• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.8-13
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• 2005

In this paper discusses single-phase DC-AC Inverter design of reversible power converter that driven by binary combination at different transformer winding ratio by BCD code level. It has a advantage that constructs a control system simply and obtain load current of good quality without filter circuit and free from noise or isolation for lower switching frequency. In this research, study on current type converter and inverter circuit that consist for possibility of AC-DC/DC-AC multi-level reversible converter.

• Journal of Environmental Health Sciences
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• v.32 no.4 s.91
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• pp.336-341
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• 2006

The biological wastewater treatment system is known to have an important role in reducing the quantify of enteric virus in water environments. To clarify the roles of activated sludge microbes in decreasing the virus infectivity, the behavior of the virus in bacteria, protozoa, and metazoa was examined by pure or mixed culture system using poliovirus type 1(Lsc, 2ab strain). In the bacterial culture systems, the virus infectivity in the liquid phase decreased by a reversible adsorption of the virus to the bacteria or bacterial flocs. On the other hand, in the protozoa and the metazoa culture systems using T. pyriformis and P. erythrophthalma, respectively, with a variety of bacterial strains as prey, the main virus decrease mechanism of reversible adsorption in early stage was changed to irreversible predation, which was not eluted in this study. The virus decrease was more effective in the P. erythrophthalma culture system, which had high predation and floc forming abilities. However, in the mixed culture system of Z. ramigera and P. erythrophthalma, the more rapid reversible adsorption of virus to Z. ramigera flocs preceded the irreversible predation of P. erythrophthalma.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.2
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• pp.275-284
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• 1997

Thermodynamic behavior of a composite system which is composed of two simple thermal subsystems with constant heat capacities is analyzed, and several thermodynamic phenomena are investigated. The changes of the states and the potential work of the composite system are shown as the interaction between the subsystems in the composite system. The potential work is defined as the possible maximum available work from the composite system, and it is a thermodynamic property of the composite system. The decrease of the potential work is the same as the available work output from the composite system in reversible processes. The dissipation of available work is directly connected to the generation of entropy. The concepts of exergy and internal energy can be explained as a special case of the potential work.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.2
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• pp.161-168
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• 2016

Abnormal localization of tumor suppressor proteins is a common feature of renal cancer. Nuclear export of these tumor suppressor proteins is mediated by chromosome region maintenance-1 (CRM1). Here, we investigated the antitumor effects of a novel reversible inhibitor of CRM1 on renal cancer cells. We found that S109 inhibits the CRM1-mediated nuclear export of RanBP1 and reduces protein levels of CRM1. Furthermore, the inhibitory effects of S109 on CRM1 is reversible. Our data demonstrated that S109 significantly inhibits proliferation and colony formation of renal cancer cells. Cell cycle assay showed that S109 induced G1-phase arrest, followed by the reduction of Cyclin D1 and increased expression of p53 and p21. We also found that S109 induces nuclear accumulation of tumor suppressor proteins, Foxo1 and p27. Most importantly, mutation of CRM1 at Cys528 position abolished the effects of S109. Taken together, our results indicate that CRM1 is a therapeutic target in renal cancer and the novel reversible CRM1 inhibitor S109 can act as a promising candidate for renal cancer therapy.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.2
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• pp.227-237
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• 1998

A numerical simulation has been carried out for the automotive air conditioning system. The purpose of this simulation is to present the methods for simulating car air conditioning components, systems and cool-down performance by computerized mathematical model and to analyze the performance of A/C system. In analyzing the heat exchanger(evaporator and condenser), the finite volume model which has a merit in predicting the temperature field in detail because it can consider partial variation of thermal property and heat transfer coefficient is used. In analyzing the compressor, the polytropic approach which regards the actual compression process as a reversible polytropic process is employed. In analyzing vehicle passenger compartment, the thermal network is employed to simulate the car cool down process. This A/C system program can be used for analyzing a component performance when a component is alternated or designed and for analyzing the engine cooling system when A/C system is operated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.5
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• pp.431-438
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• 2000

The major irreversibilities in absorption chillers are associated with the transfer of heat into and out from the machine and irreversible process inside the machine. By modeling only external irreversibilities(endo-reversible), a model was formulated to predict the ideal performance of a single-effect absorption chiller. Its actual performance including both external and internal irreversibilities was calculated with a in-house simulation program. The optimization of heat transfer area distribution was performed for both endo-reversible cycle and actual cycle. The equation of endo-reversible modeling was found to give about 2times higher cooling capacity than the simulation program. At optimal distribution, it was found that heat transfer area of the evaporator was about 30% of total area, that of the generator was 20%, and the rest 50% was for the absorber and condenser. The system COP for endo-reversible cycle was slightly higher than that for actual cycle. In the case of LiBr-water single-effect absorption chiller, the maximum cooling capacity was obtained near the condition that LMTD is same at all heat exchangers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4603-4624
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• 2016

In this paper, a new reversible watermarking algorithm with adaptive embedding threshold matrix is proposed. Firstly, to avoid the overflow and underflow, two flexible thresholds, TL and TR, are applied to preprocess the image histogram with least histogram shift cost. Secondly, for achieving an optimal or near optimal tradeoff between the embedding capacity and imperceptibility, the embedding threshold matrix, composed of the embedding thresholds of all blocks, is determined adaptively by the combination between the composite chaos and the average energy of Integer Wavelet Transform (IWT) block. As a non-liner system with good randomness, the composite chaos is suitable to search the optimal embedding thresholds. Meanwhile, the average energy of IWT block is calculated to adjust the block embedding capacity, and more data are embedded into those IWT blocks with larger average energy. The experimental results demonstrate that compared with the state-of-the-art reversible watermarking schemes, the proposed scheme has better performance for the tradeoff between the embedding capacity and imperceptibility.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.264-268
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• 2001

Aggregates of specific cells are often regarded as better from in artificial organs and mammalian cell bioreactors in terms of cell-specific functionality. In this study, the morphology and liver specific functions of freshly harvested primary rat hepatocytes, which were cultivated as spheroids and entrapped in a synthetic thermo-reversible extracellular matrix, were examined and compared to a control (hepatocytes in single cell form). A copolymer of N-isopropylacrylamide(98 mole % in feed) and acrylic acid (poly (NiPAAm-co-AAC)), a thermo- reversible copolymer gel ma- trix, was used to entrap hepatocytes either in spheroids or single cells. During a 7-day culture pe-riod, the spheroids maintained higher viability and produced albumin and urea at a relatively con-stant rate, while, the single cell culture showed a slight increase in cell numbers and a reduction in albumin secretion Hepatocytes cultrured as spheroids present a potentially useful three-dimensional cell culture system for application in bioartificial liver device.

• Journal of Korean Society of Transportation
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• v.4 no.1
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• pp.3-11
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• 1986

One important element of a systematic approach to the management and control of the flow of people over an urban street network is the monitoring and evaluation of system performance. The nature of TSM strategies that, in part, differentiates them from traditional long-range transportation improvement alternatives is that they are less costly, are more quickly implemented and modified, and are often oriented toward sub-area problems which must be addressed at a more microscopic level of analysis. These factors suggest that pre-implementation evaluations of alternative TSM actions will often have to rely on quick-turn around, manual methods of analysis to guide the choice of which management action should be implemented. This paper was prepared to focus on the definition and importance of TSM, specifically associated with monitoring and evaluating traffic performance in the context of TSM startegies. A simple case study of reversible lane technique was presented. The purposes of the case study is to illustrate the methodology of evaluating TSM strategies and demonstrate to identify the benefit from the reversible lane technique, which may otherwise be overlooked in real world. Applying the reversible lane technique to Sam-Il elevate highway, it was found to be a very promising low cost alternative to reduce total travel time(or delay) and fuel consumption.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1761-1784
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• 2017

In order to improve the embedding rate of reversible watermarking algorithm for digital image and enhance the imperceptibility of the watermarked image, an adaptive reversible image watermarking algorithm based on DE is proposed. By analyzing the traditional DE algorithm and the generalized DE algorithm, an improved difference expansion algorithm is proposed. Through the analysis of image texture features, the improved algorithm is used for embedding and extracting the watermark. At the same time, in order to improve the embedding capacity and visual quality, the improved algorithm is optimized in this paper. Simulation results show that the proposed algorithm can not only achieve the blind extraction, but also significantly heighten the embedded capacity and non-perception. Moreover, compared with similar algorithms, it is easy to implement, and the quality of the watermarked images is high.