• Bulletin of the Korean Chemical Society
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• v.35 no.3
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• pp.839-844
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• 2014

The gas-phase radical-radical reaction $O(^3P)$ + $C_2H_5$ (ethyl) ${\rightarrow}$ $H(^2S)$ + $CH_3CHO$(acetaldehyde) was investigated by applying a combination of vacuum-ultraviolet laser-induced fluorescence spectroscopy in a crossed beam configuration and ab initio calculations. The two radical reactants $O(^3P)$ and $C_2H_5$ were respectively produced by photolysis of $NO_2$ and supersonic flash pyrolysis of the synthesized precursor azoethane. Doppler profile analysis of the nascent H-atom products in the Lyman-${\alpha}$ region revealed that the average translational energy of the products and the average fraction of the total available energy released as translational energy were $5.01{\pm}0.72kcalmol^{-1}$ and 6.1%, respectively. The empirical data combined with CBS-QB3 level ab initio theory and statistical calculations demonstrated that the title exchange reaction is a major channel and proceeds via an addition-elimination mechanism through the formation of a short-lived, dynamical addition complex on the doublet potential energy surface. On the basis of systematic comparison with several exchange reactions of hydrocarbon radicals, the observed small kinetic energy release can be explained in terms of the loose transition state with a product-like geometry and a small reverse activation barrier along the reaction coordinate.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.319-325
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• 2015

Remarkable advances in wireless communication technology have enabled communications among people who are far away from each other. In recent, the needs of local area voice communication using a wireless system based on low-cost and simple hardware are rapidly rising. However, since these applications require that the multi-users communicate on the same wireless channel in a small area, the existing voice technologies are not suitable for directly applying to these applications. Therefore, in this paper I propose a novel idea enabling multi-user voice communication. In particular, as a short range wireless solution, I employ the IEEE 802.15.4 based on low power and low cost. However, since originally the standard is not developed for voice communication, we extend the original scheme to be suitable for the voice communication by utilizing the extended concept of GTS. The capacity and validity of the proposed scheme are evaluated through quantitative analysis in various voice compression rates.

• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2463-2472
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• 2000

In this paper, we consider pits and falls of V oIP service scheme over the air link environment. It results that V oIP over packet switching is a more attractive approach in several points. We point out the ffilIior requirements for successful V oIP service over the air. Also, we propose V oIP CP concept for efficient wireless channel utilization. Additionally, we analyze and evaluate the performance. According to the results, It shows that the long cycle VolP vocoder CODEC such as ITU-T G.723 is better than short cycle V oIP vocoder CODEC. In this case, the increase of the simultaneous user of system is almost 60% larger than conventional circuit switching.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6A
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• pp.820-831
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• 1999

In this paper, we have compared the performance of a D-TDMA protocol with that of a CDMA protocol, in radio access system for integrated voice/data services.The D-TDMA protocol is based on a generic dynamic channel assignment approach to be followed a combination of “circuit mode” reservation for voice calls, along with dynamic first-come-first served assignment of remaining capacity for data messages. In the CDMA protocol, we have used the voice activity detection to reduce the interface power of other mobiles in internal and external cells, and analyzed the interference power ratio. Also we have computed BER(Bit Error Rate) by using this interference power ratio and evaluated voice blocking probability(voice packet loss probability) and data transmission delay, according to average data length and average data arrival rate.We have found the CDMA protocol achieves comparatively higher performance for short data length, regardless of data arrival rate. Otherwise, the data transmission delay of D-TDMA protocol is shorter than that of the CDMA protocol for long data message.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.643-650
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• 2014

Recently, the wireless communication applications are studied in various environment by the development of short range communication system like wireless sensor networks. This paper presents the analysis of localization schemes for ship application using received signal strength. The localization schemes using received signal strength from wireless networks are classified under two methods, which are Range based method and Range free method. Range based methods estimate the location with least square estimation based on estimated distance using path-loss model. Range free methods estimated the location with the information of anchor nodes linked to target. Simulation results show the appropriate localization scheme for each cabin environments based on the empirical path-loss model in warship's internal space.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.157-157
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• 2008

As the minimum feature size of semiconductor devices scales down to nano-scale regime, ultra shallow junction is highly necessary to suppress short channel effect. At the same time, Ni-silicide has attracted a lot of attention because silicide can improve device performance by reducing the parasitic resistance of source/drain region. Recently, further improvement of device performance by reducing silicide to source/drain region or tuning the work function of silicide closer to the band edge has been studied extensively. Rare earth elements, such as Er and Yb, and Pd or Pt elements are interesting for n-type and p-type devices, respectively, because work function of those materials is closer to the conduction and valance band, respectively. In this paper, we increased the work function between Ni-silicide and source/drain by using Pd stacked structure (Pd/Ni/TiN) for high performance PMOSFET. We demonstrated that it is possible to control the barrier height of Ni-silicide by adjusting the thickness of Pd layer. Therefore, the Ni-silicide using the Pd stacked structure could be applied for high performance PMOSFET.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.146-153
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• 2006

We have been investigating InGaAs HEMTs as a future high-speed and low-power logic technology for beyond CMOS applications. In this work, we have experimentally studied the role of the side-recess spacing $(L_{side})$ on the logic performance of 50 nm $In_{0.7}Ga_{0.3}As$ As HEMTs. We have found that $L_{side}$ has a large influence on the electrostatic integrity (or short channel effects), gate leakage current, gate-drain capacitance, and source and drain resistance of the device. For our device design, an optimum value of $L_{side}$ of 150 nm is found. 50 nm $In_{0.7}Ga_{0.3}As$ HEMTs with this value of $L_{side}$ exhibit $I_{ON}/I_{OFF}$ ratios in excess of $10^4$, subthreshold slopes smaller than 90 mV/dec, and logic gate delays of about 1.3 ps at a $V_{CC}$ of 0.5 V. In spite of the fact that these devices are not optimized for logic, these values are comparable to state-of-the-art MOSFETs with similar gate lengths. Our work confirms that in the landscape of alternatives for beyond CMOS technologies, InAs-rich InGaAs FETs hold considerable promise.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.5
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• pp.517-524
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• 2004

In this paper, we investigated the compensation characteristics of distorted NRZ format and RZ format signal dependence on dispersion variation of each transmission section in 8-channel WDM system. The WDM system have two transmission sections of unequal length with respect to optical phase conjugator(OPC) position. We select highly-nonlinear dispersion shifted fiber(HNL-DSF) as a nonlinear medium of OPC in order to convert wideband signal waves to conjugated waves. First, we confirmed that RZ is better than NRZ as a modulation format for maintenance or stable performance, when total dispersion or both sections in WDM system is different each other. Also, we confirmed that total dispersion of the short length section must be smaller than that of the long length section in order to excellently compensate for NRZ format signal.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.2
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• pp.315-329
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• 2016

The $21^{st}$ century is the age when the revolution of digital technology enables two-way communication and when emotional values are emphasized. Thus, it exerts influence on the fashion industry and fashion communication. Along with fashion shows, advertising and displays, many fashion brands have increased the use of fashion films. For that reason, this study examines the characteristics of fashion films made by fashion brands, based on the frame work of persuasion communication. For the research, literature reviews and internet website research were done and films of Chanel, Prada, Kenzo and Alexander Wang were analyzed. The definition and types of fashion films were redefined as terminology varied throughout previous studies prior to analyzing each case. As a result, a fashion film would be redefined as 'a digital image which a fashion brand publishes to consumers for the promotion of brand comprehension'. Also, five fashion film types, 'short film', 'campaign film', 'animation film', 'brand film' and 'show film' were redefined. The analysis provided three communication characteristics: reliability, engagement and intuition. First, reliability is attained when a fashion brand (sender) delivers brand message to consumers (receiver) consistently and unitedly. Second, engagement is attained when the type of fashion film (channel) delivers creative image features such as format, music, video technique to attract consumers' interest. Lastly, intuition is attained when a fashion brand (sender) delivers a message akin to brand identity and deepens consumers' understanding. In addition, this study tried to identify the unique usage tendency of brands that could serve as practice guidelines for other fashion brands.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.5793-5800
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• 2015

Background: Outcome-expectation beliefs and knowledge may ultimately influence behavior for cancer prevention. The aims of this study were to measure changes in knowledge and beliefs about cancer prevention before and after viewing a television advertisement and identify the factors affecting receptivity to its messages. Materials and Methods: A one-group pretest-posttest design was used in this study of 1,000 individuals aged 20 to 65 years who were recruited online in November 2014. The outcome variables included cancer prevention beliefs based on the Health Belief Model (five items) and knowledge about risk factors for cancer (seven items). Results: Perceived susceptibility, perceived benefits, and self-efficacy increased significantly and their perceived severity and perceived barriers decreased significantly, after participants viewed the television advertisement. Correct responses to questions about risk factors also increased significantly, except for smoking. The main factors affecting changes in the outcome variables were age, interest in cancer prevention, social network, satisfaction with the ad, and pretest scores. Conclusions: Television advertisements with positive frameworks can be an efficient channel of improving beliefs and knowledge about cancer prevention in a short period. The continuous development of intervention materials that consider the demographics, needs, and satisfaction of the target group will be necessary for future studies.