• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.2
• /
• pp.484-493
• /
• 2004

A new lightwave locking technique which can be used in tuning the wavelength of a local laser diode to the reference wavelength is presented in this paper. The optical frequency from the reference laser source and the optical frequency from the local slave VCO laser are heterodyned on a optical receiver, resulting in the 1.5GHz RF signal corresponding to the difference frequency between two input optical signals. The difference frequency is locked to the reference 1.5GHz oscillator source in off-set frequency locking loop. Using the commercialized microwave components, frequency difference detector can be easily established to lock the lightwave. The optical frequency of 1.55um laser diode which keeps the frequency off-set of 1.5GHz is locked to the input reference optical signal with the locking range of 320MHz.

• Journal of English Language & Literature
• /
• v.55 no.1
• /
• pp.129-152
• /
• 2009

The paper aims to prove symmetries of the left and right edges of a morphological unit through the analysis of English blends. Blends are the words derived from two existing words by snipping the middle parts out and putting the rest together, such as smog (

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.20 no.2
• /
• pp.63-74
• /
• 2024

This Paper presents a resistive wideband fully differential low-noise amplifier (LNA) designed using a noise-cancellation technique for TV tuner applications. The front-end of the LNA employs a cascode common-gate (CG) configuration, and cross-coupled local feedback is employed between the CG and common-source (CS) stages. The moderate gain at the source of the cascode transistor in the CS stage is utilized to boost the transconductance of the cascode CG stage. This produces higher gain and lower noise figure (NF) than a conventional LNA with inductor. The NF can be further optimized by adjusting the local open-loop gain, thereby distributing the power consumption among the transistors and resistors. Finally, an optimized DC gain is obtained by designing the output resistive network. The proposed LNA, designed in SK Hynix 180 nm CMOS, exhibits improved linearity with a voltage gain of 10.7 dB, and minimum NF of 1.6-1.9 dB over a signal bandwidth of 40 MHz to 1 GHz.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.3
• /
• pp.201-205
• /
• 2009

This paper addresses issues to efficiently collect and aggregate data of sources within a local and adjacent region in geographic routing for wireless sensor networks. We first introduce the concept of a local sink which collects and aggregates data form source nodes in the region and delivers the aggregated data to a global sink. We also design a model to determine an optimal location of the local sink and propose a mechanism to collect data through the local sink. Simulation results show that the proposed mechanism with the local sink is more efficient in terms of the energy and the data delivery ratio than the existing mechanism without the local sink in a geographic routing.

• Atmosphere
• /
• v.27 no.1
• /
• pp.41-54
• /
• 2017

Organic carbon (OC) and elemental carbon (EC) in $PM_{2.5}$ were measured using Sunset OC/EC Field Analyzer at Seoul Hwangsa Monitoring Center from March to April, 2016. The mean concentrations of OC and EC during the entire period were $4.4{\pm}2.0{\mu}gC\;m^{-3}$ and $1.4{\pm}0.6{\mu}gC\;m^{-3}$, respectively. OC/EC ratio was $3.4{\pm}1.0$. The average concentrations of $PM_{10}$ and $PM_{2.5}$ were $57.4{\pm}25.9$ and $39.7{\pm}19.8{\mu}g\;m^{-3}$, respectively, which were detected by an optical particle counter. The OC and EC peaks were observed in the morning, which were impacted by vehicle emission, however, their diurnal variations were not noticeable. This is determined to be contributed by the long-range transported OC or secondary formation via photochemical reaction by volatile organic compounds at afternoon. A conditional probability function (CPF) model was used to identify the local source of pollution. High concentrations of $PM_{10}$ and $PM_{2.5}$ were observed from the westerly wind, regardless of wind speed. When wind velocity was high, a mixing plume of dust and pollution during long-range transport from China in spring was observed. In contrast, pollution in low wind velocity was from local source, regardless of direction. To know the effect of long-range transport on pollution, a concentration weighted trajectory (CWT) model was analyzed based on a potential source contribution function (PSCF) model in which 75 percentiles high concentration was picked out for CWT analysis. $PM_{10}$, $PM_{2.5}$, OC, and EC were dominantly contributed from China in spring, and EC results were similar in both PSCF and CWT. In conclusion, Seoul air quality in spring was mainly affected by a mixture of local pollution and anthropogenic pollutants originated in China than the Asian dust.

• Journal of KIISE:Software and Applications
• /
• v.35 no.7
• /
• pp.442-451
• /
• 2008

Most plagiarism detection systems evaluate the similarity of source codes and detect plagiarized program pairs. If we use the source codes in plagiarism detection, the source code security can be a significant problem. Plagiarism detection based on target code can be used for protecting the security of source codes. In this paper, we propose a new plagiarism detection technique for Java programs using bytecodes without referring their source codes. The plagiarism detection procedure using bytecode consists of two major steps. First, we generate the token sequences from the Java class file by analyzing the code area of methods. Then, we evaluate the similarity between token sequences using the adaptive local alignment. According to the experimental results, we can find the distributions of similarities of the source codes and that of bytecodes are very similar. Also, the correlation between the similarities of source code pairs and those of bytecode pairs is high enough for typical test data. The plagiarism detection system using bytecode can be used as a preliminary verifying tool before detecting the plagiarism by source code comparison.

• Journal of Korean Society for Atmospheric Environment
• /
• v.25 no.4
• /
• pp.275-288
• /
• 2009

The Korean government strengthened the environmental polices to manage and enhance Metropolitan Area air quality, and also has enforced "Special Act on Seoul Metropolitan Air Quality Improvement (SASMAQI)" issued in Dec. 2004. Recently government expanded the Seoul Metropolitan Air Quality Management District (SMAQMD) to the outskirts satellite cities of Seoul area through the "Revised Law Draft of SASMAQI". The SMAQMD has been alloted the allowable emission loads to the local governments on the basis of the carrying $PM_{10}$ capacity. However, in order to establish the effective air quality control strategy for $PM_{10}$, it is necessary to understand the corresponding sources which have a potential to directly impact ambient $PM_{10}$ concentration. To deal with the situations, many receptor methodologies have been developed to identify the origins of pollutants and to determine the contributions of sources of interests. The objective of this study was to extensively identify $PM_{10}$ sources and to estimate their contributions at the metropolitan area. $PM_{10}$ samples were simultaneously collected at the 3 semi-industrialized local cities in the Seoul metropolitan area such as Hwasung-si, Paju-si, and Icheon-si sites from April 15 to May 31, 2007. The samples collected on the teflon membrane filter by one $PM_{10}$ cyclone sampler were analyzed for trace metals and soluble ions and samples on the quartz fiber filter by another sampler were analyzed for OC and EC. Source apportionment study was then performed by using a positive matrix factorization (PMF) receptor model. A total of 6 sources were identified and their contributions were estimated in each monitoring site. Contribution results on Hwasung, Paju, and Icheon sites were as follows: 33%, 27%, and 27% from soil source, 26%, 26%, and 21% from secondary aerosol source, 11%, 11%, and 12% from biomass burning, 12%, 6%, and 5% from sea salt, 7%, 15%, and 19% from industrial related source, and finally 11%, 15%, and 16% from mobile and oil complex source, respectively. This study provides information on the major sources affecting air quality in the receptor sites and thus it will help to manage the ambient air quality in the metropolitan area by establishing reasonable control strategies, especially for the anthropogenic emission sources.

• Journal of Korean Society for Atmospheric Environment
• /
• v.22 no.5
• /
• pp.590-603
• /
• 2006

Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 23 March to 29 April 2001 at Gosan, Jeju Island, Korea, which is one of the super sites of Asia-Pacific Regional Aerosol Characterization Experiment(ACE-Asia). These samples were analyzed using synchrotron X-ray fluorescence for 3-hr average concentrations of 19 elements including Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization(PMF) technique to identify possible sources and estimate their contributions to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Twelve sources were resolved in eight size ranges($0.09{\sim}12{\mu}m$) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil combustion, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, and volcanic emission. The PMF result of size-resolved source contributions showed that natural sources represented by local soil, sea salt, continental soil, and volcanic emission contributed about 79% to the predicted primary particulate matter(PM) mass in the coarse size range ($1.15{\sim}12{\mu}m$) while anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 58% in the fine size range($0.56{\sim}2.5{\mu}m$). The diesel vehicle source contributed mostly in ultra-fine size range($0.09{\sim}0.56{\mu}m$) and was responsible for about 56% of the primary PM mass.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.517-544
• /
• 2011

Promote competition in local government and the construction of a subway construction in the vicious cycle of debt due to the operating deficit as a greater burden on local finances was leave. This government policy of public transport in the center of the metro construction costs affordable and to respond appropriately to public transport demand new transit LRT(Light rail Transit) by introducing the current Busan was the opening of Line 4, yongin line, Busan - Gimhae line, parliamentary and barge construction or ready for the opening. What is light rail, compared to the existing subway and cheaper construction cost, the existing road or bridge that runs along the track is installed, etc. Manless system construction cost and operating expenses as a possible new railway transportation has been a leading state-of-the-art mad. However, the domestic business system engineering of light rail-related companies in the developed countries are doing to advance to the national to the local engineering skills of the self-free, hurry will have to be secured. Therefore, this paper applies local light rail project on the status of the systems engineering analysis and based on this source of the latest engineering technology-intensive systems engineering to provide direction to the development of technology.

• Journal of Oral Medicine and Pain
• /
• v.35 no.4
• /
• pp.275-281
• /
• 2010

The lateral pterygoid muscle is one of the masticatory muscles basic to jaw function. Because of its deep location in the masticatory system, digital palpation of the muscle is usually difficult to perform and unreliable. Therefore, diagnosis of the myalgic disorders involving the lateral pterygoid muscle is a perplexing problem for clinicians. Local anesthetic injection can be a more effective method to examine the lateral pterygoid muscle for the purpose of discriminating the source of pain. Furthermore, immediate elimination of muscle pain facilitates stretching of the muscle in the full range. We report two cases of lateral pterygoid myalgia that were diagnosed and managed successfully through the use of intramuscular local anesthetic injection.