• Computers and Concrete
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• v.7 no.5
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• pp.455-468
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• 2010

This paper presents a prediction and simulation method of tensile stress-strain curves of Engineered Cementitious Composites (ECC). For this purpose, the bridging stress and crack opening relations were obtained by the fiber bridging constitutive law which is quantitatively able to consider the fiber distribution characteristics. And then, a multi-linear model is employed for a simplification of the bridging stress and crack opening relation. In addition, to account the variability of material properties, randomly distributed properties drawn from a normal distribution with 95% confidence are assigned to each element which is determined on the basis of crack spacing. To consider the variation of crack spacing, randomly distributed crack spacing is drawn from the probability density function of fiber inclined angle calculated based on sectional image analysis. An equation for calculation of the crack spacing that takes into quantitative consideration the dimensions and fiber distribution was also derived. Subsequently, a series of simulations of ECC tensile stress-strain curves was performed. The simulation results exhibit obvious strain hardening behavior associated with multiple cracking, which correspond well with test results.

• Nuclear Engineering and Technology
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• v.34 no.5
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• pp.421-432
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• 2002

As one of the advanced design features of the APR1400, direct vessel injection (DVI) system is being considered instead of conventional cold leg injection (CLI) system. It is known that the DVI system greatly enhances the reliability of the emergency core cooling (ECC) system. However, there is still a dispute on its performance in terms of water delivery to the reactor core during the reflood phase of a large-break loss-of-coolant accident (LOCA). Thus, experimental validation is under progress. In this paper, test results of direct ECC bypass performed in the steam-water test facility tailed MIDAS (Multi-dimensional Investigation in Downcomer Annulus Simulation) are presented. The test condition is determined, based on the preliminary analysis of TRAC code, by applying the ‘modified linear scaling method’with the l/4.93 length scale . From the tests, ECC direct bypass fraction, steam condensation rate and information on the flow distribution in the upper annulus downcomer region are obtained.

• Nuclear Engineering and Technology
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• v.32 no.4
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• pp.316-327
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• 2000

The Emergency Core Cooling System in current nuclear power plants typically has a considerable number of complex functions and largely cumbersome operator interfaces. Functions for initiation, switch-over between various phases of operation, interlocks, monitoring, and alarming are usually performed by relays and analog comparator logic which are difficult to maintain and test. To improve problems of an analog based ECC (Emergency Core Cooling) System, the trip computer for ECCS based on Dynamic Safety System (DSS) is implemented. The DSS is a computer based reactor protection system that has fail-safe nature and performs a dynamic self-testing. The most important feature of the DSS is the introduction of test signal that send the system into a tripped state. The test signals are interleaved with the plant signals to produce an output which switches between a tripped and health state. The dynamic operation is a key feature of the failsafe design of the system. In this work, a possible implementation of the DSS using PLC is presented for a CANDU Reactor. ECC System of the CANDU Reactor is selected as the reference system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.507-511
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• 2001

Electrocardiograph(ECC), one of the major vital signals, is widely used in the hospitals to check a heart disease patient. In tole-medicine information system, If the ECC signal could be acquired at the patient's home and sent to the physician via telecommunication line, the number of visit to the hospital and medical expenses can be reduced dramatically. The tole-medicine information system proposed by this paper is designed to acquire patient's ECC signal by portable ECC terminal at his or her home and to send it to the hospital server via internet. For the mobility of physicians, the patient's real-time data ran be viewed at any internet connected computer as well as server connected terminal.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.1
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• pp.41-48
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• 1989

The significance of soil and/or rhisosphere populations of Erwinia carotovora sobsp. carotovora (Ecc) as a source of primary inoculum for tobacco hollow stalk disease has been demonstrated conclusively. The survival of Ecc in field soils fter overwintering was estimated by using the enrichment technique. The population number of pectolytic erwinia (PE) in field soils relatively decreased at the rate of 102-104 colony forming unit(CFU) per g of soil after overwintering. Higher level of PE population overwintered in the rhlzosphere foils of tobacco stubbles and detected more frequently in rhizosphere soils of weed plants than in those of bare fields. All of the tobacco stubbles collected from fields where tobacco had been grown the previous year contained Ecc. The more survived population number of PE at the 30cm depth of artifitiany infested soils than at the upper of those by introducing with diseased tobacco plant tissue after overwintering. Ecc overwintered effectively in rhizosphere soils of tobacco stubbles, overwintered weeds and tobacco debris in field soils.

• Transactions on Electrical and Electronic Materials
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• v.11 no.2
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• pp.61-64
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• 2010

In this paper, we investigate the quality difference of SiC crystals grown by a conventional physical vapor transport method using various SiC powders. While the growth rate was revealed to be dependent upon the particle size of the SiC powder, the growth rate of SiC bulk crystals grown using SiC powder with a smaller particle size (20 nm) was definitely higher than those using lager particle sizes with $0.1-0.2\;{\mu}m$ and $1-10\;{\mu}m$, respectively. All grown 2 inch SiC single crystals were proven to be the polytype of 6H-SiC and the carrier concentration levels of about $10^{17}\;cm^3$ were determined from Hall measurements. It was revealed that the particle size and process method of SiC powder played an important role in obtaining a good quality, high growth rate, and to reduce growth temperature.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.5
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• pp.37-43
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• 2002

This paper proposes a password-based mutual authentication and key agreement protocol, which is designed by applying ECDSA and ECDH. The proposed protocol, AKE-ECC, computes 2 times of point multiplication over ECC on each of client and server, and generates the key pairs(public key. private key) and a common session key using ECDH that is different compare to previously proposed protocol. It is against common attacks include a dictionary attack and the security of proposed protocol is based on the ECDLP, ECDH.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.223-225
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• 2021

Modular multiplication is a key operation for point scalar multiplication of ECC, and is the most important factor affecting the performance of ECC processor. This paper describes a design of a 256-bit modular multiplier that adopts 3-way Toom-Cook multiplication algorithm and modified fast reduction algorithm. One 90-bit multiplier and three 264-bit adders were used to optimize the hardware size and the number of clock cycles required. The modular multiplier was verified by implementing it using Zynq UltraScale+ MPSoC device and the modular multiplication operation takes 15 clock cycles.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.1
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• pp.57-64
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• 2003

This study aims to discuss the characteristics on marketing distribution of landscape materials after consideration in the side of cognition on the present condition of marketing which is important factors for analysis in understanding the market of landscape materials. To do this, the investigation of marketing distribution are to collect data refer to purchases and sales reports and questionnaires, these results are used to analyzed the operative factor of forming market structure and problematic, improvement spot of marketing distribution. The periodic range of this paper is limited on 609 landscape materials and examination was performed from 21.Feb. to 15.Mar, in 2002. The results of the whole prices trends and marketing distribution survey can be summarized as follows : 1. Differences of cognition on marketing distribution among four group toward problematic spot on product and marketing of landscape materials was summarized as follows : 1) Group of landscape design : Interest of government, Various articles. 2) Group of landscape construction : Communication of marketing information, Role of intermediary ecc. 3) Group of landscape materials and cooperation between company and university : Interest of government ecc, 2. Differences of cognition on marketing distribution among four group toward improvemental spot on product and marketing of landscape materials was summarized as follows : 1) Group of landscape design and construction : Network of marketing distribution on landscape materials, Criterion of articles, Quality adiministration through establishment of sale level ecc.. 2) Group of landscape materials : Employment of specialist education program ecc.. 3) Group of cooperation between company and university : Conscious reformation of comsumer ecc.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1443-1448
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• 2006

As computers and networks become popular, distributing information on the Internet is common in our daily life. In the past, e-mail has been the primary choice of exchanging information but messengers are gaining popularity abroad and domestically because of their nature of getting immediate responses. Information leakage by invasion that is enemy of evil in communication of communications division Server and Agent between each agents that become burden of communication for effective administration of data for most of existing messenger is becoming an issue. In this paper, we design a secure messenger system that could be obtained maximum security. It use ECC based on ElGamal methodology using PKI for secure communication. For the message encryption and decryption between the same group non, each group is kept distinct by drawing an elliptic curve and an arbitrary point is chosen on the curve.