• Korean Journal of Optics and Photonics
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• 제28권1호
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• pp.22-27
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• 2017

Time-encoded near-infrared spectroscopy (NIRS) system is proposed, based on a near-infrared (NIR) swept laser source, for comparison to the conventional NIRS method using a detector-type spectrometer. The cavity of the NIR swept laser source consists of a semiconductor optical amplifier (SOA) with a gain region around 800 nm, and several fiber-optic components. To change the output wavelength in time using an applied electric radio-frequency signal, an acousto-optic tunable filter (AOTF) is introduced in the fiber ring cavity configuration. To demonstrate the feasibility of an NIR swept laser source for NIRS imaging, the spectroscopic comparison of two kinds of absorbance-measuring systems a detector-type spectrometer using a white light source, and a source-type spectrometer using an NIR swept laser is successfully performed with an NIR-absorbing dye.

• Journal of Korean Society for Atmospheric Environment
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• 제21권4호
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• pp.439-458
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• 2005

An automated analysis system for water soluble constituents in $PM_{2.5}$ has been developed. The system consists of a high capacity multi tube diffusion scrubber (MTDS), a low temperature particle impactor (LTPI), and two ion (anion and cation) chromatography (IC) systems. Atmospheric particles have been collected by passing sample air through a thermostated MTDS followed by a LTPI. This system allows simultaneous measurements of soluble ions in $PM_{2.5}$ at 30 minutes interval. At the air sampling flow rate of 1.0L/min, the detection limits of the overall system are in the order of tens of $ng/m^3$. This system has been successfully used for the measurement of particulate components of Seoul air from April 2003 to January 2004. $SO_4^{2-},\;NO_3^-,\;NH_4^+,\;NO_2^-,\;Cl^-,\;Na^+,\;K^+,\;Ca^{2+},\;and\;Mg^{2+}$ are the major ionic species for $PM_{2.5}$ at Seoul. Among them, $SO_4^{2-},\;NO_3^-\;and\;NH_4^+$ are the most abundant ions, contributed up to $86\%$ of the total and the concentrations were higher than those in any other urban sites in the world except for Chinese cities. There are high pollutant episodes which contribute about $15\~20\%$ of annual average values of the major ions. During the episode, the all parcels were transported from the asian continent and $PM_{2.5}$ were significantly neutralized. This suggests that aged and long range transported pollutants caused the high pollutant episodes. They showed a distinct daily and seasonal variations:they showed a peak in the early morning caused by the night-time accumulation of particulate matters. Atmospheric reactions including gas-to-particle reactions and inter-particle reactions and meteorological parameters including relative humidity and ambient temperature were described with related to the $PM_{2.5}$ 5 concentrations. All of the ionic species showed higher concentrations during the spring than those for summer and winter.

• Korean Journal of Agricultural and Forest Meteorology
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• 제18권1호
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• pp.16-29
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• 2016

The total area of paddy field was estimated to be 55 % of the cultivated lands in South Korea, which is approximately 1 million hectares. Organisms inhabiting paddy fields if they are sensitive to environmental changes can be environmental indicator of paddy fields. Biological indicators such as phenology and distributional range are evaluated as intuitive and quantitative method to analyze the impact of climate change. This study aims to estimate flight time change of Hydrophilidae species' based on the RCP 8.5 climate change scenario. Unmanned monitoring systems were installed in Haenam, Buan, Dangjin and Cheorwon relative to the latitudinal gradient. In the three regions excepting Cheorwon, it was able to measure the abundance of flying Hydrochara affinis and Sternolophus rufipes. Degree-day for the flight time was determined based either on field measurement values and estimates of 2020s, 2050s and 2080s from KMA climate change scenario data. As a result, it is found that date of both species of initial flight becomes 15 days earlier, that of peak flight becomes 22 days earlier and that of final flight does 27 days earlier in 2080s compared to 2020s. The climate change impact on flight time is greater in coastal area, rural area and valley than inland area, urban area and plan. H. affinis and S. rufipes can be used as climate change indicator species.

• Journal of Distribution Science
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• 제16권8호
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• pp.79-89
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• 2018

Purpose - This research aims to investigate the factors that influence consumer's overseas online shopping behavior. Consumers adopt overseas online shopping as a new buying way and more and more consumers prefer overseas online shopping than traditional shopping ways. Consumers' behaviors in this shopping experience can be different from other shopping experiences. With the increase of overseas online shopping, we need to find antecedents and results of overseas online shopping. Especially there would be positive or negative factors which influence overseas online shopping motivation. To find the relationship, this study examines self-efficacy and impulsivity as major factors which influence overseas online shopping. We also suggest that several attitude factors increase self-efficacy and it is positively related to customer satisfaction. On the other hand, we assume that overseas online shopping factors influence impulsivity of buying and it will decrease customer satisfaction. Research design, data, and methodology - This empirical study data were collected from Korean people who experience overseas online shopping. The subjects for this study were confined to shoppers who used overseas online shopping within the past six months. A total of 267 responses were gathered. SPSS 23.0, PLS 2.0 software were used in the data analysis. Descriptive statistics were used to show sample characteristics. We examined reliability, validity test for constructs. All measurement items used seven-point scales(1= very strong disagree, 7 = very strongly agree) drawn from previously published papers. Partial Least Square method was applied to find the relationship between antecedent factors and dependent factors and hypotheses were estimated. Results - Results show that perceived superiority, perceived ease of use, perceived transaction safety, perceived behavioral control positively affect self-efficacy. Self-efficacy influences positively to consumer's post purchase satisfaction. Perceived monetary benefit and perceived uniqueness motivated impulse buying. This can make consumer's post purchase dissatisfaction. Conclusions - This paper attempted to confirm the existence of both the positive and negative faces of overseas online shopping. The result reveals that self-efficacy is a major factor which may increase satisfaction in the overseas online shopping. Usually, we can think monetary benefit and uniqueness of products motivate overseas online shopping. But it can also intrigue impulse buying and negatively affect customer relationship. Therefore companies should provide enough products information to their potential customers and they might apply adequate processes such as recommendation, comparing systems to build long term relationship with their customers.

• Journal of the Institute of Electronics and Information Engineers
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• 제53권1호
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• pp.59-67
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• 2016

A novel instrumentation amplifier (IA) using fully-differential linear operational transconductance amplifier (FLOTA) for electronic measurement systems with low cost, wideband, and gain control with wide range is designed. The IA consists of a FLOTA, two resistor, and an operational amplifier(op-amp). The principal of the operating is that the difference of two input voltages applied into FLOTA converts into two same difference currents, and then these current drive resistor of (+) terminal and feedback resistor of op-amp to obtain output voltage. To verify operating principal of the IA, we designed the FLOTA and realized the IA used commercial op-amp LF356. Simulation results show that the FLOTA has linearity error of 0.1% and offset current of 2.1uA at input dynamic range ${\pm}3.0V$. The IA had wide gain range from -20dB to 60dB by variation of only one resistor and -3dB frequency for the 60dB was 10MHz. The proposed IA also has merits without matching of external resistor and controllable offset voltage using the other resistor. The power dissipation of the IA is 105mW at supply voltage of ${\pm}5V$.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제43권3호
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• pp.167-178
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• 2020

The purpose of this study is to examine the relationship between internal corporate, supplier, and customer integrations for domestic SMEs on non-financial and financial performance through SCM performance such as flexibility and reduction of uncertainties. To this end, data was collected on 286 SMEs in Korea, and the structural relationships between SCM integration level, SCM performances, and management performance were analyzed. As a result of the analysis, first, it was found that the SCM integration level had a significant positive effect on the flexibility and reduction of uncertainties, which are SCM performances. Second, the flexibility and reduction of uncertainties showed significantly positive effects on the non-financial performance of the companies, but did not directly affect the financial performance positively. Third, the non-financial performance was found to have a positive effect on the financial performance. In addition, the SCM integration level did not have a direct effect on the financial and non-financial performance, but it was found that it affected management performance by mediating the flexibility and reduction of uncertainties, which are SCM performances. That is, although the SCM integration level did not directly affect financial and non-financial performance, it was confirmed that it affects management performance by mediating SCM performances, flexibility and uncertainty reduction. In other words, it was confirmed that the SCM integration level directly or indirectly affects SCM performances and overall management performance. These results imply the necessity to focus on competency in the supply chain management area according to the SCM performance expected by SMEs, and the step by step approaches to the expected effects. In a situation where prior SCM related studies have not been able to present SCM performances and management performance of SMEs that are relatively lacking in their capital and SCM construction capabilities, the findings of this study could suggest the importance of SCM integration from the perspective of SMEs. In addition, from the viewpoint of SMEs, this study suggested that a sequential approach for performance measurement is required (SCM performance → management performance) in relation to the performance factors to be established through SCM.

• Journal of the Korean Recycled Construction Resources Institute
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• 제4권4호
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• pp.379-387
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• 2016

In this study, a survey was conducted on the required measurement and waterproofing performance for residential building underground structure leakage prevention system. According to the results of the survey, it has been determined that leakage problem is considered to be quite severe, and many respondents have agreed. The legal guidelines and regulation systems do not reflect properly on the environmental requirements or conditions, resulting in continued leakage problem. In regards to this, a standardized waterproofing technique that can be used in underground areas of residential structures is required as an obligation and the development of high performance waterproofing method that allows for wet concrete surface adhesion and a guideline, design and maintenance method that allows the control of overall situational control of leakage is required.

• Journal of Technologic Dentistry
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• 제38권2호
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• pp.57-62
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• 2016

Purpose: The purpose of this study was to assess precision of crown prostheses that were fabricated by using 2 kinds of bur or 3 kinds of bur. Methods: The crowns were fabricated by using the first molar of the right maxillary in this study. The abutments that were prepared were scanned by using a scanner and designed by using CAD software. Based on the crown design, NC data were created with CAM software. The created NC data were used while fabricating the crown prostheses by using 5-axis milling machine. Scanning was done for the internal and external surface of the completed crown prostheses and 3-dimensional measurement was conducted for precision assessment. Results: The $RMS{\pm}SD$ value for the external surface of the crown prostheses that was fabricated by using two burs and three burs were $28.5{\pm}4.1{\mu}m$ and $19.1{\pm}2.8{\mu}m$, respectively; and the value for two burs were bigger than that for three burs with statistical significance (p<0.001). The $RMS{\pm}SD$ value for the internal surface of the crown prostheses that was fabricated by using two burs and three burs were $14.9{\pm}1.9{\mu}m$ and $13.3{\pm}2.5{\mu}m$, respectively; and the value for two burs were bigger than that for three burs but with no statistical significance. Conclusion: Based on this study, the prostheses that were fabricated by using 3 bur presented better stability compared to those that were fabricated by using 2 bur and statistically significant difference was found only in the external surface.

• Journal of Environmental Policy
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• 제8권4호
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• pp.95-124
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• 2009

This study aims to introduce greenhouse gas emission trading in Korea as a highly cost-effective mechanism for controlling emissions. The Basic Act on Low-Carbon Green Growth will cover methods of emissions allocation, national inventory, and trading systems (i.e. emissions trading platforms, national registry,and clearing and settlement platforms). The Korean emission scheme will be based on the Korean Climate Change Act proposed by the National Assembly and Government with a cap-and-trade scheme. The national allowances will be allocated by the hybrid system. To establish the national inventory, TRADEMARKS (Telemetering System) and emissions factors are effective for greenhouse gas emissions measurement. It will likewise be effective for the national registry to be implemented via a Korean Integrated Registry, the emissions trading platform via the KRX (Korean Exchange), and the clearing and settlement platform via the KSD (Korean Securities Depository). In other words, the KRX will manage product development and marketing for Korean Carbon Financial Instruments (including commodities, futures, and options contracts) listed and admitted to trading on the KRX. All emissions trades will be standardized and cleared by the KSD.

• The Transactions of the Korea Information Processing Society
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• 제5권12호
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• pp.3047-3062
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• 1998

This paper deseribes the desihn and the implementation of the Realtime Transport Protocol(RTP)/ Rdaltime Control Protocol(RTCP) (RFC 1889,1890) that is used to transmit the audio/video data to any destination and to feedback the Quality of Service (QoS) information of the received media data to the sender, in the teleconferencing systems proposed by ITU-T. These protocols are implemented with multi thead technique and run on top of UDP/IP-Multicast through the socket interface as the underlying protocol. The upper layer is impelmented such that in can be accessed by the H245 comference control protocol. The RTP packetizes the digitized audio/video data from the encoder info a fixed format, and multieast to the participants. The RTCP monitors RTP packets and extracts the QoS values from it such as round-trip delay, jiter and packet loss to form RTCP packets and non periokically sends them to the sender site. In this Paper, we also descritx the study of measurement and analysis for QoS factors that observed on performing teleconferencing system over Internet. The results from this experiment is indicate that RTT and Jitter value are acceptable even entwork load is high. However, it appears that packet loss rate is high in daytime and most losses periods have length one or two.