• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.4
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• pp.231-235
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• 2015

Bimodal Tram developed by KRRI is driven by a series Hybrid propulsion system which has both the CNG engine, generator and LPB(Lithium Polymer Battery) pack. It has three driving modes; Hybrid mode, Engine mode and Battery mode. Even in case of Battery mode, LPB pack to get enough power to drive the vehicle only by itself onsists of 168 LPB cells(80Ah per lcell), 650V. It is important thing to manage LPB pack in a right way, which will extend the lifetime of LPB cells and operate in the hybrid mode effectively. This paper has shown the development of battery management system(12 BMS, 1 BMS per 14cells) to manage LPB pack which is connected with CAN(Controller Area Network) each other and measure the voltage, current, temperature and also control the cooling fan inside of LPB pack. Using the measured data, BMS can show the SOC(State of Charge), SOH(State of Health) and other status of LPB pack including of the cell balancing.

• BMB Reports
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• v.48 no.8
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• pp.429-430
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• 2015

Angiogenesis is a complex process involving dynamic interaction of various cell to cell interactions. Endothelial cell interactions regulated by growth factors, inflammatory cytokines, or hemodynamic stress are critical for balancing vascular quiescence and activation. Yes-associated protein (YAP), an effector of Hippo signaling, is known to play significant roles in maintaining cellular homeostasis. However, its role in endothelial cells for angiogenic regulation remains relatively unexplored. We demonstrated the critical role of YAP in vascular endothelial cells and elucidated the underlying molecular mechanisms involved in angiogenic regulation of YAP. YAP was expressed in active angiogenic regions where endothelial cell junctions were relatively loosened. Consistently, YAP subcellular localization and activity were regulated by VE-cadherin-mediated PI3K/Akt pathway. YAP thereby regulated endothelial sprouting via angiopoietin-2 expression. These results provide an insight into a model of coordinating endothelial junctional stability and angiogenic activation through YAP. [BMB Reports 2015; 48(8): 429-430]

• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.477-487
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• 2022

Probiotics provide a symbiotic relationship and beneficial effects by balancing the human intestinal microbiota. The relationships between microbiota changes and various diseases may predict health abnormalities and diseases. Treatment with vitamins and probiotics is one therapeutic approach. To evaluate the effect of probiotics on vitamin absorption, we chose Lactobacillus rhamnosus CBT-LR5 treatment, which has resistance to vitamin C-inducible toxicity, with vitamins in high-fat diet (HFD)-induced obesity models. CBT-LR5 affected the absorption of micronutrients, such as ionic minerals and water-soluble vitamins. An increase in vitamin C absorption by CBT-LR5 enhanced the antioxidant response in HFD-induced obesity models. Increased vitamin B absorption by CBT-LR5 regulated lipid metabolism in HFD-induced obesity models. These favorable effects of CBT-LR5 on the absorption of vitamins should be investigated as candidate therapeutic target treatments for metabolic diseases.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.3
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• pp.63-69
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• 2017

This paper presents a highly efficient power management system for UAV-drones. For free from the battery cell-balancing issue, the proposed system allows the drone to utilize a single-cell Li-Po battery. To realize low-voltage input of 3.7V, the switch-mode step-up DC-DC converter is optimally designed with high power efficiency. The prototype DC-DC converter was implemented with an output voltage of 5V, which will be provided to digital parts of the drone. The power efficiency was measured to be max. 91.3% with low surface temperature. The measured line and load regulations were 0.02V/V and 0.15V/A, respectively. Thanks to the proposed power management system, the available time-to-fly of the drone is expected to be significantly extended in virtue of the enhanced power efficiency.

• Journal of Industrial Technology
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• v.40 no.1
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• pp.7-12
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• 2020

Lithium-ion cells have become the go-to energy source across all applications; however, dendritic growth remains an issue to tackle. While there have been various research conducted and possible solutions offered, there is yet to be one that efficiently rules out the problem without, however, introducing another. This paper seeks to present a fast charging method and system to which lithium-ion batteries are charged while maintaining their lifetime. In the proposed method, various lithium cells are charged under multiple profiles. The parameters of charge profiles that inflict damage to the cell's electrodes are obtained and used as thresholds. Thus, during charging, voltage, current, and temperature are actively controlled under these thresholds. In this way, dendrite formation suppressed charging is achieved, and battery life is maintained. The fast-charging system designed, comprises of a 1.5kW charger, an inbuilt 600W battery pack, and an intelligent BMS with cell balancing technology. The system was also designed to respond to the aging of the battery to provide adequate threshold values. Among other tests conducted by KCTL, the cycle test result showed a capacity drop of only 0.68% after 500 cycles, thereby proving the life maintaining capability of the proposed method and system.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.45-47
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• 2018

This paper describes the 40kV solid state pulsed power supply for environmental applications. The output specifications of the pulsed power supply are 40kV, 300A, 3kHz, and average output power of 13kW. In order to generate a high voltage, a series stacking cell structure is used which is charged in parallel and discharged in series. Due to this structure, there is no dynamic voltage balancing problem as well as static voltage balancing problem for switches used in high voltage pulse power supplies. To verify this pulse power supply design, PSpice modeling was performed. Finally, experimental results with non-inductive resistive load and gas treatment reactor proved the reliability of the solid state pulsed power supply.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.234-237
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• 2010

This paper proposes a balancing control of DC-link voltages of a H-bridge multilevel inverter for STATCOM application. Individual DC link voltage is controlled by simply adjusting the d-q voltage reference through a PI controller in each cell while the main controller carries out the reactive power control. The correctness and effectiveness of the method are validated by PSIM simulation with unbalanced load condition data taken from a typical arc furnace load, showing the adverse effects of load unbalance to DC link voltage significantly suppressed.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.4
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• pp.330-337
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• 2015

A bucket-brigade is a way of transporting items where items are passed from one person to the next. The operation of the bucket brigade imitates the cooperative behavior of ants when brood, food or other resources are moved. Koo (2009) presented a bucket brigade-based assembly cell where each worker follows a simple rule: perform assembly operations on a product until the next worker downstream takes it over; then go back to the previous worker upstream to take over a new assembly job. In this way, the flow line is self-balanced without any predetermined job assignment. However, there are some productivity losses related to hand-off and blocking. This paper examines the hand-off and blocking losses and presents a new bucket brigade-based assembly cell where working areas for each assembler is restricted with the help of buffer interfaces. Simulation experiments are used to validate the performance of the new assembly system.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.21-24
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• 2001

For very large multimedia traffic to be supported successfully in wireless network environment, it is necessary to provide Quality-of-Service(QoS) guarantees between mobile hosts(clients). In order to guarantee the Qos, we have to keep the call blocking probability below target value during handoff session. However, the QoS negotiated between the client and the network may not be guaranteed due to lack of available channels for traffic in the new cell, since mobile clients should be able to continue their on-going sessions. In this paper we propose a efficient load-balancing algorithm based on the adaptive bandwidth reservation scheme for enlarging available channels in a cell. We design a new method to predict the mobility of clients using MPT(mobility profile table). This method is then used to reserve a part of bandwidths for handoff calls to its adjacent cells and this reserved bandwidth can be used for handoff call prior to new connection requests. If the number of free channels is also under a low threshold value, our scheme use a load-balancing algorithm with a adaptive bandwidth reservation. In order to evaluate the performance of our algorithm, we measure the metrics such as the blocking probability of new calls and dropping probability of handoff calls, and compare with other existing schemes.

• BMB Reports
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• v.48 no.6
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• pp.319-323
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• 2015

Mesenchymal stem cells (MSCs) are multipotent stem cells capable of differentiating into adipocytes, osteoblasts, or chondrocytes. A mutually inhibitory relationship exists between osteogenic and adipogenic lineage commitment and differentiation. Such cell fate decision is regulated by several signaling pathways, including Wnt and bone morphogenetic protein (BMP). Accumulating evidence indicates that microRNAs (miRNAs) act as switches for MSCs to differentiate into either osteogenic or adipogenic lineage. Different miRNAs have been reported to regulate a master transcription factor for osteogenesis, such as Runx2, as well as molecules in the Wnt or BMP signaling pathway, and control the balance between osteoblast and adipocyte differentiation. Here, we discuss recent advancement of the cell fate decision of MSCs by miRNAs and their targets. [BMB Reports 2015; 48(6): 319-323]