• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.253-261
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• 2008

Programmable metallizaton cell (PMC) memory device has been known as one of the next generation non-volatile memory devices, because it includes non-volatility, high speed and high ON/OFF resistance ratio. This paper reviews the operation principle of the device. Besides, the recent research results of professor Kozicki who firstly invented the device and investigated it for the memory applications, NEC corporation which studied it for the FPGA (field programmable gate array) switch applications, ETRI and chungnam national university which examined Te-based devices are introduced.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.1-10
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• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.

• Molecules and Cells
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• v.45 no.10
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• pp.695-701
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• 2022

Homeostatic regulation of meristematic stem cells accomplished by maintaining a balance between stem cell self-renewal and differentiation is critical for proper plant growth and development. The quiescent center (QC) regulates root apical meristem homeostasis by maintaining stem cell fate during plant root development. Cell cycle checkpoints, such as anaphase promoting complex/cyclosome/cell cycle switch 52 A2 (APC/C^CCS52A2), strictly control the low proliferation rate of QC cells. Although APC/C^CCS52A2 plays a critical role in maintaining QC cell division, the molecular mechanism that regulates its activity remains largely unknown. Here, we identified SCF^FBS1, a ubiquitin E3 ligase, as a key regulator of QC cell division through the direct proteolysis of CCS52A2. FBS1 activity is positively associated with QC cell division and CCS52A2 proteolysis. FBS1 overexpression or ccs52a2-1 knockout consistently resulted in abnormal root development, characterized by root growth inhibition and low mitotic activity in the meristematic zone. Loss-of-function mutation of FBS1, on the other hand, resulted in low QC cell division, extremely low WOX5 expression, and rapid root growth. The 26S proteasome-mediated degradation of CCS52A2 was facilitated by its direct interaction with FBS1. The FBS1 genetically interacted with APC/C^CCS52A2-ERF115-PSKR1 signaling module for QC division. Thus, our findings establish SCF^FBS1-mediated CCS52A2 proteolysis as the molecular mechanism for controlling QC cell division in plants.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.172-177
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• 2014

We present on a threshold switching device based on AsGeTeSi material which is significantly improved by two $N_2$ processes: reactive $N_2$ during deposition, and $N_2$ plasma hardening. The introduction of N2 in the two-step processing enables a stackable and thermally stable device structure, is allowing integration of switch and memory devices for application in nano scale array circuits. Despite of its good threshold switching characteristics, AsTeGeSi-based switches have had key issues with reliability at a high temperature to apply resistive memory. This is usually due to a change in a Te concentration. However, our chalconitride switches(AsTeGeSiN) show high temperature stability as well as high current density over $1.1{\times}10^7A/cm^2$ at $30{\times}30(nm^2)$ celll. A cycling performance of the switch was over $10^8$ times. In addition, we demonstrated a memory cell consisted of 1 switch-1 resistor (1S-1R) stack structure using a TaOx resistance memory with the AsTeGeSiN select device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1190-1200
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• 1993

In this work, the performance of both delay sensitive traffics and loss sensitive traffics of the output buffered ATM switch with priority control mechanisms has been evaluated. We choose the partial buffer sharing mechanism as the loss priority control mechanism and the HOL(Head Of Line) priority control mechanism as the time priority control mechanism. We model loss sensitive traffics with Poisson process and delay sensitive traffics with MMPP. With loss priority control, it is confirmed that loss probability of loss sensitive traffice decreases when the loss priority control mechanism is chosen. With time priority control, it has also been confirmed that mean cell delay of delay sensitive traffics decreases when the HOL priority control mechanism is used. From this analysis, It has been confirmed that the requirements of QOS for both loss sensitive and delay sensitive traffics can be satisfied in the ATM switch by combining both the loss priority control mechanism and the HOL priority control mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1139-1151
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• 2002

In this paper, we propose the novel module-type optical space switch, employing time division multiplexing (TDM) method and multihop structure, in order to enlarge the capacity of the switching system. And we show that the proposed structure is superior over conventional ones, in terms of power loss, the number of the devices used, and signal to crosstalk (SXR). We also analyze the saturation throughput with the number of module M. As a result, the saturation throughput of the switching system with M modules is M+ 1-√(M$^2$+1), when the number of input port in a module (N) is large. Finally, we confirmed the cell loss rate (CLR) performance with the proposed switch through simulation. For example, when p=0.9, M=8 and N=32, to get the CLR that is less than or equal to 10$\^$-6/, the number of input buffers storage unit is greater than or equal to 6 and output buffers storage unit is greater than or equal to 52.

• Journal of Digital Contents Society
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• v.19 no.7
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• pp.1281-1287
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• 2018

In this study, specific elements and functions in modules of the AAC (Augmentative and Alternative Communication) application for children with severe and multiple disabilities were elicited, and screen interface was designed accordingly. As results, screen configuration, communication display edition, audiovisual output, and switch and scanning modules were defined. Screen configuration module consists of communication category, spelling board, favorites, screen lock, and setting function. The Communication display edition module includes communication categories, symbols, and favorites edition. The audiovisual output module provides the ability to adjust the pitch, intensity, speed, and tone of the voice individually in the form of auditory output. In the form of visual output, the background color and size of the frame, border color and thickness are adjusted. The switch and scanning module provides a function to select by pressing the switch when the symbol cell is highlighted audibly and visually. The development of the AAC application designed in this study is needed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2B
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• pp.120-130
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• 2011

Recently the multicast based contents transmission is rapidly increasing due to the various multimedia services and the importance of switching technology to handle it is increasing as a consequence. Though the CICQ architecture has advantages that reduction of HoL blocking probability and simple scheduling using cross point buffer, it has disadvantage that the processing rate of multicast traffic can be significantly degraded corresponds to the traffic load increment. Several schemes have been proposed to solve this problem however they still can't provide enough processing ratio for multicast traffic. Therefore this paper proposes the BA cell assignment scheme and the VT scheme, and the processing rate of multicast traffic can be guaranteed by reducing the HoL blocking probability of multicast traffic and reservation of cross point buffer. Also simulation results verify that using the proposed scheme, the QoS of multicast service can be improved.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.51-60
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• 2003

One of the most important matters in designing network and realizing service, is to grip on the traffic characteristics. Conventional traffic prediction and analysis used the models which based on the Poisson or Markovian. Recently, experimental research on the LAN, WAN and VBR traffic properties have been pointed rut that they weren't able to display actual real traffic specificities because the models based on the Poisson assumption had been underestimated the long range dependency of network traffic and self-similar peculiarities, it has been lately presented that the new approach method using self-similarity characteristics as similar as the real traffic models. Therefore, in this paper, we generated self-similar data traffic like real traffic as background load. On the existing ABR congestion control algorithm, we analyzed by classify into ACR, buffer utilization. cell drop rate, transmission throughput with the representative EFCI, ERICA, EPRCA and NIST twitch algorithm to show the efficient reaction about the burst traffic.

• Journal of Practical Engineering Education
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• v.8 no.1
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• pp.9-14
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• 2016

Depending on the college graduation project and graduation thesis regulations for the certification and graduation requirements, the quadcopter acting as a Li-Po battery that charges by solar energy are proposed a design method and improvements in theory. Quadcopter posture is balanced and confirmed by the position sensor, through a PID (Proportional Integral Differential) control. Battery switching circuit is composed of two Li-Po battery. Driving the quadcopter as one battery, and does not use other battery is charged by solar energy. A battery switching circuit is fabricated in a manner that uses two types of relays. Even if completely not charged to the battery is being driven a certain switch by the battery charging voltage from time to time, it proposes a method for increasing the endurance time and range.