• Title/Summary/Keyword: Point Resistance

Search Result 1,390, Processing Time 0.042 seconds

A Study on the Connectivity Modeling Considering the Habitat and Movement Characteristics of Wild Boars (Sus scrofa) (멧돼지(Sus scrofa) 서식지 및 이동 특성을 고려한 연결성 모델링 연구)

  • Lee, Hyun-Jung;Kim, Whee-Moon;Kim, Kyeong-Tae;Jeong, Seung-Gyu;Kim, Yu-Jin;Lee, Kyung Jin;Kim, Ho Gul;Park, Chan;Song, Won-Kyong
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.25 no.4
    • /
    • pp.33-47
    • /
    • 2022
  • Wild boars(Sus scrofa) are expanding their range of behavior as their habitats change. Appearing in urban centers and private houses, it caused various social problems, including damage to crops. In order to prevent damage and effectively manage wild boars, there is a need for ecological research considering the characteristics and movement characteristics of wild boars. The purpose of this study is to analyze home range and identify land cover types in key areas through tracking wild boars, and to predict the movement connectivity of wild boars in consideration of previous studies and their preferred land use characteristics. In this study, from January to June 2021, four wild boars were captured and tracked in Jinju city, Gyeongsangnam-do, and the preferred land cover type of wild boars was identified based on the MCP 100%, KDE 95%, and KDE 50% results. As a result of the analysis of the home range for each individual, it was found that 100% of MCP was about 0.68km2, 2.77km2, 2.42km2, and 0.16km2, and the three individuals overlapped the home range, refraining from habitat movement and staying in the preferred area. The core areas were analyzed as about 0.55km2, 2.05km2, 0.82km2, and 0.14km2 with KDE 95%., and about 0.011km2, 0.033km2, 0.004km2, and 0.003km2 with KDE 50%. When the preferred land cover type of wild boar was confirmed based on the results of analysis of the total home range area and core area that combined all individuals, forests were 55.49% (MCP 100%), 54.00% (KDE 95%), 77.69% (KDE 50%), respectively, with the highest ratio, and the urbanization area, grassland, and agricultural area were relatively high. A connectivity scenario was constructed in which the ratio of the land cover type preferred by the analyzed wild boar was reflected as a weight for the resistance value of the connectivity analysis, and this was compared with the connectivity evaluation results analyzed based on previous studies and wild boar characteristics. When the current density values for the wild boar movement data were compared, the average value of the existing scenario was 2.76, the minimum 1.12, and the maximum 4.36, and the weighted scenario had an average value of 2.84, the minimum 0.96, and the maximum 4.65. It was confirmed that, on average, the probability of movement predictability was about 2.90% better even though the weighted scenario had movement restrictions due to large resistance values. It is expected that the identification of the movement route through the movement connectivity analysis of wild boars can be suggested as an alternative to prevent damage by predicting the point of appearance. In the future, when analyzing the connectivity of species including wild boar, it is judged that it will be effective to use movement data on actual species.

Correlation Between Primary Tuberculous Pleurisy and NRAMP1 Genetic Polymorphism (결핵성 흉막염 환자에서 NRAMP1 유전자 다형성에 대한 연구)

  • Kim, Je-Hyeong;Kim, Byung-Gyu;Jung, Ki-Hwan;Park, Sang-Myun;Lee, Sang-Youb;Lee, Sin-Hyung;Sin, Cheol;Cho, Jae-Youn;Shim, Jae-Jeong;In, Kwang-Ho;Yoo, Se-Hwa;Kang, Kyung-Ho
    • Tuberculosis and Respiratory Diseases
    • /
    • v.48 no.2
    • /
    • pp.155-165
    • /
    • 2000
  • Background: The phagolysosomal function of alveolar macrophage against M. tuberculosis infection is influenced by Nramp1, which is encoded by the NRAMP1 gene. There are several genetic polymorphisms in NRAMP1, and these polymorphisms affect the innate host resistance through the defect in production and function of Nramp1. To investigate this relationship, the NRAMP1 genetic polymorphism in patients with primary tuberculous pleurisy was determined. Methods: Fifty-six primary tuberculous pleurisy patient, who were diagnosed by pleural biopsy, were designated to the pleurisy group and 45 healthy adults were designated to the healthy control group. Three genetic polymorphisms of NRAMP1, such as a single point mutation in intron 4(469+14G/C, INT4), a nonconservative single-base substitution at codon 543 that changes aspartic acid to asparagine(D543N) and a TGTG deletion in the 3' untranslated region(1729+55delI4, 3'UTR), were determined. Polymerase chain reaction(PCR) and polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) were used. Results: The frequencies of mutant genotypes of INT4 and 3'UTR were significantly high in pleurisy group(p=0.001, p=0.023). But the frequencies of D543N were not significantly different between the two groups(p=0.079). The odds ratios, which are a comparison with wild genotype for determining mutant genotypes, were 8. 022(95% confidence interval=2.422-26.572) for INT4 and 5.733(95% confidence interval = 1.137~28.916) for 3'UTR ; these were statistically significant But the ratio for D543N was not significant In the combined analysis of the INT4 and 3'UTR polymorphisms, the odds ratios were 6.000(95% confidence interval = 1.461~24.640) for GC/++ genotype and 14.000(95% confidence interval=1.610~121.754) for GC/+del when compared with GG/++ homozygotes ; these were statistically significant. Conclusion: Among the NRAMP1 genetic polymorphisms, a single point mutation in intron 4(469+14G/C, INT4) and a TGTG deletion in the 3' untranslated region(1729+55del4, 3'UTR) were closely related to the primary tuberculous pleurisy.

  • PDF

The Origin and Formation of Korean Public Art Theories in the 1980s (1980년대 민중미술론의 기원과 형성)

  • Choi, Youl
    • The Journal of Art Theory & Practice
    • /
    • no.7
    • /
    • pp.37-64
    • /
    • 2009
  • The theories of Korean Public Art originated by the artists who were against dictatorship and they associated with democratic politicians. They criticized the Fine art that were supported by the dictatorship and gave their efforts for restoration of 'resistance paintings(against dictatorship)', 'proletarian painting', 'realism painting'. In addition, they participated new social ideology(democracy) movement and demonstrated for their rights in arts. These became the main kernel the public art theory was initiated. The public artists splitted into several different parts and participated in the democratic social movement as well as the art movement for freedom. They opened various art exhibitions within different genre, diverse space for various art section such as an exhibition hall, a factories, a university, or a congregation square. Furthermore, the public art theorists published their divergent views through newspaper/broadcasting or unauthorized printed materials. Most of the public artist and the theorists kept their relationship strongly until 1985, the time when 'National Arts Association' started. In 1983 and 1984, they were clearly separated into two parts; artists(move only in art museums) and activists(move in public spaces like school, convention square etc). Their ideological separation also took out national problems. The division; professional artists and armatures, became the social issue as a social stratification matter. And in creating method, there are also other conflicts; critical realism, and public realism as well as western painting and traditional one. These kinds of separation and conflicts made different Public artists associations, under divergent names; 'Reality and Speak'(R&S), 'KwangJu Art Association', 'Durung', 'Dang(Land)', and 'Local Youth Students Association'. In addition, their ideology and pursuit toward art movements were very difference. However, the differences and conflicts weakened When the oppression of democratic education from new dictatorship(Pres. Jun, Doo Hwan) came out. In August. 1985 the government opened to the public so called, 'The draft of School stabilization law'(Hankwon Anjung Bup) to control the teachers' rights and that initiated bigger street demonstration and conflicts between police and educators. In November.1985, assembly meeting of National Arts Association in democracy opened as 'ONE' combined organization. In this presentation, I'd like to summarize the stream of art movement until 1984, and clarify the main art theories that lead the Public Art Movements in 1980s. The main theories in 1980s are crucial because they become the origin of public art theories. This presentation started with O,youn's "Hyunsil Dong In the first declaration" and explained the absent of practice in 1970s. In addition, Won, Dong Suk 's theory was mentioned as all over struggles in theories before 1980s. GA and R&S 's founding declarations in 1970s were the start of public art theorists' activities and this article reported the activities after the declarations. First, realism base on the consciousness of reality. Second, practice art democratization based on the ideology. Third, the subject of public art movement based on understanding people's social stratification structure. Fourth, the matters of national forms and creative ways in arts based on showing reality. Fifth, the strong points in arts that the practitioners accepted. About the public art theories around 1984, I discussed the dividing point of public art theories that were shown in 'generation theory', 'organization theory', and 'popularization theory' by the practitioners. The public realism theory that subjects the contradiction of reality and point out the limits of critical realism not only showing the new creative ways but also giving the feeling of solidarity to the public art activist groups. After that, public art movements expressed 'Dismentlement of Capitalism' and 'Public revolution'. In addition, the direction of public art movements were established strongly. There were various opinions and views during the start and formation of the public art theories. The foundation of theorists activities derived from the practitioners who had the concept based on stratification and nationalism. The strong trend of group division spreaded out by practitioners who opened art work together in factories, universities, squares and rural areas. Now many lively active practitioners are gone to the other field not related with arts, and others join into professional art field not public art one with unknown reason. The theorists have the same situation with the practitioners. It means to me that theory always have to be based on the practice.

  • PDF

The Diaspora Narrative and Aesthetics in Handol's Tarae (한돌 타래의 디아스포라 서사와 미학)

  • Shin, Sa-Bin
    • Journal of Popular Narrative
    • /
    • v.26 no.3
    • /
    • pp.189-219
    • /
    • 2020
  • This study is an analysis of Handol Heung-Gun Lee's Tarae, which is a coinage combining the Korean words for "playing an instrument" and "song", in terms of narrative and aesthetics. The components for analysis are the phenomena and nature of binary oppositions between nature and human beings, between alienation and interest, between division and unification, and between diaspora and people of the national community. Tarae in the period from the late 1970s to the early 1990s described the experience of pain and loss from non-resistance and disobedience in protest against social problems that emerged during the era of miliary dictatorship, such as industrialization, urbanization, reckless development, Westernization, university-oriented education, the gap between rich and poor, human alienation, and the conflicts arising from the division of the nation. After Handol overcame the lack of creative motivation with self-reflection and effort, Tarae took the form of a diaspora epic meta-narratives integrating the "sound of nature and his true nature" and "the awareness of diaspora and the spirit of the Korean people". The epics of the homeland, the national soil and the people, which began with "Teo", became more intense in terms of a sense of diaspora as they shifted their focus from an origin to a path with "Hanmoejulghi" as the turning point. Handol seeks inspiration in the source of narrative rather than in music. His Tarae focuses on "adding rhythm for lyrics". For this reason, the semiotic features of Tarae have a limitation in that its extrinsic phonology is simple even if its intrinsic meaning (i.e., emotion of sadness) is profound and subtle. In order to elicit sympathy from the audience and impress them, it is necessary to strike a balance between the implicit (semantic) part and the explicit (phonological) part. To share the emotion of sadness with more people, it is necessary to strengthen phonological elements. Sympathy for sadness and deep impression on the audience are more often induced by the mood of similar sentiments than by the stories of the same experience. The aesthetics of sadness in Tarae began with the narratives of past experience which were expressed in the contexts of loss, loneliness, and poverty that Handol had experienced since childhood. However, the aesthetics of sadness, deepened over the period of a long hiatus in Handol's career as a composer, formed the narratives of ultimate salvation, embodying even the diaspora experience of others (e.g., displaced people, overseas adoptees, ethnic Koreans in Russia, victims of Japanese military sexual slavery, etc.). This gave Tarae the potential to go beyond the limits of the ethnic group of Korea. Tarae, as a "dispersed sound", can benefit from the appeal of deep sadness at the point of contact with other forms of world music. It may form a global diaspora discourse because Tarae is oriented towards interculturalism rather than anti-multiculturalism. The future challenge and goal of Handol's Tarae would be to continue to find areas of sympathy and broaden the horizon of awareness as diaspora music.

A Brief Review of Backgrounds behind "Multi-Purpose Performance Halls" in South Korea (우리나라 다목적 공연장의 탄생배경에 관한 소고)

  • Kim, Kyoung-A
    • (The) Research of the performance art and culture
    • /
    • no.41
    • /
    • pp.5-38
    • /
    • 2020
  • The current state of performance halls in South Korea is closely related to the performance art and culture of the nation as the culture of putting on and enjoying a performance is deeply rooted in public culture and arts halls representing each area at the local government level. Today, public culture and arts halls have multiple management purposes, and the subjects of their management are in the public domain including the central and local governments or investment and donation foundations in overwhelming cases. Public culture and arts halls thus have close correlations with the institutional aspect of cultural policies as the objects of culture and art policies at the central and local government level. The full-blown era of public culture and arts halls opened up in the 1980s~1990s, during which multi-purpose performance halls of a similar structure became universal around the nation. Public culture and arts halls of the uniform shape were distributed around the nation with no premise of genre characteristics or local environments for arts, and this was attributed to the cultural policies of the military regime. The Park Chung-hee regime proclaimed Yusin that was beyond the Constitution and enacted the Culture and Arts Promotion Act(September, 1972), which was the first culture and arts act in the nation. Based on the act, a five-year plan for the promotion of culture and arts(1973) was made and led to the construction of cultural facilities. "Public culture and arts" halls or "culture" halls were built to serve multiple purposes around the nation because the Culture and Arts Promotion Act, which is called the starting point of the nation's legal system for culture and arts, defined "culture and arts" as "matters regarding literature, art, music, entertainment, and publications." The definition became a ground for the current "multi-purpose" concept. The organization of Ministry of Culture and Public Information set up a culture and administration system to state its supervision of "culture and arts" and distinguish popular culture from the promotion of arts. During the period, former President Park exhibited his perception of "culture=arts=culture and arts" in his speeches. Arts belonged to the category of culture, but it was considered as "culture and arts." There was no department devoted to arts policies when the act was enacted with a broad scope of culture accepted. This ambiguity worked as a mechanism to mobilize arts in ideological utilizations as a policy. Against this backdrop, the Sejong Center for the Performing Arts, a multi-purpose performance hall, was established in 1978 based on the Culture and Arts Promotion Act under the supervision of Ministry of Culture and Public Information. There were, however, conflicts of value over the issue of accepting the popular music among the "culture and arts = multiple purposes" of the system, "culture ≠ arts" of the cultural organization that pushed forward its establishment, and "culture and arts = arts" perceived by the powerful class. The new military regime seized power after Coup d'état of December 12, 1979 and failed at its culture policy of bringing the resistance force within the system. It tried to differentiate itself from the Park regime by converting the perception into "expansion of opportunities for the people to enjoy culture" to gain people's supports both from the side of resistance and that of support. For the Chun Doo-hwan regime, differentiating itself from the previous regime was to secure legitimacy. Expansion of opportunities to enjoy culture was pushed forward at the level of national distribution. This approach thus failed to settle down as a long-term policy of arts development, and the military regime tried to secure its legitimacy through the symbolism of hardware. During the period, the institutional ground for public culture and arts halls was based on the definition of "culture and arts" in the Culture and Arts Promotion Act enacted under the Yusin system of the Park regime. The "multi-purpose" concept, which was the management goal of public performance halls, was born based on this. In this context of the times, proscenium performance halls of a similar structure and public culture and arts halls with a similar management goal were established around the nation, leading to today's performance art and culture in the nation.

Effect of combined exercise on metabolic bio-marker in overweight and obese children (복합운동이 과체중 및 비만 남자 초등학생의 대사적지표에 미치는 영향)

  • Kim, Hyun-Jun;Kim, Tae-Un;Lee, Sangyeoup;Shin, Goon-Soo;Kim, Young-Joo;Kim, Su-Yung
    • Clinical and Experimental Pediatrics
    • /
    • v.49 no.9
    • /
    • pp.946-951
    • /
    • 2006
  • Purpose : The purpose of this study was to demonstrate the effectiveness of combined exercise for 12 weeks on the adiponectin and obesity related variables in overweight and obese children. Methods : Eighteen children in 5th grade in a certain elementary school in Busan were recruited. They were all overweight or obese children(more than 85 percentile in body mass index). Nine children in the experimental group were given exercises consisting of walking and band resistant training for 12 weeks. Auxological data(including height, weight and body fat mass) and laboratory data (fasting blood sugar, insulin, adiponectin) were checked at baseline and at the 1 week, and at the 4 weeks and 12 weeks stages of their exercise program. Insulin resistance and sensitivity were evaluated indirectly using HOMA index and QUICKI index. Results : Adiponectin gradually decreased until the 4 weeks point and gradually increased thereafter to the starting level at the 12 weeks stage. Body weight, body mass index(BMI) and HOMA index significantly decreased more at the 1 week, 4 weeks, and 12 weeks stages in the experimental group than in the control group. Body fat mass significantly decreased at 12 weeks. The change of insulin was significantly correlated with changes of body weight and BMI. But there was no correlation between changes of adiponectin and changes of insulin. Conclusion : Exercise seems to effect the adiponectin concentration. And it might be assumed that exercise increases the adiponectin concentration if it is continued for long time(may be more than 12 weeks). More studies may be necessary to draw that conclusion.

Topoclimatological interpretation of the daily air temperature minima at 17 locations crossing over Yangpyeong basin in 1986 spring (봄철 양평지역(楊平地域)의 지형(地形) 및 고도(高度)에 따른 일최저기온(日最低氣溫)의 분포(分布))

  • Kang, An-Seok;Yun, Jin-Il;Jung, Yeong-Sang;Tani, No Bureru
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.19 no.4
    • /
    • pp.339-344
    • /
    • 1986
  • Frost damage which can reduce yields, impair fruit quality and cause loss of trees is closely related to the occurrence of daily minimum temperature. Horizontal distribution of air temperature minima can be characterized by conditions of radiational cooling and gravitational movement of cold air, which are influenced by the regional topographic features. Observations were made on the air temperature minima over Yangpyeong area, to delineate potential effects of topography on the temperature pattern during spring season. Two routes were selected for the observation. Liquid glass minimum thermometers were installed at 17 sites through the old peach orchards which had been closed due to the frequent freeze-frost hazards during the recent years. This route was 8.5km long and the highest point was 350m above mean sea level. The other route, which was 2.5km in distance, was run with a digital resistance thermometer during the hour just before sunrise. Observations were made both on a calm-clear day (April 30, 1986) and a windy-overcast day (May 1, 1986). The temperature on April 30 was in increasing trend with elevation but this was modified at near the riverside and the downtown area. An orchard lying on a hilltop showed the temperature $1^{\circ}C$ higher than near by lowland of which elevation was about 30m lower. The minimum temperature on the overcast day was little affected by terrestrial conditions but by the atmospheric lapse condition. The peach orchards severely damaged by cold air were found in the area where the lowest minimum temperature was observed. The results may be useful for selection of the proper orchard location to be developed in an area.

  • PDF

The Influence of Landscape Pavements on the WBGT of Outdoor Spaces without Ventilation or Shade at Summer Midday (조경포장이 옥외공간의 온열쾌적성지수(WBGT)에 미치는 영향 - 통풍과 차광이 배제된 하절기 주간의 조건에서 -)

  • Lee, Chun-Seok;Ryu, Nam-Hyung
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.38 no.2
    • /
    • pp.1-8
    • /
    • 2010
  • The purpose of the study was to evaluate the influence of landscaping pavements on WBGT(Wet-Bulb Globe Temperature) of outdoor spaces that lack ventilation and shade at summer midday. The relative humidity(RH), dry-bulb temperature(DT) and globe temperature(GT) were recorded every minute from June to October 2009 at a height of 1.2m above ten experimental beds with different pavements, by a measuring system consisting of an electric humidity sensor(GHM-15), resistance temperature detector(RTD, Pt-100), standard black globe(${\phi} 150mm$) and data acquisition systems(National Instrument's Labview and Compact FieldPoint). Additionally, the surface dry-bulb temperatures also were recorded and compared. The area of each experimental bed was 1.5m(W)${\times}$2.0m(L) and ten different kinds of pavement were used including grass, grass+cubic stone, grass+porous brick, brick, stone panels, cubic stone, interlocking blocks, clay brick, naked soil, gravel and concrete. To prevent interference from ventilation, a 1.5m height cubic steel frame was established around each bed and each vertical side of the frame was covered with transparent polyethylene film. Based on the records of the hottest period from noon to 3 PM on 26 days with a peak dry-bulb temperature over $30^{\circ}C$ at natural condition, the wet-bulb temperature(WT) and WBGT were calculated and compared. The major findings were as follows: 1. The average surface DT was $40.1^{\circ}C$, which is $9^{\circ}C$ higher than that of the natural condition. The surface DT of the pavements with grass were higher than those of concrete and interlocking block. The peak DT of the surface almost every pavement rose to above $50^{\circ}C$ during the hottest time. 2. The averages of DT, WT and GT were $40.1^{\circ}C$, $27.5^{\circ}C$ and $49.1^{\circ}C$, and the peak values rose to $48.1^{\circ}C$, $45.8^{\circ}C$ and $59.5^{\circ}C$, respectively. In spite of slight differences that resulted according to pavements, no coherent differentiating factor could be found. 3. The average WBGT of grass was the highest at $34.3^{\circ}C$ while the others were similar in the range of around $33{\pm}1^{\circ}C$. Meanwhile, the peak WBGT was highest with stone panel at $47.9^{\circ}C$. Though there were some differences according to pavements, and while grass seemed to be worst in terms of WBGT, it seems difficult to say ablolutely that grass was the worst because the measurement was conducted without ventilation and shade during summer daytime hours only, which had temperatures that rose to a dangerous degree(above $45^{\circ}C$ WBGT), withering the grass during the hottest period. The average WBGT resulted also showed that the thermal environment of the pavement without ventilation and shade were at an intolerable level for humans regardless of the pavement type. In summary, the results of this study show that ventilation and shade are more important factor than pavement type in terms of outdoor thermal comfort in summer daylight hours.

Discussion on the Strategic Priorities and Navy's Coping in the Interwar Period Britain, 1919?1939 (「전간기 영국의 전략 우선순위 논의와 영국해군의 대응, 1919-1939」)

  • Jeon, Yoon-Jae
    • Strategy21
    • /
    • s.32
    • /
    • pp.123-159
    • /
    • 2013
  • The purpose of this research paper is to re-valuate the factors that affected the Royal Navy's rearmament and preparation for war by conducting analysis on the discussion held in the Britain on the strategic priorities and Navy's coping measures adopted during the interwar period. After the end of the WWI, each of the military arms of the Britain faced significant difficulty in securing budget and increasing their military power all throughout the interwar period, and the Navy was not an exception. The WWII that got started on September 1939 was the turning point in which this difficulty led to full-fledged crisis. Immensely many criticisms followed after the war and problems were identified when it comes to the Royal Navy's performance during the war. This type of effort to identify problem led to the attempt to analyze whether Royal Navy's preparation for war and rearmament policy during interwar period were adequate, and to identify the root causes of failure. Existing studies sought to find the root cause of failed rearmament from external factors such as the deterioration of the Britain itself or pressure from the Treasury Department to cut the budget for national defense, or sought to detect problems from the development of wrong strategies by the Navy. However, Royal Navy's failed preparation for the war during interwar period is not the result of one or two separate factors. Instead, it resulted due to the diverse factors and situations that the Britain was facing at the time, and due to intricate and complex interaction of these factors. Meanwhile, this research paper focused on the context characterized by 'strategic selection and setting up of priorities' among the various factors to conduct analysis on the Navy's rearmament by linking it with the discussion held at the time on setting up strategic priorities, and sought to demonstrate that the Navy Department's inadequate counter-measures developed during this process waned Royal Navy's position. After the end of WWI, each of the military arms continued to compete for the limited resources and budget all throughout the interwar period, and this type of competition amidst the situation in which the economic situation of Britain was still unstable, made prioritization when it comes to the allocation of resources and setting up of the priorities when it comes to the military power build-up, inevitable. Amidst this situation, the RAF was able to secure resources first and foremost, encouraged by the conviction of some politicians who were affected by the 'theory of aerial threat' and who believed that curtailing potential attack with the Air Force would be means to secure national security at comparatively lower cost. In response, Navy successfully defended the need for the existence of Navy despite the advancement of the aerial power, by emphasizing that the Britain's livelihood depends on trade and on the maintenance of maritime traffic. Despite this counter-measuring logic, however, Navy's role was still limited to the defense of overseas territory and to the fleet run-off instead of sea traffic route production when it comes to the specific power build-up plan, and did not understand the situation in which financial and economic factors gained greater importance when it comes to the setting up of strategic priorities. As a result, Navy's plan to build its powers was met with continual resistance of the Treasury Department, and lost the opportunity to re-gain the status of 'senior service' that it had enjoyed in the past during the competition for strategic prioritization. Given that the strategic and economic situation that Korea faces today is not very different from that of the Britain during the interwar period, our Navy too should leverage the lessons learned from the Royal Navy to make the effort to secure viable position when it comes to the setting of priorities in case of national defense strategy by presenting the basis on why maritime coping should be prioritized among the numerous other threats, and by developing the measures for securing the powers needed effectively amidst the limited resources.

  • PDF

Feasibility Test on Automatic Control of Soil Water Potential Using a Portable Irrigation Controller with an Electrical Resistance-based Watermark Sensor (전기저항식 워터마크센서기반 소형 관수장치의 토양 수분퍼텐셜 자동제어 효용성 평가)

  • Kim, Hak-Jin;Roh, Mi-Young;Lee, Dong-Hoon;Jeon, Sang-Ho;Hur, Seung-Oh;Choi, Jin-Yong;Chung, Sun-Ok;Rhee, Joong-Yong
    • Journal of Bio-Environment Control
    • /
    • v.20 no.2
    • /
    • pp.93-100
    • /
    • 2011
  • Maintenance of adequate soil water potential during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil water movement within and below the rooting zone can facilitate optimal irrigation scheduling aimed at minimizing the adverse effects of water stress on crop growth and development and the leaching of water below the root zone which can have adverse environmental effects. The objective of this study was to evaluate the feasibility of using a portable irrigation controller with an Watermark sensor for the cultivation of drip-irrigated vegetable crops in a greenhouse. The control capability of the irrigation controller for a soil water potential of -20 kPa was evaluated under summer conditions by cultivating 45-day-old tomato plants grown in three differently textured soils (sandy loam, loam, and loamy sands). Water contents through each soil profile were continuously monitored using three Sentek probes, each consisting of three capacitance sensors at 10, 20, and 30 cm depths. Even though a repeatable cycling of soil water potential occurred for the potential treatment, the lower limit of the Watermark (about 0 kPa) obtained in this study presented a limitation of using the Watermark sensor for optimal irrigation of tomato plants where -20 kPa was used as a point for triggering irrigations. This problem might be related to the slow response time and inadequate soil-sensor interface of the Watermark sensor as compared to a porous and ceramic cup-based tensiometer with a sensitive pressure transducer. In addition, the irrigation time of 50 to 60 min at each of the irrigation operation gave a rapid drop of the potential to zero, resulting in over irrigation of tomatoes. There were differences in water content among the three different soil types under the variable rate irrigation, showing a range of water contents of 16 to 24%, 17 to 28%, and 24 to 32% for loamy sand, sandy loam, and loam soils, respectively. The greatest rate increase in water content was observed in the top of 10 cm depth of sandy loam soil within almost 60 min from the start of irrigation.