• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.34-42
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• 2010

The DOA(direction of arrival), which is based on parametric and nonparametric estimation algorithm, and adaptive beamforming algorithm for mobile communication environments are researched and analyzed. In parametric estimation algorithm, eigenvalues of the signal component and the noise component are obtained from correlation matrix of received signal by array antenna and power spectrum of the received signal is discriminated from them. Otherwise, in nonparametric estimation algorithm, we minimize a regularized objective function for finding a estimate of the signal energy as a function of angle, using nonquadratic norm which leads to supper resolution and noise suppression. And then, DOA is estimated by the signal and noise spatial steering vector, and adaptive beam-forming pattern is improved by weight vectors obtained from the spatial vector. Therefore, the improved directional estimation algorithm with regularizing sparsity constraints offers super-resolution and noise suppression compared to other algorithms.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.123.1-123.1
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• 2016

마그네슘 및 마그네슘 합금은 차세대 경량 구조 재료로서 많은 각광을 받고 있지만, 상대적으로 높은 반응성과 낮은 부식저항성으로 인해 사용에 제한이 있어왔다. 최근 연구결과에 따르면, 상용으로 널리 쓰이는 AZ91 마그네슘합금에 Ca과 Y을 복합 첨가하였을 경우 마그네슘합금의 발화저항성을 크게 향상시키는 것으로 알려져 있어 마그네슘합금의 적용분야를 확대할 수 있을 것으로 많은 기대를 받고 있다. 그러나 이러한 합금이 실제적으로 적용되기 위해서는 반드시 내식성에 대한 평가와 연구가 수반되어야 하며, 이를 통해 부식거동에 대한 메커니즘을 규명함으로써 고내식 합금 개발을 위한 연구로 이어질 수 있도록 해야 한다. 따라서 본 연구에서는 기존의 AZ91D 합금과 Ca, Y이 복합 첨가된 modified AZ91D 합금 다이캐스트 주조재에 대하여 내식성을 평가 및 비교하고 부식 메커니즘을 규명하기 위한 미세조직 분석 및 부식거동 평가를 실시하였다. 본 연구결과에 따르면, AZ91D 합금 주조재에 Ca과 Y을 복합첨가한 합금은 발화저항성 뿐만 아니라 내식성도 크게 향상되는 것으로 나타났다. 이러한 내식성의 향상은 Ca과 Y의 첨가에 따른 Fe와 같은 불순물의 영향 감소 및 Ca과 Y이 포함된 이차상의 형성으로 인한 상과 기지간의 부식 전위의 차이 감소로 인한 미세 갈바닉 부식 발생의 감소 효과에 기인한 것으로 판단된다.

• Korean Journal of Food Science and Technology
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• v.22 no.5
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• pp.497-502
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• 1990

The effect of sugar concentration, immersion time and temperature on water loss, solid gain or loss, and sugar molality of potatoes during osmotic concentration was analyzed by a response surface methodology (RSM), and those values were predicted by using a second degree polynomial regression model. Effect of osmotic concentration and blanching on vitamin C retention of air dried potatoes (6% MC: wet basis) was also evaluated. The most significant factor was sugar concentration for water loss, solid gain or loss, sugar molality, rate parameter and retention of vitamin C. Second and third factors were immersion time and temperature respectively. Water loss and solid gain were rapid in the first 10 min and then levelled off. A 44.6% of water loss was observed during osmotic concentration using a sugar solution $(60\;Brix,\;80^{\circ}C$) with 20 min of immersion time. Dried potatoes after osmotic concentration had higher vitamin C content than dried potatoes after blanching. Optimum regions for osmotic concentration process of potatoes were $60-70^{\circ}C$ of immersion temperature, 60 Brix of sugar solution and 16-20 min of immersion time based on above 30% of water loss and 50% of vitamin C retention.

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.734-740
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• 1995

The primary and secondary structures of Xanthomonas palargonii 5S rRNA were determined. The higher order structure of the 5S rRNA was also analysed using several ribonucleases and chemical probes, such as ethylnitrourea, Pb2+, dimethylsulfate and diethyl pyrocarbonate. Ethylnitrourea was used for probing the phosphate groups involved in the tertiary interactions in the 5S rRNA. Nucleotides G72, A73, G75, A78, G98, G100 and A101 in unstable helical region d, nucleotides C36, C37, A39, and C41 in loop c, nucleotides A29 and G33 in stem C became resistant to ethylnitrourea modification in the presence of Mg2+. On the basis of findings from chemical and enzymatic studies, and also Pb2+-induced cleavages, it was concluded that region b-C and unstable helical region d may act as hinges in the folding of 5S rRNA.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.4
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• pp.407-413
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• 1999

Maxillary duplication is a kind of proliferative neurocristopathy and considered to arise from bifurcation of neural crest elements soon after migration into mandibular arch. Sometimes this malformation is accompanied with oblique facial cleft. Usually this type of maxillofacial malformation requires multiple surgical intervention and the results are far from ideal. It became more troublesome if it had not been properly corrected on time, because secondary deformities could be developed from growth and development of abnormal tissues. This is a case of a 25-year-old-female patient who showed severe facial asymmetry thought to secondary deformity of maxillary duplication and masticatory disturbance due to multiple supernumerary teeth on posterior part right maxilla. We successully treated these deformities through four times of surgery of bone resection, orthodontic treatment, zygomatic and orbital reconstruction, orthognathic surgery and scar revision... ect. So we reported this rare case with review of literatures.

• The KIPS Transactions:PartD
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• v.8D no.5
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• pp.553-560
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• 2001

Bioinformatics is a discipline to support biological experiment projects by storing, managing data arising from genome research. In can also lead the experimental design for genome function prediction and regulation. Among various approaches of the genome research, the proteomics have been drawing increasing attention since it deals with the final product of genomes, i.e., proteins, directly. This paper proposes a data mining technique to predict the structural characteristics of a given protein group, one of dominant factors of the functions of them. After explains associations among amino acid subsequences in the primary structures of proteins, which can provide important clues for determining secondary or tertiary structures of them, it defines a sequence association rule to represent the inter-subsequences. It also provides support and confidence measures, newly designed to evaluate the usefulness of sequence association rules, After is proposes a method to discover useful sequence association rules from a given protein group, it evaluates the performance of the proposed method with protein sequence data from the SWISS-PROT protein database.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.211-216
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• 2008

Recently a lot of researches have been conducted on the progressive collapse of structures which is the total collapse of structures initiated by localized damage. Most of the previous studies on the field of progressive collapse have followed deterministic approach without considering uncertainty involved in design variables, which results in unknown reliability of the analysis results. In this study the sensitivity analyses are carried out with design variables such as yield strength, live load, damping ratio, and elastic modulus on the vertical deflection of the joint from which a column is suddenly removed. The Monte Calro simulation, tornado diagram method, and the first order second moment method(FOSM) are applied for the sensitivity study. According to the nonlinear static analysis results, the vertical deflection is most affected by the variation of yield strength of beams. The nonlinear dynamic analyses show that the behaviour of model structures is highly sensitive to variation of the yield strength of beams and the structural damping ratio.

• Journal of Digital Contents Society
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• v.19 no.1
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• pp.103-112
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• 2018

In this paper, we propose a method of recognizing emotions using PPG sensor which measures blood flow according to emotion. From the existing PPG signal, we use a method of determining positive emotions and negative emotions in the frequency domain through PSD (Power Spectrum Density). Based on James R. Russell's two-dimensional prototype model, we classify emotions as joy, sadness, irritability, and calmness and examine their association with the magnitude of energy in the frequency domain. It is significant that this study used the same PPG sensor used in wearable devices to measure the top four kinds of emotions in the frequency domain through image experiments. Through the questionnaire, the accuracy, the immersion level according to the individual, the emotional change, and the biofeedback for the image were collected. The proposed method is expected to be various development such as commercial application service using PPG and mobile application prediction service by merging with context information of existing smart phone.

• Spatial Information Research
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• v.18 no.2
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• pp.35-44
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• 2010

This research intended to estimate the damage information from torrential rainfalls using airphotos and spatial data which have been rapidly increasing their applicability recently. The study area was Bonghwagun of Gyungsangbukdo where the large amount of damages were occurred from torrential rainfall in July, 2008. For this study, the database was constructed for the study area by collecting usable data. The interpretable items from the airphotos of 40cm spatial resolution were selected. Also, the useful GIS layers such as road were selected in the digital map to extract the damage information more accurately and rapidly. The damaged area was easily identified through the comparison of pre- and post-disaster airphotos. The recovery cost was estimated by applying unit cost to the damaged area. GIS's overlay function was used to extract the damage information of for individual items damaged. The method for extracting damages information using GIS and airphotos could be more efficient and cost effective in case of relatively wide and unapproachable damaged areas. It is also expected that the method using high resolution imagery would lead to minimize the secondary damages as well since it can facilitate the damage estimation within short period of time thereby supporting early securing budget for recovery.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.12
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• pp.1043-1050
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• 2010

Fuel stratification and thermal stratification occur in the HCCI combustion chamber on a microscopic scale. They affect the ignition and combustion processes. In this study, the effect of the inhomogeneity in the mixture gas on the HCCI combustion process was investigated. Two-dimensional chemiluminescence images were captured using a framing camera to evaluate the flame structure. DME was used as the test fuel. First, the effect of inhomogeneity in the fuel distribution in the premixture was investigated for the four-stroke optically accessible engine. Then, by comparing the combustion of the homogeneous mixture in the rapid compression machine, which does not contain any residual gas, with the combustion in the four-stroke engine, the effect of inhomogeneity in temperature due to the residual gas was analyzed. The results showed that a time lag appears spatially in combustion under inhomogeneous conditions in the four-stroke engine. The spatial variation in the combustion without the residual gas in the rapid compression machine is less than that in the combustion in the four-stroke engine.