current with respect to conventional SPWM.

• 한국측량학회지
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• 제33권3호
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• pp.173-179
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• 2015

In this paper, object-based classification of urban areas based on a combination of information from lidar and aerial images is introduced. High resolution images are frequently used in automatic classification, making use of the spectral characteristics of the features under study. However, in urban areas, pixel-based classification can be difficult since building colors differ and the shadows of buildings can obscure building segmentation. Therefore, if the boundaries of buildings can be extracted from lidar, this information could improve the accuracy of urban area classifications. In the data processing stage, lidar data and the aerial image are co-registered into the same coordinate system, and a local maxima filter is used for the building segmentation of lidar data, which are then converted into an image containing only building information. Then, multiresolution segmentation is achieved using a scale parameter, and a color and shape factor; a compactness factor and a layer weight are implemented for the classification using a class hierarchy. Results indicate that lidar can provide useful additional data when combined with high resolution images in the object-oriented hierarchical classification of urban areas.

• 한국멀티미디어학회논문지
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• 제22권2호
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• pp.167-177
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• 2019

Even though so much progresses have been achieved in Multiple Object Tracking (MOT), most of reported MOT methods are not still satisfactory for commercial embedded products like Pan-Tilt-Zoom (PTZ) camera. In this paper, we propose a real-time multiple pedestrians tracking method for embedded environments. First, we design a new light weight convolutional neural network(CNN)-based pedestrian detector, which is constructed to detect even small size pedestrians, as well. For further saving of processing time, the designed detector is applied for every other frame, and Kalman filter is employed to predict pedestrians' positions in frames where the designed CNN-based detector is not applied. The pose orientation information is incorporated to enhance object association for tracking pedestrians without further computational cost. Through experiments on Nvidia's embedded computing board, Jetson TX2, it is verified that the designed pedestrian detector detects even small size pedestrians fast and well, compared to many state-of-the-art detectors, and that the proposed tracking method can track pedestrians in real-time and show accuracy performance comparably to performances of many state-of-the-art tracking methods, which do not target for operation in embedded systems.

• 센서학회지
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• 제28권4호
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• pp.240-245
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• 2019

Phase interpolation is widely adopted in frequency synthesizers and clock-and-data recovery systems to produce an intermediate phase from two existing phases. The intermediate phase is typically generated by combining two input phases with different weights. Unfortunately, this results in non-uniform phase steps. Alternatively, the intermediate phase can be generated by successive approximation, where the interpolated phase at each approximation stage is obtained using the same weight for the two intermediate phases. As a proof of concept, this study presents a 2-GHz 8-bit successive approximation digital-to-phase converter that is designed using 65-nm CMOS technology. The converter receives an 8-phase clock signal as input, and the most significant bit (MSB) section selects four phases to create two sinusoidal waveforms using a harmonic rejection filter. The remaining least significant bit (LSB) section applies the successive approximation to generate the required intermediate phase. Monte-Carlo simulations show that the proposed converter exhibits 0.46-LSB integral nonlinearity and 0.31-LSB differential nonlinearity with a power consumption of 3.12 mW from a 1.2-V supply voltage.

• 스마트미디어저널
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• 제11권8호
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• pp.84-92
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• 2022

Precision livestock monitoring promises greater management efficiency for farmers and higher welfare standards for animals. Recent studies on video-based animal activity recognition and tracking have shown promising solutions for understanding animal behavior. To achieve that, surveillance cameras are installed diagonally above the barn in a typical cattle farm setup to monitor animals constantly. Under these circumstances, tracking individuals requires addressing challenges such as occlusion and visual appearance, which are the main reasons for track breakage and increased misidentification of animals. This paper presents a framework for multi-cattle tracking in closed barns with appearance and motion models. To overcome the above challenges, we modify the DeepSORT algorithm to achieve higher tracking accuracy by three contributions. First, we reduce the weight of appearance information. Second, we use an Ensemble Kalman Filter to predict the random motion information of cattle. Third, we propose a supplementary matching algorithm that compares the absolute cattle position in the barn to reassign lost tracks. The main idea of the matching algorithm assumes that the number of cattle is fixed in the barn, so the edge of the barn is where new trajectories are most likely to emerge. Experimental results are performed on our dataset collected on two cattle farms. Our algorithm achieves 70.37%, 77.39%, and 81.74% performance on HOTA, AssA, and IDF1, representing an improvement of 1.53%, 4.17%, and 0.96%, respectively, compared to the original method.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.133-135
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• 2022

IoT 및 AI기술과 매체의 발전에 따라 다양한 디지털 장비가 사용되고 있으며, 무인화와 자동화가 급속도로 진행되고 있다. 특히 스마트 팩토리와 자율주행기술 및 지능형 CCTV와 같은 분야에서는 높은 수준의 영상처리 기술이 요구되고 있다. 하지만 영상에 존재하는 잡음은 에지 검출이나 객체 인식과 같은 과정에 영향을 미치고 있으며, 시스템의 정확성과 신뢰도 저하를 야기한다. 본 논문에서는 복합잡음에 훼손된 영상을 복원하기 위해 퍼지 가중치를 사용한 필터링 알고리즘 제안한다. 제안한 알고리즘은 잡음 판단을 사용하여 기준값을 구했으며, 퍼지가중치를 적용하여 최종출력을 계산한다. 제안한 알고리즘의 성능을 검증하기 위해 시뮬레이션을 진행하였으며, 기존 필터 알고리즘과 결과영상을 비교하여 평가하였다.

• Structural Engineering and Mechanics
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• 제90권5호
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• pp.493-504
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• 2024

This paper presents the methodology and results for the investigation of the structural safety of 40 aged underground water tanks to support the weight of photovoltaic (PV) systems that were supposed to be placed on their roof reinforced concrete (RC) slabs. The investigation procedure included (1) review of available documents; (2) visual inspection of the roof RC slabs; (3) carrying out a series of nondestructive (ND) tests; and (4) analysis of results. Out of the 40 tanks, eleven failed the visual inspection phase and were discarded from further investigation. The roof RC slabs of the tanks that passed the visual inspection were subjected to a series of ND tests that included infrared thermography, impact echo, ultrasonic pulse velocity (UPV), Schmidt hammer, concrete core compressive strength, and water-soluble chloride content. The NDT results proved that eight more tanks were not suitable to support the PV systems. Based on the results of the visual inspection and testing, a probabilistic decision-making criterion was established to reach a decision regarding the structural integrity of the roof slabs. The study concluded that the condition of the drainage filter was essential in protecting the tanks and its intact presence can be used as a strong indication of the structural integrity of the roof RC slabs.