• Journal of Korean Society of Water and Wastewater
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• v.24 no.2
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• pp.183-193
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• 2010

Well planned rehabilitation order of pipes is essential for efficient maintenance and management of Water Distribution Systems. In this study, not only deterioration rate of pipes but also structural and nonstructural failure which causes abnormal condition of WDS is considered to determine rehabilitation order. Probabilistic Neural Network is used for calculating deterioration rate at present and the importance of pipes is computed under structural and nonstructural failure by using Pipe by Pipe Failure Analysis and Effect Index. Utopian Approach, one of the Multi-Criteria Decision Making methods, is used for assessment of final rehabilitation order based on distance measure between utopian point and alternative one. Developed model in this study shows that it gives more reliable results than existing methods considering hydraulic relative importance does in application to real networks. In this point, the newly developed model, which gives advantages over existing models, can make a credible decision and simple application.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.4
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• pp.13-23
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• 2007

This paper focuses on providing a practical approach for decision making in Performance-Based Design (PBD). Satisfactory performance is defined by several performance objectives that place limits on direct (monetary) loss and on a tolerable probability of collapse. No specific limits are placed on conventional engineering parameters such as forces or deformations, although it is assumed that sound capacity design principles are followed in the design process. The proposed design procedure incorporates different performance objectives up front, before the structural system is created, and assists engineers in making informed decisions on the choice of an effective structural system and its stiffness (period), base shear strength, and other important global structural parameters. The tools needed to implement this design process are (1) hazard curves for a specific ground motion intensity measure, (2) mean loss curves for structural and nonstructural subsystems, (3) structural response curves that relate, for different structural systems, a ground motion intensity measure to the engineering demand parameter (e.g., interstory drift or floor acceleration) on which the subsystem loss depends, and (4) collapse fragility curves. Since the proposed procedure facilitates decision making in the conceptual design process, it is referred to as a Design Decision Support System, DDSS. Implementation of the DDSS is illustrated in an example to demonstrate its practicality.

• Journal of Korean Society of Disaster and Security
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• v.7 no.1
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• pp.17-25
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• 2014

Due to the recent climate change impact, natural disasters occur due to sea surface rising, typhoon attacks, flash floods, local heavy rainfalls, landslides, and coastal area erosion, continuing to cause human and property damage. These impacts, coupled with urbanization and industrialization activities, are turning the previously safe areas into disaster-vulnerable areas, increasing human and economic damage. This paper aimed to prepare measures designed to minimize human damage in natural disaster vulnerable parts of South Korea in summer. Toward that end, how vulnerable areas were managed and what the damage was like were studied. Also, cases of human damage and statistics there of were reviewed and analyzed, relevant problems were derived, and thus structural and non-structural measures designed to minimize human damage were presented.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.26-32
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• 1995

Weak persistence of white clover （Trifolium repens L.） under continuous grazing has been limited its availability in the mixture with grasses. The experiment was done to determine the effect of defoliation interval on $N_2$ fixation. nitrogen and carbohydrate partitioning of contrasting white clover cultivars. Individual plants of Osceola（large leaf）, Grasslands Huia （me-dium leaf）, and Aberystwyth S184 （small leaf） were grown in 15cm plastic pot containing a 1：2：1 soil：sand：Promix mixture for 55 days, and then clipped to remove all fully expanded leaves every 7, 14 or 28 days. To measure the cultivar response, plants were sampled immediately before final harvest （0） and on 1, 3, 7, 14, and 28 days after the final harvest, and then seperated leaves and petioles, stolons and roots for chemical analysis. Total nonstructural carbohydrate （TNC） concentrations of stolons and roots, and nitrogen con-centration of all the fractions inclined with increased defoliation interval. Those of Osceola, large leaved, were greater than the other cultivars showing different partitioning patterns between stolons and roots. Concentration of TNC was less in roots than in the other fractions while that of nitrogen declined in the order of leaves and petioles, roots and stolons. $N_2$ fixation rate of larger leaved cultivar, Osceola, was higher than that of smaller leaved cultivar. TNC and nitrogen concentrations of all the fractions and $N_2$ fixation rate were reduced as defoliation was imposed, defoliation interval declined or regrowing period become shorter. The partitioning patterns of TNC and nitrogen among the fractions were modified by defoliation interval and cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.427-435
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• 1984

Alfalfa field was established to investigate seasonal changes of nodule activity and contents of carbohydrates, and nitrogen, and also to examine their relationships in alfalfa (Medicago sativa L.). Periodical sampling of alfalfa in cutting and uncutting plots was collected to measure growth of plants, development and activity of nodule, and content of carbohydrates and nitrogen in the third year following year of establishment. Nodule activity of alfalfa root appeared to early April, increased to a maximum in beginning of June (flowering stage), and then decreased and generally remained low from late-July to mid-August, and again increased from early September, and then decreased and generally remained low for the rest of growing season. After flowering, nodule weight tended to decrease slowly throughout the growing season. Until flowering stage, increase of dry weight was closely related with that of nodule activity. But after flowering the curve pattern of dry weight did not fit to that of nodule activity due to decrease of supply of assimilate to nodule, drought, and high temperature. Total nonstructural carbohydrates in roots were closely correlated with nodule weight and nodule activity. While, nitrogen contents in leaves were closely correlated with nodule weight and nodule activity. Also cutting on July prevented unnessesary losses of respiration during summer to provide rapid recovery of nodule activity.