• Electronics and Telecommunications Trends
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• v.16 no.5 s.71
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• pp.1-11
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• 2001

본 논문은 대형 ATM 스위칭 시스템인 HANbit ACE2000 시스템의 소프트웨어를 개발하고 시스템 개발 시 필요한 각종 소프트웨어 컴포넌트들을 효율적으로 개발 및 등록, 관리하기 위해 도입된 미들웨어와 객체지향 설계 개념을 이용한 UML을 적용하여 프로그램의 에러를 줄이고 개발자와 관리자간의 규약에 의한 체계적인 종합개발 및 관리 방안에 대한 특성과 각 기능에 대해 살펴본다. 또 이것을 활용하여 ACE2000 시스템에서 개발, 등록 관리되고 있는 소프트웨어에 대해 소개함으로써 대형 시스템 개발에 유용하게 이용되도록 한다. 특히, 대형 시스템 개발에 적용된 개발체계 및 개발환경을 언급함으로써 유사 프로젝트 수행 시 추가 개선사항이나 개발환경 개선에 참고가 되도록 하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1267-1270
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• 2000

위성통신 시스템은 기존의 지상망이나 광 케이블 기술에 비해 통신 대역폭의 유연성과 다중 접속능력, 이동통신, 광역성, 멀티포인트 및 브로드캐스팅 등의 본래의 특징으로 인해 초고속정보통신망 구축에 중요한 역할을 하게 된다. 특히 OBP (On-Board Processing) 기술을 적용하면 기존 위성통신 탑재장치의 수동적인 중계 기능 이외에 복조/재변조, 부호/복호화 및 오류정정, 중계기 및 빔간의 상호 연결/절체 등의 새로운 기능이 추가되어 능동적인 중계를 가능하게 함으로써 통신 품질의 향상, 통신 링크의 전송 효율 개선, 전송 용량 증대 등의 장점을 갖고있다. OBP 탑재 위성 B-IDSN 중계망은 하나의 거대한 가상 ATM 교환기로 간주되고, 여러중계 지구국들중 목적 중계 지구국으로 패킷들을 직접 라우팅 할 수 있는 장점이 있다. 본 논문은 OBP 탑재 위성 B-ISDN 연동 프로토콜 연구를 수행하는 것으로서, 위성 B-ISDN 구조와 각 지구국별 신호 기능 및 B-IDSN 신호 시스템인 DSS2 계층 3 신호 프로토콜, B-ISUP 프로토콜, S-BISUP 프로토콜의 구조를 분석하였다. 또한 점-대-다지점을 위한 B-ISDN의 연결과 소유권 및 각각의 프로토콜에 대한 메시지와 프리미티브를 정의하여, 이를 토대로 OBP 탑재 위성 B-IDSN 연동 프로토콜의 기본 호 처리 절차를 설계 및 구현하고, 이를 테스트하였다.

• Journal of IKEEE
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• v.5 no.1 s.8
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• pp.100-110
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• 2001

In this paper, we investigated several buffer management schemes for the design of shared-memory type ATM switches, which can enhance the utilization of switch resources and can support quality-of-service (QoS) functionalities. Our results show that dynamic threshold (DT) scheme demonstrate a moderate degree of robustness close to pushout(PO) scheme, which is known to be impractical in the perspective of hardware implementation, under various traffic conditions such as traffic loads, burstyness of incoming traffic, and load non-uniformity across output ports. Next, we considered buffer management strategies to support QoS functions, which utilize parameter values obtained via connection admission control (CAC) procedures to set tile threshold values. Through simulations, we showed that the buffer management schemes adopted behave well in the sense that they can protect regulated traffic from unregulated cell traffic in allocating buffer space. In particular, it was observed that dynamic partitioning is superior in terms of QoS support than virtual partitioning.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11A
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• pp.929-935
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• 2003

An analog/digital mixed mode ASIC for network synchronization of ATM switching system has been designed and fabricated. This ASIC generates a 234.7/46.94 ㎒ system clock and 77.76/19.44 ㎒ user clock using 46.94 ㎒ transmitted clocks from other systems. It also includes digital circuits for checking and selecting of the transmitted clocks. For effective ASIC design, full custom technique is used in 2 analog PLL circuits design, and standard cell based technique is used in digital circuit design. Resistors and capacitors for analog circuits are specially designed which can be fabricated in general CMOS technology, so the chip can be implemented in 0.8$\mu\textrm{m}$ digital CMOS technology with no expensive. Testing results show stable 234.7 ㎒ and 19.44 ㎒ clocks generation with each 4㎰ and 17㎰ of low ms jitter.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.243-251
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• 2012

Real-time monitoring for environmental factors(temperature, salinity, chlorophyll, etc.) and carbonate components( pH and $fCO_2$) was conducted during 5-6th of July, 2012 at a seaweeds farm in Gijang, Busan. Surface temperature and salinity were ranged from $12.5{\sim}17.6^{\circ}C$ and 33.7~34.0, respectively, with highly daily and inter-daily variations due to tide, light frequency(day and night) and currents. Surface $fCO_2$ and pH showed a range of $381{\sim}402{\mu}atm$ and 8.03~8.15, and chlorophyll-a concentration in surface seawater ranged 0.8~5.8 ${\mu}g\;L^{-1}$. Environmental and carbonate factors showed the highest/lowest values around 5 pm of 5th July when the lowest tidal height and strongest thermocline in the water column, suggesting that biological production resulted in decrease of $CO_2$ and increase of pH in the seaweed farm. Processes affecting the surface $fCO_2$ distribution were evaluated using a simple budget model. In day time, biological productions by phytoplankton and macro algae are the main factors for $CO_2$ drawdown and counteracted the amount of $CO_2$ increase by temperature and air-sea exchange. The model values were a little higher than observed values in night time due to the over-estimation of physical mixing. The model suggested that algal production accounted about 14-40% of total $CO_2$ variation in seaweed farm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.751-762
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• 2000

In the forthcoming next generation highspeed networks, the provisioning of broadband mobile multimedia services is the most important issue while an efficient network management architecture, which can manage the network resources efficiently, is essential. The next generation highspeed networks will be composed of the ATMand SDH-based transport network systems and the H-based interworking systems. The management functions of these network systems are implemented various technologies, such as TMN and SNMP. In order to integrate these network resources efficiently with heterogeneous management functions, the distributed network management architecture such as TINA is most appropriate. In this pape, we propose an interworking architecture for TINA manager and TMN agent. where the TINA-based EML subnetwork management operations mapped into the related management operations of the TMN NE agent. The proposed interworking architecture is simpler than JIDM, and the processing overhead is minimized.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.1
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• pp.1-10
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• 2016

Currently available surface seawater partial pressure carbon dioxide ($pCO_2$) data sets in the East Sea are not enough to quantify statistically the carbon dioxide flux through the air-sea interface. To complement the scarcity of the $pCO_2$ measurements, we construct a neural network (NN) model based on satellite data to map $pCO_2$ for the areas, which were not observed. The NN model is constructed for the Ulleung Basin, where $pCO_2$ data are best available, to map and estimate the variability of $pCO_2$ based on in situ $pCO_2$ for the years from 2003 to 2012, and the sea surface temperature (SST) and chlorophyll data from the MODIS (Moderate-resolution Imaging Spectroradiometer) sensor of the Aqua satellite along with geographic information. The NN model was trained to achieve higher than 95% of a correlation between in situ and predicted $pCO_2$ values. The RMSE (root mean square error) of the NN model output was $19.2{\mu}atm$ and much less than the variability of in situ $pCO_2$. The variability of $pCO_2$ with respect to SST and chlorophyll shows a strong negative correlation with SST than chlorophyll. As SST decreases the variability of $pCO_2$ increases. When SST is lower than $15^{\circ}C$, $pCO_2$ variability is clearly affected by both SST and chlorophyll. In contrast when SST is higher than $15^{\circ}C$, the variability of $pCO_2$ is less sensitive to changes in SST and chlorophyll. The mean rate of the annual $pCO_2$ increase estimated by the NN model output in the Ulleung Basin is $0.8{\mu}atm\;yr^{-1}$ from 2003 to 2014. As NN model can successfully map $pCO_2$ data for the whole study area with a higher resolution and less RMSE compared to the previous studies, the NN model can be a potentially useful tool for the understanding of the carbon cycle in the East Sea, where accessibility is limited by the international affairs.