• Korean Journal of Soil Science and Fertilizer
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• v.5 no.1
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• pp.9-15
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• 1972

Comparative analyses of canopy structure were conducted using newly bred high yield rice cultivars (IR 667-Suwon 213 and 214) and commercial varieties (Jinhung and Paldal) under the field condition. "Canopy score" as criteria of canopy structure was proposed. The results were summerized as follows: 1. IR667 line (IR8${\times}$Taichung Native 1${\times}$Yukara) showed lower canopy height, greater tiller openness, smaller leaf openness and leaf length ratio (flag leaf/3rd), shorter 4th and 5th internode length, greater diameter of 5th internode, consequently greater leaf area index, panicle weight and leaf weight ratio (leaf/leaf sheathculm) as merits, and greater leaf width, smaller leaf number(number of leaf/$m^2$)and specific leaf area($cm^2/g$) and faster destruction of canopy by senescence as demerits comparing with commercial varieties. 2. IR 667 line showed much higher "Canopy score", subsequently higher yield. 3. The quality of individual leaf was better in the commercial varieties indicating that the best combination for the better yield would be the leaf of commercial varieties with the structure of IR667 line.

• Korean Journal of Ecology and Environment
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• v.40 no.2
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• pp.327-336
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• 2007

This study assessed ecological health using a multi-metric fish model from 15 sites in the headwater watershed of southern Han River during June${\sim}$August 1999 and then compared the health with conventional community diversity index to figure out differences between health and diversity index. For the analysis, we adopted 10 metric IBI model for regional applications. During this survey, total number of species sampled were 24 (6 families) and varied depending on magnitude of ecological disturbance and stream order. In the mountainous streams, mean proportion of sensitive and insectivore species was composed of 91% and 56%, respectively, indicating a potential healthy conditions. However, tolerant species with 66% and omnivore species with 76% were sampled from the 2nd order stream, which was shown deterioration in the physical habitat quality. In the overall watershed, mean IBI value was 38, judging as "fair" condition by the health criteria. Values of Individual IBI were closely associated with stream order and this pattern was similar to other mountainous streams showing low chemical pollutions and disturbance. Our comparison between IBI and diversity index over the stream order showed a distinct difference; Shannon-Weaver diversity index overestimated the actual community conditions and the variation range in the 2nd order stream was greater in the diversity index. Overall data suggest that the multi-metric approach may to a useful tool for stream ecosystem management and the conventional diversity index may not effective unless the stream order is considered for the stream evaluation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.70-81
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• 2024

In this study, Tridimensional Hybrid Isolation System(THIS) was proposed as a vibration isolator for traffic loads, combining vertical and horizontal isolation systems. Its efficacy in improving serviceability for vertical vibration was analytically evaluated. Firstly, for the analysis, the major vibration modes of the existing apartment were identified through eigenvalue analysis for the system and pulse response analysis for the bedroom slab using commercial structural analysis software. Subsequently, a 16-story model with horizontal, vertical and rotational degrees of freedom for each slab was numerically organized to represent the achieved modes. The dynamic analysis for the measured acceleration from an adjacent ground to high-speed railway was performed by state-space equations with the stiffness and damping ratio of THIS as variables. The result indicated that as the vertical period ratio increased, the threshold period ratio where the slab response started to be suppressed varied. Specifically, when the period ratio is greater than or equal to 5, the acceleration levels of all slabs decreased to approximately 70% or less compared to the non-isolated condition. On the other hand, it was ascertained that the influence of damping ratios on the response control of THIS is inconsequential in the analysis. Finally, the improvement in vertical vibration performance of THIS was evaluated according to design guidelines for floor vibration of AIJ, SCI and AISC. It was confirmed that, after the application of THIS, the residential performance criteria were met, whereas the non-isolated structure failed to satisfy them.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.535-542
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• 2015

A reactor containment acts as a final barrier to prevent leakage of radioactive material due to the possible reactor accidents into external environment. Because of the functional importance of the containment building, the SIT(Structural Integrity Test) for containments shall be performed to evaluate the structural acceptability and demonstrate the quality of construction. In this paper, numerical analyses are presented, which simulate the results obtained from the SIT for a prestressed concrete(PSC) structure. A sophisticate structural analysis model is developed to simulate the structural behavior during the SIT properly based on various preliminary analysis results considering contact condition among structural elements. From the comparison of the analysis and test results based on the acceptance criteria of ASME CC-6000, it can be concluded that the construction quality of the containment has been well maintained and the acceptable performance of new design features has been verified.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.1
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• pp.11-20
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• 2010

Oyster production is playing an important role in domestic aquaculture, but facing some problems such as exports decrease, a slowdown in domestic demand and marine environmental deterioration. In order to obtain the suitable and sustainable oyster production, suitable sites selection is an important step in oyster aquaculture. This study was conducted to identify the suitable sites for lunging culture of oyster using Geographic Information System(GIS)-based multi-criteria evaluation methods. Most of the parameters were extracted by Inverse Distance Weighted(IDW) methods in GIS and eight parameters were grouped into two basic sub-models for oyster aquaculture, namely oyster growth sub-model(Sea Temperature, Salinity, Hydrodynamics, Chlorophyll-a) and environment sub-model(Bottom DO, TOC, Sediment AVS, Benthic Diversity). Suitability scores were ranked on a scale from 1(leased suitable) and 8(most suitable), and about 80.1% of the total potential area had the highest scores 5 and 6. These areas were shown to have the optimum condition for oyster culture in GeojeHansan Bay. This method to identify suitable sites for oyster culture may be used to develop bivalve culture management system for supporting a decision making.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.1-12
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• 2012

This study aims to suggest ways to improve sustainability on housing complexes. This study sampled eight housing projects in Seoul and GyeongGi-Do in Korea, which were completed in June 2007 and June 2008. Then, are retention and maintenance on "constructed greens for ecological environment" including "green structures substitutes retaining walls", "green roofs", and "green walls." Study methods are field investigations of the sampled sites, and Post Occupancy Analysis. Major findings were; 1) "constructed greens" are not well retained in more sites and and this implies the GBCS(Green Building Certification System) does not meet its objectives well, 2) User showed lower user satisfaction to "constructed greens". User satisfaction concerning "green structures substitute retaining walls" was higher than the satisfaction on the other constructed green type. Satisfaction Assessment Criteria lower 1han average were "level of quality", "meet the design objectives", "vegetation management status", "vegetation maintenance". 3) User satisfaction was strongly correlated on the level of quality factor of "constructed green". In addition, tue other factors are the significant correlations between the satisfactions. The present GBCS has inadequate assessment standards for maintenance, which lead to lower the entire satisfaction. Therefore, periodic recertification system, education and information providing for the managing personals, and incentives for good maintenance or disincentive for poor maintenance of the "constructed greens" are suggested to improve the GBCS.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.950-957
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• 2023

For safe mooring and towing between the ship and port, the equipment must be designed in accordance with the relevant international regulations. However, some small shipyards and engineering companies often do not fully comprehend the core contents. Therefore, the international regulations regarding towing and mooring equipment are reviewed and the bollard and chock are newly developed based on the Mooring Equipment Guideline 4 (MEG4) standards. A bollard is a mooring equipment used to fix a mooring rope to the hull. It has two columns and is mostly used in a figure eight pattern knots under the mooring condition. The chock, which is used to change the mooring rope direction coming into the ship from outside, is manufactured using a casting with curvature. The two mooring equipment are widely used in the stern, bow, and mid-side. Owing to the increase in the size of container vessels and LNG ships, the mooring rope load has increased and the safe working load of the mooring equipment must be revised. This study summarizes and examines the results of the allowable stress method obtained using finite element analysis modelling. To consider the mesh size effect, a reasonable criteria was suggested by referring the existing class guidance. Additionally, the safe working load was verified through nonlinear collapse analysis, and the elastic region against load increments was confirmed. Furthermore, the proposed evaluation method can be used to develop similar equipment in the near future.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.986-995
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• 2016

The objective of this study was to analyze the distribution of endangered fish species and elucidate their relations on chemical water quality, physical habitat conditions and ecological stream health. The dominant species in the watershed was Pseudopungtungia nigra (Pn), Gobiobotia macrocephala (Gm), Gobiobotia brevibarba (Gb), Liobagrus obesus (Lo), and Iksookimia choii (Ic) in the order. The species of Pn designated as "critical endangered species (I) (CER)", was most widely distributed species among the endangered species, so the designation of the species should be re-evaluated. The endangered species was most popular (4 species, 384 individuals) in the Cho-River region of eighteen lotic regions. According to the analysis of chemical tolerance limits in the habitats with endangered fish species, biological oxygen demand (BOD) and total phosphorus (TP) was analyzed as "very good" (Ia) and "good condition" in the chemical criteria of the Ministry of Environment, Korea. Also, chemical conditions, based on ammonia-N ($NH_{4+}$), total nitrogen (TN), phosphate-P ($PO_{4^-}P$) were much better in the habitat with endangered species (Hw) than the habitat without endangered species (Ho). In the meantime, the species of Ic showed wide ranges on the chemical tolerance, so physical habitat conditions, such as the size of substrate particles (sand) and hydrological regime, were considered as more important factors than the chemical water quality, if the water quality is not largely degraded. The endangered species were also more distributed in the high-order (4-6) streams than the low-order (1-3) streams. The evaluation of ecological stream health, based on multi-metric model of the Index of Biological Integrity (IBI), showed the large difference between the Hw (21.6, fair condition)and Ho (30.5, good condition), indicating that the habitat maintained well chemically and physically had higher distributions of endangered species. Overall, the designation of CER on the Pn should be re-evaluated due to wide-distributions, and the protections from water pollution and the habitat conservations on the endangered species are necessary in the watershed.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.62-69
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• 2003

The aim of research is the evaluation of the $Cr^{6+}$ emission features of the liquid injection through emission experiments in varying conditions, based on a field-mixing ratio. The results showed that the content of $Cr^{6+}$ content in cement measured had an Ordinary Potland Cement (OPC) of 25.3 mg/kg, which constitute the largest portion among the other materials. Likewise, the emission experiment of homo-gel and sand-gel generally satisfied the standard of KSLT (Korea Standard Leaching Test) in waste of 1.5 mg/L, but in case of the standard of KSLT in soil the emission of OPC $Cr^{6+}$ of 4.85 mg/kg. These conditions is a little exceeded the criteria in the ‘Ga’ area in terms of Korea Soil Environmental Preservation Law. In addition, results generated by the mock-up injection facilities revealed that $Cr^{6+}$ emission increased as Water/Cement and injection pressure increased. At injection pressure higher than 4 kg/㎤, $Cr^{6+}$ emission exceeded the water preservation standard of 0.5 mg/L. Similarly, a pattern experiment of C $r^{6+}$ emission according to pH was conducted, in order to evaluate the $Cr^{6+}$ emission features of grout materials in leachate below pH 5 such as pH 4 acid rain or landfill. Results show that $Cr^{6+}$ emission dramatically increased in high acidic or basic state. It indicates that $Cr^{6+}$ emission will probably increase in an environment where grout materials are injected. On the other hand, concentration of leachate was determined in areas where grout materials are used. The results show that the concentration of emission in an ultra purity condition does not manifest intensity, and is affected in the OPC>MC>SC order. It means that the pollutants or $Cr^{6+}$ emission increases with decreasing concentration. As such, $Cr^{6+}$ emission will probably exceed the countermeasure criteria according to the types of gout materials. Similarly, high pressure or injection will cause increased $Cr^{6+}$ emission. Therefore, the selection of materials or mixing ratio should be considered in general as well as according to specific industries, based on the strength and pH of $Cr^{6+}$ emission.

• Journal of Sericultural and Entomological Science
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• no.12
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• pp.47-50
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• 1970

There are many factors affecting the development of sericultural industry in Korea. The setting of a rational pricing system for sericultural products is one of important activities of the Korean Government to improve the incentives to producers. The determination o： the prices for many years were based on the production costs including a certain level of profits. Some of cost items are in conflict both in cocoon producers and silk-reeling industries. Government officials have to evaluate these conflicting problems and estimate the consequences of their decisions. In this situation the final decision often became political decisions. This analysis is aimed at providing an alternative method of setting the prices of sericultural products. The criteria of the equilibrium employed in this analysis are based on economic principle which equilibrium condition is determined by the relationships between the marginal productivity of input factors and factor prices. In order to obtain the related information Cobb-Douglas'functions were fitted using KIST computer and data were obtained mostly from the Bank of Korea and the Ministry of Agriculture and Forestru, An important assumption is that "Opportunity Costs" of factors input in both cocoon production and silk-Peeling industries are same, The major finding s obtained are as followings. 1) The sum of coefficient of production elastisity in silk-reeling industries is greater than one. Silk-reeling industries are operating under the situation of increasing return to scale and it is, therefore, expected to develop the industries as the capital-intensive large scale. 2) The cocoon producing farmers are under the situations of the decreasing return to scale and it is expected to continue their cocoon farming as the labor-intensive small scale, assuming the present level of production technology. As the development of commercial farming, the resources input in cocoon production will be shifted to the production for higher profitable crops, 3) The price elastisity of production is higher in cocoon production than in silk-reeling industries. It is expected that the price changing effects on domestic production will be resulted from cocoon producers. 4) Based on analysis results of marginal productivities and the opportunity costs of resources, cocoon price for meeting equilibrium price condition is to be increased by 8-16 percent or standard price level of silk increased by 6-8 percent. There were the possibilities of over evaluation on opportunity cost of resources input in silk-reeling industries, or income transfered from the farmers to the industries. It is recommended that the prices for meeting equilibrium price conditions are to be determined by 72 percent for cocoon and 28 percent for silk-reeling costs, based on standard level of the exporting prices.