• Title/Summary/Keyword: 김철환

Search Result 830, Processing Time 0.026 seconds

Physico-chemical Characteristics of Biodegradable Seedling Pots Made of Paper Mill Sludges (제지공장 슬러지를 이용한 생분해성 육묘 포트의 물리화학적 특성 연구)

  • Lee, Ji-Young;Kim, Chul-Hwan;Lee, Gyeong-Sun;Jo, Hu-Seung;Nam, Hye-Gyeong;Park, Hyung-Hun;Moon, Sun-Ok
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.46 no.5
    • /
    • pp.9-18
    • /
    • 2014
  • London Convention on the prevention of marine pollution by dumping of wastes and other matter prohibits the deliberate disposal of paper mill sludges at sea. In order to explore the alternative plan on the prohibition of sludge disposal at sea, the biodegradable seedling pot was developed by mixing the sludge with old newspaper (ONP) in appropriate mixing ratios. The C/N ratio of the mixed sludge was below 20, leading to rapid deterioration of the organic matters composing the seedling pot. The increased ONP contents in the seedling pot resulted in the increase of pot thickness and thereafter in the decrease of pot density. Cellulose fibers in ONP promoted water absorption of the pot but AKD addition helped the seedling pot to repel water during raising seedling. Breaking length and burst strength of the seedling pot were improved by addition of wet strength additives but air permeability was a little diminished. Biodegradable rate of the seedling pot in a soil was accelerated by the attack of soil microbes at the beginning, and finally the pot was completely degraded in 150 days in a soil.

Effect of Precipitated Calcium Carbonate on Paper Properties and Drying Energy Reduction of Duplex-board (원료 및 건조에너지 절감을 위한 경질탄산칼슘의 백판지 공정 적용성 평가)

  • Lee, Ji-Young;Kim, Young-Hun;Lee, Se-Ran;Kim, Chul-Hwan;Sung, Yong Joo;Lim, Gi-Baek;Kim, Sun-Young;Kim, Jun-Sik;Park, Jong-Hea
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.45 no.6
    • /
    • pp.24-29
    • /
    • 2013
  • In this study, we investigated the applicability of PCC(precipitated calcium carbonate) as a raw material for the manufacture of duplex-board. Papers were made with white-ledger stock collected from the actual duplex-board mill and PCC in a laboratory, and paper properties including bulk, ash content, tensile strength, burst strength, brightness and opacity were measured. The effect of PCC on the drying energy of duplex-board was also determined by measuring the moisture content of wet web and calculating drying energy reduction. PCC increased bulk and ISO brightness significantly, which means PCC can decrease the use of virgin pulp and recycled fibers. PCC decreased the moisture content of wet web, which means PCC can decrease drying energy consumption. However, paper strength decreased as addition levels of PCC addition increased. Therefore, the addition level of PCC must be determined considering the reduction of paper strengths.

Spore morphology of Korean Polypodiaceae (한국산 고란초과 식물의 포자 형태)

  • Lim, Jin A;Kim, Chul Hwan;Kwak, Min Ju;Sun, Byung-Yun
    • Korean Journal of Plant Taxonomy
    • /
    • v.36 no.1
    • /
    • pp.1-19
    • /
    • 2006
  • Description of spore morphology of Korean Polypodiaceae has on LM and SEM and key to the genera are provided. Korean Polypodiaceae monad, monolete with bilateral symmetry, bipolar and oblete spore except for Loxogramme grammitoides having trilete spore with radial symmetry. In spore wall structure, exopore showed variable patterns enough to distinguish genera. Perispore was found in all the species examined. The patternof perispore and exospore was most similar in all the species examined except Crypsinus, Pyrrosia hastata ans P. linearifolia. The perispores of Crypsinus, Pyrrosia hastata and P. linearifolia were echinate and gemmate, rugulate, and verrucate respectively. In term of exospore wall sculpturing, Polypodium and Loxogramme showed fossulate, Lepisorus, rugulate with irregular verrucate, Crypsinus ans Coloysis showed psilate or rarely verrucate in the latter, Neocheiropteris ensata showed dense small verrucate, Lemmaphyllum microphyllum showed complex reticulate and Pyrrosia showed verrucate or psilate.

Chromosome numbers of vascular plants of Mt. Baekdu and adjacent area in China (백두산 및 인근지역 관속식물의 염색체 수)

  • Kwon, Young Ju;Sul, Mi Ra;An, Jin Kap;Kim, Chul Hwan;Sun, Byung-Yun
    • Korean Journal of Plant Taxonomy
    • /
    • v.35 no.1
    • /
    • pp.47-55
    • /
    • 2005
  • During the course of the field trip to Mt. Baekdu and Manchurian region especially along the border of North Korea, young flower buds were collected and fixed to analyze the meiotic configuration of chromosomes and to discuss the cytotaxonomic characteristics of these areas. A total of 29 taxa with 31 populations of vascular plants were analyzed chromosomally. Among them, 26 taxa with 28 populations were collected from Mt. Baekdu which include Papaver radicata var. pseudoradicata, Bupleurum euphorbioides, Oplopanax elatus, Silene jenisseensis, and Gentiana jamesii and three taxa collected from Manchurian region which include Scrophularia buergeriana, Ostericum grosseserratum and Callistephus chinensis. The first report of chromosome numbers were provided here for those species of Artemisia lagocephala as 2n = 9II, Cacalia komaroviana as 2n = 30II, Chrysanthemum zawadskii var. alpinum as 2n = 27II and Rodiola rosea as 2n = 11II,

Levee Maintenance Using Point Cloud Data Obtained from a Mobile Mapping System (모바일 매핑시스템을 이용한 제방 유지보수에 관한 연구)

  • Lee, Jisang;Hong, Seunghwan;Park, Il suk;Mohammad, Gholami Farkoushi;Kim, Chulhwan;Sohn, Hong-Gyoo
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.41 no.4
    • /
    • pp.469-475
    • /
    • 2021
  • In order to effectively maintain and manage river facilities, on going data collection of associated objects is important. However, the existing data acquisition methods of using a total station, a global navigation satellite system, or a terrestrial laser scanner have limitations in terms of cost/time/manpower when acquiring spatial information data on river facilities distributed over a wide and long area, unlike general facilities. In contrast, a mobile mapping system (MMS), which acquires data while moving its platform, acquires precise spatial information data for a large area in a short time, so it is suitable for use in the maintenance of linear facilities around rivers. As a result of applying a MMS to a research area of 4 km, 184,646,099 points were acquired during a 20-minute data acquisition period, and 378 cross-sections were extracted. By comparing this with computer-drawn river plans, it was confirmed that efficient levee management using a MMS is possible.

Two unrecorded Elymus taxa (Poaceae) newly added to Korean flora: E. humidus and E. shandongensis (한국 식물상에 새로이 추가되는 벼과 갯보리속의 2개 미기록 분류군: 둔치개밀, 여름개밀)

  • CHOI, Seung Se;KIM, Jonghwan;PARK, Yu Cheol;KIM, Chul Hwan
    • Korean Journal of Plant Taxonomy
    • /
    • v.51 no.3
    • /
    • pp.294-304
    • /
    • 2021
  • Given that the Korean genus Elymus L. (Poaceae) is often confused with Agropyron Gaertn., the categories and characteristics of Elymus s.l. have been reviewed morphologically. Two unrecorded taxa of Elymus, E. humidus (Ohwi & Sakam.) T. Osada and E. shandongensis B. Salomon, not previously recorded in Korean flora to date, we report here as an unrecorded species based on samples collected from Chungcheongbuk-do, Gyeongsangnam-do, Jeollanam-do, and Jeollabuk-do. E. humidus is distinguished from other taxa in terms of its habitat around riversides, erect inflorescences, spikelets appressed to rachides of inflorescence, and new individuals asexually propagated at the lower nodes of aerial stems. E. shandongensis is similar to E. tsukushiensis var. transiens (Hack.) H. Osada but is distinguished by the flowering time, slightly curved inflorescences, number of veins of the glumes, and spikelets appressed to the rachides. Descriptions of the two unrecorded Korean taxa, photographs, and keys to neighboring taxa are presented.

KBS ALL-IP based UHD LIVE Broadcasting System (KBS ALL-IP 기반 UHD LIVE 방송시스템)

  • Shin, Jongseob;Koh, Ujong;Lee, SeungHo;Kim, Chulhwan;Kim, Bongseong;Choi, Mugyeong;Song, Jaeho;Ko, Yongseok;Lee, Donil;Choi, Minyeong;Lee, Jaegwan;Choi, Jongcheol;Hwang, Inju;Cho, Seungwan;Kim, Byeongu;Park, Hocheol;Woo, Deokjun;Park, Insu;Kim, Jinhong;Hong, Seokmyeong;Kim, Seongtae;Kim, Haejung;Cho, Hyeongjun;Shin, Hyeonuk;Yu, Gyeongho;Lee, Munsik;Ham, Jeongwan
    • Proceedings of the Korean Society of Broadcast Engineers Conference
    • /
    • 2018.11a
    • /
    • pp.186-189
    • /
    • 2018
  • KBS는 차세대 방식인 IP전송 기술을 UHD방송에 적용하기로 결정하고 2017년 9월부터 2018년 3월까지 약 7개월에 걸쳐 ALL-IP UHD부조정실 구축을 완료했다. 이후 약 3개월간의 시뮬레이션 기간을 거쳐, 현재 KBS 1TV '아침마당'과 '무엇이든 물어보세요' 를 생방송으로 제작하고 있고 KBS 2TV '그녀들의 여유만만'을 녹화 제작하고 있다. 본 논문은 UHD비디오신호와 오디오신호를 ALL-IP로 전송하기 위해 참조한 표준기술과 각 파트별 구축 세부내용을 소개한다. 또한 향후 지속적으로 발전할 IP제작 시스템에 대해 효율적인 계획과 대응을 할 수 있도록 구축사례에 대한 경험을 결론으로 논한다.

  • PDF

Automatic Building Extraction Using SpaceNet Building Dataset and Context-based ResU-Net (SpaceNet 건물 데이터셋과 Context-based ResU-Net을 이용한 건물 자동 추출)

  • Yoo, Suhong;Kim, Cheol Hwan;Kwon, Youngmok;Choi, Wonjun;Sohn, Hong-Gyoo
    • Korean Journal of Remote Sensing
    • /
    • v.38 no.5_2
    • /
    • pp.685-694
    • /
    • 2022
  • Building information is essential for various urban spatial analyses. For this reason, continuous building monitoring is required, but it is a subject with many practical difficulties. To this end, research is being conducted to extract buildings from satellite images that can be continuously observed over a wide area. Recently, deep learning-based semantic segmentation techniques have been used. In this study, a part of the structure of the context-based ResU-Net was modified, and training was conducted to automatically extract a building from a 30 cm Worldview-3 RGB image using SpaceNet's building v2 free open data. As a result of the classification accuracy evaluation, the f1-score, which was higher than the classification accuracy of the 2nd SpaceNet competition winners. Therefore, if Worldview-3 satellite imagery can be continuously provided, it will be possible to use the building extraction results of this study to generate an automatic model of building around the world.

The Study of Failure Mode Data Development and Feature Parameter's Reliability Verification Using LSTM Algorithm for 2-Stroke Low Speed Engine for Ship's Propulsion (선박 추진용 2행정 저속엔진의 고장모드 데이터 개발 및 LSTM 알고리즘을 활용한 특성인자 신뢰성 검증연구)

  • Jae-Cheul Park;Hyuk-Chan Kwon;Chul-Hwan Kim;Hwa-Sup Jang
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.60 no.2
    • /
    • pp.95-109
    • /
    • 2023
  • In the 4th industrial revolution, changes in the technological paradigm have had a direct impact on the maintenance system of ships. The 2-stroke low speed engine system integrates with the core equipment required for propulsive power. The Condition Based Management (CBM) is defined as a technology that predictive maintenance methods in existing calender-based or running time based maintenance systems by monitoring the condition of machinery and diagnosis/prognosis failures. In this study, we have established a framework for CBM technology development on our own, and are engaged in engineering-based failure analysis, data development and management, data feature analysis and pre-processing, and verified the reliability of failure mode DB using LSTM algorithms. We developed various simulated failure mode scenarios for 2-stroke low speed engine and researched to produce data on onshore basis test_beds. The analysis and pre-processing of normal and abnormal status data acquired through failure mode simulation experiment used various Exploratory Data Analysis (EDA) techniques to feature extract not only data on the performance and efficiency of 2-stroke low speed engine but also key feature data using multivariate statistical analysis. In addition, by developing an LSTM classification algorithm, we tried to verify the reliability of various failure mode data with time-series characteristics.

Development of Korean UCS Architecture and Service Design for GCS Standardization (GCS 공통화를 위한 한국형 UCS 개발 및 서비스 설계)

  • Yoorim Choi;Sangyun Park;Chulhwan Kim;Gyeongrae Nam;So-Yeong Jeong
    • Journal of Advanced Navigation Technology
    • /
    • v.27 no.3
    • /
    • pp.314-322
    • /
    • 2023
  • The use of unmanned aerial vehicles is rapidly increasing in order to effectively utilize limited manpower and minimize casualties on the battlefield. The requirements for ground control equipment vary depending on the operating concept and environment of the unmanned aerial system, but there are still common requirements. However, the lack of standardized system configurations to meet these common requirements makes it difficult to reuse common functions, leading to continuous acquisition costs. To solve this problem, this paper develops a Korean version of the UCS model using the UCS architecture. Furthermore, after designing elements related to service development not specified in the architecture (such as framework, communication middleware, service structure, etc.), we develop a Boilerplate to enhance developers' work efficiency based on this. The results of this study will serve as a foundation for effectively and economically carrying out the development of ground control equipment for unmanned aerial systems.