• Journal of Korean Port Research
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• v.14 no.1
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• pp.37-45
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• 2000

Centralized safety stock in a periodic replenishment system which consists of one central warehouse and m regional warehouse can reduce backorders allocating the centralized safety stocks to regional warehouse in a certain instant of each replenishment cycle. If the central warehouse can not monitoring inventories in the regional warehouse, then we have to predetermine the instant of allocation according to demand distribution and this instant must be same for all different replenishment cycle. However, transition of inventory level in each cycle need not to be same, and therefore different instant of the allocation may results reduced shortage compare to the predetermined instant of allocation. In this research, we construct a dynamic model based on the assumption of monitoring inventories in the regional warehouse everyday, and develop an algorithm minimize shortage in each replenishment cycle using dynamic programming approach.

• Smart Structures and Systems
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• v.13 no.1
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• pp.41-53
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• 2014

Optical fiber Brillouin sensor in a coil winding setup is proposed in this paper to measure the expansion deformation of a concrete column with a central rebar subjected to accelerated corrosion. The optical sensor monitored the whole dynamic corrosion process from initial deformation to final cracking. Experimental results show that Brillouin Optical Time Domain Reflectometer (BOTDR) can accurately measure the strain values and identify the crack locations of the simulated reinforced concrete (RC) column. A theoretical model is used to calculate the RC corrosion expansive pressure and crack length. The results indicate that the measured strain and cracking history revealed the development of the steel bar corrosion inside the simulated RC column.

• International Journal of Control, Automation, and Systems
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• v.2 no.2
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• pp.207-219
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• 2004

This paper presents the development of a knowledge-based control system operating via the Internet. With the synergy provided by the Internet, the central expert controller with its knowledge-base has the potential to serve a multitude of front-end clients located anywhere in the world provided they have Internet access. In this way, the operational span of the knowledge-based control system can be expanded to virtually anyplace within the reach of the Internet. This configuration has positive implications in improving the efficiency of distributed operations, thereby enabling plantwide optimization and costs savings. Datasocket technology is adopted to facilitate a more efficient data exchange between the knowledge-based central server and the front-end clients. A specific application in the remote monitoring and fault diagnosis of machines using the proposed control configuration is presented in the paper.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.101-102
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• 2015

본 논문에서는 다수의 생체계측 정보를 MDEC(Medical Device Exchange Communication) 기반의 공통모듈을 이용하여 중앙 집중 관리를 위한 CMS(Central Monitoring System)를 제안한다. 기존의 바이탈사인 모니터 등은 환자별로 부착되어 다수의 환자에 대한 이상 징후를 실시간으로 모니터링하기에는 어려움이 있다. 이에 본 논문에서는 다수의 계측 장비를 통합하는 공통모듈인 MDEC을 이용하여 집중 모니터링이 가능한 CMS을 구현하였다. 계측장비와 MDEC의 패킷 송수신을 위한 프로토콜을 설계하고 네트워크로 전송된 패킷은 CMS에 표시되며 데이터베이스에 저장된다. 본 연구의 결과는 급속히 증가하는 병원내 환자 관리 및 효율적 의료서비스에 기여할 것으로 사료된다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.83-90
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• 1999

Centralized safety stock in a periodic replenishment system which consists of one central warehouse and m regional warehouse can reduce backorders allocation the centralized safety stocks to regional warehouse in a certain instant of each replenishment cycle. If the central warehouse can not monitoring inventories in the regional warehouse, then we have to predetermine the instant of allocation according to demand distribution and this instant must be same for all different replenishment cycle. However, transition of inventory level in each cycle need not to be same, and therefore different instant of the allocation may results reduced shortage compare to the predetermined instant of allocation. In this research, we construct a dynamic model based on the assumption of monitoring inventories inventories in the regional warehouse everyday, and develop an algorithm minimize shortage in each replenishment cycle using dynamic programming approach.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1765-1767
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• 2005

This paper proposes central monitoring system(PVCMS) based on a TCP/IP network for effective integrating management about photovoltaic systems. We don't gain confidence the result of production simulation, because the output of PV system have many various environmental change factor. So if we can obtain real operated data about each sites and system types to use PVCMS, we can define the environment change factor to compare with simulation data. And this paper try to access about total management and data analysis methods of renewable energy through results analysis to synthesize of the operation.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.24-30
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• 2013

The adsorption characteristics of cationic starches and starch-oligomers were investigated using the quartz crystal microbalance with dissipation monitoring (QCM-D). The adsorbed amount of modified starches was higher than that of cationic surfactants such as $C_{12{\sim}16}$ trimethylammonium bromide. Cationic starches did not show the tendency depending on the degree of cationic substitution and molecular weight. On the other hand, the softness of the adsorption layer increased with the molecular weight of cationic starches in a viscoelasticity terms. During the adsorption/desorption steps, the amount of adsorbed cationic surfactants was 4~9 times. On the other hand, the difference in the amount of adsorption of all the $C_1$ grafted cationic starches was just 0~50%. In addition, the rigidity of the adsorption layer of cationic surfactant in the desorption step decreased, while, that of cationic starches increased at the same condition.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.277-296
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• 2016

There is a need for rapid and objective assessment of concrete bridge decks for maintenance decision making. Infrared Thermography (IRT) has great potential to identify deck delaminations more objectively than routine visual inspections or chain drag tests. In addition, it is possible to collect reliable data rapidly with appropriate IRT cameras attached to vehicles and the data are analyzed effectively. This research compares three infrared cameras with different specifications at different times and speeds for data collection, and explores several factors affecting the utilization of IRT in regards to subsurface damage detection in concrete structures, specifically when the IRT is utilized for high-speed bridge deck inspection at normal driving speeds. These results show that IRT can detect up to 2.54 cm delamination from the concrete surface at any time period. It is observed that nighttime would be the most suitable time frame with less false detections and interferences from the sunlight and less adverse effect due to direct sunlight, making more "noise" for the IRT results. This study also revealed two important factors of camera specifications for high-speed inspection by IRT as shorter integration time and higher pixel resolution.

• Journal of Power Electronics
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• v.14 no.4
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• pp.733-741
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• 2014

The integration of photovoltaic (PV) energy sources into DC grid has gained considerable attention because of its enhanced conversion efficiency with reduced number of power conversion stages. During the integration process, a local control unit is normally included with every power conversion stage of the PV source to accomplish the process of maximum power point tracking. A centralized monitoring and supervisory control unit is required for monitoring, power management, and protection of the entire system. Therefore, we propose a field-programmable gate array (FPGA) based centralized control unit that integrates all local controllers with the centralized monitoring unit. The main focus of this study is on the process of integrating many local control units into a single central unit. In this paper, we present design and optimization procedures for the hardware implementation of FPGA architecture. Furthermore, we propose a transient analysis and control design methodology with consideration of the nonlinear characteristics of the PV source. Hardware experiment results verify the efficiency of the central control unit and controller design.

• ALGAE
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• v.24 no.2
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• pp.111-120
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• 2009

Choosing an appropriate sample unit is a fundamental decision in the design of ecological studies. While numer-ous methods have been developed to estimate organism abundance, they differ in cost, accuracy and precision.Using both field data and computer simulation modeling, we evaluated the costs and benefits associated with twomethods commonly used to sample benthic organisms in temperatc kelp forests. One of these methods, theTargeted Sampling method, relies on different sample units, each "targeted" for a specific species or group ofspecies while the other method relies on coefficients that represent ranges of bottom cover obtained from visual esti-mates within standardized sample units. Both the field data and the computer simulations suggest that both meth-ods yield remarkably similar estimates of organisnm abundance and among-site variability, although the Coefficientmethod slightly underestimates variability armong sample units when abundances are low. In contrast, the twomethods differ considerably in the effort needed to sample these communities; the Targeted Sampling requiresmore time and twice the persormel to complete. We conclude that the Coeffident Sampling metliod may be bettcrfor environmental monitoring programs where changes in mean abundance are of central conccm and resources arelimiting, but that the Targeted sampling methods may be better for ecological studies where quantitative reIation-ships among species and small-scale variability in abundance are of central concern.