하계 동중국해 북부 해역에서 저층 냉수괴의 거동

장성태,이재학,김철호,장찬주,장영석,Jang, Sung-Tae,Lee, Jae-Hak,Kim, Cheol-Ho,Jang, Chan-Joo,Jang, Young-Suk 한국해양학회 2011 바다 Vol.16 No.1

황해저층냉수는 지난 동계의 차고 건조한 바람에 의해 생성되어, 하계에 황해 중앙골을 따라 남하하는 것으로 알려져 있다. 동중국해 북부해역에서 황해저층냉수의 특성과 거동을 파악하기 위해 2003년부터 2009년까지 하계에 관측한 자료를 분석하였다. 수괴분석을 통해 본 연구해역에 영향을 미치는 황해저층냉수를 새롭게 정의하여 북서저층냉수라고 명명하였고, 수온 $13.2^{\circ}C$ 이하, 염분 32.6~33.7 psu와 밀도 $24.7{\sim}25.5\;{\sigma}_t$로 특성지었다. 지형류 계산에 의해 연구해역에서 북서저층냉수는 약 2 cm/s 이하의 속도로 남하하는 것으로 추정하였다. 정의한 북서저층냉수는 수온의 범위와 자지하고 있는 영역에서 연간 변동을 보이며, 이러한 변동은 이전 해 동계 황동중국해의 표층수온의 변화와 밀접한 관련이 있었고, 동계 표층수온의 변화는 동계 기온에 의한 영향이 지배적임을 확인하였다. 동계 동중국해 표층수온은 북극진동 지수와 높은 상관성을 보이며, 동계의 북극진동이 음일 때 동중국해 표층수온이 하강하였고, 이러한 영향으로 북서저층냉수 세력이 동중국해 북부 해역까지 저수온을 보이면서 확장하였다. 동 연구는 동계의 북극진동지수, 황동중국해 겨울철 표층수온, 동중국해 북부의 북서저층냉수가 역학적으로 관련이 있음을 보였고, 이를 바탕으로 하계 동중국해 북부해역에서 저층냉수의 거동을 유추할 수 있을 것으로 사료된다. The Yellow Sea Cold Water (YSCW) is formed by cold and dry wind in the previous winter, and is known to spread southward along the central trough of the Yellow Sea in summer. Water characteristics of the YSCW and its movement in the northern East China Sea (ECS) are investigated by analyzing CTD (conductivity-Temperature-Depth) data collected from summertime hydrographic surveys between 2003 and 2009. By water mass analysis, we newly define the North Western Cold Water (NWCW) as a cold water mass observed in the study area. It is characterized by temperature below $13.2^{\circ}C$, salinity of 32.6~33.7 psu, and density (${\sigma}_t$) of 24.7~25.5. The NWCW appears to flow southward at about a speed less than 2 cm/s according to the geostrophic calculation. The newly defined NWCW shows an interannual variation in the range of temperature and occupied area, which is in close relation with the sea surface temperature (SST) over the Yellow Sea and the East China Sea in the previous winter season. The winter SST is determined by winter air temperature, which shows a high correlation with the winter-mean Arctic Oscillation (AO) index. The negative winter-mean AO causes the low winter SST over the Yellow Sea and the East China Sea, resulting in the summertime expansion and lower temperature of the NWCW in the study area. This study shows a dynamic relation among the winter-mean AO index, SST, and NWCW, which helps to predict the movement of NWCW in the northern ECS in summer.

MI-MESI 쓰기-무효화 스누핑 캐쉬 일관성 유지 프로토콜

장성태,Jang, Seong-Tae 한국정보처리학회 1995 정보처리논문지 Vol.2 No.5

본 논문에서는 분리형 트랜잭션 버스를 기반으로한 다중 프로세서 환경하에서 MESI와I-MESI 캐쉬 일관성 유지 프로토콜의 문제점을 개선한 MI-MESI 쓰기-무효화 스누핑 캐쉬 일관성 유지 프로토콜을 제시한다. 이 프로토콜에서 각 캐쉬 블럭은 여섯 개의 캐쉬 상태 즉, Modified-shared, Invalid-by-other, Modified, Exclusive, Shared 및 Invalid 상태중의 하나를 유지하여, 기존의 MESI와데 I-MESI 캐쉬 일관성 유지 프 로토콜에서 발생하는 불필요한 메모리 모듈의 갱신과 메모리 모듈에서의 접근 충돌을 크게 줄여서 빠른 메모리 접근 시간을 제공할 수 있다. In this paper, we present MI-MESI write-invalidate snooping cache coherence protocol which addresses several significant drawbacks of MESI and MI-MESI write -invalidate snooping cache coherence protocols under the split transaction bus based multiprocessor environment. In this protocol, each cache block maintains one of six cache states which represent Modified-shared, Invalid-by-other, Modified, Exclusive, Shared and Invalid states. By using these cache states, our protocol reduces both the access contention and unnecessary updates for the memory modules significantly, and thus providing the fast memory access time.

NUMA 다중 프로세서 시스템을 위한 프로세서 노드의 설계

張星泰 水原大學校 1997 論文集 Vol.15 No.-

Recently, hierachical bus based NUMA multiprocessors have been widely used as sever systems. In this paper, we design and implement processor node for NUMA multiprocessor which combines 8 processors nodes, using dual P6 global system buses. The processor node is based on the Intel PentiumPro processor and external P6 bus it defines. In addition to 4 PentiumPro processors, the node contains single P6 local system bus, remote access cache which stores only the copies of remote memory blocks, local shared memory, directory cache which has the state information of each local memory block, and I/O subsystems.

하계 동중국해 북부해역에서 표층수의 거동 특성

장성태,오유리,이재학,김철호,유승협 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.6

다중 프로세서 시스템의 성능 향상을 위한 메모리 모듈 구조

장성태 수원대학교 기초과학연구소 1995 基礎科學論文集 Vol.4 No.-

Shared memory multiprocessor system has the high degree of resource sharing, which induces the bottleneck of performance improvement. To overcome this weakness, traditional cache coherence protocols pay special attention to the reducing of bus and memory traffic. In this paper, we present a new memory module structure maintaining the status information for each memory block in its directory cache. This structure enhances the system performance by reducing the memory access contention and the memory response time under split transaction bus based multiprocessor environment.

개선된 I-MESI 쓰기-무효화 스누핑 캐쉬 일관성 유지 프로토콜

장성태 수원대학교 1994 基礎科學論文集 Vol.3 No.-

In this paper, we present MI-MESI write-invalidate snooping cache coherence protocol which adresses several significant drawbacks of MESI and I-MESI write-invalidate snooping cache coherence protocols under the split transaction bus based multiprocessor environment. In this protocol, each cache block maintains six cache states(i.e., Modified-shared, Invalid-by-other, Modified, Exclusive, Shared adn Invalid). By using these cache states, our protocol reduces both the access contention and unnecessary updates for the memory mocules significantly, and thus providing the fast memory access time.

우물에 도핑된 p-형 양자우물에서의 자체 모순없는 퍼텐셜

장성태,유건호 한국물리학회 2006 새물리 Vol.53 No.3

In doped semiconductor quantum structures, the potential due to ionized impurities and free carriers can be obtained by solving the Schrodinger equation and the Poisson equation self-consistently. In this research, we studied how, in $p$-type GaAs/AlGaAs quantum wells in the well region, the self-consistent potential depends on the well width and the impurity concentration. The Schrodinger equation was written in the envelope function approximation by using the block-diagonalized Luttinger Hamiltonian including the heavy-hole and the light-hole bands, and both the Schrodinger equation and the Poisson equation were solved by using a finite-element method. The dependence of the self-consistent potential on the well width could be explained by wavefunction penetration into the barrier. For a given 2-dimensional hole density, there existed a width that minimized the self-consistent potential, and that width increased as the hole concentration increased. The results of this study may be useful in understanding and designing diluted magnetic semiconductor quantum wells. 도핑된 반도체 양자구조에서는 자유 운반자의 재배치에 의해 퍼텐셜이 변형되는데, 이 퍼텐셜의 모양은 슈뢰딩거 방정식과 푸아송 방정식을 자체 모순없이 풀어서 구할 수 있다. 이 연구에서는 우물 영역에 $p$-형으로 도핑된 GaAs/AlGaAs 양자우물에서의 자체 모순없는 퍼텐셜의 모양이 양자 우물의 너비와 불순물 농도에 따라 어떻게 변하는지 살펴보았다. 슈뢰딩거 방정식은 중양공띠와 경양공띠를 포함하며 구역대각화된 루틴저 해밀토니안을 사용하는 싸개선함수근사법을 써서 기술하였고, 슈뢰딩거 방정식과 푸아송 방정식은 각각 유한원소법을 사용하여 풀었다. 자체 모순없는 퍼텐셜 모양의 양자 우물 너비에 따른 변화는 파동함수가 장벽물질로 새나가는 정도에 의해 설명할 수 있었다. 주어진 2차원 양공 밀도에서 자체 모순없는 퍼텐셜에 의한 띠 모양의 일그러짐이 가장 작은 우물의 너비가 존재하였고, 이 너비는 받개 농도가 높아질수록 넓어졌다. 이 연구의 결과는 희석자성반도체 양자우물의 이해와 설계에 도움이 되리라고 생각된다.

적외선을 이용한 액체 유기물 내 수분 농도 감지기

장성태,정종대,정경석 한국기술교육대학교 2004 論文集 Vol.10 No.2

Water in liquid organic chemicals tends to lower power output or result in the failure of internal combustion engines. There have been lots of proved standard techniques of measuring the water contents in oil, such as distillation, coulometric Karl Fischer titration, and centrifuge. These techniques, however, are mainly for laboratory uses and hard to be used for the continuous monitoring application. Light absorption of water in the near-IR has been used to develop a sensor system to continuously detect water presence in the oil flow. Result shows functional correspondence in the output voltage of the sensor system and water concentration.

가덕수도 근해에서 물리적 현상과 해류의 계절 변동

장성태,전동철,신창웅 한국해양과학기술원 2008 Ocean and Polar Research Vol.30 No.1

In order to investigate seasonal variations of the physical environments in the region of Jinhae Bay-Nakdongpo, we carried out hydrographic surveys from November 2000 to November 2001. Horizontal and vertical distribution of salinity and temperature shows large seasonal variations. Water column is well mixed in winter and stratified in summer. Low-salinity water is distributed in the form of patches because of the drainage control at the Nakdong River. Seasonal variations in the sea near Gadeok-Sudo are affected by topography, river discharge and tidal current. Currents have been measured using a bottom mounted ADCP and DCM12 between November 2000 and August 2001 in the Gadeok-Sudo. The current in the Gadeok- Sudo shows a distinct two-layer structure with reversed current. Low-pass filtered time series of wind, sea elevation and current are coherent for the period of 1-2 days and are ttributed to Ekman-like dynamics. Spatial and temporal circulation pattern shows a slight different. The subtidal current in Jinhae Bay goes northward, however is reversed in the Gadeok-Sudo mouth. In order to investigate seasonal variations of the physical environments in the region of Jinhae Bay-Nakdongpo, we carried out hydrographic surveys from November 2000 to November 2001. Horizontal and vertical distribution of salinity and temperature shows large seasonal variations. Water column is well mixed in winter and stratified in summer. Low-salinity water is distributed in the form of patches because of the drainage control at the Nakdong River. Seasonal variations in the sea near Gadeok-Sudo are affected by topography, river discharge and tidal current. Currents have been measured using a bottom mounted ADCP and DCM12 between November 2000 and August 2001 in the Gadeok-Sudo. The current in the Gadeok- Sudo shows a distinct two-layer structure with reversed current. Low-pass filtered time series of wind, sea elevation and current are coherent for the period of 1-2 days and are ttributed to Ekman-like dynamics. Spatial and temporal circulation pattern shows a slight different. The subtidal current in Jinhae Bay goes northward, however is reversed in the Gadeok-Sudo mouth.

낙동강 하구에서의 해양 환경 변화

장성태,김기철,JANG SUNG-TAE,KIM KI-CHEOL 한국해양학회 2006 바다 Vol.11 No.1

낙동강 하구는 담수와 해수가 만나 복잡한 순환 양상을 보이는 지역으로, 1987년에 준공된 하구둑의 건설로 지형적인 변화와 함께 여러 가지 해양 환경적인 변화를 가져왔다. 하구둑 건설 전과 후의 특징을 보면, 건설 전에 비해 흐름이 약해졌고 조류가 흐름을 주도하던 혼합 기작이 담수의 방류가 주도하는 체계로 변하였다. 이러한 담수의 방류는 그 정도에 따라 낙동강 하구둑 하류부 담수의 거동과 혼합 특성을 변화시켰으며 해수 순환에도 큰 영향을 주었다 본 연구에서는 낙동강 하구둑 하류부의 유동 특성을 하구둑의 수문 개폐에 초점을 맞춰 분석하였다. The Nakdong Estuary is complex water system, where sea water and fresh water meet each other. It has undergone the significant change of its environmental conditions since the construction of the Nakdong River Barrier in 1987. Prior to its construction, mixing and circulation processes in the Nakdong Estuary was dominated by tidal current. However, after the dam construction, those processes were greatly altered by the artificial control of the fresh river water discharge. In this paper, the influence of opening and closing the floodgate of Nakdong River on the outflow behavior of estuarine water from the Nakdong Estuary is analyzed in detail.