• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.463-481
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• 2020

Cutter suction dredgers (CSDs) are widely used in various dredging constructions such as channel excavation, wharf construction, and reef construction. During a CSD construction, the main operation is to control the swing speed of cutter to keep the slurry concentration in a proper range. However, the slurry concentration cannot be monitored in real-time, i.e., there is a "time-lag effect" in the log of slurry concentration, making it difficult for operators to make the optimal decision on controlling. Concerning this issue, a solution scheme that using real-time monitored indicators to predict current slurry concentration is proposed in this research. The characteristics of the CSD monitoring data are first studied, and a set of preprocessing methods are presented. Then we put forward the concept of "index class" to select the important indices. Finally, an ensemble learning algorithm is set up to fit the relationship between the slurry concentration and the indices of the index classes. In the experiment, log data over seven days of a practical dredging construction is collected. For comparison, the Deep Neural Network (DNN), Long Short Time Memory (LSTM), Support Vector Machine (SVM), Random Forest (RF), Gradient Boosting Decision Tree (GBDT), and the Bayesian Ridge algorithm are tried. The results show that our method has the best performance with an R² of 0.886 and a mean square error (MSE) of 5.538. This research provides an effective way for real-time predicting the slurry concentration of CSDs and can help to improve the stationarity and production efficiency of dredging construction.

• Asian-Australasian Journal of Animal Sciences
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• 제18권11호
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• pp.1529-1534
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• 2005

Individual-breed assignments were implemented in six swine populations using twenty six microsatellites recommended by the Food and Agriculture Organization and the International Society for Animal Genetics (FAO-ISAG). Most microsatellites exhibited high polymorphisms as shown by the number of alleles and the polymorphism information content. The assignment accuracy per locus obtained by using the Bayesian method ranged from 33.33% (CGA) to 68.47% (S0068), and the accumulated assignment accuracy of the top ten loci combination added up to 96.40%. The assignment power of microsatellites based on the Bayesian method had positive correlations with the number of alleles and the gene differential coefficient ($G_{st}$) per locus, while it has no relationship to genetic heterozygosity, polymorphism information content per locus and the exclusion probabilities under case II and case III. The percentage of corrected assignment was highest for the Bayesian method, followed by the gene frequency and distancebased methods. The assignment efficiency of microsatellites rose with increase in the number of loci used, and it can reach 98% when using a ten-locus combination. This indicated that such a set of ten microsatellites is sufficient for breed verification purposes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.620-636
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• 2015

Survivability is a necessary property of network system in disturbed environment. Recovery ability is a key actor of survivability. This paper concludes network survivability into a novel composite metric, i.e. Network Recovery Degree (NRD). In order to measure this metric in quantity, a concept of Source-Destination Pair (SD Pair), is created to abstract end-to-end activity based on end nodes in network, and the quality of SD Pair is also used to describe network performance, such as connectivity, quality of service, link degree, and so on. After that, a Survivability Test method in large scale Network based on SD pairs, called STNSD, is provided. How to select SD Pairs effectively in large scale network is also provided. We set up simulation environment to validate the test method in a severe destroy scenario and evaluate the method scalability in different large scale network scenarios. Experiment and analysis shows that the metric NRD correctly reflects the effort of different survivability strategy, and the proposed test method STNSD has good scalability and can be used to test and evaluate quantitative survivability in large scale network.

• 공학교육연구
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• 제6권1호
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• pp.56-64
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• 2003

본 논문에서는 클라이언트/서버 분산 환경을 설계하여 전자회로에 대한 웹 기반 가상실험 시스템을 개발하였다. 제안된 가상실험실은 실제 대학에서 운영되는 실험실 환경을 묘사하도록 구현되었기 때문에 학습자들은 실제 실험실 유사한 실험결과를 가상실험실에서 얻을 수 있다. 제안된 가상실험시스템은 원리학습실, 가상실험학습실, 평가학습실 그리고 전체 관리시스템의 4가지 중요한 구성요소로 이루어져 있다. 제안된 가상실험실을 통해 학습자들은 전자회로 실험과 관련된 개념이나 이론을 학습할 수 있으며, 멀티미터나 신호발생기 그리고 디지털 오실로스코프나 DC전원공급기 같은 계측장비의 동작방법을 웹상에서 학습할 수 있다. 또한 가상실험실에서 일어나는 모든 실험 활동은 전체 관리시스템에 의해 데이터베이스에 기록되어 예비보고서 형태로 출력된다. 웹상에서 데이터베이스의 연결은 PHP에 의해 이루어지며 가상실험실 환경은 각 학습자들에 대해 조금씩 다른 결과가 나타나도록 구성하였다. 마지막으로 가상실험실을 운영한 결과 전체 실험시간과 실험장비의 손상율이 감소되며, 교수생산성이나 학습효율이 증가되는 긍정적인 결과를 얻을 수 있었다.

• 대한임상검사과학회지
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• 제47권3호
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• pp.153-158
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• 2015

임상병리학과 학생들의 법의학 교육에 대한 인식개선의 방법을 개선하고, 활성화를 위한 방안을 제시할 목적으로 대구지역 대구보건대학교 임상병리학과 학생 100명을 대상으로 설문 조사를 실시하여 법의학 과목에 대한 인식 및 요구도에 대한 항목들을 빈도 분석하였다. 그 결과 대부분의 학생들이 법의학이라는 인식이 많이 높은 수준으로 조사되었다. 100 응답자 중, 법의학대한 인식 질문에 94 (94 %) 그것을 알고 있다고 조사되었으며 법의학에 대한 기대 또한 높게 조사되었다. 현재 임상병리과 학생들에게서는 법의학 교육의 인식 및 교육의 요구도가 매우 높았다. 따라서 대학 교육과정에 임상병리사가 되기 위한 중점과목에만 집중하는 것보다 전문적 영역 확대와 활성화를 위해 법의학 과목을 통해 특히 임상병리사의 취업을 위한 방안으로 소개하는 프로그램의 도입이 필요하다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권1호
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• pp.404-421
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• 2020

A reversible data hiding scheme in JPEG compressed bitstreams is proposed, which could avoid decoding failure and file expansion by means of removing of bitstreams corresponding to high frequency coefficients and embedding of secret data in file header as comment part. We decode original JPEG images to quantified 8×8 DCT blocks, and search for a high frequency as an optimal termination point, beyond which the coefficients are set to zero. These blocks are separated into two parts so that termination point in the latter part is slightly smaller to make the whole blocks available in substitution. Then spare space is reserved to insert secret data after comment marker so that data extraction is independent of recovery in receiver. Marked images can be displayed normally such that it is difficult to distinguish deviation by human eyes. Termination point is adaptive for variation in secret size. A secret size below 500 bits produces a negligible distortion and a PSNR of approximately 50 dB, while PSNR is also mostly larger than 30 dB for a secret size up to 25000 bits. The experimental results show that the proposed technique exhibits significant advantages in computational complexity and preservation of file size for small hiding capacity, compared to previous methods.

• Mass Spectrometry Letters
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• 제7권1호
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• pp.21-25
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• 2016

Dual-channel nano-electrospray has recently become an ionization technique of great promise especially in biological mass spectrometry. This unique approach takes advantage of the mixing processes that occurs during electrospray. Understanding in more detail the fundamental principles influencing spray formation further study of the origins of the mixing processes: (1) in a Taylor cone region, (2) in charged droplets or (3) in both environments. The dual-channel emitters were made from borosilicate theta-shape glass tubes (O.D. 1.2 mm) and had a tip diameters of less than 4 μm. Electrical contact was achived by deposition of a thin film of an appropriate metal onto the surface of the emitter. The experimental investigation of the Taylor cone formation in a dual-channel electrospray emitter has been carried out by injection of polystyrene beads (diameter 3 μm) at very low concentrations into one of the channels of the non-tapered theta-glass tubes. High-speed camera experiments were set up to visualize the mixing processes in Taylor cone regions for dual-channel emitters. Mass spectra from dual nano-electrospray are presented.

• Advances in concrete construction
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• 제6권1호
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• pp.15-28
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• 2018

In the present investigation, influence of various material parameters on the cavitation erosion resistance of concrete was investigated on the basis of laboratory experiments. As there is no well-established laboratory test method for evaluating the cavitation resistance of concrete, a test set up called 'cavitation jet' was specially established in the present study in order to simulate the cavitation phenomenon experienced in the hydraulic structures. Various mixtures of concrete were designed by varying the grade of concrete, type and quantity of pozzolana, type of aggregates and cement type to develop good cavitation resistant concrete constructed using marginal aggregates. Three types of aggregates having three different Los Angeles abrasion values (less than 30%, between 30% and 50% and more than 50%) were employed in this study. To evaluate the cavitation resistance a total of 60 cylindrical specimens and 60 companion cubes were tested in the laboratory respectively. The results indicate that cavitation resistance of concrete degrades significantly as the L.A. abrasion value of aggregates goes beyond the 30% value. Incorporation of pozzolanic admixtures was seemed to be beneficial to enhance the cavitation resistance of concrete. Influence of other material parameters on the cavitation resistance of concrete was also noted and important observations have been made in the paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1813-1815
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• 2002

As the statistical data, the electrical shock accidents by electrical power facilities of 22.9kV substation is about 100 per years which shows very high occupation rate of 11.3%. There is many hazard factors in this place using high voltage because electrical accident can be occurred in near live part as well as contact. Regarding electrical shock accident in 22.9kV substation as there are many cases that have not been exposed industrial disaster, it is very hard to know exact causes of such accidents in many cases, and therefore it is difficult to set up effective preventive measures. Therefore in this paper, it is intended to prepare the basic data to establish more effective preventive measures of electric shock accidents in 22.9kV substation through understanding the real conditions based on investigation and analysis in various types.

• Journal of the Optical Society of Korea
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• 제17권6호
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• pp.513-517
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• 2013

Recently, maskless lithography (ML) systems have become popular in digital manufacturing technologies. To achieve high-throughput manufacturing processes, digital micromirror devices (DMD) in ML systems must be driven to their operational limits, often in harsh conditions. We propose an instrument and algorithm to detect DMD malfunctions to ensure perfect mask image transfer to the photoresist in ML systems. DMD malfunctions are caused by either bad DMD pixels or data transfer errors. We detect bad DMD pixels with $20{\times}20$ pixel by white and black image tests. To analyze data transfer errors at high frame rates, we monitor changes in the frame rate of a target DMD pixel driven by the input data with a set frame rate of up to 28000 frames per second (fps). For our data transfer error detection method, we verified that there are no data transfer errors in the test by confirming the agreement between the input frame rate and the output frame rate within the measurement accuracy of 1 fps.