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Development of Respiration Gating RT Technique using Moving Phantom and Ultrasound Sensor: a feasibility study (동 팬텀과 초음파 센서를 이용한 호흡운동 조절 방사선치료 기술 개발)

  • Lee, Suk;Lee, Sang-Hoon;Shin, Dong-Ho;Yang, Dae-Sik;Choi, Myung-Sun;Kim, Chul-Yong
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2004.11a
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    • pp.122-125
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    • 2004
  • In radiotherapy of tumors in liver, enough planning target volume (PTV) margins are necessary to compensate breathing-related movement of tumor volumes. To overcome the problems, this study aims to obtain patients' body movements by using a moving phantom and an ultrasonic sensor, and to develop respiration gating techniques that can adjust patients' beds by using reversed values of the data obtained. The phantom made to measure patients' body movements is composed of a microprocessor (BS II, 20 MHz, 8K Byte), a sensor (Ultra-Sonic, range 3 cm ${\sim}$3 m), host computer (RS232C) and stepping motor (torque 2.3Kg) etc., and the program to control and operate it was developed. The program allows the phantom to move within the maximum range of 2 cm, its movements and corrections to take place in order, and x, y and z to move successively. After the moving phantom was adjusted by entering random movement data(three dimensional data form with distance of 2cm), and the phantom movements were acquired using the ultra sonic sensor, the two data were compared and analyzed. And then, after the movements by respiration were acquired by using guinea pigs, the real-time respiration gating techniques were drawn by operating the phantom with the reversed values of the data. The result of analyzing the acquisition-correction delay time for the three types of data values and about each value separately shows that the data values coincided with one another within 1% and that the acquisition-correction delay time was obtained real-time (2.34 ${\times}$ 10$^{-4}$sec). This study successfully confirms the clinic application possibility of respiration gating techniques by using a moving phantom and an ultra sonic sensor. With ongoing development of additional analysis system, which can be used in real-time set-up reproducibility analysis, it may be beneficially used in radiotherapy of moving tumors.

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Analysis of Microsatellite DNA Polymorphism for Parentage Testing in Dog Breeds (개의 친자감정을 위한 Microsatellite DNA 다형성 분석)

  • Cho, G. J.;Cho, B. W.;Kim, S. K.;Lee, K. W.;Kim, Y. K.
    • Journal of Animal Science and Technology
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    • v.45 no.2
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    • pp.191-198
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    • 2003
  • This study was carried out to investigate a usefulness of the microsatellite DNA markers for individual identification and parentage verification in three dog breeds. A total of 59 random dog (31 Chiwawa, 20 Poongsan, 8 Labrador Retriever) samples were genotyped by using 14 markers (Chiwawa dog), 16 markers (Poongsan dog), and 12 markers (Labrador Retriever dog) among the 17 international standard markers (PEZ1, 3, 5, 6, 8, 10, 11, 12, 13, 15, 16, 17, 20, 21, FHC2010, FHC2054 and FHC2079), respectively. The number of alleles per locus varied from 4 to 14 with a mean value of 6.07 in Chiwawa dog, 2 to 9 with a mean of 4.75 in Poongsan dog, and 3 to 5 with a mean of 4.00 in Labrador Retriever dog. Observed heterozygosity was ranged 0.419${\sim}$0.968 (mean 0.755), 0.300${\sim}$0.950 (mean 0.597) and 0.125${\sim}$0.750 (mean 0.604), and expected heterozygosity was ranged 0.432${\sim}$0.883 (mean 0.711), 0.262${\sim}$0.817 (mean 0.559) and 0.425${\sim}$0.808 (mean 0.660) in these three dog breeds. PIC value was ranged 0.397${\sim}$0.856 (mean 0.659), 0.222${\sim}$0.772 (mean 0.503) and 0.354${\sim}$0.717 (mean 0.563) in these three dog breeds. Of the 17 markers, PEZ1, PEZ3, PEZ6, PEZ10, PEZ12 loci, PEZ1, PEZ6, PEZ13 loci, and PEZ8, PEZ12 loci have relatively high PIC value (>0.7) in Chiwawa dog, Poongsan dog and Labrador Retriever dog, respectively. The exclusion probability was ranged 0.240${\sim}$0.741, 0.111${\sim}$0.616, and 0.198${\sim}$0.529, and the combination of microsatellite loci was 0.9999, 0.9991, and 0.9968 in Chiwawa dog, Poongsan dog and Labrador Retriever dog, respectively. These results can give basic information for developing parentage verification and individual identification system in these three dog breeds.

Development of Respiration Gating RT Technique using Moving Phantom and Ultrasound Sensor: a feasibility study (동 팬텀과 초음파 센서를 이용한 호흡운동 조절 방사선치료 기술 개발)

  • Lee Suk;Lee Sang Hoon;Shin Dongho;Yang Dae Sik;Choi Myung Sun;Kim Chul Yong
    • Radiation Oncology Journal
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    • v.22 no.4
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    • pp.316-324
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    • 2004
  • Purpose : In radiotherapy of tumors in liver, enough planning target volume (PTV) margins are necessary to compensate breathing-related movement of tumor volumes. To overcome the problems, this study aims to obtain patients' body movements by using a moving phantom and an ultrasonic sensor, and to develop respiration sating techniques that can adjust patients' beds by using reversed values of the data obtained. Materials and Methods : The phantom made to measure patients' body movements is composed of a microprocessor (BS II, 20 MHz, 8K Byte), a sensor (Ultra-Sonic, range $3\~3$ m), host computer (RS232C) and stepping motor (torque 2.3 Kg) etc., and the program to control and operate it was developed. The program allows the phantom to move within the maximum range of 2 cm, its movements and corrections to take place In order, and x, y and z to move successively. After the moving phantom was adjusted by entering random movement data (three dimensional data form with distance of 2 cm), and the phantom movements were acquired using the ultra sonic sensor, the two data were compared and analyzed. And then, after the movements by respiration were acquired by using guinea pigs, the real-time respiration gating techniques were drawn by operating the phantom with the reversed values of the data. Results : The result of analyzing the acquisition-correction delay time the three types of data values and about each value separately shows that the data values coincided with one another within $1\%$ and that the acquisition-correction delay time was obtained real-time $(2.34{\times}10^{-4}sec)$. Conclusion : This study successfully confirms the clinic application possibility of respiration gating techniques by using a moving phantom and an ultrasonic sensor. With ongoing development of additional analysis system, which can be used in real-time set-up reproducibility analysis, it may be beneficially used in radiotherapy of moving tumors.

Brief Introduction of Research Progresses in Control and Biocontrol of Clubroot Disease in China

  • He, Yueqiu;Wu, Yixin;He, Pengfei;Li, Xinyu
    • 한국균학회소식:학술대회논문집
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    • 2015.05a
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    • pp.45-46
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    • 2015
  • Clubroot disease of crucifers has occurred since 1957. It has spread to the whole China, especially in the southwest and nourtheast where it causes 30-80% loss in some fields. The disease has being expanded in the recent years as seeds are imported and the floating seedling system practices. For its effective control, the Ministry of Agriculture of China set up a program in 2010 and a research team led by Dr. Yueqiu HE, Yunnan Agricultural University. The team includes 20 main reseachers of 11 universities and 5 institutions. After 5 years, the team has made a lot of progresses in disease occurrence regulation, resources collection, resistance identification and breeding, biological agent exploration, formulation, chemicals evaluation, and control strategy. About 1200 collections of local and commercial crucifers were identified in the field and by artificiall inoculation in the laboratories, 10 resistant cultivars were breeded including 7 Chinese cabbages and 3 cabbages. More than 800 antagostic strains were isolated including bacteria, stretomyces and fungi. Around 100 chemicals were evaluated in the field and greenhouse based on its control effect, among them, 6 showed high control effect, especially fluazinam and cyazofamid could control about 80% the disease. However, fluzinam has negative effect on soil microbes. Clubroot disease could not be controlled by bioagents and chemicals once when the pathogen Plasmodiophora brassicae infected its hosts and set up the parasitic relationship. We found the earlier the pathogent infected its host, the severer the disease was. Therefore, early control was the most effective. For Chinese cabbage, all controlling measures should be taken in the early 30 days because the new infection could not cause severe symptom after 30 days of seeding. For example, a biocontrol agent, Bacillus subtilis Strain XF-1 could control the disease 70%-85% averagely when it mixed with seedling substrate and was drenching 3 times after transplanting, i.e. immediately, 7 days, 14 days. XF-1 has been deeply researched in control mechanisms, its genome, and development and application of biocontrol formulate. It could produce antagonistic protein, enzyme, antibiotics and IAA, which promoted rhizogenesis and growth. Its The genome was sequenced by Illumina/Solexa Genome Analyzer to assembled into 20 scaffolds then the gaps between scaffolds were filled by long fragment PCR amplification to obtain complet genmone with 4,061,186 bp in size. The whole genome was found to have 43.8% GC, 108 tandem repeats with an average of 2.65 copies and 84 transposons. The CDSs were predicted as 3,853 in which 112 CDSs were predicted to secondary metabolite biosynthesis, transport and catabolism. Among those, five NRPS/PKS giant gene clusters being responsible for the biosynthesis of polyketide (pksABCDEFHJLMNRS in size 72.9 kb), surfactin(srfABCD, 26.148 kb, bacilysin(bacABCDE 5.903 kb), bacillibactin(dhbABCEF, 11.774 kb) and fengycin(ppsABCDE, 37.799 kb) have high homolgous to fuction confirmed biosynthesis gene in other strain. Moreover, there are many of key regulatory genes for secondary metabolites from XF-1, such as comABPQKX Z, degQ, sfp, yczE, degU, ycxABCD and ywfG. were also predicted. Therefore, XF-1 has potential of biosynthesis for secondary metabolites surfactin, fengycin, bacillibactin, bacilysin and Bacillaene. Thirty two compounds were detected from cell extracts of XF-1 by MALDI-TOF-MS, including one Macrolactin (m/z 441.06), two fusaricidin (m/z 850.493 and 968.515), one circulocin (m/z 852.509), nine surfactin (m/z 1044.656~1102.652), five iturin (m/z 1096.631~1150.57) and forty fengycin (m/z 1449.79~1543.805). The top three compositions types (contening 56.67% of total extract) are surfactin, iturin and fengycin, in which the most abundant is the surfactin type composition 30.37% of total extract and in second place is the fengycin with 23.28% content with rich diversity of chemical structure, and the smallest one is the iturin with 3.02% content. Moreover, the same main compositions were detected in Bacillus sp.355 which is also a good effects biocontol bacterial for controlling the clubroot of crucifer. Wherefore those compounds surfactin, iturin and fengycin maybe the main active compositions of XF-1 against P. brassicae. Twenty one fengycin type compounds were evaluate by LC-ESI-MS/MS with antifungal activities, including fengycin A $C_{16{\sim}C19}$, fengycin B $C_{14{\sim}C17}$, fengycin C $C_{15{\sim}C18}$, fengycin D $C_{15{\sim}C18}$ and fengycin S $C_{15{\sim}C18}$. Furthermore, one novel compound was identified as Dehydroxyfengycin $C_{17}$ according its MS, 1D and 2D NMR spectral data, which molecular weight is 1488.8480 Da and formula $C_{75}H_{116}N_{12}O_{19}$. The fengycin type compounds (FTCPs $250{\mu}g/mL$) were used to treat the resting spores of P. brassicae ($10^7/mL$) by detecting leakage of the cytoplasm components and cell destruction. After 12 h treatment, the absorbencies at 260 nm (A260) and at 280 nm (A280) increased gradually to approaching the maximum of absorbance, accompanying the collapse of P. brassicae resting spores, and nearly no complete cells were observed at 24 h treatment. The results suggested that the cells could be lyzed by the FTCPs of XF-1, and the diversity of FTCPs was mainly attributed to a mechanism of clubroot disease biocontrol. In the five selected medium MOLP, PSA, LB, Landy and LD, the most suitable for growth of strain medium is MOLP, and the least for strains longevity is the Landy sucrose medium. However, the lipopeptide highest yield is in Landy sucrose medium. The lipopeptides in five medium were analyzed with HPLC, and the results showed that lipopeptides component were same, while their contents from B. subtilis XF-1 fermented in five medium were different. We found that it is the lipopeptides content but ingredients of XF-1 could be impacted by medium and lacking of nutrition seems promoting lipopeptides secretion from XF-1. The volatile components with inhibition fungal Cylindrocarpon spp. activity which were collect in sealed vesel were detected with metheds of HS-SPME-GC-MS in eight biocontrol Bacillus species and four positive mutant strains of XF-1 mutagenized with chemical mutagens, respectively. They have same main volatile components including pyrazine, aldehydes, oxazolidinone and sulfide which are composed of 91.62% in XF-1, in which, the most abundant is the pyrazine type composition with 47.03%, and in second place is the aldehydes with 23.84%, and the third place is oxazolidinone with 15.68%, and the smallest ones is the sulfide with 5.07%.

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Health Assessment of the Nakdong River Basin Aquatic Ecosystems Utilizing GIS and Spatial Statistics (GIS 및 공간통계를 활용한 낙동강 유역 수생태계의 건강성 평가)

  • JO, Myung-Hee;SIM, Jun-Seok;LEE, Jae-An;JANG, Sung-Hyun
    • Journal of the Korean Association of Geographic Information Studies
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    • v.18 no.2
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    • pp.174-189
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    • 2015
  • The objective of this study was to reconstruct spatial information using the results of the investigation and evaluation of the health of the living organisms, habitat, and water quality at the investigation points for the aquatic ecosystem health of the Nakdong River basin, to support the rational decision making of the aquatic ecosystem preservation and restoration policies of the Nakdong River basin using spatial analysis techniques, and to present efficient management methods. To analyze the aquatic ecosystem health of the Nakdong River basin, punctiform data were constructed based on the position information of each point with the aquatic ecosystem health investigation and evaluation results of 250 investigation sections. To apply the spatial analysis technique, the data need to be reconstructed into areal data. For this purpose, spatial influence and trends were analyzed using the Kriging interpolation(ArcGIS 10.1, Geostatistical Analysis), and were reconstructed into areal data. To analyze the spatial distribution characteristics of the Nakdong River basin health based on these analytical results, hotspot(Getis-Ord Gi, $G^*_i$), LISA(Local Indicator of Spatial Association), and standard deviational ellipse analyses were used. The hotspot analysis results showed that the hotspot basins of the biotic indices(TDI, BMI, FAI) were the Andong Dam upstream, Wangpicheon, and the Imha Dam basin, and that the health grades of their biotic indices were good. The coldspot basins were Nakdong River Namhae, the Nakdong River mouth, and the Suyeong River basin. The LISA analysis results showed that the exceptional areas were Gahwacheon, the Hapcheon Dam, and the Yeong River upstream basin. These areas had high bio-health indices, but their surrounding basins were low and required management for aquatic ecosystem health. The hotspot basins of the physicochemical factor(BOD) were the Nakdong River downstream basin, Suyeong River, Hoeya River, and the Nakdong River Namhae basin, whereas the coldspot basins were the upstream basins of the Nakdong River tributaries, including Andong Dam, Imha Dam, and Yeong River. The hotspots of the habitat and riverside environment factor(HRI) were different from the hotspots and coldspots of each factor in the LISA analysis results. In general, the habitat and riverside environment of the Nakdong River mainstream and tributaries, including the Nakdong river upstream, Andong Dam, Imha Dam, and the Hapcheon Dam basin, had good health. The coldspot basins of the habitat and riverside environment also showed low health indices of the biotic indices and physicochemical factors, thus requiring management of the habitat and riverside environment. As a result of the time-series analysis with a standard deviation ellipsoid, the areas with good aquatic ecosystem health of the organisms, habitat, and riverside environment showed a tendency to move northward, and the BOD results showed different directions and concentrations by the year of investigation. These aquatic ecosystem health analysis results can provide not only the health management information for each investigation spot but also information for managing the aquatic ecosystem in the catchment unit for the working research staff as well as for the water environment researchers in the future, based on spatial information.

Effects of Ovarian Function on the Hypophyseal Gonadotropin Secretion in Rats (흰쥐의 난소기능(卵巢機能)이 하수체(下垂體)의 성선(性腺) 날극(剌戟)호르몬 분비(分泌)에 미치는 영향(影響))

  • Seo, Kil Woong;Kim, Chong Sup;Park, Chang Sik;Lee, Kyu Seung
    • Korean Journal of Agricultural Science
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    • v.16 no.2
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    • pp.169-178
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    • 1989
  • The study was carried out to elucidate the feedback mechanism on the hypothalamo-hypophyseal system from the functional changes of ovary in female rats. One hundred and forty-four mature female rats were lloted into the three groups; ovariectoimzed group, estradiol treated group and intact control group. The varies of 48 heads of rat were completely removed. Forty eight heads of rat were administered with $200{\mu}g$ of estradiol benzoate every 48 hours. Serum FSH, LH and prolactin levels were determined with radioimmunoassay method at 3,6,12,24 ours, and 5,10, and 15days after treatment. The rats were necropsied to measure the weights of hypophysis and to examin the histological changes in the organs. The results obtained were as follows: The weights of hypophysis were increased after ovariectomy and decreased after estradiol injection. The differences in hypophysis weights were significant between the group from 5 days after treatment. The histological changes in hypophysis were appeared from 5th day after ovariectomy. Proliferation and hypertrophy began to occur in basophilic from 10th day after ovariectomy, chromophobes were slightly hypertrophied and acidophilic cells were atrophied. In estradiol injected rats the histological findings were appeard to be contrary to those of ovariectomized rats. Serum FSH levels significantly changed after ovariectomy and estradiol injection and were higher in both the treated groups than in the intact control group. Within 18 hours after treatment the level was the highest in ovariectomized group, and thereafter the highest level was found in estradiol treated gorup. In ovariectomized rats the levels were rapidly increased 3 hours after treatment and maximum levels were found 18 hours after treatment. In estradiol treated rats the levels started to increase 18 hours after treatment and reached maximum levels 24 hours treatment. 4. Serum LH levels started to increase 3 hours after ovariectomy and estradiol injection and reached maximum levels 12 hours after ovariectomy and 24 hours after estradiol injection. There were significant differences in LH levels between the groups in each observation time. Up to 18 hours after treatment levels were higher in ovariectomized rats than in estradiol treated rats. but thereafter the levels were higher in estradiol treated rats than in ovariectomized rats. The multiple range test showed that a significant difference in LH levels was not found between ovariectomized group and estradiol treated group 18 hours and 5 days after treatment. 5. Serum prolactin levels were significantly changed after ovariectomy and estradiol injection. The levels were lower in ovariectomized rats than in intact control rats.

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Economic Analysis of Rice Production by Seed Broadcasting -In the Case of Daeho Large Scale Tidal and Development Area- (수도 직파재배의 경제성분석 -대단위 대호간척농지를 중심으로-)

  • Lim, Jae Hwan;Ryu, Yong Hee
    • Korean Journal of Agricultural Science
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    • v.23 no.2
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    • pp.301-322
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    • 1996
  • This study is first aimed at identifying the possibility of labour saving and production cost decreasing in rice production with respect to seed broad casting technology. Comparison of labour inputs and production costs of rice in-between USA and Korea and recommendation of policy guidelines for the continous rice cultivation are the second objective of this study. Under the WTO system, rice enterprice is the most vulnerable crop in the sense of labour productivity and price competitiveness in the international market. How to adapt labour saving technology and how to decrease production costs are the most imminent problems to be solved in rice production. To achieve the objectives, survey on nine rice enterprice farms were made in Daeho tidal farmland with respect to the size of farm, labour inputs, productivity, farm mechanization and farm land base development. The existing data on labour saving technology by seed broadcasting which had surveyed by Rural Development Administration were collected to compare the surveyed data from Daeho tidal farm land The study results and policy recommendation are summarized as follows; 1. Labour requirements per 10a for rice enterprise farms with seed broadcasting and with transplanting were estimated 11.4 and 18.5hours respectively. 'This above labour inputs were equivalent to 1/3-1/5 of the national average labour inputs of 53.6 hours which were included transplanting and harvesting by machinery. Considering the labour requirement of 1.7 hours per 10a for the USA rice production, Korea rice culture has possibility to decrease labour demand upto USA level of labour inputs. 2. Production cost of rice in Korea were estimated US$4,181 per ha which were higher than that of USA by 3.00 times and production costs per ton were shown as US$313 for USA rice and US$1,018 for Korean rice. 3. Land productivity of rice per 10a in America was reached to 4,325kg and the counterpart of Korea was about 4,181kg in recent year. In the sense of land productivity, both yields of rice were comparable. 4. The price of japonica type rice similar to Korean traditional rice in international market in 1994 was f.o.b US$466 per ton which was equivalent to import parity price of US$830 per ton in domestic market. The price of rice purchased by Korean G't and received by farmers were amounted to US$ 2,013 and US$ 1,663 respectively in the same year. Domestic prices mentioned above were higher than the import parity price as US$830 by 2.0-2.4 times. 5. American rice production competitive to Korean rice was equivalent to 17,012 thousand tons, 1.28% of the world production of rice in 1991 and consumption of rice in America was amounted to 2,633 thousand tons. Exportable quantity of USA rice were estimated as 4,379 thousand tons of which 52.3%, 2,300 thousand tons, were exported indeed in the same year. 6. The quantity of Korean rice produced in 1991 was estimated 1.00% of the world production. The world amount of rice exported in 1991 was reached to 2.45% of the world production of which 34.2% was occupied by USA The remaining quantities of world exported rice were dominated by Tiland, Pakistan and Vietnam where produced indica variety. 7. Under the given technology, labour inputs per 10a for rice production could be possible to save by 70% of the national average labour requirement of 53.6 hours through implmenting complete farm mechanization with land consolidation and on-farm development and improvement of fanning practices like seedbroad casting txchnology etc. On the other hand, prduction costs of rice could be decreased by 10% rather than 49% as target indicated in the Rural Development Counter Measures of Korean Government in 1994 owing to increasing farm mechanization cost and interest on land service with high price. Accordingly production cost of rice per kg could be decreased only by 10% of the 1994 production cost. 8. Rice policy of Korean government in the future should take into account the labour saving technology to solve labour shortage in rural area and to enhance off-farm incomes by creating job opportunities in agro-industrial zones and special production area. On account of the staple food and main energy source for people's health, rice production even encountered vulnerable economic settings should be continued without price distortion policies and discouraging farmer's intention to cultivate rice by importing institutionally the direct income subsidy system.

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A Proposal for Korean armed forces preparing toward Future war: Examine the U.S. 'Mosaic Warfare' Concept (미래전을 대비한 한국군 발전방향 제언: 미국의 모자이크전 수행개념 고찰을 통하여)

  • Chang, Jin O;Jung, Jae-young
    • Maritime Security
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    • v.1 no.1
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    • pp.215-240
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    • 2020
  • In 2017, the U.S. DARPA coined 'mosaic warfare' as a new way of warfighting. According to the Timothy Grayson, director of DARPA's Strategic Technologies Office, mosaic warfare is a "system of system" approach to warfghting designed around compatible "tiles" of capabilities, rather than uniquely shaped "puzzle pieces" that must be fitted into a specific slot in a battle plan in order for it to work. Prior to cover mosaic warfare theory and recent development, it deals analyze its background and several premises for better understanding. The U.S. DoD officials might acknowledge the current its forces vulnerability to the China's A2/AD assets. Furthermore, the U.S. seeks to complete military superiority even in other nation's territorial domains including sea and air. Given its rapid combat restoration capability and less manpower casualty, the U.S. would be able to ready to endure war of attrition that requires massive resources. The core concept of mosaic warfare is a "decision centric warfare". To embody this idea, it create adaptability for U.S. forces and complexity or uncertainty for the enemy through the rapid composition and recomposition of a more disag g reg ated U.S. military force using human command and machine control. This allows providing more options to friendly forces and collapse adversary's OODA loop eventually. Adaptable kill web, composable force packages, A.I., and context-centric C3 architecture are crucial elements to implement and carry out mosaic warfare. Recently, CSBA showed an compelling assessment of mosaic warfare simulation. In this wargame, there was a significant differences between traditional and mosaic teams. Mosaic team was able to mount more simultaneous actions, creating additional complexity to adversaries and overwhelming their decision-making with less friendly force's human casualty. It increase the speed of the U.S. force's decision-making, enabling commanders to better employ tempo. Consequently, this article finds out and suggests implications for Korea armed forces. First of all, it needs to examine and develop 'mosaic warfare' in terms of our security circumstance. In response to future warfare, reviewing overall force structure and architecture is required which is able to compose force element regardless domain. In regards to insufficient defense resources and budget, "choice" and "concentration" are also essential. It needs to have eyes on the neighboring countries' development of future war concept carefully.

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Application of unmanned helicopter on pest management in rice cultivation (무인 항공기 이용 벼 병해충 방제기술 연구)

  • Park, K.H.;Kim, J.K.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.10 no.1
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    • pp.43-58
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    • 2008
  • This research was conducted to determine the alternative tool of chemical spray for rice cultivation using the unmanned helicopter(Yamaha, R-Max Type 2G-remote controlled system) at farmer's field in Korea. The unmanned helicopter tested was introduced form Japan. In Korea the application of chemicals by machine sprayer for pest management in rice cultivation has been ordinarily used at the farmer's level. However, it involved a relatively high cost and laborious for the small scale of cultivation per farm household. Farm population has been highly decreased to 7.5% in 2002 and the population is expected to rapidly reduce by 3.5% in 2012. In Japan, pest control depending on unmanned helicopter has been increased by leaps and bounds. This was due in part to the materialization of the low-cost production technology under agricultural policy and demand environmentally friendly farm products. The practicability of the unmanned helicopter in terms of super efficiency and effectiveness has been proven, and the farmers have understood that the unmanned helicopter is indispensable in the future farming system that they visualized. Also, the unmanned helicopter has been applied to rice, wheat, soybean, vegetables, fruit trees, pine trees for spraying chemicals and/or fertilizers in Japan Effect of disease control by unmanned helicopter was partially approved against rice blast and sheath blight. However, the result was not satisfactory due to the weather conditions and cultural practices. The spray density was also determined in this experiment at 0, 15, 30, and 60cm height from the paddy soil surface and there was 968 spots at 0cm, 1,560 spots at 15cm, 1,923 spots at 30cm, and 2,999 spots at 60cm height. However, no significant difference was found among the treatments. At the same time, there was no phytotoxicity observed under the chemical stray using this unmanned helicopter, nor the rice plant itself was damaged by the wind during the operation.

Planktic Foraminiferal Assemblages of Core Sediments from the Korea Strait and Paleoceanographic Changes (대한해협 코아 퇴적물의 부유성 유공충 군집 특성과 고해양 환경 변화)

  • Kang, So-Ra;Lim, D.I.;Rho, K.C.;Jung, H.S.;Choi, J.Y.;Yoo, H.S.
    • Journal of the Korean earth science society
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    • v.27 no.4
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    • pp.464-474
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    • 2006
  • The paleoceanography since 14 ka was reconstructed based on the planktic foraminiferal assemblages of core sediments from the outer shelf of the Korea Strait. Planktic foraminifera in the core sediments can be divided into four assemblages: A, B, C, and D. Assemblage A consists mainly of Globigerinoides ruber group and Globigerinoides conglobatus with low abundance (less than 10%), indicating the tropical-subtropical water mass. Assemblage B is composed of Pulleniatina obliquiloculata and Neogloboquadrina dutertrei, the indicator of Kuroshio Current, and shows the aspect of the inflow of the Tsushima Current into the Korea Strait. Assemblage C yields polar-subpolar species, mainly Neogloboquadrina incompta and N. pachyderma. It decreases upward of the core. Assemblage D contains coastal water species such as Globigerina bulloides and G. quinqueloba. It is abundant in the lower to middle region of the core. From the analysis of distributions of each assemblage and the result of age datings in the core, it is suggested that the Korea Strait played a role of channelling the East China Sea and the East Sea after the LGM (ca. 14 ka). During this time, the coastal water, affected by fresh waters originated from the river systems of China and/ or the Korean Peninsula, flourished around the Korea Strait and theses coastal water might entered to the East Sea. Around 8.5 ka, the effect of the Tsushima Current started to strengthen in this region, and the present current system seems to be formed at about $7{\sim}6ka$.