• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.336-348
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• 2010

The Single-channel seismic survey with the source of bubble pulser and drilling survey was carried out in 2008 and 2009 for the site survey of Daecheon-Wonsando area, which was a proposed area of Korea-China subsea tunnel. The goal of this study is to analyze the depth and characteristics of acoustic basement for the stability assessment and tunnel design in this proposed area through combining drilling data with this single-channel seismic data after detailed processing. For this purpose, among the data processing schemes which are usually applied to multi-channel seismic data, we applied the F-K filtering to eliminate the AC(alternating current) noise and the post-stack depth migration to produce depth section. As a result, we verified that the improved depth section could be obtained from single-channel seismic data, and the distribution and characteristics of basement could be analyzed in survey area through the combined analysis with drilling data. However, we could not interpret the detailed structures, fault and fracture zone, due to the quality of bubble pulser source and single-channel data. We expect that those detailed structures can be analyzed when higher resolution seismic data is provided. Therefore, we recommend some items for future seismic survey of subsea tunnel to obtain the high resolution seismic data.

• Korean Journal of Materials Research
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• v.13 no.11
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• pp.711-716
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• 2003

Gate length, height, and silicide thickness have all been shrinking linearly as device density has progressively increased over the years. We investigated the effect of the cobalt diffusion during the silicide formation process on the 60$\AA$-thick gate oxide lying underneath the Ti/Co and Co/Ti bilayers. We prepared four different cobalt silicides, which have similar sheet resistance, made from the film structure of Co/Ti(interlayer), and Ti(capping layer)/Co, and peformed the current-voltage, time-to-break down, and capacitance-voltage measurements. Our result revealed that the cobalt silicide process without the Ti capping layer allowed cobalt atoms to diffuse into the upper interface of gate oxides. We propose that 100$\AA$-thick titanium interlayer may lessen the diffusion of cobalt to gate oxides in 1500-$\AA$ height polysilicon gates.

• Journal of Korean society of Dental Hygiene
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• v.16 no.3
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• pp.409-415
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• 2016

Objectives: The purpose of the study is to investigate the correlation between stress and oral health in some high school students. Methods: The subjects were 224 students from three high schools in Daejeon, Daecheon, and Incheon. from November to December, 2015. A self-reported questionnaire was filled out from November to December, 2015. The questionnaire consisted of general characteristics of the subjects, awareness toward stress, stress-coping pattern, oral health-related quality of life and oral health care. Data were analyzed by SPSS 18.0 program. Results: In the analysis of academic stress level by the general characteristics and stress level, higher stress group showed higher experience in stress expectation(high group 16.43, subgroup 9.21), internal stress(high group 13.97, subgroup 6.16), expression type stress(high 10.06, sub-4.95). The higher stress group had emotional stress management in stress-coping pattern and less experience in difficulty of tooth brushing, chewing discomfort, and oral health-related quality of life management(p<0.001). Conclusions: The stress had a negative impact on the oral health related quality of life. The high school students should be able to manage the physical and mental stress. It is necessary to provide the continuous oral health care management against the stress by the dental hygienists.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.3
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• pp.237-243
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• 1990

For the improvement of the traditional pots which is using purple spirals for fishing webfoot octopus, Octopus Ocellatus GRAY, some experiments are carried out on the color preference in water tank and also operated practical experiment with PVC pots at sea for the comparison on the basis of the above water tank experiment. The results obtained are as follows: 1. The colors which webfoot octopus prefer in water tank or at sea are gray, red and green in order. 2. The catching efficiency of the pots with small spout(dia. 40mm) is better than that of large spout(dia. 50mm). 3. The results of fishing efficiency between PVC pots and purple spirals are shown almost same tendency.

• Annual Conference of KIPS
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• 2016.10a
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• pp.501-502
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• 2016

최근 스마트기기 사용량이 증가함에 따라 NFC나 Bluetooth 등 다양한 근거리 통신 서비스가 제공되고있다. 그러나 이들 통신방식은 별도의 통신 모듈을 필요로 하는 단점이 있다. 이러한 단점을 해결하기 위해 비가청주파수 대역을 이용한 통신이 연구되고 있다. 비가청주파수 대역은 18kHz~22kHz 사이의 사람에게 들리지 않는 주파수 대역으로 마이크와 스피커만 있으면 비가청주파수 통신이 가능하다. 기존 연구는 특정 사용자를 식별하여 데이터를 보안상 안전하게 전송하는 방식이 없다. 본 논문에서는 통신에 사용되는 두 기기가 본 논문에서 제안한 공유키를 활용하여 3단계의 과정을 거쳐 사용자를 식별하는 방법을 제안한다. 또한 식별 과정에서 만들어진 값은 메시지를 암호화하는데 사용되어 보안을 강화한다. 이 식별 방법은 비가청주파수 통신을 IoT 등 다양한 분야에 활용하는데 사용할 수 있다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.9-11
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• 2014

As Daecheon beach, which is the study area, has problem of erosion and loss of most beach under the extraordinary wave during the typhoon event, it is necessary to apply erosion control measures for short term impact. Therefore, we analyzed the status and reason of the erosion by field survey, collection of hydraulic model test, and numerical model experiment. For the erosion control measure, we adopted beach feeding and submerged reef method available at that site among various counter measures. Numerical analyses were made for both beach feeding only and beach feeding with submerged reefs and these were compared with the present status to find out the optimum design and to contribute for preparing a long term plan of beach loss protection.

• Proceedings of the KIEE Conference
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• 1998.11b
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• pp.555-557
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• 1998

본 연구에서는 PCS(개인통신서비스)를 이용한 신호처리를 하기위한 시스템의 구축과 그의 응용에 관해서 알아보고자 한다. 신호처리를 위해서는 GPS(Global Positioning System)신호를 사용하였으며 그 응용을 위해서 GIS(Geographic Information System)를 이용하고자 한다. GPS(Global Positioning System)는 안테나 및 엔진을 이용하여 이동 물체의 현재의 위치를 파악하는 위치판별시스템이다. 종래에는 이러한 시스템의 통신을 위해서 RF 무선통신을 이용하였으나 본 연구에서는 PCS(Personal Communication Service)를 이용하여 통신을 함으로써 이러한 위치정보시스템을 설치하는 비용을 최소화 할 수 있는 방안을 강구하여 실용성 있는 시스템을 개발하고자 한다. 또한 이동체의 GPS신호를 기지국이나 기타 다른 이동체의 PCS에서도 송신할 수 있는 다중통신 시스템을 갖추고자 하며 이를 위해서 수신국은 PCS 뿐만 아니라 유선전화망을 이용할 수 있게 개발 하고자 한다. 한편 개발된 시스템을활용하기 위해서 기존의 GIS(Geographic Information System)에의 적용을 위한 기초실험을 하고자 한다.

• Ocean and Polar Research
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• v.42 no.2
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• pp.141-155
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• 2020

Species composition of fish in the shallow water at Daecheon beach was determined using monthly beach seine samples collected from April 2010 to March 2011. These data were compared with the previous data, one just after reclamation in 1984-1985, and the other in 1995-96, in order to assess the post-reclamation impact of the environmental change on the fish assemblage. A total of 30 species from 1,464 individuals with biomass of 17,808 g were identified. Dominant species in the number of individuals were Chelon haematocheilus (49.3%), Takifugu niphobles (13.7%) and Paralichthys olivaceus (10.0%). Among pelagic fish, migrant juvenile fish such as Sardinella zunasi and Thryssa kammalensis were abundantly collected in 1984-85, but the catch amount was gradually decreased as time untill only few pelagic fish were collected in 2010-2011. The benthic fish were most abundant in 1984-1985 among habitat groups, and Favonigobius gymnauchen and Kareius bicoloratus were the top two predominants. Species composition of benthic fish did not exhibited drastic changes in 1995-1996, but both the abundance decline and the species composition change was evident in 2010-2011. Among the semi-benthic fish from 1984-1985 samples, Sillago japonica and Konosirus punctatus predominated. Species composition was slightly changed in 1995-1996, but significant changes were met in 2010-2011 with the two predominats, Chelon haematocheilus and Takifufu niphobles. These changes in fish species composition may reflect the post-reclamation effect of the impaired water quality and the accumulation of organic rich fine sediments.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.2
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• pp.6-12
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• 1998

Thin film SOI(Silicon-on-insulator) device offer unique advantages such as reduction in short channel effects, improvement of subthreshold slope, higher mobility, latch-up free nature, and so on. But these devices exhibit floating-body effet such as current kink which inhibits the proper device operation. In this paper, the SOI NMOSFET with a T-type gate structure is proposed to solve the above problem. To simulate the proposed device with TSUPREM-4, the part of gate oxide was considered to be 30nm thicker than the normal gate oxide. The I-V characteristics were simulated with 2D MEDICI. Since part of gate oxide has different oxide thickness, the gate electric field strength is not same throughout the gate and hence the impact ionization current is reduced. The current kink effect will be reduced as the impact ionization current drop. The reduction of current kink effect for the proposed device structure were shown using MEDICI by the simulation of impact ionization current, I-V characteristics, and hole current distribution.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2001.12a
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• pp.122-122
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• 2001

쌀과 같은 곡류는 전분질을 당분으로 전환시켜 술을 제조하여야 하므로 미생물이 생성하는 효소가 필요한데 그 효소원이 누룩이며 누룩은 주류의 품질이나 생산량에 영향을 미치는 가장 중요한 요소라고 할 수 있다. 본 연구는 전국44개 지역의 누룩에서 순수 분리된 89종의 곰팡이 중 효소역가와 당화력이 비교적 뛰어난 10종(Aspergillus sp. SH-412 Heunghae, Aspergillus sp. SH-422 Ulsan, Rhizopis sp. SH-606 Imdeok, Aspergillus sp. SH-607 Yhesan, Aspergilus sp. SH-613 Wolseong, Rhizopus sp. SH-654 Uncheon, Aspergillus sp. SH-660 Jeonkok, Aspergillus sp. SH-667 Dongseong, Aspergillus sp. SH-669 Uncheon, Aspergillus sp. SH-696 Daecheon)과 대조균주로 Aspergillus kawachii CF1002 그리고 효모 Saccharomyces cerevisiae를 사용하셨으며 탁주제조 중 균주별 술덧의 산도, 환원당, 아미노산도와 제조된 완성주의 유기산, 유리아미노산, 유리당, 휴젤유 및 색도를 HPLC, GC Mass, 색차계로 측정한 결과 다음과 같은 결론을 얻었다. 균주별 술덧의 주정도는 모든 실험구에서 Aspergillus kawachii보다 높았으며 특히 Aspergillus sp. SH-422는 14.9%로 가장 수율이 좋았다. 환원당은 Aspergillus sp. SH-613이 0.49%로 가장 높았고 Aspergillus sp. SH-422는 0.37%로 가장 낮았으며 산도는 시간의 경과에 따라 감소했으며 술덧 발효중 아미노산도는 시간의 경과에 따라 약간 상승 후 다소 낮아지는 경향을 보였다. 각 균주별 술덧의 유기산은 tataric acid, malic acid, succinic acid, lactic acid, acetic acid가 검출되었으며 lactic acid 함량이 2.0∼3.2g/100ml로 가장 많이 검출되었다. 유기산은 Aspergillus sp. SH-669가 가장 높게 확인되었으며 Aspergillus sp. SH-607이 가장 낮게 분석되었다. 술덧의 주 아미노산은 histidine, alanine, glutamic acid, leucine, tryptophan순으로 검출되었으며 특히 alanine은 주류에 단맛을 주는 성분으로 모든 실험구에서 많은 양이 검출되었다. 각 균주별 술덧의 유리당은 glucose가 가장 많이 검출되었으며 Fusel oil은 iso-butyl alcohol과 iso-pentyl alcohol 이 가장 많이 검출되었다. 한편 균주별 술덧의 색차를 측정한 결과 L값은 63.33∼41.98, a값은 0.09∼-3.47, b값은 17.41∼4.90으로 나타났다.