• Journal of the Korean Geotechnical Society
• /
• v.25 no.9
• /
• pp.93-100
• /
• 2009

A core procedure of the direct search method used in this study is optimizing a difference between objective function and real displacement and correcting unknown variables. Because the research procedure comes from back-analyzing of the unknown variable of each layer, back-analyzing results need an additional optimization to minimize interferential effects of unknown variables. Therefore, the direct search method Is used to obtain optimized solutions without a partial differentiation of an objective function. The object of this research is developing the back analysis technique for multi-unknown variables by modeling the soil including underground structure Into upper and lower layer. In order to minimize interferent errors, repeated back analysis is performed and applicability on the real tunnel is examined. Consequently, the multi-layer analysis model is more precise in describing the real behavior of underground structure. It shows the validity of back analysis far multi-layer model which is the understructure placed on multi-layer boundaries.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.29 no.3 s.234
• /
• pp.369-386
• /
• 2005

Various aspects of structural optimization techniques under transient loads are extensively reviewed. The main themes of the paper are treatment of time dependent constraints, calculation of design sensitivity, and approximation. Each subject is reviewed with the corresponding papers that have been published since 1970s. The treatment of time dependent constraints in both the direct method and the transformation method is discussed. Two ways of calculating design sensitivity of a structure under transient loads are discussed - direct differentiation method and adjoint variable method. The approximation concept mainly focuses on re- sponse surface method in crashworthiness and local approximation with the intermediate variable Especially, as an approximated optimization technique, Equivalent Static Load method which takes advantage of the well-established static response optimization technique is introduced. And as an application area of dynamic response optimization technique, the structural optimization in flexible multibody dynamic systems is re- viewed in the viewpoint of the above three themes

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.2
• /
• pp.917-923
• /
• 2014

Chondrosarcomas are malignant cartilage-forming tumors of bone which exhibit resistance to both chemotherapy and radiation treatment. miRNAs have been well demonstrated to regulate gene expression and play essential roles in a variety of biological processes, including proliferation, differentiation, migration, cell cycling and apoptosis. In this study, we obtained evidence that miR-100 acts as a tumor suppressor in human chondrosarcomas. Interestingly, cisplatin resistant chondrosarcoma cells exhibit decreased expression of miR-100 compared with parental cells. In addition, we identified mTOR as a direct target of miR-100. Overexpression of miR-100 complementary pairs to the 3' untranslated region (UTR) of mTOR, resulted in sensitization of cisplatin resistant cells to cisplatin. Moreover, recovery of the mTOR pathway by overexpression of S6K desensitized the chondrosarcoma cells to cisplatin, suggesting the miR-100-mediated sensitization to cisplatin dependent on inhibition of mTOR. In summary, the present studies highlight miR-100 as a tumor suppressor in chondrosarcoma contributing to anti-chemoresistance. Overexpression of miR-100 might be exploited as a therapeutic strategy along with cisplatin-based combined chemotherapy for the treatment of clinical chondrosarcoma patients.

• Proceedings of the KIEE Conference
• /
• 2001.07e
• /
• pp.47-52
• /
• 2001

This paper presents a high-performance control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consist of stator flux observer, rotor position/speed estimator, torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source inverter, and F240/C31DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated by the observed stator flux-linkage space vector. The estimated rotor speed can be determinated by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. To prove the suggested control algorithm, we have a simulation and testing at actual experimental system. The developed digitally high-performance position sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw RSM.

• Journal of Power Electronics
• /
• v.2 no.2
• /
• pp.146-153
• /
• 2002

this paper presents an implementation of digital control system of speed sensorless for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The problem of DTC for high-dynamic performance RSM drive is generating a nonlinear torque due to a saturated nonlinear inductance curve with various load currents. The control system consists of stator flux observer, compensating inductance look-up table, rotor position/speed/torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source unverter, and TMS320C31 DSP controller. The stator flux observer is based on the combined voltage and current model with stator flux feedback adapitve control that inputs are the compensated inductances, current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated rotor speed is determined by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operation area. It does not requrie the knowledge of any montor paramenters, nor particular care for moter starting, In order to prove the suggested control algorithm, we have simulation and testing at actual experimental system. The developed sensorless control system is showing a good speed control response characterisitic result and high performance features in 20/1500 rpm with 1.0Kw RSM having 2.57 ratio of d/q reluctance.

• Proceedings of the KIEE Conference
• /
• 2001.10a
• /
• pp.161-164
• /
• 2001

This paper presents a digital speed sensorless control system for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The system consist of stator flux observer, rotor speed estimator, torque estimator two hysteresis band controllers, an optimal switching look-up table. IGBT voltage source inverter, and TMS320C31DSP controller by using fully integrated control software. The stator flux observer is based on the combined voltage and current model with stator flux feedback adaptive control that inputs are current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor speed is estimated by the observed stator flux-linkage space vector. The estimated rotor speed can be determinated by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operating area. In order to prove the suggested speed sensorless control algorithm. There are some simulation and testing at actual experimental system. The developed digitally high- performance speed sensorless control system are shown a good speed control response characteristic results and high Performance features using 1.0Kw RSM.

• Journal of the Korean association of regional geographers
• /
• v.10 no.2
• /
• pp.371-388
• /
• 2004

EU is enlarging geographically by the process of expansion and is intensifying the economic bloc by the formation of European Union and European Monetary Union. This situation increases the direct investment in the intra-EU members and changes the intra-EU flows. First, EU is formed by the economic geographical space of the North and the South with a differentiation of economic factors and the degree of economic development. The North played a leading role for an augmentation of the intra-EU direct investment after the formation of EU. Second, the manufacturing industry of the intra-EU direct investment by industry was increased remarkably. In the intra-EU direct investment flow by region and industry, the South made relatively an outflow of the service industry and an inflow of the manufacturing industry. But the North made an outflow of the manufacturing industry and an inflow of the service industry. Third, in the intra-EU direct investment flows by manufacturing industry, the North concentrated in the petro-chemistry, metal-machinery and agro-food industry, however, the South which have relatively weak competitiveness compared to the North tends to show balanced investment patterns in all industries.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.40 no.3
• /
• pp.185-193
• /
• 2013

Mineral trioxide aggregate (MTA) has recently been used as a pulpotomy medicament for primary molars. The aim of this study was to evaluate and compare the proliferation and differentiation potential of dental pulp stromal cells of permanent teeth and deciduous teeth cultured on MTA-coated surface. Human dental pulp stromal cells were obtained from human permanent premolars and deciduous teeth and cultured on MTA-coated culture plates. The cells were subjected to proliferation assay and cell cycle analysis. Their differentiation potential was evaluated by analysing changes in the mRNA expressions of runt-related transcriptional factor 2 (Runx2) and alkaline phosphatase (ALP). Morphological changes of cells in direct contact with MTA were observed using scanning electron microscopy (SEM). The proliferation rates, distribution of cell cycles and mRNA expression patterns of Runx2 and ALP were similar in both types of pulpal cells. SEM observations revealed that both types changed into more dendrite-like cells. On the surface of MTA, human dental pulp stromal cells from deciduous and permanent teeth were able to both proliferate and differentiate into cells that induce mineralization. MTA is suitable as a biocompatible pulpotomy medicament for primary teeth.

• Journal of Life Science
• /
• v.25 no.12
• /
• pp.1425-1431
• /
• 2015

The lymphocyte component of the immune system is divided into B lymphocytes and T lymphocytes. B lymphocytes produce antibodies (humoral immunity) via maturation into plasma cells, and T lymphocytes kill other cells or organisms (cellular immunity). A traditional immunological paradigm is that B lymphocyte and T lymphocyte interactions are a one-way phenomenon, with T lymphocytes helping to induce the terminal differentiation of B lymphocytes into immunoglobulin class-switched plasma cells. A deficiency of T lymphocytes was reported to result in defective B lymphocyte function. However, evidence for a reciprocal interaction between B and T lymphocytes is emerging, with B lymphocytes influencing the differentiation and effector function of T lymphocytes. For example, B lymphocytes have been shown to induce direct tolerance of antigen-specific CD8⁺ T lymphocytes and induce T lymphocytes anergy via transforming growth factor-beta (TGF-β) production. The present study showed that LPS-stimulated B lymphocytes inhibited the differentiation of Th1 lymphocytes by inhibiting the production of interleukin-12 (IL-12) from dendritic cells. An interaction between the B lymphocytes and dendritic cells was not needed for this inhibition, and the B lymphocytes did not alter dendritic cell maturation. B lymphocyte-derived soluble factor (BDSF) suppressed the LPS-induced IL-12p35 transcription in the dendritic cells. Overall, these results point to a novel B lymphocyte- mediated immune suppressive mechanism. The findings cast doubt on the traditional paradigm of immunological interactions involving B lymphocyte and T lymphocyte interactions.

• International Journal of Concrete Structures and Materials
• /
• v.6 no.2
• /
• pp.101-110
• /
• 2012

This paper focuses on the finite element (FE) response sensitivity and reliability analyses considering smooth constitutive material models. A reinforced concrete frame is modeled for FE sensitivity analysis followed by direct differentiation method under both static and dynamic load cases. Later, the reliability analysis is performed to predict the seismic behavior of the frame. Displacement sensitivity discontinuities are observed along the pseudo-time axis using non-smooth concrete and reinforcing steel model under quasi-static loading. However, the smooth materials show continuity in response sensitivity at elastic to plastic transition points. The normalized sensitivity results are also used to measure the relative importance of the material parameters on the structural responses. In FE reliability analysis, the influence of smoothness behavior of reinforcing steel is carefully noticed. More efficient and reasonable reliability estimation can be achieved by using smooth material model compare with bilinear material constitutive model.