• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.61
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• pp.23-31
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• 2000

This paper addresses the static operator allocation problem in celluar manufacturing systems(CMS). An assembly environment is considered where each component going into the final product is manufactured in an individual cell. There are m such cells and it is required to manufacture n varieties of products where n>m. An mathematical model and two heuristic algorithms for static operators allocation to the cells to balance workload for minimizing makespan are developed and tested.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.4
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• pp.63-73
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• 1998

With the success of flexible manufacturing systems(FMSs), flexible assembly systems(FASs) have been developed to automatic factories further. As in a cellular FMS, a celluar FAS is considered as the most flexible and feasible assembly systems configuration. This paper presents a method for the integrated layout design in cellular FASs. Unlike the traditional paper, this paper deals with the formation of cells and the layout of cells for jobs with operation times on different machines. The procedure in this paper consists of two distinct phases. The first phase presents machine arrangement in a double rows flowline. cell formation not to allow intercellular movements, and integrated layout design in cellular FASs considering the characteristics of FAS, layout, and production factors This phase uses older optimal algorithm. The second phase proposes to balance the system with an objective of reducing the degree of workload deviation in the cells. Simulated annealing method is used to balance the system. This phase also shows the integrated layout design in cellular FASs with the cost less than total cost of the first phase.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.4
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• pp.379-389
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• 2000

A cellular automaton is well-known for self-organizing and dynamic behavions in the filed of artifial life. This paper addresses a new neuronic architecture called an evolvable celluar classifier which evolves with the genetic rules (chromosomes) in the non-uniform cellular automata. An evolvable cellular classifier is primarily based on cellular programming, but its mechanism is simpler becaise it utilizes only mutations for the main genetic operators and resmbles the Hopfield network. Therefore, the desirable bit-patterns could be obtained through evolutionary processes for just one individual agent, As a rusult, an evolvable hardware is derived which is applicable to clessification of bit-string information.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2414-2417
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• 2005

Compact Camera Module(CCM) is widely used in PDA, Celluar phone and PC web camera. With the greatly increasing use for mobile applications, there has been a considerable demands for high speed production of CCM. The major burden of production of CCM is assembly of lens module onto CCD or CMOS packaged circuit board. After module is assembled, the CCM is inspected. In this paper, we developed the image capture board for CCM and the imaging processing algorithm to inspect the defects in captured image of assembled CCMs. The performances of the developed inspection system and its algorithm are tested on samples of 10000 CCMs. Experimental results reveal that the proposed system can focus the lens of CCM within 5s and we can recognize various types of defect of CCM modules with good accuracy and high speed.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.2
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• pp.89-95
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• 2004

CDMA is the way that more than one users can share the time and frequency at the same time and connect with multiple access in mobile communication. Multiple Access is indispensible for mobile communication because the limited frequency is able to be used by many users in mobile communication. CDMA is also applied to home network, military, business and medical sectors. This paper, presents a users should share limited frequency resource. CDMA module implemented with 8-layer PCB which consists of the Slice-board circuit, keeping Radio frequency characteristics and a slot type connector.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.42-54
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• 2008

In recent years, embedded systems have been expanding their application domains from traditional embedded systems such as military weapons, robots, satellites and digital convergence systems such as celluar phones, PMP(Portable Multimedia Player), PDAs(Personal Digital Assistants) to Next Generation Personal Computers(NGPCs) such as eating PCs, wearable computers. The NGPCs are network-based, human-centric digital information devices diverged from the traditional PCs used mainly for document writing, internet searching and database management. Wearable computers with battery capacity and memory size limitations have to use real-time operating systems with small footprints and low power management techniques to provide user's QoS in spite of hardware constraints. In this paper, we have designed and implemented a low-power RTOS (called eRTOS) for wearable computers. The implemented eRTOS has 18KB footprints and the dynamic power management and the device power management schemes are adapted in it. Experimental results with wearable computer applications show that the low power techniques could save energy up to 47 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.11
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• pp.1256-1263
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• 2012

Assigning different frequency resources among adjacent cells, namely the frequency reuse technique can be utilized to mitigate intercell interference, which is a major cause of performance degradation in cellular systems. Since most of conventional frequency reuse patterns are limited to the two-dimensional environment, the research for the three-dimensional frequency reuse would be beneficial especially for the implementation of femto cells in downtown office buildings. We propose frequency reuse patterns in three-dimensional space and evaluate their performance of each pattern in terms of channel capacity. In particular, we show that the proposed three-dimensional frequency reuse patterns can be applied for carrier-aggregated transmission of LTE-Advanced systems. The performance of the proposed patterns is evaluated using computer simulation.

• Journal of Pharmaceutical Investigation
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• v.34 no.4
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• pp.263-267
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• 2004

Branched and linear polyethylenimines (PEIs) have been studied as efficient and versatile agents for gene delivery in vitro and in vivo. PEIs exist in a linear or branched topology and are available in a wide range of molecular weight (Mw). Most studies have been done using PEIs with Mw higher than 10Kd. This study was aimed to test the transfection efficiency and the cell viability following gene delivery using PEI of Mw 2Kd, a relatively lower Mw cationic polymer. We used murine interleukin-2(mIL-2) plasmid DNA complexed with branched PEI 2Kd or 25Kd, and transfected them into a myoblast muscle cell line, C2C12. The cellular uptake of mIL-2 plasmid DNA was determined using quantitative polymerase chain reaction. RNA transcript levels were studied in the myoblast cells. Our results show that PEI 2Kd was as effective as PEI 25Kd in celluar gene delivery and transfection efficiency in C2C12 cells. Moreover, MTT assay indicated that PEI 2Kd/DNA complexes did not significantly reduce the cell viability regardless of N/P ratios. These results suggest that PEI of Mw 2Kd might play a role as effective and low toxic nonviral vector systems for muscular cell lines.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.2
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• pp.61-67
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• 2007

In this study, the antioxidative effects of Equisetum arvense extracts were investigated. The free radical (1,1 diphenyl-2-picrylhydrazyl, DPPH) scavenging activity ($FSC_{50}$) of extract/fractions of Equisetum arvense was in the order: 50 % ethanol extract ($182.04{\mu}g/mL$) < ethylacetate fraction ($54.50{\mu}g/mL$) < deglycosylated flavonoid aglycone fraction ($14.13{\mu}g/mL$). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of some Equisetum arvense extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol- dependent chemiluminescence assay. The order of ROS scavenging activity was deglycosylated flavonoid aglycone fraction ($OSC_{50}$, $3.54{\mu}g/mL$) < 50 % ethanol extract ($0.80{\mu}g/mL$) < ethylacetate fraction ($0.006{\mu}g/mL$). Ethylacetate fraction showed the most prominent scavenging activity. The protective effects of extract/fractions of Equisetum arvense on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The ethanol extract (50%) suppressed photohemolysis in a concentration dependent manner, particularly deglycosylated aglycone extract exhibited the most prominent celluar protective effect ($\tau_{50}$, 161.10 min at $10{\mu}g/mL$). These results indicate that extract/fractions of Equisetum arvense can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.3
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• pp.145-152
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• 2007

In this study, the antioxidative effects of Sueada asparagoides and Salicornia herbacea extracts were investigated. The free radical(1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activity($FSC_{50}$) of extract/fractions of Sueada asparagoides was in the order: 100 % ethanol extract(329.33 ${\mu}g/mL$) < 50 % ethanol extract(40.73) < ethylacetate fraction(13.87) < deglycosylated aglycone fraction (7.80). In case of Salicornia herbacea, the free radical scavenging activities of ethylacetate fraction and aglycone fraction were 13.87 and 7.80 ${\mu}g/mL$, respectively. Reactive oxygen species(ROS) scavenging activities($OSC_{50}$) of Sueada asparagoides and Solicornia herbacea extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The order of ROS scavenging activity of Sueada asparagoides extracts was 50 % ethanol extract($OSC_{50}$, $0.99{\mu}g/mL$) < ethylacetate fraction (0.05) < aglycone fraction (0.03). Aglycone fraction showed the most prominent scavenging activity. In case of Salicornia herbacea, the ROS scavenging activities of ethylacetate fraction and aglycone fraction were 0.10 and 0.20 ${\mu}g/mL$, respectively. The protective effects of extract/fractions of Sueada asparagoides and Salicornia herbacea on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The ethanol extract(100%) of Sueada asparagoides diminished photohemolysis in a concentration dependent manner($1{\sim}100{\mu}g/mL$). Particularly deglycosylated aglycone fraction exhibited the most prominent celluar protective effect($\tau_{50}$, 310 min at 50 ${\mu}g/mL$). In case of Salicornia herbacea, ethylacetate fraction exhibited more potent protective effect. These results indicate that extract/fractions of Sueada asparagoides can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS.