• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.131-142
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• 2002

The Langmuir adsorption isotherms of the under-potentially deposited hydrogen (UPD H) and the over-potentially deposited hydrogen (OPD H) at the poly-Pt/0.5M $H_2SO_4$ and 0.5 M LiOH aqueous electrolyte interfaces have been studied using cyclic voltammetric and ac impedance techniques. The behavior of the phase shift $(0^{\circ}{\leq}{-\phi}{\leq}90^{\circ})$ for the optimum intermediate frequency corresponds well to that of the fractional surface coverage $(1{\geq}{\theta}{\geq}0)$ at the interfaces. The phase-shift method, i.e., the phase-shift profile $({-\phi}\;vs.\;E)$ for the optimum intermediate frequency, can be used as a new electrochemical method to determine the Langmuir adsorption isotherms $({\theta}\;vs.\;E)$ of the UPD H and the OPD H for the cathodic $H_2$ evolution reactions at the interfaces. At the poly-Pt/0.5M $H_2SO_4$ aqueous electrolyte interface, the equilibrium constant (K) and the standard free energy $({\Delta}G_{ads})$ of the OPD H are $2.1\times10^{-4}$ and 21.0kJ/mol, respectively. At the poly-Pt/0.5M LiOH aqueous electrolyte interface, K transits from 2.7(UPD H) to $6.2\times10^{-6}$ (OPD H) depending on the cathode potential (E) and vice versa. Similarly, ${\Delta}G_{ads}$ transits from -2.5kJ/mol (UPD H) to 29.7kJ/mol (OPD H) depending on I and vice versa. The transition of K and ${\Delta}G_{ads}$ is attributed to the two distinct adsorption sites of the UPD H and the OPD H on the poly-Pt surface. The UPD H and the OPD H on the poly-Pt surface are the independent processes depending on the H adsorption sites themselves rather than the sequential processes for the cathodic $H_2$ evolution reactions. The criterion of the UPD H and the OPD H is the H adsorption sites and processes rather than the $H_2$ evolution reactions and potentials. The poly-Pt wire electrode is more efficient and useful than the Pt(100) disc electrode for the cathodic $H_2$ evolution reactions in the aqueous electrolytes. The phase-shift method is well complementary to the thermodynamic method rather than conflicting.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.513-523
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• 1993

Varietal difference in structural and physical characteristics of rice starch and interrelationships between these starch properties and the physicochemical components of rice grains were investigated for twenty four rice varieties, which were considerably different in amylose content, gelatinization temperature and gel consistency, to obtain the basic informations for diversifying the utility of rice grains and for developing various rice cultivars adaptable to rice food processing. Wave length of maximum absorbance for blue color reaction of starch-I$_2$ complex was 520nm for glutinous rice and 560～600nm for nonglutinous rice. The higher amylose rice showed the longer wave length but there was considerable difference of the wave length among rice materials with similar amylose content. Varietal difference in frequency distribution of debranched starch molecules by isoamylase hydrolysis was largest in amylose fraction, the longest fraction(Fr. I), and was next bigger in intermediate fraction(Int.Fr.) and the ratio between short and long glucose chain of amylopectin fraction(Fr. III /Fr. II). The Fr. III / Fr II ratio was higher in glutinous rice than in nonglutinous one but it was considerably different among nonglutinous rice varieties without any connection with amylose content. The lower alkali digestible rice showed the longer half-hydrolysis time in acid solution. Both soft and hard gel rice varieties in gel consistency test revealed significant varietal difference of 50% acid hydrolysis time. The harder rice in gel consistency exhibited the less frequency of short branch fraction of amylopectin (Fr. III) and the higher amylose content. Twenty four rice varieties were cleary classified by upper two principal components contracted from structural or physical traits of rice starch and some physicochemical properties of rice grain by principal component analysis. The 1st and 2nd principal components can be characterized to components related with amylose and amylopectin structure respectively.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.190-199
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• 2014

In this paper, the vestibular hair bundle feature model and integrated vestibular hair cell model were proposed. In conventional modeling studies of vestibular system, only partial mechanisms were modeled, such as the characteristics of the vestibular hair bundles without external forces or the action potential of synapse, and the study about action potential of vestibular afferent considering the characteristics of the vestibular hair bundle was not performed. The proposed integrated vestibular hair cell model reflects external forces considering negative stiffness features of each hair bundles with different regularities of hair cells and our model was compared with conventional model without external forces. As a result, irregular afferent and intermediate afferent with high ratio of firing frequency variations to the changes of external stimulation had small width of negative stiffness section, but the width of the negative stiffness of regular afferent with low ratio was similar to that of conventional negative stiffness features. And the proposed integrated vestibular hair cell model showed almost same results with conventional data with animal experiments in 11 chosen frequency bands. It is verified that our proposed hair bundle feature model is adequately modeled.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10A
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• pp.922-929
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• 2005

This paper proposes an adaptive pilot beacon equipment for mobile communication systems based on direct spread spectrum technology which generates the pilot channel for handoff between base stations by using the information acquired from the downstream wireless signal regarding the overhead channel information. Such an adaptive pilot beacon equipment will enable low power operation since among the wireless signals, only the pilot channel will be generated and transmitted. The pilot channel in the downstream link of the CDMA receiver is used to acquire time and frequency synchronization and this is used to calibrate the offset for the beacon, which implies that time synchronization using GPS is not required and any location where forward receive signal can be received can be used as the installation site. The downstream link pilot signal searching within the CDMA receiver is performed by FPGA and DSP. The FPGA is used to perform the initial synchronization for the pilot searcher and DSP is used to perform the offset correction between beacon clock and base station clock. The CDMA transmitter the adaptive pilot beacon equipment will use the timing offset information in the pilot channel acquired from the CDMA receiver and generate the downstream link pilot signal synchronized to the base station. The intermediate frequency signal is passed through the FIR filter and subsequently upconverted and amplified before being radiated through the antenna.

• Journal of the Korean Electrochemical Society
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• v.2 no.2
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• pp.70-74
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• 1999

The electrode kinetic parameters at the Pd/0.5 M LiOH electrolyte interface have been qualitatively studied using the phase-shift method. The phase shift $(\phi)$ depends on both the cathode potential (E>0) and frequency (f), and $\theta$ is inversely proportional to the fractional surface coverage $\theta$. At an intermediate frequency (10 Hz), the phase-shift profile $(\phi\;vs.\;E)$ can be related to the fractional surface coverage $(\theta\;vs.\;E)$. The phase-shift method can be used to estimate or plot the Frumkin adsorption isotherm. The rate (r) of change of the free energy of adsorption with $({\theta})$ is 22.3 kJ/mol. The equilibrium constant (K) for adsorption and the standard free energy $({\Delta}G_{\theta})$ of the adsorbed hydrogen atom $(H_{ads})$ are $3.7\times10^{-3}{\Delta}G_{\theta}>-8.4kJ/mol$, respectively. For 1$0.38>\theta>0$, the energy liberation or the exothermic reaction for hydrogen adsorption at the Pd cathode can be occurred. The electrode kinetic parameters $(r,\;K,\;{\Delta}G_{\theta}$ depend on the fractional surface coverage $({\theta})$ or the phase shift $(\phi)$.

• Journal of the Korean Society of Radiology
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• v.8 no.7
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• pp.455-459
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• 2014

We grew the $Li_6Gd(BO_3)_3:Ce^{3+}$ scintillator and determined the scintillation and thermoluminescence properties for X-rays. The emission spectrum of $Li_6Gd(BO_3)_3:Ce^{3+}$ is located in the range of 370~500 nm, peaking at 423 nm an 455 nm, due to the $4f{\rightarrow}5d$ transition of $Ce^{3+}$ ions. The fluorescence decay time of the crystal is composed three components. The fast component is 60 ns (25%), the intermediate component is 787 ns (29%) and the slow component is $5.9{\mu}s$ (46%) of the crystal. The after-glow is caused by the electron and hole traps in the crystal lattice. We determined physical parameters of the traps in the crystal. The thermoluminescence trap are composed two traps. The determined activation energy (E), kinetic order (m) and frequency factor (s) of the first trap are 0.65 eV, 1.01 and $6.9{\times}10^8s^{-1}$. And, the determined activation energy, kinetic order and frequency factor of the second trap are 0.96 eV, 1.79 and $3.1{\times}10^{12 }s^{-1}$, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.180-188
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• 2013

A W-band waveguide noise measurement system for calibrating noise sources was implemented and its basic characteristics were discussed. The measurement system consists of a commercial noise figure analyzer, a full W-band frequency converter, and a local oscillator. To measure the noise temperature of a noise source, the Y-factor method is generally used. Since the Y-factor method is based on the assumption that the receiving system is linear, linearity is one of important performance parameters of the measurement system. In this paper, the linearities for mixer, intermediate frequency(IF), and RF parts were evaluated to be 0.24 dB, 0.05 dB, and 0.20 dB, respectively. The noise figure of the measurement system evaluated is 5 dB to 17 dB in W-band. The measurement system can be used to measure thermal noise characteristics of electronic and electrical devices, equipments, and systems as well as to calibrate noise sources.

• Journal of KIISE:Databases
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• v.33 no.6
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• pp.578-589
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• 2006

Owing to the proliferation of Radio Frequency Identification (RFID) technologies which is being watched as a core technology of ubiquitous computing, applications which offer convenience to people using RFID technologies are more and more increased. To easily develop these applications, a middleware system which acts as a bridge between RFID hardware and application is essential. In this paper, we propose a novel XML-based RFID middleware system called UbiCore (Ubiquitous Core). UbiCore has following features: First, UbiCore employs its own query language called XQueryStream (XQuery for Stream Data) which is originated from XQuery. Second, UbiCore has the preprocessing phase called pre-filtering prior to query evaluation and reuses the intermediate result of previous evaluation to speed up the processing of RFID tag data stream. Third, UbiCore supports query on both continuously generated stream data and archived historical data. And last, UbiCore offers a distinct markup language called Context-driven Service Markup Language (CSML) to easily specify the linking information between context and service.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.661-672
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• 2009

Recently it was found that various genetic structural variations such as CNV(copy number variation) exist in the human genome, and these variations are closely related with disease susceptibility, reaction to treatment, and genetic characteristics. In this paper we propose a new CNV detection algorithm using millions of short DNA sequences generated by giga-sequencing technology. Our method maps the DNA sequences onto the reference sequence, and obtains the occurrence frequency of each read in the reference sequence. And then it detects the statistically significant regions which are longer than 1Kbp as the candidate CNV regions by analyzing the distribution of the occurrence frequency. To select a proper read alignment method, several methods are employed in our algorithm, and the performances are compared. To verify the superiority of our approach, we performed extensive experiments. The result of simulation experiments (using a reference sequence, build 35 of NCBI) revealed that our approach successfully finds all the CNV regions that have various shapes and arbitrary length (small, intermediate, or large size).

• Journal of Preventive Medicine and Public Health
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• v.39 no.2
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• pp.135-140
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• 2006

Objectives : Polymorphisms of genes from glutathione Stransferases (GSTs) and N-acetyltransferase 2 (NAT2) have been associated with increased susceptibility to various cancers. Previous results showed that East Asians such as Koreans, Japanese and Chinese have a much higher frequency of the GSTM1 and GSTT1 null genotypes and NAT2 rapid acetylator type. Therefore, we investigated the association between the polymorphic types of GSTs (GSTM1, GSTT1, GSTP1) and NAT2 and the incidence of gastric cancer which is one of the most prevalent cancers among the East Asians. Methods : It was performed in a case-control study consisting of 238 healthy subjects and 108 cancer patients (54 distal and 54 proximal carcinomas). We also evaluated the association between GSTs and NAT2 and the risk factors for gastric cancer such as alcohol consumption, smoking, H. pylori infection, family history of gastric cancer, and tumor location. Results : In our study, the percentage of cases whose hometown was rural was higher than those of controls (odds ratio (OR) =2.88; 95% CI=1.72-4.76), and the frequency of the lower socio-economic status increased significantly in patients (OR=2.53; 95% CI=1.59-4.02). There was no significant difference in the GST polymorphic types between the cases and controls. However, NAT2 rapid or intermediate acetylator types were frequently detected in the cases with family history of gastric cancer (OR=1.92; 95% CI=1.79-26.0). Conclusions : These results suggest that the hometown and socio-economic status are important environmental factors for gastric carcinogenesis, and NAT2 polymorphic types could be associated with familial gastric carcinoma.