• Geotechnical Engineering
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• v.4 no.4
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• pp.19-28
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• 1988

An underground explosion crests shock waves, which propagate to a buried structure through the이 ground. Due to the explosion, very high stresses and large deformation occur in the ground so that the shock waves decay gradually. In this study the numerical simulation of the ground shock attenuation has teen performed. One dimensional wave equation is presented and the finite difference method is applies. A Cap model is adopted to describe the stress-strain behavior of the ground. The results are expressed by the attenuation of the peak stress and the particle vrelocity by the time and the distance.

• Nuclear Engineering and Technology
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• v.1 no.2
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• pp.87-90
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• 1969

Halogen exchange reactions of trans-cinnnamyl chloride and bromide with radioactive chloride, bromide and iodide ions in acetone have teen studied. Relative nucleophilicity of halide ions and relative leaving ability have been discussed invoking the principle of HSAB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11A
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• pp.903-911
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• 2011

In this paper we proposed an energy adaptive data aggregation and transmission mechanism to solve the problem of energy limitation in wireless sensor networks (WSNs). Hierarchical structure methods are wildly used in WSNs to improve the energy efficiency. LEACH and TEEN protocols are the typical techniques. In these methods, all nodes, including nodes who have sensed data to transmit and nodes who haven't, are set frame timeslots in every round. MNs (member nodes) without sensed data keep active all the time, too. These strategies caused energy waste. Furthermore, if data collection in MNs is same to the previous transmission, it increases energy consumption. Most hierarchical structure protocols are developed based on LEACH. To solve the above problems, this paper proposed a method in which only MNs with sensed data can obtain allocated frame to transmit data. Moreover, if the MNs have same sensed data with previous, MNs turn to sleep mode. By this way redundant data transmission is avoided and aggregation in CH is lightened, too.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.91-96
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• 1999

This study involves the research about relationship between visual charts and illumination. The subjects were both males and females in their teens and twenties. The examination instrument used was a B-VAT II BVS(Mentol) which was produced in the USA, and the illumination used was a low illumination of 100LUX and a high illumination of 1500LUX in the clinical examination room. The results were as follows: 1. Different types of illumination resulted in similar values of visual acuity. 2. In the male teen subjects, the Snellen visual acuity was better than the numerical visual acuity when using low illumination. But the Landolt visual acuity presented similar results when using both low and high illumination. 3. In male subjects in their twenties, the Numerical visual acuity was better than the Landolt and Snellen visual acuity under low illumination. 4. In the female teen subjects, The Snellen visual acuity was better than the Landolt and Numerical visual acuity under low illumination. 5. In the female subjects in their twenties, The Snellen, Landolt and numerical visual acuities were high under low illumination. 6. Different types of illumination resulted in 0.3 or 0.4 variation of visual acuity. 7. The males and females was similar to the visual acuity.

• The Korean Journal of Pharmacology
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• v.19 no.2
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• pp.17-24
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• 1983

Buxus leaves(Buxus microphylla var. koreana Nakai) have been used as a folk medicine in treating woman's disease. The chemical constituents, which have teen identified from Buxus sempervirens L. in Europe, are so far known in isolation of buxus alkaloids, cyclobuxine, buxamine, norbuxamine and buxaminol. But But any study on the pharmacological action of Buxus microphylla var. koreana Nakai has not yet teen rallied out, however, active substances have not been identified. As an attempt to isolate the biologically active substances from this plant, the examination of chemical constituents was undertaken. In the experiment, the crystalline component$(C_{10}H_8O_4)$ obtained from Buxus microphylla var. koreana Nakai was identified as a 6-methoxy, 7-hydroxy coumarin by chemical and physical methods. We named this crystal buxuletin. Therefore, we intended to screen the pharmacological action of buxuletin, especially, its diuretic effects in rabbits. Buxuletin was intraveneously injected to the rabbit in the dose of 20 mg/kg, 10 mg/kg and 5 mg/kg. The variations of urine volume and minerals $(Na^+,\;K^+\;and\;Cl^-)$ in urine were measured at an interval of 15 minutes for 4 hours after the treatment of buxuletin. The observed results are as follows: 1) With the administration of buxuletin (20 mg/kg, 10 mg/kg), the remarkable increment of the excreted urine volume was observed during the relatively long period. Excretion rates of urinary minerals $(Na^+,\;K^+\;and\;Cl^-)$ were also increased. 2) In a dose of 5 mg/kg, the slight increment on the diuretic actions of rabbits was observed. From the above results, authors name this crystal buxuletin and buxuletin shows the diuretic action.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.1
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• pp.45-50
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• 2013

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to a sink node to pass collected data. If clusters are located at a long distance from the sink node, the cluster headers exhaust a lot of energy in order to transfer the data. As a consequence, the life of sensors is shorten and re-clustering is needed. In the process of clustering, sensor nodes consume some energy and the energy depletion of the cluster headers meet another energy exhaustion. A method of transferring data from cluster headers to the sink using neighbor clusters is needed for saving energy. In this paper, we propose a novel routing method using a multi-hop transmission method in cluster sensor networks. This method uses the topology matrix which presents cluster topology. One-hop routing and two-hop routing are proposed in order to increase the energy efficiency.

• International journal of advanced smart convergence
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• v.3 no.2
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• pp.1-5
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• 2014

Sensor nodes depend on batteries for energy source in Wireless Sensor Networks (WSNs). Low Energy Adaptive Clustering Hierarchy (LEACH) is a representative cluster-based routing protocol designed to ensure energy use efficiency whereas the virtual cluster exchange routing (VCR) information only with its closest node to build a network. In this paper, a protocol scheme was proposed wherein member nodes are designed to compare the currently sensed data with the previously sensed one and to switch to sleep mode when a match is achieved. The design is to help improve the transmission energy efficiency too.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.355-358
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• 2003

Recently, micro forming process technology have been developed since the size of machine parts become the crucial factor for minimizing of products in general electronic products. Most small machine parts consist of gear and rotation axis and the wear by mechanical contact is known as the primary factor for life reduction of high precision machine part. Lots of studies for mechanical wear and friction have been reported and many researches of MEMS technology have been studied recently. But just few studies for wear of micro or milli sized machine part have teen implemented. In this research, the wear equation is suggested according to the contact shape of axial part in micro or milli sized machine part. And wear analysis model which can predict the magnitude of wear through this suggested equation with numerical analysis program.

• Journal of Nutrition and Health
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• v.20 no.4
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• pp.281-288
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• 1987

In this study we have evaluated daily beverage intake of the inhabitants in Seoul by a 24 hrs. recall procedure from 1145 respondents between pre-school children to adults in the period of June-July 1985. Estimates of consumption were made for each of seven beverage groups and comparisons were made within age, sex and body weight. Significant differences existed for certain beverage in each category analyzed. Total Fluid intake was greater for male than female at all ages and tended to be lower in the older age group with adjustment for differences in body weight. Milk was the major beverage among children while soft drinks were the predominant beverage for teen-ages. Alcoholic drinks represented the smallest component of daily fluid intake among women but were the second largest component of daily fluid levels for men over the age of 24 years.

• Journal of Korea Multimedia Society
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• v.19 no.5
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• pp.910-917
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• 2016

Sensors have limited resources in sensor networks, so efficient use of energy is important. Representative clustering methods, LEACH, LEACHC, TEEN generally use direct transmission methods from cluster headers to the sink node to pass collected data. However, the communication distance of the sensor nodes at low cost and at low power is not long, it requires a data transfer through the multi-hop to transmit data to the sink node. In the existing cluster-based sensor network studies, cluster process and route selection process are performed separately in order to configure the routing path to the sink node. In this paper, in order to use the energy of the sensor nodes that have limited resources efficiently, a cluster-based multi-hop routing protocol which merges the clustering process and routing process is proposed. And the proposed method complements the problem of uneven cluster creation that may occur in probabilistic cluster methods and increases the energy efficiency of whole sensor nodes.