• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.987-990
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• 2009

The MAC protocol of HiperLAN/2 is based on TDMA/TDD. The radio channels are assigned by AP(Access Point) that is centrally operated. Mobile terminal that data transmission is necessary to uplink requests radio resource to AP through RCH channel. The changing number of RCHs in each MAC frame is important because too many RCHs may result in a waste of radio resources and too few RCHs may result in many access collisions and prolong time that connect to AP. Therefore, number of RCH should be allocated properly according to traffic. From these viewpoint, this paper proposes an advanced scheme that dynamically changed the number of RCH which is based on the number of success and collision of RR message in previous MAC frame. To prove efficiency of proposed scheme, a lots of simulations are conducted and analyzed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.4
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• pp.132-144
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• 2022

In response to the recent surge in aviation demand, major airport and aviation authorities continue to make efforts to formulate arrival procedures that take into account efficient aircraft separation, noise and environmental issues related to carbon (CO₂) emissions. In order to ensure efficient traffic control and environmental issues, as a result, a new concept Trombone, Point Merge, etc. have been introduced and widely used. However, these new concept incisions are becoming a factor that hinders operational efficiency and stability due to the restricted domestic airspace such as military airspace and excessive constraints of altitude, speed, etc. which do not reflect the concept of continuous descent operation and eventually needs to be modified to make continuous descent operation as feasible as possible. We herewith analyze and propose the way of improving flight safety and efficiency in the arrival operation procedure by supplementary modification which consequently contribute to the aviation industry international competitiveness.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.476-478
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• 2006

To analyze subcellular localization of betanodavirus protein B2, a plasmid expressing Betanodavirus protein B2 fused to enhanced green fluorescent protein (EGFP-Nl) was constructed. The transient expression of full-length B2 fused to EGFP in GF cells confirmed the equal distribution of protein B2 between cytoplasm and nucleus. However, transfection of N-terminal half of the B2 revealed that this truncated form predominantly localized to the cytoplasm. By using several deletion mutants and point mutants, we determined the regions and/or motif responsible for the subcellular localization of betanodavirus.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2583-2605
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• 2016

Fingerprint positioning is a main stream and key technique for seamless positioning systems. In this paper, we develop a performance evaluation testbed for fingerprint based Wireless Local Area Network (WLAN) positioning system. The testbed consists of positioning server, positioning terminal, Access Point (AP) units, positioning accuracy analysis system and testing scenarios. Different from other testbeds tended to focus on testing in same situation, in the proposed testbed, a couple of scenarios are set to test the positioning system including indoor and outdoor environments. Handset-side positioning mode and network-side positioning mode are provided simultaneously. Variety of motion models, such as static model, low-speed model and high-speed model are considered as well as different positioning algorithms. Finally, some implementation cases are analyzed to verify the credibility of the testbed.

• ETRI Journal
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• v.30 no.2
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• pp.301-307
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• 2008

As broadband access is evolving from digital subscriber lines to optical access networks, Ethernet passive optical networks (EPONs) are considered a promising solution for next generation broadband access. The point-to-multipoint topology of EPONs requires a time-division multiple access MAC protocol for upstream transmission. In this paper, we propose a new enhanced dynamic bandwidth allocation algorithm with fairness called EFDBA for multiple services over EPONs. The proposed algorithm is composed of a fairness counter controller and a fairness system buffer in the optical line terminal. The EFDBA algorithm with fairness can provide increased capability and efficient resource allocation in an EPON system. In the proposed EFDBA algorithm, the optical line termination allocates bandwidth to the optical network units in proportion to the fairness weighting counter number associated with their class and queue length. The proposed algorithm provides efficient resource utilization by reducing the unused remaining bandwidth made by idle state optical network units.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.402-406
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• 1996

Inulin fructotransferase (depolymerizing) (EC 2.4.1.93) was purified 34-fold from the culture broth of Arthrobacter sp. A-6 by using a combination of ammonium sulfate fractionation, DEAE-Sepharose CL-6B chromatography and Sephacryl S-200 gel filtration. The purified enzyme converts inulin into di-D-fructofuranose dianhydride III(DFA III) and small quantities of fructo-oligosaccharides. The temperature and pH optima of the enzyme were $70^{\circ}C$ and 6.0, respectively. Molecular weight of the enzyme was determined to be 49 kDa by 12$%$ SDS-polyacrylamide gel electrophoresis, and 145 kDa by Sephacryl S-200gel filtration. This indicates that the functional inulin fructotransferase of Arthrobacter sp. A-6 has a homomeric trimer structure. The enzyme had an isoelectric point of pH 4.6. The N-terminal amino acid sequence of the purified enzyme subunit was Ala-Asp-Asn-Pro-Asp-Gly(\ulcorner)-Ser-Asn-Met(or Glu)-Tyr-Asp-Val.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1306-1307
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• 2011

Recently, the small scale photovoltaic (PV) electronic devices are drawing attention as the upcoming PV generation system. The PV system is commonly used in small scale PV applications such as LED lighting and cell phone. This paper proposes photovoltaic output sensorless (POS) maximum power point tracking (MPPT) control for a small scale charging system of PV-nickel metal hydride battery using field-programmable gate array (FPGA) controller. A converter is connected to a small scale PV cell and battery, and performs the POS MPPT at the battery terminal current instead of being at the PV cell output voltage and current. The FPGA controller and converter operate based on POS MPPT method. The experimental results show that the nickel metal hydride battery is charged by the maximum PV output power.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.88-93
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• 1994

The mechanisms controlling the intensity and duration of synaptic transmission are numerous. Once an action potential reaches a nerve terminal, the stored neurotransmitters are released in a quantum fashion into the synaptic cleft. At that point neurotransmitters can act on post-synaptic receptors to elicit an action on the post-synaptic cell or net at so-called auto-receptors that are located on the presynaptic side and which often regulate the further release of the neutotransmitter. Whereas the action of the neurotransmitter receptors is regulated by desensitization phenomenon, the major mechanism by which the intensity and duration of neurotransmitter action is presumably regulated by either its degradation or its removal from the synaptic cleft. In the central nervous system, specialized proteins located in fe plasma membrane of presynaptic terminals function to rapidly remove neurotransmitters from the synaptic cleft in a sodium chloride-dependent fashion. These proteins have been referred to as uptake sites or neurotransmitter transporters. Once taken up by the plasma membrane transporters, neurotransmitters are repackaged into secretory vesicles by distinct transporters which depend on a proton gradient.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.491-499
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• 2017

The Information & Communication Technology (ICT) and the Internet of Things (IoT) have become the major issues in Republic of Korea recently. While RS-232, Zigbee, and WiFi-related technologies are used in the ICT-based systems, we focus on the Power Line Communication (PLC) in this paper. By carrying out OPNET simulations, we've implemented the PLC Router Node Model, PLC Terminal Node Model, PLC Link Model, and PLC Palette Model and executed the simulations arranging 20 holds within the range of 400m (20m apart). As a result, we confirmed that the slient node problem had occurred at the point of 200m-2000m (as of 2016) distance preventing further communications. However, the control group, by contrast, was able to carry out the communications by installing a router. We expect that this paper will contribute to the development of a foundation technology which will saves costs by performing the simulation prior to building actual large-scale ICT Complex in the future work.

• Journal of Korean Neurosurgical Society
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• v.63 no.3
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• pp.272-278
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• 2020

Compared to any other decade, the last two decades have been the most dynamic period in terms of advances in the knowledge on spinal dysraphism. Among the several factors of rapid advancement, such as embryology during secondary neurulation and intraoperative neurophysiological monitoring, there is no doubt that Professor Dachling Pang stood high amidst the period. I review here the last two decades from my personal point of view on what has been achieved in the field of spinal dysraphism, focusing on occult tethered cord syndrome, lumbosacral lipomatous malformation, terminal myelocystocele, retained medullary cord, limited dorsal myeloschisis and junctional neural tube defect. There are still many issues to revise, add and extend. Profound knowledge of basic science is critical, as well as refined clinical analysis. I expect that young scholars who follow the footsteps of precedent giants will shed bright light on this topic in the future.