• Convergence Security Journal
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• 제3권1호
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• pp.7-22
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• 2003

The legal dispute of electronic commerce and computer crimes are increasing because the electronic services like e-government and e-commerce are now widely used. Computer Forensics becomes the method for recovery, preservation, analysis and report regarding digital evidence essential to resolve the legal dispute and computer crime. In this paper, the developmental process of Computer Forensics is discussed. It is intended to elicit constructive discussion regarding the domestic Computer Forensics. And this discussion will be of help to establish the secure e-business and e-government services in the field of the research, legal system and technical skill of domestic Computer Forensics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.636-639
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• 2001

InGaN/GaN multiple quantum wells (MQWs) grown with various growth interruptions between the InGaN well and GaN barrier by metal-organic chemical vapor deposition were investigated using photoluminescence, high-resolution transmission electron microscopy, and energy filtered transmission electron microscopy (EFTEM). The luminescence intensity of the MQWs with growth interruptions is abruptly reduced compared to that of the MQW without growth interruption. Also, as the interruption time increases the peak emission shows a continuous blue shift. Evidence of indium clustering is directly observed both by using an indium ratio map of the MQWs and from indium composition measurements along an InGaN well using EFTEM. The higher intensity and lower energy emission of light from the MQW grown without interruption showing indium clustering is believed to be caused by the recombination of excitons localized in indium clustering regions and the increased indium composition in these recombination centers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제15권3호
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• pp.208-213
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• 2002

We present the temperature and excitation power density dependence of the photoluminescence from carbon-doped GaAs epilayers grown on GaAs (311)A substrate by atmospheric pressure metalorganic chemical vapor deposition. The measured temperature dependence of the PL peak energy is well expressed by an empirical formula proposed by Varshni. The thermal quenching mechanism of the intensity of 16 K luminescence peak at 1.480 eV is described with the dominant activation energy of 27$\pm$2 meV. The activation energy shows an evidence that the emission band involves the carbon acceptor in the recombination process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권1호
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• pp.87-107
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• 2015

Considering the localization estimation issue in mixed line-of-sight (LOS)/non-LOS(NLOS) environments based on received signal strength (RSS) measurements in wireless sensor networks, a grid-based correlation method based on the relationship between distance and RSS is proposed in this paper. The Maximum-Likelihood (ML) estimator is appended to further improve the localization accuracy. Furthermore, in order to reduce computation load and enhance performance, an improved recursively version with NLOS mitigation is also proposed. The most advantages of the proposed localization algorithm is that, it does not need any prior knowledge of the propagation model parameters and therefore does not need any offline calibration effort to calibrate the model parameters in harsh environments, which makes it more convenient for rapid implementation in practical applications. The simulation and experimental results evidence that the proposed localization algorithm exhibits good localization performance and flexibilities for different devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.33-35
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• 2000

Na-K-Nb system showed a number of ferroelectric phases in bulk ceramic. [001]-axis oriented single-phase Na$_{0.5}$K$_{0.5}$NbO$_3$ (NKN) thin film have been grown on LaA1O$_3$ substrates using KrF excimer laser. X-ray diffraction $\theta$-2$\theta$ scan, rocking curves, and $\phi$ scan data evidence highly c-axis oriented along the [001] direction.ion.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제13권11호
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• pp.938-942
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• 2000

Radiation effects on dielectric properties of low density polyethylene(LDPE) were investigated using the various measurements of FT-IR, gel content and elongation at break. FT-IR spectra showed that polar groups were comprised in LDPE due to radiation treatment. It was also confirmed that the formation of polar groups on LDPE caused the increased dielectric properties such as permittivity and tan $\delta$. However, in this study, any evidence of decreasing permittivity was not found although the morphological change of LDPE could be identified from the increasing gel content and the decreasing elongation.

• Journal of Korean Institute of Industrial Engineers
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• 제27권2호
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• pp.214-225
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• 2001

This research deals with an off-line learning method targeted for systematically constructing negotiation strategies in automated electronic commerce. Single-issue negotiation is assumed. Variants of competitive learning and hierarchical clustering method are devised and applied to extracting negotiation strategies, given historical negotiation data set and tactics. Our research is motivated by the following fact: evidence from both theoretical analysis and observations of human interaction shows that if decision makers have prior knowledge on the behaviors of opponents from negotiation, the overall payoff would increase. Simulation-based experiments convinced us that the proposed method is more effective than human negotiation in terms of the ratio of negotiation settlement and resulting payoff.

• Smart Media Journal
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• 제6권1호
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• pp.39-46
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• 2017

The internet has become an important part of the many aspects of people's daily lives such as work, study, entertainment and in form of electronic commerce, shopping. Electronic commerce is growing rapidly in Kenya. There are many successful business-to-business, business-to-customer and customer-to-customer online shopping companies in Kenya. As a consequence, competition between vendors is intense and, therefore, mitigating the negative effects of high product uncertainty is necessary requirement as it remains a biggest hindrance for success of the online shopping. The purpose of this research is to investigate how online product description, third party product assurance, customer service and website design mitigate the negative impact of high product uncertainty. A questionnaire with 28 items is designed to collect data from online customers. Using multiple regression analysis, the relationship between dependent variable (product uncertainty) and independent variables such as product description, third party assurance, website design and customer service is tested. The result shows that all the independent variables are negatively correlated with dependent variable, which means that product description, third party assurance, website design and customer service can be used by online vendors to lessen the problem of product uncertainty in online markets.

• Bulletin of the Korean Chemical Society
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• 제19권1호
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• pp.5-21
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• 1998

The purpose of this paper is to show that X-ray absorption spectroscopy (XANES and EXAFS) is a powerful technique for characterizing both crystalline and amorphous solids from structural (local order) and electronic point of view. The principle of this technique is briefly described by showing the main factors which must be considered for recording and fitting the experimental results. Some non-trivial examples have been selected for demonstrating that XAS spectroscopy is the only technique for bringing a definitive answer as for example: the determination of the local distortion of the $NiO_6$ octahedra in the $Li_{1-z}Ni_{1+z}O_2$ layered oxides and the evidence of the presence of copper pairs in the NASICON-type phosphate $CuZr_2 (PO_4)_3$. Are also reported some significant examples for which XAS spectroscopy is decisive with other characterization methods as (i) Raman spectroscopy for glasses (ii) Mossbauer spectroscopy for $LiNi_{1+z-t}Fe_To_2$ oxides (iii) magnetic measurements for Ce-based intermetallic compounds.

• Bulletin of the Korean Chemical Society
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• 제15권9호
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• pp.762-765
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• 1994

Picosecond time-resolved resonance Raman spectroscopy has been used to study the photochemistry of Cr(CO$)_6$ in cyclohexane following photoexcitation at 266 nm. Photodissociative loss of CO is found to occur within our pulse width of ${\leq}$5 ps by probing the 533 c$m^{-1}$ vibrational mode of ground state Cr(CO$)_6$. The subsequent dynamics after photodissociation are interpreted in terms of solvation, vibrational and electronic relaxations. The vibrational relaxation time of 100 ps and 83 ps are observed by monitoring v=O and v=l of the 381 c$m^{-1}$ transient mode, respectively. No evidence was found for solvation and electronic relaxation occurring on a time scale of ${\leq}$5 ps.