• Journal of the Microelectronics and Packaging Society
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• v.13 no.1 s.38
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• pp.1-5
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• 2006

We prepared 80 nm-thick TiSix on each 70 nm-thick amorphous silicon and polysilicon substrate using an RF sputtering with $TiSi_2$ target. TiSix composite silicide layers were stabilized by rapid thermal annealing(RTA) of $800^{\circ}C$ for 20 seconds. Line width of $0.5{\mu}m$ patterns were embodied by photolithography and dry etching process, then each additional annealing process at $750^{\circ}C\;and\;850^{\circ}C$ for 3 hours was executed. We investigated the change of sheet resistance with a four-point probe, and cross sectional microstructure with a field emission scanning electron microscope(FE-SEM) and transmission electron microscope(TEM), respectively. We observe an abrupt change of resistivity and voids at the silicide surface due to interdiffusion of silicide and composite titanium silicide in the amorphous substrates with additional $850^{\circ}C$ annealing. Our result implies that the electrical resistance of composite titanium silicide may be tunned by employing appropriate substrates and annealing condition.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.12
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• pp.1-9
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• 2001

In the APON(ATM Passive Optical Network), the transmission of the upstream traffic is based on a TDMA(Time Division Multiple Access) method that an OLT(Optical Line Termination) permits ONUs(Optical Network Units) sending cells by allocating time slots. Because the upstream is not a streaming mode, the cell synchronizer has to be operated in the burst mode. Also, the cell phase monitor is required to prevent collisions between cells which are transmitted by multiple ONUs through a single optical fiber. In this paper, a TDMA burst cell synchroniser is implemented with the FPGA(Field Programmable Gate Array) being used in the APON based on G.983.1 for transmitting upstream cells. It has two main functions which are the upstream data recovery and the phase monitoring. The former is to recover the upstream data and clock in the OLT by seeking the preamble which is the overhead of the upstream time slot and by aligning the phase of the bit and cell with the system clock. The latter is to provide the information to the ONU to compensate for the equalization delay by monitoring continuously the phase difference between adjacent cells to avoid the cell collision on the upstream.

• Applied Microscopy
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• v.37 no.4
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• pp.219-230
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• 2007

The morphological effects of intranasal zinc sulfate(5% solution) irrigation on the mouse olfactory epithelium and the regeneration process of olfactory receptor cells following nasal irrigation were studied with scanning and transmission electron microscope. The results were as follows: 1. The septal epithelium except some basal cells was wholly detached from the basement membrane, during the first 6 to 24 hours after 5% zinc sulfate irrigation. 2. 3 days after $ZnSO_4$ treatment, two layered septal epithelium was formed from basal cells. And microvilli were observed in the apical epithelium of newly formed olfactory epithelial cells. 3. 5 days after treatment, a lot of centrosomes and basal bodies were observed in the olfactory receptor cells, and cilia were lined up between microvilli on the apical membrane of olfactory receptor cells. And immature olfactory knob was first observed in the newly formed olfactory receptor cells. Mature olfactory knob was observed 1 week after treatment. 4. There are very many mature olfactory knobs in the olfactory receptor cells 2 weeks after intranasal zinc sulfate irrigation. These results support that treatment with 5% zinc sulfate is a good experimental model for the regeneration of mammalian nervous tissues because this method could thoroughly detach the septal epithelium. During the regeneration of olfactory receptor cells, the surface membrane of the olfactory receptor cells widen the surface with the microvilli. Then cilia, which arranged in a line, substituted for the microvilli. The part of the surface membrane with cilia protruded and finally formed the olfactory vesicle.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.8
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• pp.105-111
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• 2004

In this paper, millimeter-wave high gain and broadband MHEMT cascode amplifiers were designed and fabricated. The 0.1 ${\mu}{\textrm}{m}$ InGaAs/InAlAs/GaAs Metamorphic HEMT was fabricated for cascode amplifiers. The DC characteristics of MHEMT are 640 mA/mm of drain current density, 653 mS/mm of maximum transconductance. The current gain cut-off frequency(f$_{T}$) is 173 GHz and the maximum oscillation frequency(f$_{max}$) is 271 GHz. By using the CPW transmission line, the cascode amplifier was designed the matched circuit for getting the broadband characteristics. The designed amplifier was fabricated by the MHEMT MIMIC process that was developed through this research. As the results of measurement, the 1 stage amplifier obtained 3 dB bandwidth of 37 GHz between 31.3 to 68.3 GHz. Also, this amplifier represents the S21 gain with the average 9.7 dB gain in bandwidth and the maximum gain of 11.3 dB at 40 GHz. The 2 stage amplifier has the broadband characteristics with 3 dB bandwidth of 29.5 GHz in the frequency range from 32.5 to 62.0 GHz. The 2 stage cascode amplifier represents the high gain characteristics with the average gain of 20.4 dB in bandwidth and the maximum gain of 22.3 dB at 36.5 GHz.z.z.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.417-426
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• 2010

This paper describes the 6-way power divider to be used as a feeding structure of the waveguide array antenna generating the plane wave at the near distance. The SMA connector has been connected at the center of the power divider in order to feed the radiating element. The six output ports made of waveguide are positioned on the peripheral of the divider. This paper proposes the method utilizing the inductive post in order to decrease the return loss. The height of the feeding pin, the diameter of the inductive post, and the distance between the feeding pin and inductive post have been investigated, and as a result, the power divider has been optimized. The simulated and measured results show the low return loss of about -40 dB. The calculated and measured transmission coefficients are -7.78 dB and -8.06 dB, respectively. The output power of the six waveguide port show equal-amplitude and equal-phase distribution. Since the power divider proposed in this paper can be expanded to the divider having several output ports, it could be easily applied to the various array antennas.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3175-3178
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• 2014

Background: Gastric cancer is a common malignant tumor. Our previous study demonstrated inhibitory effects of 3-bromopyruvate (3-BrPA) on pleural mesothelioma. Moreover, we found that 3-BrPA could inhibit human gastric cancer cell line SGC-7901 proliferation in vitro, but whether similar effects might be exerted in vivo have remained unclear. Aim: To investigate the effect of 3-BrPA to human gastric cancer implant tumors in nude mice. Materials and Methods: Animals were randomly divided into 6 groups: 3-BrPA low, medium and high dose groups, PBS negative control group 1 (PH7.4), control group 2 (PH 6.8-7.8) and positive control group receiving 5-FU. The TUNEL method was used to detect apoptosis, and cell morphology and structural changes of tumor tissue were observed under transmission electron microscopy (TEM). Results: 3-BrPA low, medium, high dose group, and 5-FU group, the tumor volume inhibition rates were 34.5%, 40.2%, 45.1%, 47.3%, tumor volume of experimental group compared with 2 PBS groups (p<0.05), with no significant difference between the high dose and 5-FU groups (p>0.05). TEM showed typical characteristics of apoptosis. TUNEL demonstrated apoptosis indices of 28.7%, 39.7%, 48.7% for the 3-BrPA low, medium, high dose groups, 42.2% for the 5-FU group and 5% and 4.3% for the PBS1 (PH7.4) and PBS2 (PH6.8-7.8) groups. Compared each experimental group with 2 negative control groups, there was significant difference (p<0.05); there was no significant difference between 5-FU group and medium dose group (p>0.05), but there was between the 5-FU and high dose groups (p<0.05). Conclusions: This study indicated that 3-BrPA in vivo has strong inhibitory effects on human gastric cancer implant tumors in nude mice.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.63-68
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• 2017

Although automated metro subway systems have the advantage of operating a train without a train driver, it is difficult to detect an immediate fault condition and take countermeasures when an unusual situation occurs. Therefore, it is important to construct a maintenance information system (MIS) that detects the vehicle failure/status information in real time and maintains it efficiently in the depot of the railway's vehicles. This paper proposes a conceptual design method that realizes the interface between the train control system (TCS), the operation control center train control monitoring system (OCC-TCMS) console, and the MIS using wireless communication network in real-time. To transmit a large amount of information on 800,000 occurrences per day during operation, data was collected in a 56 byte data table using a data processing algorithm. This state information was classified into 4 hexadecimal codes and transmitted to the MIS by mapping the status and the fault information on the vehicle during the main line operation. Furthermore, the transmission and reception data were examined in real time between the TCS and MIS, and the implementation of the failure information screen was then displayed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1922-1931
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• 1999

A multicast traffic’s feature is the function of providing a point to multipoints cell transmission, which is emerging from the main function of ATM switch. However, when a conventional point-to-point switch executes a multicast function, the excess load is occurred because unicast cell as well as multicast cell passed the copy network. Additionally, due to the excess load, multicast cells collide with other cells in a switch. Thus a deadlock that losses cells raises, extremely diminishes the performance of switch. An input queued switch also has a defect of the HOL (Head of Line) blocking that less lessens the performance of the switch. In the proposed multicast switch, we use shared memory switch to reduce HOL blocking and deadlock. In order to decrease switch’s complexity and cell's processing time, to improve a throughput, we utilize the method that routes a cell on a separated paths by traffic pattern and the scheduling algorithm that processes a maximum 2N cell at once in the control part. Besides, when cells is congested at an output port, a cell loss probability increases. Thus we use the Output Memory (OM) to reduce the cell loss probability. And we make use of the method that stores the assigned memory (UM, MM) with a cell by a traffic pattern and clears the cell of the Output memory after a fixed saving time to improve the memory utilization rate. The performance of the proposed switch is executed and compared with the conventional policy under the burst traffic condition through both the analysis based on Markov chain and simulation.

• KIEAE Journal
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• v.15 no.5
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• pp.113-118
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• 2015

Purpose: In Korea, buildings make up 20.5% (2012) of the gross national energy consumption, so they are a major target for greenhouse gas reduction. In particular, energy consumption in multihousing represents approximately 32.6% of the entire building sector. With improving energy performance being the focus, efforts are continuously being made to reinforce standards and systems in greenhouse gas reduction. This study investigated the current status of multihousing in Korea in terms of energy performance as described in the performance evaluation reports submitted (to an institution that specializes in reviewing the performance evaluation of green homes) based on the construction criteria and performance codes for green homes and examined if the evaluation criteria using related methodologies were appropriate. The results will provide helpful information for reviewing the future directions of operations and amendments to the systems. Method: The overall characteristics of the system were examined using the evaluation methodologies (and current state of revisions) of the performance codes for green homes and comparing them with similar systems. Also, the current state of application and energy performance (conducted according to the evaluation methodologies) were compared by the evaluation institution for multihousing neighborhoods that were assessed for five years from 2010 to 2014. Result: It has been confirmed that the performance codes for green homes are different from other similar systems in evaluating performances of multihousing in that they allow both quantitative and qualitative methods of evaluation, and they consider both energy and sustainability simultaneously in the evaluation. Furthermore, regarding the adoption rate of the forms for the two evaluation methods (Form 1 - quantitative and Form 2 - qualitative), the rate preferring Form 2 increased gradually in time to reach 55.3% in 2014. In analyzing the rate of overall energy reduction (submitted in Form 1) and the coefficient of thermal transmission for each part (submitted in Form 2), it was observed that the deviation between the performance submitted and the criteria decreased in line with the level of reinforcement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.449-455
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• 2006

Due to advance in multimedia applications and integrated Internet services, the optical access networks have been actively studied. In particular, Ethernet passive optical network (EPON) has received much attention due to high bandwidth provision with low cost. In EPON system, the data transmission is carried out in two directions: downstream (from OLT to ONU) and upstream (from ONU to OLT). The downstream data is broadcasted to every ONUs, while the upstream data is point-to-point transmitted between each ONU and OLT, where the uplink is shared by all ONUs in the form of TDMA. The bandwidth allocation algorithm is required to efficiently manage the bandwidth on the uplink. The limited algorithm was proposed to enhance the capability of dynamic bandwidth allocation. In this paper, we propose the adaptive limited algorithm to enhance the shortcomings of limited algorithm. The adaptive limited algorithm enhances the dynamics on bandwidth allocation, and at the same time controls the fairness on packet delay. Through the computer simulations, it is shown that the adaptive limited algorithm achieves high dynamic on bandwidth allocation, maintains a good fairness on packet delay between ONUs, and keeps the fairness on the bandwidth on the demand basis.