• 제목/요약/키워드: Turning Characteristics

검색결과 504건 처리시간 0.025초

우리나라 수산업의 시기별 특징과 구조변화에 관한 연구 (A Study on the Periodic Characteristics and the Structural Change in Korean Fisheries)

  • 홍현표;이헌동
    • 수산경영론집
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    • 제36권3호
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    • pp.65-88
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    • 2005
  • The fisheries industry has been changed drastically during the so - called Golden Growth Era of Korea. Recently, WTO/DDA agenda drove industries out of their safe refuges toward infinite competitions in the world. This paper aims at finding out distinguished features in the structural changes of fisheries since 70s. Furthermore, policy implications are investigated in order for the fisheries to survive in the outdoors. The paper consists of the following sections. First, we consider why and for what the structural change of fisheries in historical perspective should be investigated. And we introduce how we can approach to the goal in various aspects in the second section. In the third section, we examine the historical change of Korean fisheries in respect of national economy, resource allocation mechanism, industrial structure, and fisheries society. In the fourth section, we extract the development steps in fisheries from the periodic characteristics, using various methods of the above approaches. And we deduce the next step for Korean fisheries in the future. Finally, we conclude that there needs some turning point of fisheries policies in Korea, striving to foster the fisheries industry in the future. As results of empirical analysis in this paper, we find that fisheries industry in Korea has experienced some momentous changes during 30 years, using I/O data of B.O.K. The weight of fisheries sector in the whole economy of Korea increased during early 70s, initially leading the national economy to export - oriented engine for growth. But fisheries sector has shrunk rapidly since late 70s. Almost resources in Korea were allocated to expanding manufacturing industries. Further, fisheries industry has encountered perfect international competitions since the late 90s. This paper draws that fisheries industry in Korea will jump across to next step of qualitative growth in the future. Therefore, we recommend that the policies should be focused on enhancing the industrial competitiveness, switching quantitative growth to qualitative advance in fisheries.

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벼의 자연통풍건조에 있어서 통풍량이 건조에 미치는 영향에 관한 연구 (A Study on Effects of Air-delivery Rate upon Drying Rough Rice with Unheated Air.)

  • 이상우;정창주
    • 한국농공학회지
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    • 제16권1호
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    • pp.3293-3301
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    • 1974
  • An experimental work was conducted by using a laboratory-made model dryer to investigate the effect of the rate of natural forced-air on the drying rate of rough rice which was deposited in the deep-bed. The dryer consisted of 8 cylinderical containers with grain holding screen at their bottoms, each of which having 30cm in diameter and 15cm in height. The containers were sacked vertically with keeping them air-tight by using paper tape during dryer operation. Two separate layers of containers were operated in the same time to have two replications. The moisture contents of grains within each bins after predetermined period of dryer operation were determined indirectly by measuring the weight of the individual containers. The air-rates were maintained at 6 levels, or 5, 8, 10, 15, 18 and 20 millimenters of static head of water. The roomair conditions during dryer operation were maintained in the range of 10-l5$^{\circ}C$ in temperature and 40-60% in relative humidity. The results of the study are summarized as follows: 1. Drying characteristics of the grains in the bottom layers were approximately the same regardless of airdelivery rates, giving the average drying rate as about 0.35 percent per hour after 40-hour drying period, during which moisture content (w. b.) reduced from 24 percent to about 10 percent. 2. After about 40-hour drying period, the mean drying rates increased from 0.163 percent per hour to 0.263 percent per hour as air-flow rates increased from 5mm to 87.16mm of static head of water. In the same time, the moisture differences of grains between lower and upper layers varied from 12.7 percent at the air rate of 5mm of water head to 7.5 percent at the air-flow rate of 20mn of water head. Thus, the greater the air-flow rate was, the more overall improvement in drying performance was. Additionally, from the result of ineffectiveness of drying grain positioned at 70cm depth or above by the air rate of 5mm of static head of water it may be suggested in practical application that the height of grain deposit would be maintained adequately within the limits of air-rates that may be actually delivered. 3. Drying after layer-turning operation was continued for about 30 hours to test the effectiveness of reducing moisture differences in the thick layers. As a result of this layer-turning operation, moisture distribution through layers approached to narrow ranges, giving the moisture range as about 7 percent at air-flow rate of 5mm head of water, about 3 percent at 10mm head about 2 percent at 15mm head, and less than 1 percent at 20mm head. In addition, from the desirable results that drying rate was rapid in the lower layers and dully in the upper layers, layer-turning operation may be very effective in natural air drying with deep-layer grain deposit, especially when the forced air was kept in low rate. 4. Even though the high rate of air delivery is very desirable for deep-layer natural-air drying of rough rice, it can be happened that the required air delivery rate could not be attained because of limitation of power source available on farms. To give a guide line for the practical application, the power required to perform the drying with the specified air rate was analyzed for different sizes of drying bin and is given in Table (5). If a farmer selects a motor of which size is 1 or {{{{1 { 1} over {2 } }}}} H.P. and air-delivery rate which ranges from 8~10mm of head, the diameter of grain bin may be suggested to choose about 2.4m, also power tiller or other moderate size of prime motor may be recommended when the diameter of grain bin is about 5.0m or more for about 120cm grain deposit.

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선회다짐기를 이용한 노상토의 다짐특성 (Characteristic of Subgrade Soil using Gyratory Compactor)

  • 이관호
    • 한국산학기술학회논문지
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    • 제19권4호
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    • pp.571-577
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    • 2018
  • 본 선회다짐기는 도로 현장에서 가장 많이 사용하는 다짐 롤러의 다짐 특성을 반영하기 위해 개발된 실내 다짐장비이다. 기존의 충격을 이용한 프록터 다짐과는 달리 압축력과 회전을 통한 전단력을 이용한 현장 롤러의 다짐특성을 모사하였다. 본 연구의 목적은 기존의 프록터 다짐과정에서 얻기 힘든 전단응력 및 다짐중의 밀도변화 특성 등을 선회다짐기를 이용하여 평가하고, 이를 도로설계에 반영할 수 있는 기초자료로 활용하는 것이다. 이러한 선회다짐기를 이용하여 도로 현장 및 지하매설물 시공 시 가장 많이 사용되는 모래 및 노상토의 다짐 특성을 분석 및 평가하였다. 선회다짐기를 이용한 다짐 특성은 기본적으로 선회다짐 횟수와 시편의 높이, 다짐밀도, 간극비, 포화도 및 전단응력이다. 선회다짐 횟수가 증가할수록 시편의 높이는 작아지고, 간극비는 작아지고, 다짐 밀도는 증가하고, 포화도는 증가하며, 전단응력은 커지는 경향을 보였다. 전단응력은 다짐 초기에 200kPa 수준에서 시작하여 선회다짐 횟수 50회 정도가 되면 대략 330-350 kPa 수준으로 증가하였다. 동일한 시편의 경우 함수비가 커짐에 따라 다짐 밀도, 포화도 및 전단응력이 증가하는 경향을 보였다. 선회다짐기를 이용한 다짐은 밀도 및 전단응력 등 도로 설계 시 필요한 물성을 측정할 수 있는 장점을 가지고 있어 이를 도로설계시 반영한다면 더 공학적인 도로설계를 할 수 있을 것이다.

USN기반 PDR 센서의 검출 시간차를 이용한 표적 경로 검출 알고리즘 (Target Path Detection Algorithm Using Activation Time Lag of PDR Sensors Based on USN)

  • 이재일;이종현;배진호
    • 한국인터넷방송통신학회논문지
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    • 제15권1호
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    • pp.179-186
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    • 2015
  • 본 논문에서는 탐지영역에 존재하는 이동 표적의 유무 정보만을 제공하는 USN(Ubiquitous Sensor Network) 기반 PDR(Pulse Doppler Radar) 센서 노드 환경에서 인접한 PDR 센서로 부터 이동하는 표적의 경로에 따른 검출 시간차의 통계적 특성을 이용한 표적 경로 검출 알고리즘을 제안한다. 알고리즘에 사용된 변수는 실측 실험정보를 기반으로 도출한 표적 검출 시간차와 비검출 시간차이다. 그리고 PDR 센서 탐지 영역에서 발생되는 표적 이동경로는 센서를 관통하는 경로, 센서와 병렬로 이동하는 경로 그리고 두 센서 사이를 바라보고 진입한 후 한쪽 센서 방향으로 향하는 3가지 경우이고, 각 경우에 대해 500회의 실험을 수행 하였다. 그 결과 각 경우에 따른 오류 검출 백분율은 각각 5.67%, 5.83% 그리고 7.17% 으로 제한된 표적 검출 환경에서 정확하게 표적 경로를 검출한다.

복막투석, 혈액투석 및 정상 신 기능 집단간의 인지기능 비교 연구 (A Comparative Study in the Cognitive Functions of Peritoneal Dialysis, Hemodialysis and Normal Kidney Function Groups)

  • 이기숙;최송희
    • 성인간호학회지
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    • 제13권3호
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    • pp.451-462
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    • 2001
  • This study was conducted to examine and compare the characteristics in the cognitive functions of peritoneal dialysis, hemodialysis and normal kidney function groups as basic data for effectively educating dialysis patients. The data were collected from May 10 to October 30. 2000, collected from each of 20 patients with peritoneal dialysis, hemodialysis and normal Kidney function and who registered for the dialysis room at a general hospital affiliated to a university in Seoul and sampled by age and educational level through personal interviews with the researchers of this study. As a measuring tool, MMSE developed by Folstein et al.(1975) to measure cognitive function disorder was used, slightly revised for hemodialysis patients. Collected data were processed into frequency, percentage, mean, and standard deviation by the use of SAS. The results of this study are as follows : 1. With a maximum of 30 points for cognitive function, the mean of the peritoneal dialysis patients was $27.06{\pm}2.06$, while that of the hemodialysis patients was $27.25{\pm}2.76$; that of the normal Kidney function patients was $27.85{\pm}2.00$, indicating no significant difference among those three groups. 2. As for the subjects who scored 23 points, the turning point of confirming the cognitive disorder, the percentage was 5% in the case of the peritoneal dialysis, 10% in the case of the hemodialysis and 5% in the case of the normal Kidney function group. 3. Differences between the peritoneal dialysis and hemodialysis patients by gender, occupation, spouse, diabetes, hypertension, the period of dialysis, number of hospitalizations, and the use of erythropoietin were not significant in the scoring of cognitive function. 4. There was no significant correlation between the level of Hb, Hct, albumin, aluminium, PTH, BUN, Cr, dialysis adequacy and the cognitive function. Considering such results, it is clear that there is no significant difference in the cognitive functions of the sampled subjects. Therefore, the nurse in the dialysis room should continually carry out assessment and intervention against elements degrading the effect of patients' education to improve self- care.

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Morphogenetic Alterations of Alternaria alternata Exposed to Dicarboximide Fungicide, Iprodione

  • Kim, Eunji;Lee, Hye Min;Kim, Young Ho
    • The Plant Pathology Journal
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    • 제33권1호
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    • pp.95-100
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    • 2017
  • Fungicide-resistant Alternaria alternata impede the practical control of the Alternaria diseases in crop fields. This study aimed to investigate cytological fungicide resistance mechanisms of A. alternata against dicarboximide fungicide iprodione. A. alternata isolated from cactus brown spot was cultured on potato-dextrose agar (PDA) with or without iprodione, and the fungal cultures with different growth characteristics from no, initial and full growth were observed by light and electron microscopy. Mycelia began to grow from one day after incubation (DAI) and continued to be in full growth (control-growth, Con-G) on PDA without fungicide, while on PDA with iprodione, no fungal growth (iprodione-no growth, Ipr-N) occurred for the first 3 DAI, but once the initial growth (iprodione-initial growth, Ipr-I) began at 4-5 DAI, the colonies grew and expanded continuously to be in full growth (iprodione-growth, Ipr-G), suggesting Ipr-I may be a turning moment of the morphogenetic changes resisting fungicidal toxicity. Con-G formed multicellular conidia with cell walls and septa and intact dense cytoplasm. In Ipr-N, fungal sporulation was inhibited by forming mostly undeveloped unicellular conidia with degraded and necrotic cytoplasm. However, in Ipr-I, conspicuous cellular changes occurred during sporulation by forming multicellular conidia with double layered (thickened) cell walls and accumulation of proliferated lipid bodies in the conidial cytoplasm, which may inhibit the penetration of the fungicide into conidial cells, reducing fungicide-associated toxicity, and may be utilized as energy and nutritional sources, respectively, for the further fungal growth to form mature colonies as in Ipr-G that formed multicellular conidia with cell walls and intact cytoplasm with lipid bodies as in Con-G.

랜덤 선로상의 광 국재현상에 관한 해석(1) : 해의 국재성에 대한 이론적 고찰 (Theoretical analysis of the lightwave localization phenomenon on the random transmission line (part 1) : localization characteristics of the solution of propagation equation)

  • 최영규
    • 한국광학회지
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    • 제14권4호
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    • pp.429-433
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    • 2003
  • 전파정수가 랜덤하게 분포하는 선로 상에서 파동함수의 해의 성질을 고찰함으로써 랜덤한 매질 내의 파동의 국재현상에 대한 이론적 해석을 시도하였다 파동의 국재는 함수의 해가 증대에서 감쇠로 전환하는 과정에서 발생하므로, 먼저 파동의 증대가 감쇠로 전환되는 과정을 이론적으로 규명하기 위하여 2차 파동방정식을 Bragg조건 등을 이용하여 근사적으로 1차 슐뢰딩거의 방정식의 형태로 유도하였다. 그리고 이 방정식이 취할 수 있는 여러 가지 해의 성질과 그 해가 성립하기 위한 조건에 대하여 고찰하였으며, 파동방정식의 해의 국재성과 전파정수의 변동에 대한 관계에 대하여 몇 가지 조건을 조사하였다. 지수형의 해에서 유전율이 $\varepsilon$=(0,0,$\varepsilon$$_{0}$)인 경우 $\varepsilon$$_{0}$는 파동의 위상에 관여하여 국재현상을 일으키는 요소가 된다는 것을 확인하였다.

조선시대 남자용 화에 관한 연구 (A Study on Man's Boots of the Joseon Dynasty)

  • 곽경희;홍나영
    • 복식
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    • 제56권1호
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    • pp.44-55
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    • 2006
  • The purpose of this study is to examine the characteristics of man's boots in the Joseon Dynasty and compared them with those of the Ming and Qing Dynasty to find the influential relationships between them. Boots in the Joseon Dynasty are divided into several kinds such as Heukgwejapihwa, Hheuksapihwa(黑斜皮靴), Heukpihwa(黑皮靴), Mokhwa(木靴), Hyeopgeumhwa(挾金靴), Suhwaja (水靴子), Jeonpihwa, Gijahwa(起子靴), and Baekhwa(白靴). In addition, Jeong(精: footwear) was put inside boots. They tend to be named according to their materials or ornaments on them. First, Jeong put inside the boots is regarded as footwear for the comfort of the feet or protection against cold. Mokhwa appears in literature around the 19th century. As shown by remains and paintings of those days, it is considered to have become the common name of boots as it underwent many changes. On the other hand, a book in the era of King Gojong includes pictures of Suhwaja. Compared to Hukpihwa in the same book. The topside seems to have been raised in order to make the wearer who put on a military uniform feel comfortable when walking, since the bottom piece is hard. Baekhwa is worn not only with funeral garments but also with Sibok(時服), one of official uniforms. Boots in the Joseon Dynasty had been made following the design of the Ming Dynasty since official uniforms were conferred upon King Gongmin in the late Koryo Dynasty. But turning the late Joseon Dynasty its detailed design changed little by little. The topside of the boots became more round, the entrance part became wider, height of the shoes became taller, and the bottom piece became parallel to the ground.

궤도회로의 유지보수 효율화를 위한 동조 유니트 특성 분석 (Analysis of Tuning Unit Characteristic for Track Circuit Maintenance Efficiency)

  • 김용규;백종현;박재영
    • 한국산학기술학회논문지
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    • 제10권12호
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    • pp.3594-3599
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    • 2009
  • 경부고속선에서 사용하는 열차제어시스템은 ATC, IXL, CTC로 분류되며, 열차 속도 제어 및 간격 제어에 관련된 ATC 정보는 UM71 AF 궤도회로와 BSP Loop를 통해 지상에서 차상으로 전송된다. 궤도회로를 통해 전송되는 정보는 주로 열차 운행에 직접적인 영향을 주는 운영 정보로 구성된다. 특히 BSP Loop를 통해 전송되는 정보는 터널, 차축온도 검지장치, 또는 절연구간과 같이 특수한 선로변 환경에 대해 추가적인 정보 전송을 필요로 하는 구간에서 사용된다. 본 논문에서는 경부고속선 개통 이후부터 현재까지 기존선과 고속선 연결 구간에서 주로 사용되는 UM71 AF 궤도회로의 BA형 동조 유니트 특성을 기준값과 측정값을 비교하여 분석하였다. 이러한 분석을 통해 BA형 동조 유니트가 설치된 구간의 궤도회로 장애와 같은 문제 발생시 원인규명 및 유지보수를 보다 쉽게 이룰 수 있을 것이다.

퇴비재료의 교반빈도가 육계분과 유우분 혼합물 퇴비화 성능에 미치는 영향 (Influences of Mixing Frequency on the Composting Performance of the Broiler and Dairy Manure Mixtures)

  • 박금주;배영환;홍지형;위태욱
    • 한국축산시설환경학회지
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    • 제12권1호
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    • pp.41-44
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    • 2006
  • 2중필름 온실계사에서 육계를 사육하였을 때 발생하는 계분을 처리할 수 있는 수동 교반형 퇴비화시스템을 개발하였으며, 교반빈도가 퇴비화 온도에 미치는 효과를 분석하였다. 병원균 사멸에 필요한 $55^{\circ}C$ 이상의 온도를 유지한 기간은 무교반에서 88시간 1회/4일의 교반에서는 179 시간, 1회/2일의 교반에서는 200 시간으로 교반회수가 빈번할수록 그 기간이 길어지는 것으로 나타났다.

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