• Title/Summary/Keyword: particular matters

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Aesthetic Consciousness and Literary Logic in the Jamesian Transatlantic Perspective: Towards a Dialectic of "a big Anglo Saxon total"

  • Kim, Choon-hee
    • Journal of English Language & Literature
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    • v.57 no.3
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    • pp.367-389
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    • 2011
  • The aesthetic attitude, in general or in particular, represented in matters of taste through aesthetic ideas and value judgments postulates a certain literary logic. And this literary logic reveals itself a sense of morality, philosophy, or moral aesthetic consciousness through the moments of act and thought demonstrated in the characters invented in literary works. Henry James, among many others, offers a very special cultural paradigm for transnational argument because of his diverse ways of shaping transatlantic relations in terms of aesthetic consciousness. And this international paradigm produced varied expressions referring to Henry James as "an American expatriate," "an Anglicized American artist," "a Europeanized aesthete," "a cosmopolitan intelligence," "a bohemian cosmopolitan" to designate his literary career and its characteristics shaped in Europe. Such expressions resonate with Transatlantic Sketches, James's first collection on travel and cultures in 1875 which heralded his long "expatriation" in terms of self-distantiation. James's temperament of mind, far from being always identified with shared values within an ideological framework, never avoided friction with fixed ideas but rather absorbed it fully for another friction which intervenes in his house of fiction. My question arises here regarding his cultural belonging or dislocation: where is the place of his mind or what could be his ultimate destination? In this essay, I'd like to define a place or rather the place of James's literary mind by proving a certain "sympathetic justice" for his literary logic. For this purpose, I'll try to examine: how James used transatlantic perspective, a spatio-temporal assessment to formulate his moral aesthetic consciousness; and how the aesthetic framework functions in assessing his literary logic of aesthetic consciousness. To start with the first argument, I'll analyze some essential aspects of aesthetic attitude of his characters to postulate a persona capable of theorizing James's aestheticism conditioned by the transatlantic context. And for the second argument, I'll examine how the persona functions in formulating a proper cultural stance of James's aesthetic consciousness in transatlantic perspective to illuminate the way of how Jamesian individuality reflects the American mind. This process of theorizing a place of James's own will lead, I hope, to our discovering James's ultimate destination on the assumption that it'll prove or create a certain "sympathetic justice" for his humanist aestheticism, a Jamesian absolute morality.

Why Culture Matters: A New Investment Paradigm for Early-stage Startups (조직문화의 중요성: 초기 스타트업에 대한 투자 패러다임의 전환)

  • Daehwa Rayer Lee
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.19 no.2
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    • pp.1-11
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    • 2024
  • In the midst of the current turbulent global economy, traditional investment metrics are undergoing a metamorphosis, signaling the onset of what's often referred to as an "Investment cold season". Early-stage startups, despite their boundless potential, grapple with immediate revenue constraints, intensifying their pursuit of critical investments. While financial indicators once took center stage in investment evaluations, a notable paradigm shift is underway. Organizational culture, once relegated to the sidelines, has now emerged as a linchpin in forecasting a startup's resilience and enduring trajectory. Our comprehensive research, integrating insights from CVF and OCAI, unveils the intricate relationship between organizational culture and its magnetic appeal to investors. The results indicate that startups with a pronounced external focus, expertly balanced with flexibility and stability, hold particular allure for investment consideration. Furthermore, the study underscores the pivotal role of adhocracy and market-driven mindsets in shaping investment desirability. A significant observation emerges from the study: startups, whether they secured investment or failed to do so, consistently display strong clan culture, highlighting the widespread importance of nurturing a positive employee environment. Leadership deeply anchored in market culture, combined with an unwavering commitment to innovation and harmonious organizational practices, emerges as a potent recipe for attracting investor attention. Our model, with an impressive 88.3% predictive accuracy, serves as a guiding light for startups and astute investors, illuminating the intricate interplay of culture and investment success in today's economic landscape.

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The study of the status of teaching and learning and needs assessment for 'The basis of the Invention Patent' subjects ('발명.특허 기초' 과목의 교수.학습 방법 실태 및 요구 조사 연구)

  • Lee, Chan Joo;Lee, Byung Wook;Kang, Kyoung Kyoon;Im, Yoo Hwa
    • 대한공업교육학회지
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    • v.38 no.1
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    • pp.105-124
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    • 2013
  • This study aims to analyze the teaching and learning methods realities and needs in the subjects 'The basis of the Invention Patent'. To this end, research and analysis of the subjects 'The basis of the Invention Patent' the teacher and take advantage of their current teaching and learning methods, 'The basis of the Invention Patent' subject teachers to recognize the most desirable teaching and learning methods, subjects 'The basis of the Invention Patent' of teaching and learning and the operating requirements of the difficult matters. Survey of 48 schools across the country in high school teachers to teach the subjects 'The basis of the Invention Patent' was conducted, the results of this study are as follows. First, a high percentage of theoretical learning activities, teaching methods, such as 'lectures' and take advantage of the higher percentage. Module was to conduct classes such as 'project', 'lab experiments', 'discussion', 'investigation' by taking advantage of the high proportion of practice learning activities. Second, Higher requirements for the experience and practice of student-centered 'lab experiments', 'project', 'Case Studies', 'field trips' and theory-driven rather than 'lectures'. Third, 'The basis of the Invention Patent' subjects 'Teaching and learning important when operating requirements for the degree' as a whole was highly recognized. in particular, operating requirements for teaching and learning in accordance with the former college of education of education than non-group differences were higher overall response. Fourth, 'The basis of the Invention Patent' subjects 'Teaching and learning difficult when operating your degree' as a whole was highly recognized. In particular, was recognized by difficult questions, such as lack of preparation classes due to excessive work, educational facilities and equipment shortage, lack of prior knowledge about the subject, individual differences of the students considering the difficulties, student's

Interface structure and anisotropic strain relaxation of nonpolar a-GaN on r-sapphire

  • Gong, Bo-Hyeon;Jo, Hyeong-Gyun;Song, Geun-Man;Yun, Dae-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.31-31
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    • 2010
  • The growth of the high-quality GaN epilayers is of significant technological importance because of their commercializedoptoelectronic applications as high-brightness light-emitting diodes (LEDs) and laser diodes (LDs) in the visible and ultraviolet spectral range. The GaN-based heterostructural epilayers have the polar c-axis of the hexagonal structure perpendicular to the interfaces of the active layers. The Ga and N atoms in the c-GaN are alternatively stacked along the polar [0001] crystallographic direction, which leads to spontaneous polarization. In addition, in the InGaN/GaN MQWs, the stress applied along the same axis contributes topiezoelectric polarization, and thus the total polarization is determined as the sum of spontaneous and piezoelectric polarizations. The total polarization in the c-GaN heterolayers, which can generate internal fields and spatial separation of the electron and hole wave functions and consequently a decrease of efficiency and peak shift. One of the possible solutions to eliminate these undesirable effects is to grow GaN-based epilayers in nonpolar orientations. The polarization effects in the GaN are eliminated by growing the films along the nonpolar [$11\bar{2}0$] ($\alpha$-GaN) or [$1\bar{1}00$] (m-GaN) orientation. Although the use of the nonpolar epilayers in wurtzite structure clearly removes the polarization matters, however, it induces another problem related to the formation of a high density of planar defects. The large lattice mismatch between sapphiresubstrates and GaN layers leads to a high density of defects (dislocations and stacking faults). The dominant defects observed in the GaN epilayers with wurtzite structure are one-dimensional (1D) dislocations and two-dimensional (2D) stacking faults. In particular, the 1D threading dislocations in the c-GaN are generated from the film/substrate interface due to their large lattice and thermal coefficient mismatch. However, because the c-GaN epilayers were grown along the normal direction to the basal slip planes, the generation of basal stacking faults (BSFs) is localized on the c-plane and the generated BSFs did not propagate into the surface during the growth. Thus, the primary defects in the c-GaN epilayers are 1D threading dislocations. Occasionally, the particular planar defects such as prismatic stacking faults (PSFs) and inversion domain boundaries are observed. However, since the basal slip planes in the $\alpha$-GaN are parallel to the growth direction unlike c-GaN, the BSFs with lower formation energy can be easily formed along the growth direction, where the BSFs propagate straightly into the surface. Consequently, the lattice mismatch between film and substrate in $\alpha$-GaN epilayers is mainly relaxed through the formation of BSFs. These 2D planar defects are placed along only one direction in the cross-sectional view. Thus, the nonpolar $\alpha$-GaN films have different atomic arrangements along the two orthogonal directions ($[0001]_{GaN}$ and $[\bar{1}100]_{GaN}$ axes) on the $\alpha$-plane, which are expected to induce anisotropic biaxial strain. In this study, the anisotropic strain relaxation behaviors in the nonpolar $\alpha$-GaN epilayers grown on ($1\bar{1}02$) r-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVO) were investigated, and the formation mechanism of the abnormal zigzag shape PSFs was discussed using high-resolution transmission electron microscope (HRTEM).

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Reading the text of transformation from Seoljanggo Nori to dance - Regarding the transformation of Honam Udo Farmers' Music Lee Gyeonghwa Seoljanggo Dance - (설장고 놀이로부터 춤 변용으로의 텍스트 읽기 - 호남우도농악 이경화 설장고춤의 변용에 관해 -)

  • Kim, Ji-Won
    • (The) Research of the performance art and culture
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    • no.19
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    • pp.161-190
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    • 2009
  • This study presents matters of how to analyse the dance of artistic form on the course of transforming folk art to be separated from leisure to become the art form. In particular, the traditional art of dance in Korea has been of collective act like dureh, rather than of individual art, that it had to choose the repeated style of same form and rhythm. In this respect, before it can be said that the dance in its own form became more sophisticated and adopted the artistic segment in the time of modernisation, it is viewed that in the very heart of folk dance there was sufficient ability of artistic material to seek its own right. In this regard, the artistic transformation of seoljanggo nori into seoljanggo dance is an art form which is found in Korea, and expressing rhythm and playfulness is evident and sought attention. Therefore this study puts its importance in analysing how, in the aspect of the course of life of traditional arts, dance is formed in its own right and developed a form of art from fun entertainment. I have chosen, among them, seoljanggo, which used to be a form of fun entertainment and later transformed into a form of art on stage, in particular LeeGyeongh wa seoljanggo dance which maintains the style of Honam Udo farmers' music, and tried to read the text from it. It has resulted in that, Lee Gyeonghwa seoljanggo dance did a new try on tradition, in its development of expressing art through dance and onto more technical sophistication, found in the style of tune and choreography fused into its distinctive form. The art of traditional dance concerns here that seoljanggo has changed from agrarian entertainment to modern stage art, which shows how tradition can be adopted to the contemporary cultural life or to be reinvented to the needs of the aesthetic style that the current society consumes. Thus, it is necessary to think about its role in education and to represent cultural creativity from local developments.

A Study on the Effective Independent Study of Nursing Student (간호학생의 효과적인 자율학습을 위한 조사연구)

  • 김광주;이향련
    • Journal of Korean Academy of Nursing
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    • v.8 no.1
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    • pp.16-42
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    • 1978
  • This survey was made for a month starting from November 15 to December 15, 1977 covering 711 students taking the junior. (3rd-yea.) and the senior. (4th-year) at nine college of nursing in Seoul concerning their perception and Attitude toward the profession of nursing, motive for the necessity of learning, environment of study, attitude of study and particulars relevant with study performance, particulars of library, references and reading, assignments and particulars of the degree of confidence for the learning achievement. Through the survey of the above Particulars, the following results were obtained by classifying all subject matters and by analysing motive of the selection of their course, awarding or not awarding of scholarships. 1. General characteristics: it was revealed that 406 students (57.1%) were attending at the junior. while 305 students (42.9%) were taking the senior. Thus, the total number was 711 and their average age was 21.4 years. Their dwelling category was; 73.9 percent of them resided at their parent's home, 214 students (30.1%) were awarded with scholarships. The reason to be attracted by nursing science was the possibility of continuing social life after graduation (43.5%). 2. Their perception and attitude toward the profession of nursing: According to the perception of profession by the students of each grade, students of the 4th grade showed comparatively strong conception. Also, students of the 4th grade showed more positive attitude in the purchase and reading of magazines relative with the science of nursing, in the reading of Code for Nurses and in their interest in the activity of nursing field. For the necessity of mission of nurse, 97.7 percent of the entire number of students covered responded to necessity. For the necessity of the particular humanity and particularity in the character of nurses, 95.8 percent of those students responded to necessity. By the each grade, students of the 4th grade showed more response. 3. As to professional field desired after completing the professional course: 57 percent of those students desired for clinician nurse while 55 percents desired for community health-nurse. 4. As to the environment of study: they were mostly satisfied with their present residential environment. However, they complained of inconvenience at their lecture-halls. Students of the 3rd grade showed more complain. As to their attitude toward the adjustment of environment of study, they showed a affirmative response. As to the opinion of factors which interfere with their study, comparatively strong response was showed in their scepticism in the science of nursing, insufficient comprehension in general learning, relation with professors n4 discrepancy in the method of study. According to opinions of students at each grade, students of the 4th grade showed more scepticism. 5. Particulars relative with their attitude and performance of study : As to their knowledge of the objectives of their study of subject, the majority was to study with a partial knowledge of the objectives of their study. As to the plan of study, a low percentage indicated management of routine life under regular scheduling. Students of the 4th grade responded to rather planned life. As to time spent in independent study, response to concentrated study when necessary was stronger than that to regular daily study. Students of the 4th grade showed stronger response to regular study than that of the 3rd grade. As to the contents of their note-taking, 67.4 percents of those students responded to such regulatory procedure performing in the lecture-hall as they listen to lectures. 17.3 percents of those students showed response to adding supplementary informations from references to what was entered in choir note-taking at their lecture-halls. 6. Particulars of library, references and reading books: As to receiving of instruction for the utilization of library and time of receiving such instruction 64.7 percents of those students had received such instruction. 66.7 percents of the those responded received such instruction at orientation conducted for freshmen. As to the convenience of the utilization of library, 49.9 percents of those students responded to convenience. However, students of the 3rd grade showed a much stronger response to inconvenience. As to the time of the utilization of library,92.5 percents of those students showed a response to occasional utilization for particular purpose than regular utilization. 53.2 percents of those students responded to ordinary in quantity that library have references. 34.2 percents of those students responded to insufficient. As to the particular relative with the method and field of reading: 53.5 percents of those students responded to intensive reading and was the majority. As to the reading field, fiction u as the majority. When read any books for their major, they usually rend Korean text-b, oks. 7. Particular relative with giving assignment: All respondents were well aware of the objectives of giving home tasks. As to the attitude toward assignments and performing home tasks, 54.8 percents of those students to making ostentatious study because of an excessive quantity of assignments imposed. For performing assignment, they showed comparatively positive response. Also, 52.2 percents of those students responded that they usually submitted complected assignment with references. 8. As to motive to realize the necessity of study : 55.6 percents of those students responded that they realized such necessity in communication with patients when they were engaged in clinical practice. Also, 8.6, the lowest percents of those students responded that they realized such necessity in the course of conversation with nurses when they were engaged in clinical practice. 9. As to the determination of their confidence in the performance of study relative with clinical experience: They showed a general inclination of having in nursing. The major response was that they came to well comprehend the patients families. the lowest response was that they could apply what was learned at lecture-hall to practice. This response incidentally showed the distance the lecture-hall and practical study. In general items, students of the 4th grade showed more favorable response than students of the 3rd grade and there was a significant difference. 10. As to the perception and attitude toward profession according to the motive of selecting the nursing science : Those who selected the nursing voluntarily showed stronger conception than those who selected the nursing through indirect influence. However, there was no significant difference on this point. Only there was a remarkable difference in the reading of Code for Nurses. 11. Those who showed a stronger conception in the profession of nursing according to the motives of attractive nursing science indicated a strong will and ability to manage stable life and comparatively strong response was shown in the management of good home life because of the good adaptability of the science to their character. This group showed a strong conception of the profession than those who responded that they prefer this profession out of a longing for the work of a hospital and for the easy obtaining of opportunity to immigrate to over seas and for economic cause and for high school grade. There was significant difference between these two groups, 12. As to the conception and attitude toward the profession of nursing according to benefits by scholarships, those who were benefitted by scholarship showed stronger conception of profession than those who did not receive scholarship and there was a remarkable difference between these two categories. However, there was no remarkable difference between these two categories in the extent of interest of the activities of nursing fields and in the reading of Code for Nurses. 13. As activation for study according to the benefits of scholarships, those who were benefitted by scholarships showed stronger response to the motive for study comparing with those who receive. 14. As to tile field of reading according to the benefits by scholarships, those who received scholarships tended to read autobiographies and essayers to a considerable extent. Those who did not receive scholarships tended to read novels. Those who received scholarships more read nursing boots than those who did not receive scholarships. 15. As to the attitude of study and doing of assignment according to benefits of scholarships, those who received scholarships managed a favorable life with schedules for study, More students of receiving scholarship showed a regular study for more than one hour per day. Also, in the method of doing home tasks, more students of receiving scholarship showed reference to relative books frequently for the submission of completed assignments.

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Study on 3D Printer Suitable for Character Merchandise Production Training (캐릭터 상품 제작 교육에 적합한 3D프린터 연구)

  • Kwon, Dong-Hyun
    • Cartoon and Animation Studies
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    • s.41
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    • pp.455-486
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    • 2015
  • The 3D printing technology, which started from the patent registration in 1986, was a technology that did not attract attention other than from some companies, due to the lack of awareness at the time. However, today, as expiring patents are appearing after the passage of 20 years, the price of 3D printers have decreased to the level of allowing purchase by individuals and the technology is attracting attention from industries, in addition to the general public, such as by naturally accepting 3D and to share 3D data, based on the generalization of online information exchange and improvement of computer performance. The production capability of 3D printers, which is based on digital data enabling digital transmission and revision and supplementation or production manufacturing not requiring molding, may provide a groundbreaking change to the process of manufacturing, and may attain the same effect in the character merchandise sector. Using a 3D printer is becoming a necessity in various figure merchandise productions which are in the forefront of the kidult culture that is recently gaining attention, and when predicting the demand by the industrial sites related to such character merchandise and when considering the more inexpensive price due to the expiration of patents and sharing of technology, expanding opportunities and sectors of employment and cultivating manpower that are able to engage in further creative work seems as a must, by introducing education courses cultivating manpower that can utilize 3D printers at the education field. However, there are limits in the information that can be obtained when seeking to introduce 3D printers in school education. Because the press or information media only mentions general information, such as the growth of the industrial size or prosperous future value of 3D printers, the research level of the academic world also remains at the level of organizing contents in an introductory level, such as by analyzing data on industrial size, analyzing the applicable scope in the industry, or introducing the printing technology. Such lack of information gives rise to problems at the education site. There would be no choice but to incur temporal and opportunity expenses, since the technology would only be able to be used after going through trials and errors, by first introducing the technology without examining the actual information, such as through comparing the strengths and weaknesses. In particular, if an expensive equipment introduced does not suit the features of school education, the loss costs would be significant. This research targeted general users without a technology-related basis, instead of specialists. By comparing the strengths and weaknesses and analyzing the problems and matters requiring notice upon use, pursuant to the representative technologies, instead of merely introducing the 3D printer technology as had been done previously, this research sought to explain the types of features that a 3D printer should have, in particular, when required in education relating to the development of figure merchandise as an optional cultural contents at cartoon-related departments, and sought to provide information that can be of practical help when seeking to provide education using 3D printers in the future. In the main body, the technologies were explained by making a classification based on a new perspective, such as the buttress method, types of materials, two-dimensional printing method, and three-dimensional printing method. The reason for selecting such different classification method was to easily allow mutual comparison of the practical problems upon use. In conclusion, the most suitable 3D printer was selected as the printer in the FDM method, which is comparatively cheap and requires low repair and maintenance cost and low materials expenses, although rather insufficient in the quality of outputs, and a recommendation was made, in addition, to select an entity that is supportive in providing technical support.

Trends and Prospects of N. Korea Military Provocations After the Sinking of ROKS Cheon-an (천안함 폭침 이후 북한의 군사도발 양상과 전망)

  • Kim, Sung-Man
    • Strategy21
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    • s.34
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    • pp.58-92
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    • 2014
  • Even after S. Korea took 5.24 Measure(24 May 2014), N. Korea has not stopped raising provocations such as the shelling of Yeonpyeong Island, electronic and cyber attacks. To make matters worse, the communist country lunched long-range missiles(twice) and conducted 3rd nuclear test, escalating tensions which could possibly lead to an all-out war. Korean Government failed to respond properly. However, escalation into an all-out war was deterred by the CFC immediately carrying out its peacetime duty(CODA). The US made a rapid dispatch of its augmentation forces(Aircraft carrier, nuclear-powered submarine, strategic bomber, F-22) to the Korean Peninsula. In recognition of the importance of the Combined Forces Command, since May 2013 the Park Geun-Hye Administration has been pushing ahead with re-postponement of Wartime Operational Control Transfer(which initially meant the disassembling of the CFC as of 1 December 2015) More recently, there has been a series of unusual indicators from the North. Judging from its inventory of 20 nuclear weapons, 1,000 ballistic missiles and biochemical weapons, it is safe to say that N. Korea has gained at least war deterrence against S. Korea. Normally a nation with nuclear weapons shrink its size of conventional forces, but the North is pursuing the opposite, rather increasing them. In addition, there was a change of war plan by N. Korea in 2010, changing 'Conquering the Korean Peninsula' to 'Negotiation after the seizure of the Greater Seoul Metropolitan Area(GSMA)' and establishing detailed plans for wartime projects. The change reflects the chain reaction in which requests from pro-north groups within the South will lead to the proclamation of war. Kim, Jeong-Un, leader of N. Korean regime, sent threatening messages using words such as 'exercising a nuclear preemptive strike right' and 'burning of Seoul'. Nam, Jae-June, Director of National Intelligence Service, stated that Kim, Jung-Un is throwing big talks, saying communization of the entire Korean Peninsula will come within the time frame of 3 years. Kim, Gwan-Jin, Defense Minister, shared an alarming message that there is a high possibility that the North will raise local provocations or a full-fledged war whenever while putting much emphasis on defense posture. As for the response concept of the Korean Government, it has been decided that 'ROK·US Combined Local Provocation Counter-Measure' will be adopted to act against local provocations from the North. Major provocation types include ▲ violation of the Northern Limit Line(NLL) with mobilization of military ships ▲ artillery provocations on Northwestern Islands ▲ low altitude airborne intrusion ▲ rear infiltration of SOF ▲ local conflicts within the Military Demarcation Line(MDL) ▲ attacking friendly ships by submarines. Counter-measures currently established by the US involves the support from USFK and USFJ. In order to keep the sworn promise, the US is reinforcing both USFK and USFJ. An all-out war situation will be met by 'CFC OPLAN5027' and 'Tailored Expansion Deterrence Forces' with the CFC playing a central role. The US augmentation forces stands at 690,000 troops, some 160 ships, 2,000 aircraft and this comprise 50% of US total forces, which is estimated to be ninefold of Korean forces. The CFC needs to be in center in handling both local provocations and an all-out war situation. However, the combat power of S. Korean conventional forces is approximately around 80% of that of N. Korea, which has been confirmed from comments made by Kim, Gwan-Jin, Defense Minister, during an interpellation session at the National Assembly. This means that S. Korean forces are not much growing. In particular, asymmetric capabilities of the North is posing a serious threat to the South including WMD, cyber warfare forces, SOF, forces targeting 5 Northwestern Islands, sub-surface and amphibious assault forces. The presence of such threats urgently requires immediate complementary efforts. For complementary efforts, the Korean Government should consider ① reinforcement of Korean forces; putting a stoppage to shrinking military, acquisition of adequate defense budget, building a missile defense and military leadership structure validity review, ② implementation of military tasks against the North; disciplinary measures on the sinking of ROKS Cheon-an/shelling of Yeonpyeong Islands, arrangement of inter-Korean military agreements, drawing lessons from studies on the correlation between aid for N. Korea, execution of inter-Korean Summit and provocations from the North, and ③ bolstering the ROK·US alliance; disregarding wartime operational control transfer plan(disassembling of CFC) and creation of a combined division.

Classification by Zooplankton Inhabit Character and Freshwater Microbial Food Web: Importance of Epiphytic Zooplankton as Energy Source for High-Level Predator (동물플랑크톤의 서식 특성에 따른 분류와 먹이망: 상위포식자의 에너지원으로서 부착성 동물플랑크톤의 중요성)

  • Choi, Jong-Yun;La, Geung-Hwan;Jeong, Kwang-Seuk;Kim, Seong-Ki;Chang, Kwang-Hyeon;Joo, Gea-Jae
    • Korean Journal of Ecology and Environment
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    • v.45 no.4
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    • pp.444-452
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    • 2012
  • We conducted a comprehensive monitoring for freshwater food web in a wetland system (Jangcheok Lake), from May to October, 2011. Monthly sampling for zooplankton, fish as well as organic matters, was implemented. In order to understand the food web structure and energy flow, we applied stable isotope analysis to the collected samples, based on ${\delta}^{13}C$ and ${\delta}^{15}N$ values of epiphytic particulate organic matter(EPOM) and particulate organic matter (POM), epiphytic and planktonic zooplankton, fish (Lepomis macrochirus). In the study site, epiphytic and planktonic zooplankton was 24 and 30 species, respectively, and coincidence species between epiphytic and planktonic zooplankton were 20 species. Epiphytic zooplankton were more abundant during the spring and early summer (May to July); however, planktonic zooplankton were more abundant during the autumn (September to October) season. Stable isotope analysis revealed that fish and epiphytic zooplankton had seasonal variations on their food sources. EPOM largely contributed epiphytic zooplankton in spring (May), but increasing contribution of POM in autumn (September) was detected. However, planktonic zooplankton depended on only POM in both seasons. Fish utilized both epiphytic and planktonic zooplankton, but small sized (1~3 cm), fish preferred epiphytic zooplankton, where as larger sized (4~7 cm) fish tended to consume planktonic zooplankton, and epiphytic zooplankton had important role in energy transfer. This pattern was clear when results of spring and autumn stable isotope analysis were compared. From the results of this study, we confirmed that wetlands ecosystem supported various epiphytic and planktonic zooplankton species, they depend on other food items, respectively. L. macrochirus also showed a difference of food source according to the body size, they depend on seasonal density change of zooplankton. In particular, epiphytic zooplankton was very important for growth and development of young fish in the spring.

Evaluation of Soil Redox Capacity using Chromium Oxidation-reduction Reactions in Volcanic Ash Soils in Jeju Island (크롬산화환원반응을 이용한 제주도 화산회토양 내 토양산화환원능 평가)

  • Chon, Chul-Min;Ahn, Joo-Sung;Kim, Kue-Young;Park, Ki-Hwa
    • Journal of the Mineralogical Society of Korea
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    • v.21 no.2
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    • pp.161-175
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    • 2008
  • The soil developed from volcanic ash in Jeju Island, Korea, were classified as typical Andisols. The soils had acidic pH, high water contents, high organic matters and clay-silty textures. The crystalline minerals of the samples were mainly composed of ferromagnesian minerals such as olivine and pyroxene, and iron oxides such as magnetite and hematite derived from basaltic materials. A large amount of gibbsite was found at the subsurface horizon as a secondary product from the migration of excessive aluminum. In addition, our study has shown that considerable amounts of poorly ordered minerals like allophane and ferrihydrite were present in Jeju soils. The contents of $SiO_2$ were lower than those of other soil orders, but $A1_2O_3$ and $Fe_2O_3$ contents were higher. These results are some of the important chemical properties of Andisols. The contents of heavy metals were in the range of $84{\sim}198$ for Zn, $56{\sim}414$ for Ni, $38{\sim}150$ for Co, $132{\sim}1164\;mg\;kg^{-1}$ for Cr, which are higher than the worldwide values in most of the soils. Some soil samples contained relatively high levels of Cr exceeding 1000 mg/kg. Mean reduction capacity of the Jeju soils was $6.53\;mg\;L^{-1}$ reduced Cr(VI), 5.1 times higher than that of the non-volcanic ash soils from inland of Korea. The soil reduction capacity of the inland soils had a good correlation with total carbon content (R = 0.90). However, in spite of 20 times higher total carbon contents in the Jeju soils, there was a week negative correlation between the reduction capacity and the carbon content (R = -0.469), suggesting that the reduction capacity of Jeju soils is not mainly controlled by the carbon content and affected by other soil properties. Correlations of the reduction capacity with major elements showed that Al and Fe were closely connected with the reduction capacity in Jeju soil (R = 0.793; R = 0.626 respectively). Moreover, the amounts of Ni, Co and Cr had considerable correlations with the reduction capacity (R = 0.538; R = 0.647; R = 0.468 respectively). In particular, in relation to the behavior of redox-sensitive Cr, the oxidation of the trivalent chromium to mobile and toxic hexavalent chromium can be restricted by the high reduction capacity in Jeju soil. The factors controlling the reduction capacity in Jeju soils may have a close relation with the andic soil properties explained by the presence of considerable allophane and ferrihydrite in the soils.