한국 남동해역 시질퇴적물의 물리적 성질

김길영(Gil Young KIM),김대철(Dae Choul KIM),박수철(Soo Chul PARK),유동근(Dong Geun YOO),최진혁(Jin Hyuk CHOI),김정창(Jeong Chang KIM) 한국수산과학회 1996 한국수산과학회지 Vol.29 No.5

Physical properties and textural parameters of thirty-five piston core samples recovered from the southeastern coast of Korea (Korea Strait), were investigated using the autopycnometer. The physical properties (porosity, water content, wet bulk density, dry bulk density, grain density, and void ratio) were measured at rather uniform intervals along each core. Sediment texture (grain size, sand, silt, and clay contents) was also measured at the same subbottom depth. The measured and calculated results are; mean grain size 0.57∼8.09 Φ (average: 3.67 Φ), porosity 26∼81% (average: 55%), water content 16.7∼61.4% (average: 31.6%, wet bulk density 1.37∼2.18 g/㎤ (average: 1.85 g/㎤), dry bulk density 2.55∼3.11 g/㎤ (average: 2.35 g/㎤), grain density 2.40∼3.10 g/㎤ (average: 2.85 g/㎤), and void ratio 0.56∼2.54 (average: 0.94). The sediment texture generally coincides well with the bathymetry indicating the influence of Pleistocene-Holocene sea level changes. Also the contours of physical properties are closely related to the sediment texture. Fluctuation of physical properties are similar to the textural variation. It seems that sediment texture is a significant factor in determining physical property in this study area.

HF 데이터 통신에서 디지털 모뎀을 위한 RS 및 컨볼루션 부호의 연접 부호 성능

김정창 ( Jeong Chang Kim ),양규식 ( Gyu Sik Yang ),정기룡 ( Gi Ryong Jeong ),박동국 ( Dong Kook Park ),정성훈 ( Sung Hun Jung ) 한국항행학회 2012 韓國航行學會論文誌 Vol.16 No.2

본 논문에서는 HF (high frequency) 데이터 통신을 위한 디지털 모뎀의 성능 향상을 위하여 개선된 오류정정부호 방식을 제안하고 성능을 검증한다. 제안하는 오류정정부호 방식은 외부의 Reed-Solomon 부호와 내부의 컨볼루션 부호를 연접하여 만들어진다. 시뮬레이션 결과는 제안하는 시스템이 기존 PACTOR-Ⅲ 규격의 오류정정부호 방식을 사용하는 시스템에 비해 비트 오율 성능을 크게 향상시킴을 보여준다. 따라서 제안하는 부호화 방식을 사용하여 HF 데이터 통신을 위한 디지털 모뎀의 대역폭 효율성을 크게 향상시킬 수 있을 것이다. In this paper, we propose an improved error correction code in order to improve the performance of digital modems for HF data communications and verify the performance of the proposed scheme. The proposed scheme employs outer Reed-Solomon codes concatenated with inner convolutional codes. Numerical results show that the proposed system significantly improves the bit error rate performance compared to the conventional PACTOR-Ⅲ modems. Hence, the proposed system can improve the bandwidth efficiency of digital modems for HF data communications.

해양관련학과 승선실습의 문제점과 개선을 위한 방안

김정창(Jeong-Chang KIM) 한국수산해양교육학회 1998 水産海洋敎育硏究 Vol.17 No.-

탐양호(探洋號)의 조종성능(操縱性能)에 관한 연구(硏究)

김정창 ( Jeong Chang Kim ) 한국어업기술학회 1995 수산해양기술연구 Vol.31 No.2

광양만 북동부 해역의 해류관측

이재철,김정창,박명원,Lee, Jae-Chul,Kim, Jeong-Chang,Park, Myug-Won 한국해양학회 2006 바다 Vol.11 No.4

ITS에 있어서 Hi-Pass 시스템의 성능 개선을 위한 전파흡수체의 개발

김동일,김정창,주양익,Kim, Dong Il,Kim, Jeong Chang,Joo, Yang Ick 한국정보통신학회 2014 한국정보통신학회논문지 Vol.18 No.7

하이패스 시스템은 5.8 GHz대 무선통신방식을 채용하는 기본 요소 중의 하나이며, 지능교통정보시스템(ITS; Intelligent Traffic System)을 실현하는 한 부분이다. 그러나, 하이패스 시스템에서 신호에러, 다중반사, 또는 시스템간 간섭으로 인한 통신 오류는 자주 발생한다. 이와 같은 문제점을 해결하기 위하여 전자파흡수체가 적용될 수 있으며, 이를 위하여 카본, 센더스트 및 CPE의 조성비가 각각 다른 몇 가지 샘플을 제작하여 최적의 조성비를 탐색하였다. 그 결과 최적 조성비는 Carbon : Sendust : CPE is 10 : 40 : 50 wt.%임이 확인되었다. 복소 비유전율과 복소 비투자율은 측정 데이터를 이용하여 도출하였으며, 흡수체의 최적 설계 파라미터들은 시뮬레이션에 의하여 결정하였다. 나아가서, 전파흡수능을 흡수체의 두께를 변화시키면서 계산한 결과, 설계한 전파흡수체의 흡수능은 5.8 GHz에서 22.4 dB였다. 설계치에 기반을 두고 제작한 흡수체의 특성은 설계/시뮬레이션 값과 잘 일치하므로, 논문에 제안 개발된 하이패스용 전파흡수체는 실제 상황에 적용될 수 있을 것이다. High-Pass (ETC ; Electronic Toll Collection) system is one of the basic elements, which adopts a wireless communication method using 5.8 GHz and can realize a part of ITS (Intelligent Traffic System). On the other hand, communication errors occur frequently in Hi-Pass system due to signal erros, multi-path reflection, and/or system-to-system interferences. To solve these problems, an EM (Electro-Magnetic) wave absorber can be used. To solve these Problems, we fabricated some samples in the different composition ratios of Carbon, Sendust, and CPE, and it was confirmed that the optimum composition ratio of Carbon : Sendust : CPE is 10 : 40 : 50 wt.%. The complex relative permittivity and complex relative permeability were derived by using the measured data. In addition, the optimum design parameters for the absorber were determined by simulation. Then the absorption abilities were calculated by changing the thickness of the EM wave absorbers. As a result, the optimum thickness of the developed EM wave absorber was 2.85 mm with absorption ability over 22.4 dB at 5.8 GHz. Futhermore, the EM wave absorber was fabricated based on the simulated and designed values. The measured values agreed well with the simulated ones. Therefore, it was clearly shown that the developed EM wave absorber in this paper is to be applied in actual situations.

2006년 봄철 광양만 해류의 구조와 변동

이재철,김정창,Lee, Jae-Chul,Kim, Jeong-Chang 한국해양학회 2007 바다 Vol.12 No.3

광양만의 순환을 이해하기 위하여 2006년 봄철에 수심이 가장 깊은 두 지점을 선정하여 ADCP가 장착된 모니터링 부표 2대를 이용하여 유속관측을 하였다. 두 지점에서 공통적으로 북향류가 지배적인데, 이는 서쪽의 남향류를 동반하는 반시계 방향의 순환 이 있음을 뒷받침 하고 있다. 남쪽에서는 14 m 수심에서 유향이 반전되는 2층 구조가 뚜렷하며 저층의 북향류는 바닥에 가까운 36 m 수심까지 증가한다. 북쪽 지점에서는 북향류가 더욱 강해져서 북쪽의 단면적 감소에 따른 해류의 가속 효과가 있으며 상층부에서도 북향류가 우세하다. EOF 분석을 통한 연직구조에 있어서 첫 번째 모드는 북쪽 부표에서 전체 분산의 74%인데 비하여 남쪽 부표에서는 67%로 감소하고 상대적으로 2층 구조의 비중이 크다. 반시계 방향의 순환과 관련된 북향류의 전형적인 유속은 약 10 cm/s이다. 여기에 중첩되는 변동성으로서 국지적인 바람의 영향은 거의 받지 않는 반면에 동-서 방향의 바람에 의한 외해의 에크만 수송과 관련된 비국지적 영향은 주로 풍속이 강할 경우에 나타난다. Two monitoring buoys equipped with ADCP were deployed at the deepest positions along the trough of the central Gwangyang Bay in spring 2006 in order to study the circulation in the bay. Northward velocity is commonly dominant at both stations located in the eastern part of the channel, which supports the cyclonic circulation accompanied by the southward flow in the western part. The southern station has a distinct two-layer structure with current reversal at 14 m depth and increasing northward velocity in the lower layer to 36 m depth close to the bottom. At the northern station the northward flow becomes accelerated due to the decrease in the cross-sectional area and this northward current is dominant even in the upper layer. In the modal structure from the EOF analysis, the first mode has 74% of total variance at the northern station whereas it is 67% but the baroclinic portion increases at the southern station. The typical northward velocity is about 10 cm/s which is associated with the cyclonic circulation. Subtidal variability due to the local wind effect is negligible, but the nonlocal response associated with offshore Ekman flux by the zonal wind is found during strong wind events.

남해 Sand ridge 퇴적물의 퇴적상과 물리적 특성

천희정(Hee Jeong Chon),서영교(Yong Kyo Seo),김대철(Dae Choul Kim),김정창(Jeng Chang Kim),(Jock Keene) 한국수산과학회 1998 한국수산과학회지 Vol.31 No.5

Sand ridges in the South Sea of Korea have been investigated to reveal the surface morphology and vortical variation in sediment physical property, Both field and laboratory methods such as high resolution subbottom profiling, side scan sonar, and physical property and sediment textural study on cored sediments were employed. Asymmetric sand waves are fecund on the ridge. No prominent difference in the sediment was recorded throughout the ridge area. Sediment sorting is generally poor due to interbedded mud. Average compressional wave velocity is 1753 m/sec for the sand dominated core section. Most of cores show two prominent facies : facies A and B. Facies A is defined as modern mud sediment and B is dominated by relict sand. Facies B is characterized by gravel, sand, and shell fragment. It is suggester that the Facies B was developed in transgressive environment by tide and sporadic high energy events.

저서성 요각류 Tigriopus japonicus의 nauplii 생산에 미치는 미세조류의 영향

김미정 ( Mi Jeong Kim ),김정창 ( Jeong Chang Kim ),허성범 ( Sung Bum Hur ) 한국수산학회 2009 한국수산과학회지 Vol.42 No.3

The survival and growth of marine benthic invertebrate larvae such as abalone depend on the nutritional value of microalgae. However, it is difficult to determine the dietary value of the many microalgal species used for food by benthic larvae. Therefore, we tested the benthic copepod, Tigriopus japonicus, which grazes microalgae on substrata in a manner similar to abalone larvae. It also has short generation time and is easy to rear which makes to be easier to examine the dietary value of each microalgal species. We measured the daily production of nauplii from gravid females of T. japonicus fed 26 microalgal species separately. Amino acid and fatty acid content of the microalgae and the copepod was also analyzed. The nauplii production of T. japonicus was the highest (10.7) when they were fed Navicula sp. (B-394) and the lowest (0.8) when they were fed Scrippsiella trochoidea. In Tetraselmis suecica the nauplii production was so high (8.2), which was not significantly different with the diatom group. We determined that Navicula sp. (B-394), Rhaphoneis sp. and T. suecica were good sources of food for T. japonicus. We suggest that a diet of with a mixture of these three microalgal species may be also good for invertebrate larvae such as abalone.

多變量解析法에 의한 海難事故의 分析

金永植(Yeong-Sik KIM),金珽昌(Jeong-Chang KIM) 한국수산해양교육학회 1994 水産海洋敎育硏究 Vol.10 No.-