• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.158-165
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• 2003

A specific experimental method, the Split Hopkinson pressure bar (SHPB) technique has been widely used to determine the dynamic material properties under the impact compressive loading conditions with strain rate of the order of 10$^3$/s∼l0$^4$/s. In this paper, dynamic deformation behaviors of rubber materials widely used for the isolation of vibration from structure under varying dynamic loading are determined by using plastic SHPB technique. A transition point to scope with the dynamic deformation behavior of rubber-like material is defined in this paper and used to characterize the specifics of the dynamic deformation of rubber materials.

• Environmental Analysis Health and Toxicology
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• v.16 no.3
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• pp.115-120
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• 2001

The predictive screening of various molecular descriptors for predicting cyclooxygenase inhibitor, lipooxygenase inhibitor, leucotriene synthesis inhibitor, leucotriene antagonist activities of Stilbene moieties have been investigated for the application of quantitative structure-activity relationships (QSAR). The biological activities for 36 compounds were computed by the PASS program and molecular descriptors are cited from literatures or calculated, to investigate feasibility of screening relevant descriptors and of their applications among biological endpoints. Fairly good correlations varying from 0.7828 to 0.9032 were obtained using 12 descriptors with 29 Stilbene derivatives and 5 diazo-compounds. Our studies reveal that LogKow, electron density(X), electron density (Y),4th-order valence connectivity and water solubility can be usefully employed to predict biological activities of stilbene derivatives with simple regression models.

• Proceedings of the Korean Society for Information Management Conference
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• 2004.08a
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• pp.61-66
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• 2004

본 연구에서는 시소러스를 구축하기 위해 필요한 디스크립터 수집원으로써 이용자 로그데이터를 분석하여 후보 디스크립터의 외형적 특성을 분석하였다. 분석대상인 이용자 로그데이터는 국내 검색엔진가운데 야후와 라이코스를 대상으로 하였다. 분석결과, 이용자들은 대부분 검색어로써 명사와 복합명사를 사용하였으며, 조사 '의'이외에는 다른 품사로 이루어진 검색어는 거의 존재하지 않음을 알 수 있었다. 또한 검색어로써 이용자들은 고유명사(외국어 포함)를 많이 사용함으로써, 국내외 지침에서 권고하는 고유명사의 최소한 사용지침과 실제 이용자 사이의 이용행태와의 차이를 알 수 있었다. 따라서 국내외 시소러스 개발지침을 수용하면서, 이용자 중심의 시소러스를 개발하기 위해서는 전거어나 유사어 사전을 대등관계와 연동하여 개발하는 것을 고려해야 한다.

• Journal of Plant Biology
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• v.22 no.3
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• pp.59-62
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• 1979

Distribution and standing crops of seedling and sapling as undergrowing tree were investigated in a Pinus rigida forest. The relative light intensity(RLI) on the ground level was 3.9∼59.3% which indicates a wide range. Under this range of RLI seedlings and saplings distribute well in the stand. Eight trees were selected from the stand, then measured dry weight of stem, branches and leaves using thestratified clip technique. A possible relationship between the diameter at the bottom of the tree (Do) and standing crops was investigated. As Do increased from 0.8cm (T1) to 7.2cm (T8), the standing crops also increased from 42.6g to 7,410.4g. Since semi-log values between Do and standing crops clearly indicates a straight line, there is close relationship between these two factors. Therefore it is possible to estimate the standing crops of seedling and sapling by measuring Do. Productive structure shows that phytosynthetic layer is located above the 1/2 height of the tree and maximum photosynthetic layer apperars on 2/3 level in height.

• ETRI Journal
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• v.35 no.6
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• pp.1094-1104
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• 2013

Home appliance manufacturers have recently been trying to provide smart products capable of various Internet services. For example, one health care manufacturer provides a Wi-Fi-capable scale. Once users register their information with the manufacturer's server, their weight and body fat records are automatically uploaded to the server whenever they measure their weight. The users can then watch and check their weight log easily using a smart device, such as a smartphone or tablet. One of the biggest problems, however, is that the initial configuration of the appliances and the user registration process may be quite complicated to typical users who are unfamiliar with such IT devices. This paper proposes an autoconfiguration system structure and protocol for Internet-capable home appliances, which supports the initial configuration and remote maintenance service of the device with only little user effort. Manufacturers can develop their own information appliances and provide differentiated services using the proposed system and protocol.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.971-980
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• 2010

Evaluation of permeability and coefficient of consolidation of clayey sand is critical to analyze ground stability or environmental problems such as diffusion and dispersion in groundwater flow. Permeability tests using a flexible wall permeameter were performed to derive the coefficient of consolidation and permeability of reconstituted soil samples with various mixing ratios of kaolin clays and two different types of sands, Jumunjin sand and Ottawa sand. The test results indicated that coefficient of consolidation and permeability in log scale have linear relationships with clay contents in low clay mixing ratio. It is also recognized that coefficient of consolidation and permeability of sand and clay mixture are also dependent on the soil structure.

• Journal of The Korean Astronomical Society
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• v.24 no.1
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• pp.95-105
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• 1991

In the presence of synchrotron losses, diffusion of an ensembel of relativistic particles in an intraculster medium is investigated. The diffusion coefficient in the medium is found to be constrained by $28.8\;{\pm}\;0.4\;{\leq}\;Log\;D\;{\leq}\;30.5\;{\pm}\;0.4\;cm^2s^{-1}$ with the energy dependency of $D_0{\varepsilon}^{\mu}$ of ${\mu}=0.4{\pm}0.2$ as the previous observations suggested. As an important implication of the result, the brightest head-tail radio source NGC 4869, whose radio tail structure is indicative for its orbit within the cluster core, is considered to be the major contributor of particles for the formation of the Coma radio halo.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.604-609
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• 2003

Flaw geometries, applied stress, and material properties are major input variables for the fracture mechanics analysis. Probabilistic approach can be applied for the consideration of uncertainties within these input variables. But probabilistic analysis requires many assumptions due to the lack of initial flaw distributions data. In this study correlations are examined between initial flaw distributions and in-service flaw distributions on structures under cyclic load. For the analysis, LEFM theories and Monte Carlo simulation are applied. Result shows that in-service flaw distributions are determined by initial flaw distributions rather than fatigue crack growth rate. So initial flaw distribution can be derived from in-service flaw distributions.

• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.69-73
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• 1963

The basicities of 16 substituted azoxybenzenes have been measured by U.V. spectrophotometric method. The effects of substituents on the basicities are discussed in terms of Hammett's equation. The reaction constants, ${\rho}^X_Y$ and ${\rho}^Y_X$ , in a modified equation, log $K_{XY}/K_{\infty}={\sigma}_X{\rho}^Y_X+{\sigma}_Y{\rho}^X_Y$, are $2.46{\pm}0.12$ and $2.25{\pm}0.26$ respectively. The validity of the equation is analysed by a statistical method, and the structure of the conjugate acid of the substituted azoxybenzenes is proposed.

• Journal of Sensor Science and Technology
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• v.26 no.6
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• pp.397-401
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• 2017

A DC resistance type humidity sensor using conductive carbon ink was fabricated and its performance was evaluated. The humidity sensor was fabricated using a screen printing technique and have a structure that does not require additional metal electrodes to measure resistance change. To evaluate the performance of the humidity sensor, we measured the DC resistance change under various relative humidity levels. The fabricated humidity sensor showed a resistance change of about $2.5{\sim}50k{\Omega}$ in 11 ~ 95% RH environment. It also shows a linear relationship in the relative humidity versus log DC resistance graph. In comparison with commercial humidity sensor under real environment, it can be confirmed that the resistance of the humidity sensor changes to almost the same level as the measured humidity. These results show that the resistance type humidity sensor can be operated stably in actual environment.