• Steel and Composite Structures
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• v.29 no.6
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• pp.735-748
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• 2018

In this paper, the cyclic behavior of steel beam-concrete encased steel (CES) column joints was investigated experimentally and numerically. Three frame middle joint samples with varying concrete slab widths were constructed. Anti-symmetrical low-frequency cyclic load was applied at two beam ends to simulate the earthquake action. The failure modes, hysteretic behavior, ultimate load, stiffness degradation, load carrying capacity degradation, displacement ductility and strain response were investigated in details. The three composite joints exhibited excellent seismic performance in experimental tests, showing high load-carrying capacity, good ductility and superior energy dissipation ability. All three joint samples reached their ultimate loads due to shear failure. Numerical results from ABAQUS modelling agreed well with the test results. Finally, the effect of the concrete slab on ultimate load was analyzed through a parametric study on concrete strength, slab thickness, as well as slab width. Numerical simulation showed that slab width and thickness played an important role in the load-carrying capacity of such joints. As a comparison, the influence of concrete grade was not significant.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.116-120
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• 2003

In general, industrial rotating machinery have been designed to have critical speed that is above operating speed. But nowadays, they should be operated more than the first critical speed as usual with the trend of high speed and high performance of rotating machinery. Therefore, it is important to predict the accuracy rotordynamic characteristics of the high speed rotating system in advance. In this paper, the results of rotordynamic analysis about FWP(Feed Water Pump) drive turbine rotor are showed. Because the FWP drive turbine analyzed is high speed machinery operated more than the operation speed of conventional FWP drive turbine, Seismic response analysis as well as unbalance response analysis is done in order to improve the reliability of the new turbine rotor-bearing system.

• Nutrition Research and Practice
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• v.10 no.4
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• pp.418-423
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• 2016

BACKGROUND/OBJECTIVES: Spirulina, a blue-green alga, is widely produced and commercialized as a dietary supplement with bio- and immune-modulatory functions. We have previously shown that spirulina had favorable effects on lipid profiles, immune functions, and antioxidant capacity in healthy Korean elderly. Despite favorable effect of spirulina supplementation, some sub-populations have shown a poor response to supplementation. Obesity is a factor related to poor-response. Therefore, the purpose of this study was to determine the immuno-modulation, antioxidant capacity, and lipid-lowering effect of spirulina in obese and non-obese Korean elderly. SUBJECTS/METHODS: The subjects were 78 elderly aged 60-87 years. In a randomized double blind, placebo-controlled study, subjects were fed either placebo or spirulina daily, at 8 g for 12 weeks. Subjects were divided into the non-obese group and the obese group based on body mass index (BMI) criteria for Asians suggested by the International Obesity Task Force: $BMI<25kg/m^2$ (non-obese) and $BMI{\geq}25kg/m^2$ (obese). RESULTS: In the non-obese group, spirulina supplementation showed a significant lowering effect on plasma concentration of total cholesterol and LDL-cholesterol, a significant increase in interleukin (IL)-2 concentration (P < 0.01) and a significant increment (P < 0.05) in IL-2/IL-6 ratio, and a significant increase in total antioxidant status level and a significant decrease in thiobarbituric acid reactive substances level. However, these effects were not observed in the obese group. CONCLUSION: These results demonstrated that blood lipid lowering and immune and antioxidant improving response for spirulina supplement was affected by obesity in Korean elderly.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.3 s.43
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• pp.1-8
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• 2005

This paper describes a new objective methodology of seismic building damage assessment which is called Advanced Component Method(ACM). ACM is a major attempt to replace the conventional loss estimation procedure, which is based on subjective measures and the opinions of experts, with one that objectively measures both earthquake intensity and the response ol buildings. First, response of typical buildings is obtained analytically by nonlinear seismic static analysis, push-over analyses. The spectral displacement Is used as a measure of earthquake intensity in order to use Capacity Spectrum Method and the damage functions for each building component, both structural and non-structural, are developed as a function of component deformation. Examples of components Include columns, beams, floors, partitions, glazing, etc. A repair/replacement cost model is developed that maps the physical damage to monetary damage for each component. Finally, building response, component damage functions, and cost model were combined probabilistically, using Wonte Carlo simulation techniques, to develop the final damage functions for each building type. Uncertainties in building response resulting from variability in material properties and load assumptions were incorporated in the Latin Hypercube sampling technique. The paper also presents and compares ACM and conventional building loss estimation based on historical damage data and reported loss data.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.2
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• pp.1-8
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• 2008

Friction pendulum system is developed to prevent the damage of transformer, which is the most important among the electric power facilities, due to the earthquake and its seismic capacity is verified through the shaking table test. The applicability of friction pendulum system is confirmed as test results of compressive capacity test and friction test. Especially, as a result of shaking table test with a large scale transformer model, friction pendulum system gives to the reduction of maximum response acceleration by 30% at anchorage of transformer and 59% at the top of porcelain bushing comparing with the existing anchorage type. In addition to the reduction of maximum response acceleration, natural frequency of transformer is shifted to long period due to the friction pendulum system. In case that friction pendulum system is applied to the transformer, the damage of transformer can be prevented effectively under the earthquake.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.4
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• pp.216-223
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• 2013

As the fast growth of using Internet, the requests of clients having different types and pressing loads on the server have been increased in World Wide Web. Thus the interesting issue is how to measure the real capacity of a Web Server. There have been much recent studies about measuring the capacity of web server. But the cause of Server response time delay is not just server itself but also network packet loss. To measure the practical capacity of web server, we generate scalable clients using Posix Thread, transport packets which were generated by scalable clients to the server using UDP and receive the packets which were the remain packet from network packet loss using TCP. In this paper, we propose a method to measure the practical capacity of a web server using the Scalable Clients based on Posix Thread and the transport on Application level.

• Environmental and Resource Economics Review
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• v.14 no.3
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• pp.753-773
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• 2005

This paper is a study of the investment dynamics focusing on crude oil supply by OPEC and non-OPEC. Oil supply capacity is first determined by a leader, OPEC, and by an aggregate that represents non-OPEC producers. OPEC wants to increase a gain from oil price increase while keeping its market share relative to non-OPEC's share. An investment rule model is developed for OPEC crude oil supply capacity in response to non-OPEC's decision. In presence of oil price uncertainty, oil price threshold is derived above which it is optimal for OPEC to expand oil supply capacity since otherwise the increased supply of non-OPEC results in weakening of OPEC market share in the world oil market. In addition, a lower threshold price is derived below which OPEC triggers a capacity reduction to regain its otherwise forgone profits. A simulation is provided for calculating the capacity expansion and reduction thresholds.

• IMMUNE NETWORK
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• v.4 no.2
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• pp.88-93
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• 2004

Background: Bone marrow mesenchymal stem cells (MSC) inhibit the immune response of lymphocytes to specific antigens and dendritic cells (DC) are professional antigenpresenting cells whose function is to present antigen to naive T-lymphocytes with high efficiency and play a central role in the regulation of immune response. We studied the effects of MSC on DC to evaluate the relationship between MSC and DC in transplantation immunology. Methods: MSC were expanded from the bone marrow and DC were cultured from peripheral blood mononuclear cells (PBMNC) of 6 myelogenous leukemia after achieving complete response. Responder cells isolated from PBMNC and lysates of autologous leukemic cells are used as tumor antigen. The effect of MSC on the DC was analyzed by immunophenotype properties of DC and by proliferative capacity and the amount of cytokine production with activated PBMNC against the allogeneic lymphocytes. Also, cytotoxicity tests against leukemic cells studied to evaluate the immunologic effect of MSC on the DC. Results: MSC inhibit the CD83 and HLA-class II molecules of antigen-loaded DC. The proliferative capacity and the amount of INF-$\gamma$ production of lymphocytes to allogeneic lymphocytes were decreased in DC co-cultured with MSC. Also the cytotoxic activity of lymphocytes against leukemic cells was decreased in DC co-cultured with MSC. Conclusion: MSC inhibit the activation and immune response of DC induced by allogeneic or tumor antigen.

• Journal of Korean Association for Spatial Structures
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• v.15 no.4
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• pp.91-98
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• 2015

This paper has proposed a reinforcing method for damaged RC columns with SRF sheets and Aramid rods. In order to verify the effectiveness and performance, two original columns and two reinforced columns with SRF sheets and Aramid rods were developed and tested under lateral cyclic displacement and a constant axial load. The test showed that the improvement of energy dissipation capacity was increased in terms of strength and ductility. In addition, an analytical modeling of the standard specimens was proposed using Response-2000 and ZeusNL program. The results of analytical and experimental studies for two standard columns were compared in terms of loading-displacement curve and energy dissipation capacity based on the nonlinear static analysis.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.83-86
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• 2005

This paper proposed a hydraulic pump system which uses a variable SR drive and constant capacity pump. The base and maximum speed, torque are determined from displacement capacity of the pump and maximum pressure. The drive system is set to have a minimum power consumption having hydraulic preset pressure, which is operated within a maximum capacity and maximum preset pressure. This is achieved by controlling motor speed and power with feedback signal of pressure of the hydraulic pump. A 2.2kw, 12/8-pole SR motor and DSP based digital controller are designed and prototype drive system is manufactured. The proposed variable speed SR drive system is simulated and tested with experimental set-up. The test results show that the system has some good features such as high efficiency and high response characteristics.