• The Korean Journal of Ecology
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• v.16 no.1
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• pp.93-114
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• 1993

The vegetation of Mt. Mudeung was investigated from April, 1991 to September, 1992. The units of vegetation were classified 10 units by the Braun-Blanquet's phytosociological method. The forest vegetation was classified into 10 communities, Pinus densiflora, Pinus vigida, Chamaecyparis obtusa afforestation, Quercus mongolica, Q. variabilis, Q. serrata, Q. acutissima, Miscanthus sinensis var. purpurascens, Hylomecon hylomeconoides and Drosera rotundifolia community. Based on the classification, the actual vegetation map and degree of green naturality were drawn in 1:50,000 scale. The vertical distribution of the main component species was investigated based on the vegetation data of the EN slope and SW slope of Mt. Mudeung from altitude 200m to top.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.5
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• pp.1-15
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• 1993

In DQDB networks, the bandwidth can be increased considerably be using the EN(Erasure Node) algorithms and DR(Destination Release) algorithms. However, the important issue in implementing them is using method of extra capacity fairly. To improve it, this paper proposes AEN(Adaptive Erasure Node) algorithm which erasure function is activated by network traffic load. Its functional architecture consists of SESM, RCSM, LMSM in addition to the basic DQDB state machines (DQSM, RQM). The SESM and RCSM state machines are placed in front of the DQSM and RQM state machines in order for the node to take advantage of the newly cleared slots. This paper also presents some simulation results showing the effect of AEN algorithm on access delay, throughput and segment erasing ratio in the single and multiple priority networks. The results show that the AEN algorithm offer the better performance characteristics than existing algorithms under overload conditions.

• The Korean Journal of Quaternary Research
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• v.7 no.1
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• pp.103-111
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• 1993

Apres le Perigordien ancien, les proportions de l'outillage archaique du Prerigordien decroissent progressivement au fur et a mesure que les industries perigordiennes se developpent. Dans le Perigordien superieur ( couche Ⅵ du Flageolet I ) les outils archaiques sont beaucoup moins frequents que dans le Perigordien ancien, mais ils perdurent encore en proportion notable et leur indice atteint 31,23. Par la suite, dans le Perigordien superieur evolue la frequence de l'outillage archaique est naturellement la plus faible pour le Perigordien et 1'indice moyen d'outils archaiques y descend a 17,99.

• Journal of Korean Society of Steel Construction
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• v.27 no.6
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• pp.503-511
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• 2015

In long span steel structure, the plate girder reinforced with stiffeners are commonly used. When choosing the cross section with deep depth of girder as well as narrow width, however, out of plane buckling can be a problem due to web slenderness. In an effort to solve this issue, current study determined the applicability of using corrugated web girder with deep depth as bending member, which is generally being utilized in both factory and warehouse nationwide. To accomplish this, we performed the loading test of H-shaped beam with sinusoidal corrugated web. Corrugated web CP-2.3 specimen exhibited 12% less maximal bending strength but CP-3.2 specimen exerted 24% increase in strength compared to plate web P-4.5. this result indicates that corrugated web provides enough strength even with unfavorable width-thickness ratio of plate. And bending as well as shear strength estimated by the Eurocode (EN 1993-1-5) were compared with both bending strength by loading test and shear strength estimated by KBC2009. In case of eurocode, increase in plate thickness did not help in bending performance improvement. moreover, shear performance was sensitive to the thickness of the web folds and the shape of the web plate.

• Journal of Korean Public Health Nursing
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• v.8 no.1
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• pp.73-83
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• 1994

This study was conducted to investigate rural residents' health status and lifestyle before inputing the health promotion services in CHP post juridiction area. For the survey. questionaire survey was done during the period from September 1993 to October 1993. Questionare was composed 14 items of general characteristics and 12 items of health age. Respondents were 119 residents among 300 residents in a rural area. For the analysis. descriptive statistics were used by calculating frequencies. percentages and $x^2-test$ Were employed to test the differences and the statistical significance. The major results are as follows; 1. Characteristics of the objects: The sex $61.0\%$ of female. the age was $36.0\%$ of over the fifties. the educational background was $47.4\%$ of elementary graduation. the marital status was $94.9\%$ of married and the monthly income was $35.3\%$ of less than 600,000 won. 2. Health status of the objects; Hepatitis antibody was possessed only $6.2\%$. hypertension was $27.3\%$. pulse rate and disease status were. for the most part, normal. 3. Health care status of the objects: They didn't use $74.1\%$ of medical services for the two weeks and regular health check-up. 4. Health behavior of the objects: The diet was $78.1\%$ of intaking meats and fish below 4 times for 1 week, no smoking was $66.1\%$. drinking was $70.83\%$ below two and half times for 1 week, life satisfaction was $21.8\%$. stress management was $41.5\%$ and exercise for health was $25.2\%$. 5. Experience of common cold for 3 years was $46.2\%$. hypertention by sex was $8.7\%$ of males and $19.4\%$ of females and diabetus was $1.7\%$ 6. Helth behavior by educational background didn't do in low educational background. 7. Health age of the objects was $62.3\%$ of $+1\~+4$ than actual age.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.2
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• pp.4-10
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• 1993

In mobile radio communication, propagation paths are time or spacial varying because of the motion of mobile unit. The propagation path loss not only involves frequency and distance but also the antenna height at both the base station and the mobile unit, terrain configuration, and the man made en- vironment. Thhese additional factors make the prediction of propagation path loss of mobile radio signals more difficult. In this paper, it is measured field strenght of mobile radio signals in Daejeon and Seoul area, also calculated local median, 500m sample mean, and stadard deviation. As the result of analysis, it can be seen that propagation path loss of measured data is similiar to predicted field strength, especially local median is dependent upon base antenna height, terrain configuration and the man-made environment. The standard deviation has been noted to lie between 2 and 10 dBuV.

• Structural Engineering and Mechanics
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• v.67 no.6
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• pp.629-641
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• 2018

The paper describes the development of a two-dimensional (2D) co-rotational nonlinear beam finite element that includes advanced path-following capabilities for detecting bifurcation instability in elasto-plasticity of steel elements subjected to fire without introducing imperfections. The advantage is twofold: i) no need to assume the magnitude of the imperfections and consequent reduction of the model complexity; ii) the presence of possible critical points is checked at each converged time step based on the actual load and stiffness distribution in the structure that is affected by the temperature field in the elements. In this way, the buckling modes at elevated temperature, that may be different from the ones at ambient temperature, can be properly taken into account. Moreover, an improved displacement predictor for estimating the displacement field allowed significant reduction of the computational cost. A co-rotational framework was exploited for describing the beam kinematic. In order to highlight the potential practical implications of the developed finite element, a parametric analysis was performed to investigate how the beam element compares both with the EN1993-1-2 buckling curve and with experimental tests on axially compressed steel members. Validation against experimental data and numerical outcomes obtained with commercial software is thoroughly described.

• Structural Engineering and Mechanics
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• v.63 no.2
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• pp.195-206
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• 2017

This paper presents the parametric numerical analysis on the ultimate bearing capacity of the purlin-sheet roofs connected by standing seam clips. The effects of several factors on failure modes and ultimate bearing capacity of the purlins are studied, including setup of anti-sag bar, purlin type, sheet thickness and connection type et al. A simplified design formula is proposed for predicting the ultimate bearing capacity of purlins. Results show that setting the anti-sag bars can improve the ultimate bearing capacity and change the failure modes of C purlins significantly. The failure modes and ultimate bearing capacity of C purlins are significantly different from those of Z purlins, in the purlin-sheet roof connected by standing seam clips. Setting the anti-sag bars near the lower flange is more favorable for increasing the ultimate bearing capacity of purlins. The ultimate bearing capacity of C purlins increases slightly with sheet thickness increasing from 0.6 mm to 0.8 mm. The ultimate bearing capacity of the purlin-sheet roofs connected by standing seam clips is always higher than those by self-drilling screws. The predictions of the proposed design formulas are relatively in good agreement with those of EN 1993-1-3: 2006, compared with GB 50018-2002.

• Economic and Environmental Geology
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• v.26 no.4
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• pp.499-505
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• 1993

The Imgye hornblendites occur as intrusive sills or dykes within the mylonite zone developed along the contact boundary between Precambrian Jungbongsan granite and Cambrian Jangsan quartzite or Myobong slate formations. The hornlendites belong to the subalkaline and tholeiitic series. In tectonomagmatic discrimination diagrams such as $TiO_2-K_2O-P_2O_5$, 2Nb-Zr/4-Y and $TiO_2-10MnO-10P_2O_5$, the hornblendites are classified into continental- and island-arc tholeiites. The hornblendites show fractionated REE patterns with $(La/Yb)_{CN}$ ranging from 3.73-4.56. In incompatible element abundance variations, the hornblendites show distinctive positive and negative anomalies for Rb and Nb, respectively, and unfractionated patterns of immobile incompatible elements such as Y and Yb. The REE patterns of the hornblendites are also similar to those of typical continental back-arc tholeiites and those of the Precambrian Okbang amphibolites in the Socheon-meon, Bonghwa-gun. Accoiding to geochemical characteristics above-mentioned, the hornblendites seem to have been formed from tholeiitic magmas of depleted upper mantle source, contaminated by crustal material en route to continental back-arc basin.

• Journal of Korea Foundry Society
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• v.13 no.4
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• pp.359-368
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• 1993

Mg-9wt.%Al and Mg-9wt.%-1.6wt%Zn/SiCp(particle size $40{\mu}m$) metal-matrix-composite specimens were manufactured by rheo-compocasting method, known for its effect of improving the wettability. The ceramic reinforcement particles(SiCp) were dispersed in the semi-solid magnesium alloy matrix slurry being vigorously stirred in a high frequency induction furnace under inert atmosphere. A microstructural study of the dispersed particles in the specimens, prepared under different conditions as regards the time(10min, 20min, 30min) and temperature of the stirring, was made with the aid of optical microscope and SEM. The effect of superheating was also observed. It is revealed that 30 minutes' stirring time of the semi-solid at 40% solid fraction temperature(Mg-9wt.%Al : $590^{\circ}C$, AZ91 : $576^{\circ}C$), as determined by the lever rule, gives a satisfactorily uniform distribution of the particles. The superheating is observed to enhance further the uniformity.