• 대한기계학회논문집B
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• 제29권1호
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• pp.123-130
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• 2005

A digital in-line holographic particle image velocimetry (HPIV) which can be applied to measure three-dimensional velocity fields of turbulent flows was developed. There are three different implementation methods of HPIV: traditional film-based HPIV, intermediate HPIV and digital HPIV. The traditional film-based HPIV and intermediate HPIV method is rather troublesome to do experiments and takes long calculation time, compared with the digital HPIV, Configuration of the digital in-line HPIV is simple and the data processing routine is similar to conventional 2D PIV methods. The digital HPIV velocity field measurement consists of four steps: recording, numerical reconstruction, particle extraction and velocity extraction. In the velocity extraction process, we improved PTV algorithm to extract the displacement of particle each placed in 3D space. The developed digital in-line HPIV system was applied to a vertical jet flow. The 3D velocity vectors measured by the digital HPIV method in the near field are in a good agreement with 2D PIV results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.2051-2054
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• 2002

In this research, we had two experiments. In the first experiment we focused on the comparison of loaming between two groups of hearing impaired students (multimedia training group and traditional print-based method group). The results from the first experiment indicated that there was no numerical difference in test scores between the two groups of students but the students enjoyed learning with computer. We then carried out the second experiment. This time, we focused more on measuring the qualitative nature of the learning using multimedia technology. The results of the second experiment indicated that the two methods of teaching and learning affected students similarly since the average scores of both groups showed no statistically significant difference. About 89% of the students in the second experiment enjoyed learning from the CD-ROM. This result was based not just on the CD-ROM Life in Saskatchewan, but included any kinds and subjects of CD-ROM used in the classroom. Although multimedia training is as good as, but no better than, the traditional print-based method, multimedia can be used as a valuable supplement in adaptive technology.

• 컴퓨터교육학회논문지
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• 제19권1호
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• pp.111-118
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• 2016

협력 필터링 기반의 추천시스템에서 유사도 측정은 시스템의 성능에 큰 영향을 미치는데, 이는 유사한 다른 사용자들로부터 항목을 추천받기 때문이다. 본 연구에서는 전통적인 유사도 측정 방법의 가장 큰 문제인 데이터 희소성을 극복하기 위해, 기존의 유사도 측정값과 공통평가항목수의 반영값을 최적으로 결합하는 새로운 유사도 측정방식을 제안한다. 제안 방식의 성능 평가를 위해 다양한 조건으로 실험한 결과 기존 방식들보다 우수한 예측 정확도를 나타냈으며, 구체적으로 전통적인 피어슨 상관보다 최대 약 7%, 코사인 유사도보다는 최대 약 4% 향상된 결과를 보였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권9호
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• pp.521-530
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• 2005

In this paper, a new high resolution reflectometry scheme, time-frequency domain reflectometry(TFDR), isproposed to detect and estimate a fault in a transmission line. Traditional reflectometry methodologies have been achieved either in the time domain or in the frequency domain only. However, the TFDR can jump over the performance limits of the traditional reflectometry methodologies because the acquired signal is analyzed in time and frequency domain simultaneously. In the TFDR, the new reference signal and the novel TFDR algorithm are proposed for analyzing the acquired signal in the time-frequency domain. Because the reference signal of Gaussian envelop chirp signal is localized in the time and frequency domain simultaneously, it is suitable to the analysis in the time-frequency domain. In the proposed TFDR algorithm, the time-frequency distribution function and the normalized time-frequency cross correlation function are used to detect and estimate a fault in a transmission line. That algorithm is verified for real-world coaxial cables which are typical transmission line with different types of faults by the TFDR system composed of real instruments. The performance of the TFDR methodology is compared with that o( the commercial time domain reflectomeoy(TDR) experiments, so that concludes the TFDR methodology can detect and estimate the fault with smaller error than TDR methodology.

• Applied Biological Chemistry
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• 제35권5호
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• pp.346-350
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• 1992

한국 재래식 간장의 많은 휘발성 향기성분 중에서 특징적인 향기성분을 규명하고자 하였다. 연속 수증기 증류 추출장치로 휘발성 향기성분을 추출하고 재래식 간장향을 나타내는 중성획분을 분획하여 농축하였다. 이를 GC-관능검사에 의해 각 peak성분의 방향성을 조사하고, 이 각 peak성분을 fraction collector APP-5가 부착된 preparative GC로 분획포집한 후, 이를 GC/MS로 분석 동정하였다. 그 결과 GC-관능검사에서 불쾌취를 나타내는 향기성분으로는 3-methyl-1-butanol을, 간장향을 나타내는 향기성분으로는 dimethyl trisulfide, benzeneacetaldehyde, benzeneethanol을 각각 동정하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.224-230
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• 2005

In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience due to cleaning process. This paper introduces a new rapid manufacturing process called Rapid Heat Ablation process (RHA) using the rotary hot tool to overcome limitations of traditional machining process. The rotary hot tool to satisfy requirements of RHA process is designed and produced. In order to examine relationships between kerfwidth and process parameters such as heat input, speed of tool and speed of revolution, experiments were carried out. In addition, relationship between the kerfwidth and the effective heat input was obtained. Based on the experimental results, double-curved shape was ablated to show the validity of proposed process. In the procedure, the rough cut and fine cut were performed according to the conditions of process parameters without tool change process. The practicality and effectiveness of the proposed process have been verified through ablation of three-dimensional shape.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.4126-4142
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• 2015

Finger vein recognition is a biometric technology using finger veins to authenticate a person, and due to its high degree of uniqueness, liveness, and safety, it is widely used. The traditional Symmetric Local Graph Structure (SLGS) method only considers the relationship between the image pixels as a dominating set, and uses the relevant theories to tap image features. In order to better extract finger vein features, taking into account location information and direction information between the pixels of the image, this paper presents a novel finger vein feature extraction method, Multi-Orientation Weighted Symmetric Local Graph Structure (MOW-SLGS), which assigns weight to each edge according to the positional relationship between the edge and the target pixel. In addition, we use the Extreme Learning Machine (ELM) classifier to train and classify the vein feature extracted by the MOW-SLGS method. Experiments show that the proposed method has better performance than traditional methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.395-405
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• 2012

A joint template matching algorithm is proposed in this paper to reduce the high rate of miss-detection and false-alarm caused by the traditional template matching algorithm during the process of multi-object detection. The proposed algorithm can reduce the influence on each object by matching all objects together according to the correlation information among different objects. Moreover, the rate of miss-detection and false-alarm in the process of single-template matching is also reduced based on the algorithm. In this paper, firstly, joint template is created from the information of relative positions among different objects. Then, matching criterion according to normalized cross correlation is generated for multi-object matching. Finally, the proposed algorithm is applied to the detection of watermarks in bill. The experiments show that the proposed algorithm has lower miss-detection and false-alarm rate comparing to the traditional NCC algorithm during the process of multi-object detection.

• 한국식품영양학회지
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• 제20권3호
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• pp.259-264
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• 2007

Ginger(Zingiber officinale Roscoe) has been used as a raw material in many various traditional preparations since the ancient times. As a component of traditional health products, ginger is known to be effective as an appetite enhancer, and has anti-cold and anti-inflammatory activities. This study was performed to investigate the immunomodulative effects of Zingiber officinale Roscoe in mice, using ex vivo experiments. In order to elucidate ginger's immunomodulative effects of Ginger, water extracts were orally administered to mice, and isolated macrophages were used as the experimental model. To identify the ex vivo effects, six to seven week old Balb/c mice were fed a chow diet ad libitum and the ginger water extracts were administered orally every other day for two or four weeks at two different concentrations(50 and 500 mg/kg b.w.). The results show that IL-IO and $IFN-{\gamma}$ were detected in the 500 mg/kg b.w. supplemented group with LPS stimulation in all cases. Also, the $IFN-{\gamma}$ /IL-10 ratio ranged from 3~5 with mitogen stimulation such as Con A and LPS. In conclusion, this study suggests that ginger extracts may enhance the immune function by regulating the cytokine(IL-10 and $IFN-{\gamma}$) production capacity of activated macrophages in mice.

• Smart Structures and Systems
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• 제18권3호
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• pp.585-599
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• 2016

Steel cables serve as the key structural components in long-span bridges, and the force state of the steel cable is deemed to be one of the most important determinant factors representing the safety condition of bridge structures. The disadvantages of traditional cable force measurement methods have been envisaged and development of an effective alternative is still desired. In the last decade, the vision-based sensing technology has been rapidly developed and broadly applied in the field of structural health monitoring (SHM). With the aid of vision-based multi-point structural displacement measurement method, monitoring of the tensile force of the steel cable can be realized. In this paper, a novel cable force monitoring system integrated with a multi-point pattern matching algorithm is developed. The feasibility and accuracy of the developed vision-based force monitoring system has been validated by conducting the uniaxial tensile tests of steel bars, steel wire ropes, and parallel strand cables on a universal testing machine (UTM) as well as a series of moving loading experiments on a scale arch bridge model. The comparative study of the experimental outcomes indicates that the results obtained by the vision-based system are consistent with those measured by the traditional method for cable force measurement.