• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.182-182
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• 2018

한강의 제1지류인 홍제천 수계에 속하는 지방2급 하천인 불광천 유역을 연구대상지로 선정하여 기후변화에 따른 유출량 영향성 분석을 수행하였다. 연구대상지인 불광천은 서울특별시의 서북쪽에 위치하여 $21.72km^2$의 유역면적과 9.83km의 유로연장을 갖고 행정구역상 은평구, 마포구, 서대문구에 걸쳐있다. 본 연구에서는 불광천 유역을 503개의 소유역으로 분할하였으며, 유역의 하수관망은 976개의 노드와 989개의 링크를 사용하여 XP-SWMM 모형으로 구축하였다. 또한 국토지리정보원에서 제공하는 1:5000축척의 수치지도를 DTM으로 변환하여 하수관에서 월류된 이후의 2차원 흐름분석을 위한 지형자료로 활용하였다. 기후변화를 고려한 유출량을 분석하기 위해 S0(1961년~2016년)인 1개의 과거기간과 S1(2017년~2046년), S2(2047년~2076년), S3(2077년~2100년)인 3개의 미래기간을 설정하여 총 4개의 시나리오를 구성하였다. 과거기간인 S0는 강우관측소에서 계측된 자료를 사용하여 빈도별 확률강우량을 구하였으며, 미래기간인 S1, S2, S3는 기상청에서 제공하는 기후변화 시나리오인 RCP 4.5의 강우자료를 사용하여 확률강우량을 산출하였다. 빈도별 확률강우량은 S0기간의 강우자료와 가장 유사한 Gumbel 모형을 사용하였으며, 도출된 확률강우량은 치수에 가장 보수적인 Huff의 4분위로 강우를 분포시켜 유출모형에 적용하였다. 976개의 노드 중 불광천 유역의 주요 76개 지점을 선정하여 유역면적에 따른 기후변화의 영향성을 분석하였다. 그 결과 유역면적과 재현기간이 작을수록 최대 유출량은 큰 변동성을 보이는 것으로 나타났으며, 과거기간인 S0 대비 미래기간인 S1, S2, S3의 최대 유출량 비율은 유역면적 100ha를 기준으로 100ha 미만은 80%~200%의 변동성을 100ha이상에서는 120%에 수렴하는 양상을 보이는 것으로 확인되었다.

• Nuclear Engineering and Technology
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• v.27 no.2
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• pp.216-225
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• 1995

Simulation for a dynamic analysis of the electrolytic preparation of U(IV) in two-phases system, which consisted of mass transfer of U(VI) from TBP phase into HNO$_3$ solution and electrolytic re-duction of U(VI) to U(IV) at a cathode in aqueous phase, was carried out in order to establish the most suitable operating condition and best electrode area as basic design data for the system. It was found that maintaining an appropriate mass transfer rate was more significant rather than enlarging the surface area of the cathode for more effective production yield of U(IV). The electrode area and the operation time affected deeply the production composition of U(IV) in the resulting aqueous phase. And optimal electrode areas ore evaluated to meet production criteria of U(IV) of resulting solution in several system conditions. Though about 0.37M HNO$_3$ was preferable to prepare the solution of U(IV), nitric acid concentration should be higher than 0.5M to prevent a hydrolysis of U(IV) in the aqueous phase.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.103-107
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• 2019

Recently, many technologies have been developed to realize low power high speed digital data communication and one of them is related to duty cycle correction. In this paper, a low-area duty cycle correction circuit for a voltage-controlled ring generator is proposed. The duty cycle correction circuit is a circuit that corrects the duty cycle using a 180 degree phase difference of a voltage controlled ring oscillator. The proposed low-area duty cycle circuit changes a conventional flip-flop to a true single phase clocking (TSPC) flip-flop And a low-area high-performance circuit is realized. By using TSPC flip-flop instead of general flip-flop, it is possible to realize low-area circuit compared to existing circuit, and it is expected to be used for high-performance circuit for low-power because it is easy to operate at high speed.

• Journal of the Korean Association of Geographic Information Studies
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• v.27 no.2
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• pp.19-33
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• 2024

CCTV for crime prevention is expanding; however, due to the absence of guidelines for determining installation locations, CCTV is being installed in locations unrelated to areas with frequent crime occurrences. In this study, we developed a CCTV Priority Installation Index and applied it in a case study area. The index consists of crime vulnerability and surveillance vulnerability indexes, calculated using machine learning algorithms to predict crime incident counts per grid and the proportion of unmonitored area per grid. We tested the index in a pilot area and found that utilizing the Viewshed function in CCTV visibility analysis resolved the problem of overestimating surveillance area. Furthermore, applying the index to determine CCTV installation locations effectively improved surveillance coverage. Therefore, the CCTV Priority Installation Index can be utilized as an effective decision-making tool for establishing smart and safe cities.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.814-817
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• 2010

본 연구에서는 록본기 힐즈를 공간적으로 조사, 분석하였다. 록본기 힐즈의 공간을 주변, 가로, 외부, 내부 공간과 동선으로 나누어 조사, 분석한 결과, 우리나라의 재개발은 정부의 주도하에 규모가 큰 개발이 여러 곳에서 진행되고 있지만, 주변과의 연계를 무시한 채 오직 그곳만을 위한 완전히 새로운 계획을 하며, 공간 구성은 아무 의미 없는 공간으로 면적을 채우고 있다. 그에 반해, 록본기 재개발의 공간구성은 우리에게 많은 시사점을 제공한다. 때문에 우리는 더 이상 의미 없는 공간을 구성하는 것이 아니라 록본기 힐즈와 같은 주변 환경과 연계된 공간을 만들어 줄 수 있도록 계획해야 할 것이다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.2
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• pp.66-74
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• 1985

An idea is presented in this paper that control panel be implemented with a ${\mu}$-processor instead of interrupt based logic circuits. To prove that the idea is reasonable, a ${\mu}$-computer controlled traffic light control system is chosen as a model, and its control panel is imple-mented witll a f-processor. The result is that the microprocessor-based control panel performs its function very well.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.326-333
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• 2015

A tidal sandshoal, called 'Puldeung' in the Daeijackdo Marine Protected Area(DMPA), is facing erosion due to sand mining in the nearby coastal region. To monitor the morphologic change and erosion of Puldeung, a camera monitoring system was established at the top of Song-Ee Mountain in Daeijack Island. The system consists of 2 Cannon digital cameras, Eye-fi memory card/Long-Term Evolution wireless network, and solar power supply. The acquired camera images were analyzed to obtain the area of Puldeung by the following methods: geometric correction of image, identification of shoreline, areal measurement of Puldeung and its error estimation. To compare the Puldeung area with previously measured area of 1.79 km2 at tidal height of 137 cm in 2008 and of 1.59 km2 at tidal height of 148 cm in 2010, we selected images with same tidal heights. The Puldeung area was 1.37 and 1.23 km2 at the tidal height of 137 and 148 cm, respectively. The erosion at DMPA is very severe and thus it is imperative to initiate the morphodynamical study on the seasonal variation and long-term evolution of Puldeung as well as the causes and measures of Puldeung erosion.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.9
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• pp.31-39
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• 2011

In this paper, we propose a signal readout system with small area and low power consumption for CNT sensor arrays. The proposed system consists of signal readout circuitry, a digital controller, and UART I/O. The key components of the signal readout circuitry are 64 transimpedance amplifiers (TIA) and SAR-ADC with 11-bit resolution. The TIA adopts an active input current mirror (AICM) for voltage biasing and current amplification of a sensor. The proposed architecture can reduce area and power without sampling rate degradation because the 64 TIAs share a variable gain amplifier (VGA) which needs large area and high power due to resistive feedback. In addition, the SAR-ADC is designed for low power with modified algorithm where the operation of the lower bits can be skipped according to an input voltage level. The operation of ADC is controlled by a digital controller based on UART protocol. The data of ADC can be monitored on a computer terminal. The signal readout circuitry was designed with 0.13${\mu}m$ CMOS technology. It occupies the area of 0.173 $mm^2$ and consumes 77.06${\mu}W$ at the conversion rate of 640 samples/s. According to measurement, the linearity error is under 5.3% in the input sensing current range of 10nA - 10${\mu}A$. The UART I/O and the digital controller were designed with 0.18${\mu}m$ CMOS technology and their area is 0.251 $mm^2$.

• Journal of Nutrition and Health
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• v.51 no.1
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• pp.31-39
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• 2018

Purpose: The aim of study was to determine the effects of carbohydrate, fat, protein, and fiber contents on glycemic responses in a single food item or meal. Methods: Glycemic responses were measured in 30 healthy young adults (17 males and 13 females) with various test foods, including rice, egg whites, bean sprouts, olive oil, noodles, prune, broccoli, Korean dishes, Western dishes, and salad dishes, etc. Test foods were designed to contain various carbohydrate, fat, protein, and fiber contents in single or mixed foods or dishes. After 12 hours of fasting, participants consumed test foods, and the glycemic response was measured for a subsequent 120 min (0, 15, 30, 60, 90, and 120 min). Three hundred and fifty three glycemic responses from 62 foods were collected. The incremental area under the curve (AUC) was calculated for each test food for each subject to examine glycemic responses. Statistical analysis was conducted to identify which macronutrient (carbohydrate, fat, protein and fiber) affected the AUC using a mixed model. Results: Carbohydrates (${\beta}=37.18$, p < 0.0001) significantly increased while fat (${\beta}=-32.70$, p = 0.0054) and fiber (${\beta}=-32.01$, p = 0.0486) significantly reduced the glycemic response. Conclusion: It can be concluded that the glycemic response of a meal can be modified depending on the fat and fiber contents of ingredient foods, even though carbohydrate content is maintained.

• Membrane Journal
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• v.32 no.2
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• pp.140-149
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• 2022

In this study, the conditions of low temperature and high pressure of biogas upgrading process using polysulfone membrane have been designed and tested to achieve the high recovery and efficiency corresponding to those of the highly selective polymeric materials. Polysulfone hollow fiber membrane with 4-component dope solution was spun via non-solvent induced phase separation. The hollow fiber membrane was mounted into a 1.5 inch housing. The effective area was 1.6 m², and its performance was examined in various operation temperatures and pressures. CO₂ and CH₄ permeances were 412 and 12.7 GPU at 20℃, and 280 and 3.6 GPU at -20℃, respectively, while the CO₂/CH₄ selectivity increased from 32.4 to 77.8. Single gas test was followed by the mixed gas experiments using single-stage and double stage where the membrane area ratio varied from 1:1 to 1:3. At the single-stage, CH₄ purity increased and the recovery decreased as the stage-cut increased. At the double stage, the area ratio of 1:3 showed the higher CH₄ recovery as decreasing the operation temperature at the same purity of CH₄ 97%. Finally, polysulfone hollow fiber membranes have yielded of both CH₄ purity and recovery of 97% at -20℃ and 16 barg.