• Journal of the Korean Vacuum Society
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• v.12 no.2
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• pp.112-117
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• 2003

MgO films is widely used in plasma display panel (PDP) technology. In this work, structural and optical properties of the MgO films deposited by e-beam evaporation, reactive magnetron sputtering, which are commercially used, and arc deposition were compared. MgO thin films were deposited on glass substrates by vacuum arc deposition equipment using a magnesium metal target at various oxygen gas flows. In order to investigate the packing density by ellipsometer, to measure reasonable erosion-rates of the MgO protective layers, we introduced an acceleration test method, namely, Ar+ ion beam induced erosion test. Also, XPS and UV test were adopted to examine the effect of the moisture on the optical transmittance of the MgO protective layers, which showed that these of MgO films by arc deposition method sustained more 90% and were insensitive to effect of the moisture. XRD and AFM have been also used to study behaviors of the structure and surface morphology.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.122-129
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• 2006

Shearography is one of optical methods that has been applied to nondestructive testing (NDT) and strain/stress analysis. The technique has the merit of the directly measuring relative displacement, which is insensitive to environmental vibration disturbance. Previous studies about the method have emphasized on extending its application to new fields and lack insufficient research on effective parameters for qualitative and quantitative evaluation of defects. In this paper, the influence of shearing amount on the detection of an internal defect is investigated. In experiment, slender defects along longitudinal direction of pipeline are artificially designed and detection results according to the change of shearing amount are analyzed. Based on the investigation, we propose the technique for the determination of defect size and accurate source location.

• Journal of Sensor Science and Technology
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• v.9 no.5
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• pp.357-364
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• 2000

The structural, electrical and gas sensing characteristics of $LaFeO_3$ thin films fabricated by r.f. magnetron sputtering method on $Al_2O_3$ substrates were investigated. (121) domonant crystalline plane was observed for the films heat-treated at above $600^{\circ}C$ and gas sensing properties showed p-type semiconductor behaviors. Gas sensing characteristics of the $LaFeO_3$ thin films was studied as a function of film thicknesses and heat treatment temperatures. While the variation of the film thickness showed a little effect on the sensitivity, the heat treatment temperature was critical to the sensitivity. The thin films with thickness of 400 nm heat-treated at $800^{\circ}C$ showed the sensitivity of 400% for 5000ppm CO and 60% for 350ppm $NH_3$ at the working temperature of $300^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.33 no.4
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• pp.343-349
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• 1988

In order to get informations for breeding early barley cultivars, the thermosensitivity and low temperature growth ability about the breeding materials vernalized were tested at the high '||'&'||'amp; low temperature and field conditions. The temperature coefficient (Q10), ratio and thermosensitivity for plant height were various among cultivars versus temperature treatments. The early cultivars had greater Q10 values and insensitive responses to temperature changes. The Q10 and thermosensitivity for the time of flag leaf unfolding were various among cultivars, but the coefficient of variation in the thermosensitivity was greater, so the character would be more useful for investigating the varietal differences. The Q10 and thermosensitivity for plant height were not significantly correlated with Q10 and thermosensitivity for the time of flag leaf unfolding. The periods from heading to flowering were 2 to 4 days at the high temperature plot, but 1 to 11 days at the low temperature plot, showing much greater variations. In general the cultivars with greater difference of heading time between the high and low temperature plots were Suwon 218, SB 76588, Oweolbori, and Jogangbori, showing the sensitive thermophase and early heading.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.351-359
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• 2004

Velocity-type repisratory air flow transducer measures dynamic pressure converted from air velocity based on the we1l-known Bernoulli's principle. It requires multiple velocity sampling holes on the flow plane. Measurement error theoretica1ly estimated by computer simulation was demonstrated to significantly reduce by unequally locating the velocity sampling holes. The flow plane was divided into multiple equi-area rings and the sampling holes were located on the circles also equally dividing each ring's area, which decreased measurement error down to 1/5 of the simple equi-radius ring division method. Also, less than 1 ％ relative error was estimated with 4 or more sampling holes. The present technique was less sensitive by <1/2 to the velocity profile change compared to the euqi-radius sampling. Therefore, the present unequal distance velocity sampling technique should be of great use to design the structure of the velocity-type respiratory air flow transducer.

• Journal of the Korean Geosynthetics Society
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• v.12 no.1
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• pp.1-10
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• 2013

In this study, the characteristics of particle crash of decomposed granite soil sampled at Pocheon area were presented. The degree of weathering was artificially achieved by means of hydrofluoric acid. Weathering index was firstly determined by the analysis of mineral composition. Then, particle distribution, permeability tests were conducted. The results showed that weathering effects on particle crash over entire particle sizes. Comparative analysis on specific surface between $D_{10}$ and $D_{50}$ indicated that the smaller the particle size, the more the particle crash. In addition, the most particle crashing due to compaction appeared around the optimum moisture content. The incremental ratio of specific surface appeared to decrease as weathering proceeds, which means that the higher the weathering index the less the particle crash.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8B
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• pp.514-524
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• 2005

In optical burst switching(OBS) networks, the ingress edge router assembles packets in the same class queue into the appropriate size of burst. A burst control packet(BCP) is generated for channel reservation of corresponding data burst and sent earlier than the corresponding data burst with an offset time. Offset time is determined considering the number of hops from source to destination and the required quality of service(QoS). After offset time, the burst data is passed through tile pre-configured optical switches without any O/E/O conversion. But a failure in OBS networks may lead to the loss of bursts until the ingress nodes receive the failure indication signal. This results in a significant degradation in QoS. Therefore, in this paper, we propose a fault-tolerant node architecture based on sub-carrier multiplexing to reduce the effects of failure in OBS networks. The Performance of the proposed fault-tolerant node architecture exhibits considerable improvement as compared with the previous ones.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.447-451
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• 2007

A triplexer based on a silica planar lightwave circuit Mach-Zehnder nterferometer(MZI) is proposed and its characteristics are analyzed through simulations. To separate 1310 nm band and $1480{\sim}1560nm$ band properly, the path length difference of an MZI is set to be the multiple and half of the wavelength 1310 nm and the balance of the directional coupler is optimized in the $1480{\sim}1560nm$ band. The same MZI is additionally cascaded to provide good crosstalk characteristics. The 1490 nm band and 1550 nm band are further separated using additional two stage MZI's. A three-dimensional BPM and transfer matrix method analysis predicts the low crosstalk characteristics and the fabrication-error-tolerance of the proposed triplexer.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.7
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• pp.939-944
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• 2007

Edge is a significant element to represent boundary information between objects in images. There are various edge detection methods, which are based on differential operation, such as Sobel, Prewitt, Roberts, Canny, Laplacian, and etc. However the conventional methods have drawbacks as follow : (i) insensitivity to edges with gentle curve intensity, (ii) detection of double edges for edges with one pixel width. For the detection of edges, not only development of the effective operators but also that of appropriate thresholding methods are necessary. But it is very complicate problem to find an appropriate threshold. In this paper, we propose an edge detection method based on the region separateness between objects to overcome the drawbacks of the conventional methods, and a thresholding method for the proposed edge detection method. We show the effectiveness of the proposed method through experimental results obtained by applying the proposed and the conventional methods to well-known test images.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.223-231
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• 2020

Older drivers have an increased risk of accidents due to poor function, but they also develop self-regulation ability to check their own changes. Thus, information on whether the actual elderly driver responds to changes in driving ability and risk may provide a meaningful basis for the clinic and research of the elderly's driving ability assessment. Therefore, the purpose of this study is to provide basic data for the evaluation of elderly drivers by analyzing the driving risk self-perception characteristics in terms of driving behavior and function with Korean elderly drivers. A self-reporting assessment was conducted on 500 elderly drivers living in the community and the characteristics of driving risk perception were analyzed. As a result, it was confirmed that many elderly drivers are aware of the driving risk when their vision and hearing are impaired or when they find it difficult to adapt to changes in driving conditions. On the other hand, the characteristics of insensitive reactions to changes in medical health conditions, such as drug use or epilepsy, seizures, and loss of consciousness, were identified. The researcher hopes this study will contribute to the safety management of elderly drivers in Korea, where aging is accelerating.