• Molecules and Cells
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• v.25 no.1
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• pp.119-123
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• 2008

Pyrimidine antagonists including 5-Fluorouracil (5-FU) have been used in chemotherapy for cancer patients for over 40 years. 5-FU, especially, is a mainstay treatment for colorectal cancer. It is a pro-drug that is converted to the active drug via the nucleic acid biosynthetic pathway. The metabolites of 5-FU inhibit normal RNA and DNA function, and induce apoptosis of cancer cells. One of the major obstacles to successful chemotherapy is the resistance of cancer cells to anti-cancer drugs. Therefore, it is important to elucidate resistance mechanisms to improve the efficacy of chemotherapy. We have used C. elegans as a model system to investigate the mechanism of resistance to 5-FU, which induces germ cell death and inhibits larval development in C. elegans. We screened 5-FU resistant mutants no longer arrested as larvae by 5-FU. We obtained 18 mutants out of 72,000 F1 individuals screened, and mapped them into three complementation groups. We propose that C. elegans could be a useful model system for studying mechanisms of resistance to anti-cancer drugs.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.246-257
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• 2010

Autonomous guided robot navigation which consists of following unknown paths and avoiding unknown obstacles has been a fundamental technique for unmanned robots in outdoor environments. The unknown path following requires techniques such as path recognition, path planning, and robot pose estimation. In this paper, we propose a novel sensor fusion system for autonomous guided robot navigation in outdoor environments. The proposed system consists of three monocular cameras and an array of nine infrared range sensors. The two cameras equipped on the robot's right and left sides are used to recognize unknown paths and estimate relative robot pose on these paths through bayesian sensor fusion method, and the other camera equipped at the front of the robot is used to recognize abrupt curves and unknown obstacles. The infrared range sensor array is used to improve the robustness of obstacle avoidance. The forward camera and the infrared range sensor array are fused through rule-based method for obstacle avoidance. Experiments in outdoor environments show the mobile robot with the proposed sensor fusion system performed successfully real-time autonomous guided navigation.

• Transactions of Materials Processing
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• v.25 no.6
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• pp.359-365
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• 2016

The rate-controlling mechanisms for time-dependent plastic deformation of eutectoid and hyper-eutectoid pearlitic steels at low $T/T_m$ temperatures were explored. The strain rate - stress data obtained from a series of constant load tensile tests at $0.25{\sim}0.30T/T_m$ were applied to the power law, the lattice friction controlled plasticity, and the obstacle controlled plasticity. Of these models, the obstacle controlled plasticity was found to best-describe the rate-controlling mechanism for time-dependent plastic deformation of two steels at low $T/T_m$ temperatures in terms of the activation energy for overcoming the obstacles against dislocation glide in ferrite. The deformed microstructures revealed the dislocation forests of a high density as the main obstacles. In addition, the obstacle controlled plasticity well-explained the effects of cementite on the $0^{\circ}K$ flow stress of two steels.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2004.10a
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• pp.246-251
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• 2004

• Journal of the Korea Safety Management & Science
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• v.5 no.3
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• pp.121-131
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• 2003

This study centers on how the electronic democracy which is expected to be a political system of information society may increase civic participation and develop political system. On the other hand, critics of internet voting claim that the technology required to properly authenticate voters and assure the accuracy and integrity of the election system either does not exist or is not widespread enough in society to be equitable and effective. In order to capture the potential that this new technology offers, it must be implemented correctly, upon a well-conceived framework of standards and procedures. At the same time, government must seek the advice of industry leaders as well as social activists so as to avoid the many obstacles that will undoubtedly arise.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.107-109
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• 2006

This study focuses on a determination of amount of Pt in the Pt/C for catalysts of polymer electrolyte membrane fuel cells (PEMFC). PEMFC offer low weight and high power density and being considered for automotive and stationary power applications. The PEMFC performance is influenced by several factors, including catalysts and structure of electrode and membrane type. Catalyst of electrode is important factor for PEMFC. One of the obstacles prevent ing polymer electrolyte membrane fuel cells from commercialization is the high cost of noble metals to be used as catalyst, such as platinum To effectively use these metals, they have to be will dispersed to small particles on conductive carbon supports. The optimal amount of Pt in Pt/C for cathode catalyst was investigated by using polarization curves in single cell with $H_2/O_2$ operation.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.278-288
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• 2020

Modular Integrated Construction (MiC) has gained quite momentum as it provides solutions for several problems in the construction sector, particularly in Hong Kong. MiC is converting the building into modules and erecting them easily on site providing various benefits, such as cost and time savings, better quality, lower risk, higher sustainability, less injuries and accidents, etc. The MiC is considered the best alternative to traditional construction approaches in solving the huge housing demand problem in many cities all over the world due to the time-saving privilege. The utilization of MiC is facing a lot of challenges, which are considered obstacles to the wide acceptance of this technique in the construction industry in Hong Kong. This, in turn, has led the interests of the research community to investigate its benefits and challenges aiming at addressing several solutions to harness the benefits of this technique and to tackle these challenges. The present research aims to review the main concept of MiC and to determine the benefits and the challenges of implementing MiC in construction industry. The findings of this research highlight the advantages and limitations of incorporating MiC technique in Hong Kong, which will help the stakeholders to effectively utilize this technique in the construction industry.

• Archives of design research
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• no.16
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• pp.17-25
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• 1996

, \l!ernatives in multi dimensional decision prohlems generally possess numerous attrihutes by which they can be describ('d and compared, The ('\';dllation factors include all attributes that have Ic\'(']s specified by quantitative and qualitativc objectil'l'S, Howev'('f since qualitative factors arc difficul! to quantify as num('ral estimates, these factors have tended to bl' ignored without regard for their importance to human contrnl. In this study, the author adapted :j ('va]uation methods with critrria which have qualitative and qualitative attributes: the Intuitive Evaluation ~1cthods the Accumulativc' Evaluation Model the Benchmarking Evaluation Methods, and studied the corrC'iation between them, The results show that Ill(' :j Mrthods have reciprocal relationships under reliability (r=O, (XX)]] In order to removl' obstacles of desi!;n ev'aluation ( lots of timl' l'llnsumption, constr;lints of placc" difficulties of hu!;!' data procc'ssin!;), it is necessary to be developed a new ('va]uation syst('rn which could prov'idc' effective rat in!; of desi!;n v'alm's 10 make value judw'rnents, , \l!ernatives in multi dimensional decision prohlems generally possess numerous attrihutes by which they can be describ('d and compared, The ('\';dllation factors include all attributes that have Ic\'(']s specified by quantitative and qualitativc objectil'l'S, Howev'('f since qualitative factors arc difficul! to quantify as num('ral estimates, these factors have tended to bl' ignored without regard for their importance to human contrnl. In this study, the author adapted :j ('va]uation methods with critrria which have qualitative and qualitative attributes: the Intuitive Evaluation ~1cthods the Accumulativc' Evaluation Model the Benchmarking Evaluation Methods, and studied the corrC'iation between them, The results show that Ill(' :j Mrthods have reciprocal relationships under reliability (r=O, (XX)]] In order to removl' obstacles of desi!;n ev'aluation ( lots of timl' l'llnsumption, constr;lints of placc" difficulties of hu!;!' data procc'ssin!;), it is necessary to be developed a new ('va]uation syst('rn which could prov'idc' effective rat in!; of desi!;n v'alm's 10 make value judw'rnents,alm's 10 make value judw'rnents,

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.8
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• pp.1250-1256
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• 2017

In this research, a high-performance ultrasonic positioning system is proposed to track the positions of an indoor mobile object. Composed of an ultrasonic sender (mobile object) and a receiver (anchor), the system employs three ultrasonic time-off-flights (TOFs) and trilateration to estimate the positions of the object with an accuracy of sub-centimeter. On the other hand, because ultrasonic waves are interfered by temperature, wind and various obstacles obstructing the propagation while propagating in air, ultrasonic pulse debounce technique and Kalman filter were applied to TOF and position calculation, respectively, to compensate for the interference and to obtain more accurate moving object position. To perform tasks in real time, ultrasonic signals are processed full-digitally with a Zynq SoC, and as a software design tool, Vivado IDE(integrated design environment) is used to design the whole signal processing system in hierarchical block diagrams. And, a hardware/software co-design is implemented, where the digital circuit portion is designed in the Zynq's fpga and the software portion is c-coded in the Zynq's processors by using the baremetal multiprocessing scheme in which the c-codes are distributed to dual-core processors, cpu0 and cpu1. To verify the usefulness of the proposed system, experiments were performed and the results were analyzed, and it was confirmed that the moving object could be tracked with accuracy of sub-cm.

• MALSORI
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• no.50
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• pp.41-50
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• 2004

Recently, there has been considerable progress in the natural language processing and digital signal processing components and this progress has led to the improved synthetic speech qualify of many commercial TTS systems. But there still remain many obstacles to overcome for the practical application of TTS. To resolve the problems, the cooperative research among the related areas is highly required and a common Korean TTS platform is essential to promote these activities. This platform offers a general framework for building Korean speech synthesis systems and a full C/C++ source for modules supports to implement and test his own algorithm. In this paper we described the aspect of a Korean TTS platform to be developed and a developing plan.