• Title/Summary/Keyword: Required performance

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CO and Soot Yields of Wood Combustibles for a Kitchen Fire Simulation (주방 화재시뮬레이션을 위한 목재 가연물의 CO 및 Soot Yields)

  • Mun, Sun-Yeo;Hwang, Cheol-Hong;Kim, Sung-Chan
    • Fire Science and Engineering
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    • v.33 no.1
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    • pp.76-84
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    • 2019
  • Experimental studies using an open cone calorimeter were conducted to provide information on the CO and soot yields of wood combustibles required for a kitchen fire simulation of PBD. A total of eight specimens were examined for medium density fiberboard (MDF) and particle board (PB), which are used widely in kitchen furniture production, depending on the water content, surface processing method, and surface color. The thermal penetration time related to the fire spread rate in the depth direction differed significantly according to the surface processing treatment method, even for a specimen of identical thickness. The CO yield ($y_{CO}$) of the MDF and PB series did not change significantly according to the combustion mode and surface treatment process in flaming mode. On the other hand, $y_{CO}$ was approximately 10 times higher in smoldering mode than in flaming mode. The soot yield ($y_{soot}$), however, varied considerably depending on the combustion mode and surface treatment process. In particular, a higher $y_{soot}$ was found in flaming mode and in the surface-treated specimens. Finally, the $y_{CO}$ and $y_{soot}$ of MDF and PB measured for the kitchen fire simulation of PBD were applied.

Polarimetry of solar system small bodies using the Seoul National University 61cm telescope and TRIPOL

  • Jin, Sunho;Ishiguro, Masateru;Kwon, Yuna Grace;Geem, Jooyeon;Bach, Yoonsoo P.;Seo, Jinguk;Sasago, Hiroshi;Sato, Shuji
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.64.2-64.2
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    • 2019
  • It is known that lights scattered by comets and asteroids are partially polarized. From polarimetric observations of those objects, we can investigate physical properties, such as albedos, sizes of cometary dust particles and regolith of asteroids. Since the polarization degrees of those objects highly depend on their phase angles (Sun-object-observer's angles), long-term monitoring observations are required. Moreover, comets show unforeseeable activations (i.e., outbursts) which need follow-up observations to understand the mechanism. In order to realize such monitoring and transient observations, we installed the Triple-Range Imager and POLarimeter (TRIPOL) on the 61cm telescope of Seoul National University (Hereafter, SNU) Gwanak campus. With this combination, we can obtain g', r', i' bands photopolarimetric images simultaneously with $8.0^{\prime}{\times}8.0^{\prime}$ field of view and pixel resolution of 0.94" pixel-1. Here, we make a presentation regarding the photometric and polarimetric performances of TRIPOL on the SNU 61cm telescope. In addition, we introduce initial polarimetric results of asteroid and comets with the instruments. First, we determine the limiting magnitudes (defined as magnitudes for S/N=5) of $15.17{\pm}0.06$ (g'-band), $15.68{\pm}0.01$ (r'-band), $16.24{\pm}0.03$ (I'-band), respectively, with total 240-seconds exposure (four 60-seconds exposure images, each was taken at different rotation angle for the half-wave plate). Second, we found that the instrumental polarization is negligibly small, ($-0.32{\pm}0.04%$ in the g', $-0.36{\pm}0.05%$ in the r' and $-0.21{\pm}0.04%$ in the i'-bands), while the polarization efficiencies are large enough to maximize the performance (i.e., $97.52{\pm}0.03%$ in the g', $98.83{\pm}0.02%$ in the r' and $99.15{\pm}0.02%$ in the i'-bands). With the instruments, we made observations of three Jupiter-family comets, 21P/Giacobini-Zinner, 38P/Stephan-Oterma, and 46P/Wirtanen and plan to observe one near-Earth asteroid, (433) Eros, on a trial basis. Especially for comets, we discriminate signals from dust and gas to eliminate gas contamination, which are known to change observed degree of linear polarization, using multi-band images. We confirm that the phase angle dependency of these comets are consistent with previous observations, probably because polarimetric property of Jupiter-family comets are broadly homogeneous unlike asteroids. We will also describe future observation plans using TRIPOL and SNU 61cm telescope.

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Study of In-Memory based Hybrid Big Data Processing Scheme for Improve the Big Data Processing Rate (빅데이터 처리율 향상을 위한 인-메모리 기반 하이브리드 빅데이터 처리 기법 연구)

  • Lee, Hyeopgeon;Kim, Young-Woon;Kim, Ki-Young
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.2
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    • pp.127-134
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    • 2019
  • With the advancement of IT technology, the amount of data generated has been growing exponentially every year. As an alternative to this, research on distributed systems and in-memory based big data processing schemes has been actively underway. The processing power of traditional big data processing schemes enables big data to be processed as fast as the number of nodes and memory capacity increases. However, the increase in the number of nodes inevitably raises the frequency of failures in a big data infrastructure environment, and infrastructure management points and infrastructure operating costs also increase accordingly. In addition, the increase in memory capacity raises infrastructure costs for a node configuration. Therefore, this paper proposes an in-memory-based hybrid big data processing scheme for improve the big data processing rate. The proposed scheme reduces the number of nodes compared to traditional big data processing schemes based on distributed systems by adding a combiner step to a distributed system processing scheme and applying an in-memory based processing technology at that step. It decreases the big data processing time by approximately 22%. In the future, realistic performance evaluation in a big data infrastructure environment consisting of more nodes will be required for practical verification of the proposed scheme.

Experimental study of the air emission effect in the tangential and the multi-stage spiral inlet (접선식 유입구와 다단식 나선 유입구의 공기 배출 효과에 관한 실험적 연구)

  • Seong, Hoje;Rhee, Dong Sop;Park, Inhwan
    • Journal of Korea Water Resources Association
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    • v.52 no.4
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    • pp.235-243
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    • 2019
  • Recently, urban inundation was frequently occurred due to the intensive rainfall exceeding marginal capacity of the flood control facility. Furthermore, needs for the underground storage facilities to mitigate urban flood are increasing according to rapidly accelerating urbanization. Thus, in this study, drainage efficiency in drain tunnel connecting to underground storage was investigated from the air-core measurements in the drop shaft against two types of inlet structure. In case of the spiral inlet, the multi-stage structure is introduced at the bottom of the inlet to improve the vortex induction effect at low inflow discharge (multi-stage spiral inlet). The average cross-sectional area of the air-core in the multi-stage spiral inlet is 10% larger than the tangential inlet, and show the highly air emission effect and the highly inflow efficiency at the high inflow discharge. In case of the tangential inlets, the air emission effect decreased after exceeding the maximum inflow discharge, which is required to maintain the inherent performance of the tangential inlet. From the measurements, the empirical formula for the cross-sectional area of the air-core according to locations inside the drop shaft was proposed in order to provide the experimental data available for the inlet model used in experiments.

A Study on the Strategy for Improvement of Operational Test and Evaluation of Weapon System and the Determination of Priority (무기체계 운용시험평가 개선전략 도출 및 우선순위 결정)

  • Lee, Kang Kyong;Kim, Geum Ryul;Yoon, Sang Don;Seol, Hyeon Ju
    • Convergence Security Journal
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    • v.21 no.1
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    • pp.177-189
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    • 2021
  • Defense R&D is a key process for securing weapons systems determined by mid- and long-term needs to cope with changing future battlefield environments. In particular, the test and evaluation provides information necessary to determine whether or not to switch to mass production as the last gateway to research and development of weapons systems and plays an important role in ensuring performance linked to the life cycle of weapons systems. Meanwhile, if you look at the recent changes in the operational environment of the Korean Peninsula and the defense acquisition environment, you can see three main characteristics. First of all, continuous safety accidents occurred during the operation of the weapon system, which increased social interest in the safety of combatants, and the efficient execution of the limited defense budget is required as acquisition costs increase. In addition, strategic approaches are needed to respond to future battlefield environments such as robots, autonomous weapons systems (RAS), and cyber security test and evaluation. Therefore, in this study, we would like to present strategies for improving the testing and evaluation of weapons systems by considering the characteristics of the security environment that has changed recently. To this end, the improvement strategy was derived by analyzing the complementary elements of the current weapon system operational test and evaluation system in a multi-dimensional model and prioritized through the hierarchical analysis method (AHP).

Working Conditions that Impact the Workload of Cytotechnologists: A Study Calculating the Actual Man Power Required (세포병리사의 업무량에 따른 적정인력 산정을 위한 업무실태 조사 연구)

  • Jee, Soo Il;Ahn, Yong Ho;Ha, Hwa-Jeong;Kang, Jeong Eun;Won, Jun Ho
    • Korean Journal of Clinical Laboratory Science
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    • v.53 no.2
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    • pp.174-187
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    • 2021
  • Cytotechnologists evaluate and analyze disorders of cells that constitute the human body, and are involved in the primary assessment of diverse diseases, including cancer. However, the employment conditions and workload of cytotechnologists are poorly understood. This study was undertaken to provide basic data for establishing the criteria for quality control certification factors based on the scope of effective task performance of cytotechnologists, and to provide results of their workload analysis according to the type of medical institution. The study was conducted by enrolling certified cytotechnologists working at various nationwide medical institutions. Our analysis revealed that 178 personnel (72.7%) were involved in primary screening of samples. On an average, the daily number of primary screening of samples performed per cytotechnologist (76 respondents) was determined to be 75.4 chapters (16.8 chapters/hours) at the university hospital level, 72.4 chapters (18.6 chapters/hours) at the general hospital level, and 231 chapters (32.6 chapters/hours) at professional trust institutions. Our results indicate the necessity to establish a consultant with the Korean Cell Pathology Association, to enable finding solutions to solve existing issues by establishing accurate standard guidelines for assessing cell screening.

Crack Detection on Bridge Deck Using Generative Adversarial Networks and Deep Learning (적대적 생성 신경망과 딥러닝을 이용한 교량 상판의 균열 감지)

  • Ji, Bongjun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.9 no.3
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    • pp.303-310
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    • 2021
  • Cracks in bridges are important factors that indicate the condition of bridges and should be monitored periodically. However, a visual inspection conducted by a human expert has problems in cost, time, and reliability. Therefore, in recent years, researches to apply a deep learning model are started to be conducted. Deep learning requires sufficient data on the situations to be predicted, but bridge crack data is relatively difficult to obtain. In particular, it is difficult to collect a large amount of crack data in a specific situation because the shape of bridge cracks may vary depending on the bridge's design, location, and construction method. This study developed a crack detection model that generates and trains insufficient crack data through a Generative Adversarial Network. GAN successfully generated data statistically similar to the given crack data, and accordingly, crack detection was possible with about 3% higher accuracy when using the generated image than when the generated image was not used. This approach is expected to effectively improve the performance of the detection model as it is applied when crack detection on bridges is required, though there is not enough data, also when there is relatively little or much data f or one class.

Analysis of vitamin E and K contents in sea algae and vegetables frequently consumed in Korea for National Standard Food Composition Database (국가표준식품성분표 개정을 위한 국내 다소비 해조류 및 채소류의 비타민 E 및 K 분석)

  • Kim, Hyo Jin;Lee, Seogyeong;Park, Jin Ju;Kim, Hyun Jung
    • Korean Journal of Food Science and Technology
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    • v.53 no.1
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    • pp.19-28
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    • 2021
  • Vitamin E and K are essential micronutrients required by our body in small amounts for proper metabolic functions; however, the content of vitamin E and K commonly consumed in foods has not been comprehensively defined. In this study, the contents of vitamins E and K in sea algae and vegetables were analyzed and the analytical methods were validated. The α-tocopherol equivalent (α-TE) and vitamin K1 content in sea algae ranged from 0.15 to 1.14 mg/100 g and from 11.91 to 1,629.5 ㎍/100 g, respectively. In addition, α-TE and vitamin K1 of vegetables were detected in the range of 0.02-2.48 mg/100 g and 16.15-979.60 ㎍/100 g, respectively. In particular, β- and γ-tocopherol and α- and β-tocotrienol were detected in several vegetables. The analytical methods were accurate and reproducible. These results provide reliable data on the vitamin E and K contents of foods consumed in Korea for the development of National Standard Food Composition Database.

A Study on the Application of Composites to Pipe Support Clamps for the Light-weight LNGC (LNGC 경량화를 위한 파이프 지지용 클램프의 복합소재 적용 연구)

  • Bae, Kyong-Min;Yim, Yoon-Ji;Yoon, Sung-Won;Ha, Jong-Rok;Cho, Je-Hyoung
    • Composites Research
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    • v.34 no.1
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    • pp.8-15
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    • 2021
  • In the shipbuilding and marine industry, as a technology for reducing the weight of parts to reduce energy and improve operational efficiency of ships is required, a method of applying fibers-reinforced composites which is high-strength lightweight materials, as part materials can be considered. In this study, the possibility of applying fibers-reinforced composites to the pipe support clamps was evaluated to reduce the weight of LNGC. The fibers-reinforced composites were manufactured using carbon fibers and glass fibers as reinforcing fibers. Through the computer simulation program, the properties of the reinforcing materials and the matrix materials of the composites were inversely calculated, and the performance prediction was performed according to the change in the properties of each fiber lamination pattern. In addition, the structural analysis of the clamps according to the thickness of the composites was performed through the finite element analysis program. As a result of the study, it was confirmed that attention is needed in selecting the thickness when applying the fibers-reinforced composites of the clamp for weight reduction. It is considered that it will be easy to change the shape of the structure and change the structure for weight reduction in future supplementary design.

A Review of Structural Batteries with Carbon Fibers (탄소섬유를 활용한 구조용 배터리 연구 동향)

  • Kwon, Dong-Jun;Nam, Sang Yong
    • Applied Chemistry for Engineering
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    • v.32 no.4
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    • pp.361-370
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    • 2021
  • Carbon fiber reinforced polymer (CFRP) is one of the composite materials, which has a unique property that is lightweight but strong. The CFRPs are widely used in various industries where their unique characteristics are required. In particular, electric and unmanned aerial vehicles critically need lightweight parts and bodies with sufficient mechanical strengths. Vehicles using the battery as a power source should simultaneously meet two requirements that the battery has to be safely protected. The vehicle should be light of increasing the mileage. The CFRP has considered as the one that satisfies the requirements and is widely used as battery housing and other vehicle parts. On the other hand, in the battery area, carbon fibers are intensively tested as battery components such as electrodes and/or current collectors. Furthermore, using carbon fibers as both structure reinforcements and battery components to build a structural battery is intensively investigated in Sweden and the USA. This mini-review encompasses recent research trends that cover the classification of structural batteries in terms of functionality of carbon fibers and issues and efforts in the battery and discusses the prospect of structural batteries.