• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.4
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• pp.43-61
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• 2017

The wetlands are facing environmental changes such as desiccation that occurs with the passage of time and reduced ecosystem services from wetlands in the city. In order to maintain the ecosystem services provided by wetlands in urban areas, a system thinking about the trade-off phenomenon of ecosystem services occurring as the wetlands undergo environmental changes is needed. Therefore, the purpose of this study is to develop strategies for wetland design using system thinking approach to enhance the resilience of ecosystem services degraded by the desiccation of wetlands and other disturbances. The objectives of this study include the system boundary and variables. Second, analyzing the dynamics of wetland design strategy. Third, it analyzes the trade-off phenomenon of ecosystem services in terms of the hydrology, hydric soil, and plants strategies to mitigate these effects. Fourth, wetland basic design to improve the resilience of ecosystem services. A wetland in Abuk-Mountain Neighborhood Park, Miryang-si, Gyeongsangnam-do, has been selected as a case study. Causal loop diagrams(CLDs) are used to analyze feedback in the wetland regime. In summary, hydrology, hydric soil, and plants is suggested as system boundaries to design plan. Design strategies for the wetland focused on robustness, redundancy, rapidity, and resourcefulness as a result of CLD analysis are first proposed in order to effectively maintain the wetland regime over the long term. Secondly, in a section related to hydrology, the CLD results show the trade-offs between provisioning-cultural services and regulating services. In order to control these services, a "water cycling system" has been implemented due to its strength in terms of robustness. The CLDs for hydric soil showed the trade-offs between regulating services and supporting services. An "installation of storm drainage for maintaining water levels" was selected due to the strength offered in terms of redundancy and rapidity. The CLDs for plants showed the trade-offs between provisioning - cultural services and regulating services. In order to control the strategic points, the "planting of indigenous vegetation" was suggested given the strength in terms of redundancy. In this study, a wetland design method is proposed that can improve the resilience of wetland ecosystem services by analyzing the dynamics overtime. The results of this research can theoretically be applied to help restore ecosystem services in wetlands using ecological landscape design. In addition, this study will contribute to reducing maintenance costs by improving wetland resilience.

• Proceeding of KASS Symposium
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• 2008.05a
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• pp.37-42
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• 2008

Cable member in structure is tension systems in which the load carrying members transmit loads to support system by tensile stress with no compression or flexure allowed. Cable system have been widely used large span structure roof, air-supported structure, prestressed membrane, cable network roof, suspension structures, guyed tower, ocean platforms, suspension bridges. Cable member can transmit loads by the edge connected system such as socket, swaging, mechanical splice sleave, clip, wedge, loop splice etc. This study will shown an experimental results on the strength of connection socket of cables. In the results of experiment, most of cable connection specimen occurred the failure at the connection socket part before the cable arrived at tensile failure load.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.41.2-41.2
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• 2016

We perform three statistical studies on the physical properties and oscillations in the confined plasma such as a photospheric sunspot and confined coronal loop. From the statistical studies on the sunspot umbra and its oscillation, we find that (1) the total magnetic flux inside the umbra for the three groups increases proportionally with the powers of the umbral area and the power indices in the three groups significantly differ from each other; (2) the three groups have different characteristics in their umbral area, intensity, magnetic field strength, and Doppler velocity as well as their relationships; (3) the mean frequency of the umbral oscillations increases with the umbral mean magnetic field strength and height; (4) the time delay of the core intensity of Fe I absorption line relative to the continuum which are de-convolved with the frequency range higher than 3.5 mHz is mostly positive, implying that the photospheric umbral oscillations are likely upwardly propagating; (5) the umbral mean plasma beta ranges approximately 0.6-1.1 and does not vary significantly from pores to mature sunspots. From the comparative study on the quasi-periodic pulsations (QPPs) in the solar and stellar flares, (6) we find that the power index of the periods scaling the damping times observed in the stellar QPPs is consistent with that observed in the solar QPPs, suggesting that physical mechanisms responsible for the stellar QPPs are likely the magneto-hydrodynamic oscillation of solar coronal loops.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.590-599
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• 2006

In this study, Liquefaction characteristics of saturated sand under various dynamic loadings such as sinusoidal loading, increasing wedge loading, and real earthquake loading were investigated focusing on the dissipated energy. From the results of cyclic triaxial test, liquefaction resistance strength was calculated by the concept of energy according to the type of input loading. Liquefaction resistance strength was expressed in accumulated dissipated energy calculated from stress-strain curve(hysteresis loop). The dissipated energy according to loading type was compared and the energy-based evaluation was proposed. The procedures are presented in terms of normalized energy demand(NED), normalized energy capacity(NEC), and factor of safely, where NED is the load imparted to the soil by the loading(both amplitude and duration), NEC is the demand required to induce liquefaction, and factor of safely is defined as the ratio of NEC and NED.

• Journal of the Korean Ceramic Society
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• v.52 no.3
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• pp.209-214
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• 2015

Silicon nitride films were deposited at $100^{\circ}C$ by using the catalytic chemical vapor deposition technique. The source gas mixing ratio, $R_N=[NH_3]/[SiH_4]$, was varied from 10 to 30, and the hydrogen dilution ratio, $R_H=[H_2]/[SiH_4]$, was varied from 20 to 100. The breakdown field strength reached a maximum value at $R_N=20$ and $R_H=20$, whereas the resistivity decreased in the same sample. The relative permittivity had a positive correlation with the breakdown field strength. The capacitance-voltage threshold curve showed an asymmetric hysteresis loop, which became more squared as $R_H$ increased. The width of the hysteresis window showed a negative correlation with the slope of the transition region, implying that the combined effect of $R_N$ and $R_H$ overides the interface defects while creating charge storage sites in the bulk region.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.06a
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• pp.34-39
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• 2000

Today's size of production operations in the packaging paper sector I sconstantly increasing , featuring integral processing systems, high-speed paper machines, and the increased marketing of lower basis weight products. The risk factors involved in these large investments lie more than ever in the available furnish potential and ongoing requirements for further closure of water loops and lower operating costs. A comparison is drawn between recovered paper furnish mixtures used in European mills with regard to fibre properties, strength potential and contaminant content, Both the furnish situation and development trends in modern fluting and testliner machines are instigating concept changes in stock preparation, the approach flow as well as in process water and rejects technology. Developments are currently focussed for example on more efficient debris separation using fine slotted screening, optimized refining , more systematic process water management with loop separation and integral water clarification as well as more efficient removal of microstickies, fillers and fines through appropriate combination of rejects handling and water clarification processes. Product quality differentiation depends decisively on strength characteristics as a function of refining , fines removal , paper machine technology, and sizing . Maximum availability of today's high speed paper machines and , as a result, cost effective production can be ensured by optimum balancing of all subsystems with in the overall concept and by reliable control of problems with contaminants and deposits.

• Steel and Composite Structures
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• v.19 no.2
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• pp.309-325
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• 2015

A convenient procedure for seismic retrofit of existing buildings is to use passive control methods, like using friction dampers in steel frames with bracing systems. In this method, reduction of seismic demand and increase of ductility generally improve seismic performance of the structures. Some of its advantages are development of a stable rectangular hysteresis loop and independence on environmental conditions such as temperature and loading rate. In addition to friction dampers, masonry-infill panels improve the seismic resistance of steel structures by increasing lateral strength and stiffness and reducing story drifts. In this study, the effect of masonry-infill panels on seismic performance of a three-span four-story steel frame with Pall friction dampers is investigated. The results show that friction dampers in the steel frame increase the ductility and decrease the drift (to less than 1%). The infill panels fulfill their function during the imposed drift and increase structural strength. It can be concluded that infill panels together with friction dampers, reduced structural dynamic response. These infill panels dissipated input earthquake energy from 4% to 10%, depending on their thickness.

• Steel and Composite Structures
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• v.45 no.3
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• pp.455-466
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• 2022

Despite the considerable lateral stiffness and strength of the Concentrically Braced Frame (CBF), it suffers from low ductility and low seismic dissipating energy capacity. The buckling of the diagonal members of the CBF systems under cyclic loading ended up to the shortcoming against seismic loading. Comprehensive researches have been performing to achieve helpful approaches to prevent the buckling of the diagonal member. Among the recommended ideas, metallic damper revealed a better success than other ideas to enhance the behavior of CBFs. While metallic dampers improve the behavior of the CBF system, they increase constructional costs. Therefore, in this paper, a new steel damper with flexural mechanism is proposed, which is investigated experimentally and numerically. Also, a parametrical revision was carried out to evaluate the effect of thickness, slenderness ratio, angle of the main plate, and height of the main plates on the proposed damper. For the parametrical study, 45 finite element models were analyzed and considered. Experimental results, as well as the numerical results, indicated that the proposed damper enjoys a stable hysteresis loop without any degradation up to a high rotation equal to around 31% that is significantly considerable. Moreover, it showed a suitable performance in case of ductility and energy dissipating. Besides, the necessary formulas to design the damper, the required relations were proposed to design the elements outside the damper to ensure the damper acts as a ductile fuse.

• Journal of the Korean Society of Clothing and Textiles
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• v.9 no.2
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• pp.1-11
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• 1985

The purpose of this study was to research the effect of sewing threads on sewability. The materials used in this study were cotton threads, p/c spun thread, polyester spun thread and core-spun thread, which were the same in count, but different in fibers. In order to approach the purpose of this study, the change of sew-ability was measured according to the number of laundering. The results from this measure were as follows; 1. The order of seam strength according to the sewing threads was polyester spun threads, p/c spun thread, core-spun thread, and cotton thread in proportion to the loop strength of the sewing threads. The preserving rate of strength after laundering was the highest in core spun thread. 2. The order of seam elongation according to the sewing threads was polyester spun thread, p/c spun thread, core-spun thread and cotton thread in proportion to the elongation of the sewing threads. The preserving rate of elongation after laundering was the highest in core spun thread. 3. The order of seam puckering according to the sewing threads' was core-spun thread, p/c spun thread, polyester spun thread and cotton thread. The order of changing rate after laundering was the same as the former order. 4. The order of the needle temperature according to the sewing threads was polyester spun thread, core-spun thread, p/c spun thread and cotton thread.

• The Journal of Advanced Prosthodontics
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• v.4 no.3
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• pp.127-133
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• 2012

PURPOSE. Many dentists use desensitizing agents to prevent hypersensitivity. This study compared and evaluated the effect of two desensitizing agents on the retention of cast crowns when cemented with various luting agents. MATERIALS AND METHODS. Ninety freshly extracted human molars were prepared with flat occlusal surface, 6 degree taper and approximately 4 mm axial length. The prepared specimens were divided into 3 groups and each group is further divided into 3 subgroups. Desensitizing agents used were GC Tooth Mousse and $GLUMA^{(R)}$ desensitizer. Cementing agents used were zinc phosphate, glass ionomer and resin modified glass ionomer cement. Individual crowns with loop were made from base metal alloy. Desensitizing agents were applied before cementation of crowns except for control group. Under tensional force the crowns were removed using an automated universal testing machine. Statistical analysis included one-way ANOVA followed by Turkey-Kramer post hoc test at a preset alpha of 0.05. RESULTS. Resin modified glass ionomer cement exhibited the highest retentive strength and all dentin treatments resulted in significantly different retentive values (In Kg.): GLUMA ($49.02{\pm}3.32$) > Control ($48.61{\pm}3.54$) > Tooth mousse ($48.34{\pm}2.94$). Retentive strength for glass ionomer cement were GLUMA ($41.14{\pm}2.42$) > Tooth mousse ($40.32{\pm}3.89$) > Control ($39.09{\pm}2.80$). For zinc phosphate cement the retentive strength were lowest GLUMA ($27.92{\pm}3.20$) > Control ($27.69{\pm}3.39$) > Tooth mousse ($25.27{\pm}4.60$). CONCLUSION. The use of $GLUMA^{(R)}$ desensitizer has no effect on crown retention. GC Tooth Mousse does not affect the retentive ability of glass ionomer and resin modified glass ionomer cement, but it decreases the retentive ability of zinc phosphate cement.