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The Paradox of the Plankton (플랑크톤 패러독스)

  • Lee, Hak Young;Moon, Sung-Gi;Huh, Man-Kyu
    • Journal of Life Science
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    • v.25 no.5
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    • pp.601-606
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    • 2015
  • Hutchinson (1961) proposed that the large number of species in most plankton communities is remarkable in review of the competitive exclusion principle, which suggests that in homogeneous, well-mixed environments species that compete for the same resources cannot coexist. The principle of competitive exclusion would lead us to conclude that only a few species could coexist in such circumstances. Nevertheless, numerous competing species in most natural habitats are able to coexist, while generally only few resources (niches) limit these communities. It is coined “the paradox of plankton” by Hutchinson. We reviewed some literature of the proposed solutions and give a brief overview of the mechanisms proposed so far. The proposed mechanisms that we discuss mainly include spatial and temporal heterogeneity in physical and biological environment, externally imposed or self-generated spatial segregation, horizontal mesoscale turbulence of ocean characterized by coherent vortices, oscillation and chaos generated by several internal and external causes, stable coexistence and compensatory dynamic under fluctuating temperature in resource competition, and finally the role of toxin-producing phytoplankton in maintaining the coexistence and biodiversity of the overall plankton populations. Especially we sited Roy and Chattopadhyay’s reviews and their toxin-producing hypothesis by phytoplankton. This review may be some information to study plankton communities and effect to put the solutions to the paradox that have been proposed over the years into perspective.

Genetic Relationships of Internal Transcribed Spacer (ITS) Regions on Entomopathogenic Fungi by RFLP (Entomopathogenic Fungi의 ITS 영역에 대한 RFLP 분석)

  • Choi, In-Young;You, Young-Jin;Choi, Joung-Sik;Lee, Wang-Hyu
    • The Korean Journal of Mycology
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    • v.28 no.2
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    • pp.112-117
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    • 2000
  • A similarity coefficient were analyzed by RFLP of fourteen species of entomopathogenic fungi, isolated from inhabiting pupa and adult insect at forest. Each rDNA ITS I and ITS II with primers of ITS 1 and ITS 4 was amplified by PCR. The amplified products were conserved to 500 bp were not demarcated between genus and species. Four Paeciliomyces tenuipes, two Beauveria bassiana and six Cordyceps militaris were treated by seven restriction enzymes and confirmed in species except JB3 by electrophoresis band. However, the band of C. scarabaeicola showed the identity with B. bassiana. The result of this experiment indicated that the teleomorph of C. scarabaeicola was the same as that of B. bassiana. CfoI and HpaII of seven restricted enzymes were easily discriminating in the genus between Paecilomyees and Cordyceps. Especially, CfoI was more effective to classify the genera of Paecilomyees, Cordyceps and Beauveria than other restriction enzymes. The band patterns of RFLP of P. tenuipes, C. militaris, C. scarabaeicola and B. bassiana were also analyzed by UPGMA program of NTSYS-pc and showed 100% significance. Thus, the similarity coefficient tended to be lower between genera by RFLP analysis, but was higher between species.

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Development and Verification of Static-Dynamic Cone Penetrometer (정동적 콘관입실험 장비의 개발과 검증)

  • Bae, Myeong-Ho;Yu, Jung-Dong;Kim, Ju-Han;SaGong, Myung;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.27 no.1
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    • pp.77-86
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    • 2011
  • The advanced geotechnical information has been required to determine the accurate design parameters for complex construction. However, the Standard Penetration Test (SPT), which has low reliability, has been used to estimate the subsurface condition in the field. The objective of this paper is development and application of the Static-Dynamic penetrometer, which detects the resistances in soft clay, sand and rock. The energy losses according to the rod connection methods (perfect or non-perfect connection, and number rods) are experimentally evaluated. The reflection and transmission ratios are used to investigate the energy loss by a simulation. The static-dynamic cone penetrometer, in which the accelerometers and strain gauges are installed on the cone tip and the rod head, is used to estimate the energy loss during penetration by impacts. The experimental and simulation studies show that the transferred energy through rods with non-perfect connection dramatically decreases. Furthermore, the transferred energy on the rod head is not the same as that on the cone tip. This study demonstrates that the energy loss should be evaluated on the cone tip.

An Analysis on the Elementary Preservice Teachers' Problem Solving Process in Intuitive Stages (직관적 수준에서 초등 예비교사들의 문제해결 과정 분석)

  • Lee, Dae Hyun
    • School Mathematics
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    • v.16 no.4
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    • pp.691-708
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    • 2014
  • In general, the intuitive knowledge that can use in mathematics problem solving is one of the important knowledge to teachers as well as students. So, this study is aimed to analyze the elementary preservice teachers' intuitive knowledge in relation to intuitive and counter-intuitive problem solving. For this, I performed survey to use questionnaire consisting of problems that can solve in intuitive methods and cause the errors by counter-intuitive methods. 161 preservice teachers participated in this study. I got the conclusion as follows. preservice teachers' intuitive problem solving ability is very low. I special, many preservice teachers preferred algorithmic problem solving to intuitive problem solving. So, it's needed to try to improve preservice teachers' problem solving ability via ensuring both the quality and quantity of problem solving education during preservice training courses. Many preservice teachers showed errors with incomplete knowledges or intuitive judges in counter-intuitive problem solving process. For improving preservice teachers' intuitive problem solving ability, we have to develop the teacher education curriculum and materials for preservice teachers to go through intuitive mathematical problem solving. Add to this, we will strive to improve preservice teachers' interest about mathematics itself and value of mathematics.

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Archival Appraisal and Classification of the Official Documents of the Government-General of Choson Related to Urban District Planning (조선총독부 시가지계획 관련 공문서의 분류와 평가)

  • Lee, Song-Soon
    • The Korean Journal of Archival Studies
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    • no.14
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    • pp.53-89
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    • 2006
  • The historical value of the official documents of the Government General of Choson preserved as permanent archived documents has long been recognized. However, the fact that only parts of the overall documents were preserved and that the contents of the existing documents is not uniform, results in many problems regarding the evaluation and usage of such documents as archives. This study attempts to appraise a series of archival documents related to urban district planning compiled during the colonial era. Although limited in terms of its applicability to the development of an evaluation method for the official documents of the Government General of Choson as a whole, by evaluating the value of these documents based on the background of the documents produced during the Government General of Choson's implementation of its colonial policy, this study provides an important indicator of how such documents should be used in the future. On the other hand, the assessment of historical records such as the official documents of the Government General of Choson which have already been designated and preserved as permanent archived documents should not be perceived as an attempt to dispose of the relevant documents. With regard to the appraisal of historical archives, it is necessary to consider measures to link such documents with existing databases or information contents in order to heighten access to and usage of the relevant documents in the future.

Expansion of the Value and Prospect of the Human Rights Documentary Heritage : Focusing on the 5·18 archives (인권기록유산 가치와 지평의 확산 5·18민주화운동기록물을 중심으로)

  • Lee, Jung Yeon
    • The Korean Journal of Archival Studies
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    • no.45
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    • pp.121-153
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    • 2015
  • Struggles to gain acknowledgement of identity have a characteristic of movement to recover human dignity. Participants in this movement come to confirm themselves as the subject of rights and communicate one another, free from oppression. Being guaranteed the opportunity to participate in the public opinion formation process is an indispensable element of human rights. In 1980, though it was short and incomplete, Gwangju experienced communal autonomy under the condition that state power was temporarily stopped. The contents and memories of the Gwangju Democratization Movement that intended to protect autonomy of civil society, resisting pillage of state power, remain intact in the 1980 Archives for the May 18th. The 5.18 archives were registered in UNESCO's Memory of the World in 2011, with its value of human rights and protection of democracy being acknowledged. The 5.18 archives have memories of resistance and struggles for justice, and sacrifices and pains of citizens under oppressive political authority in Gwangju, 1980. Thus, these archives are related to the historical struggles for democracy, and suggest a lesson on the transition process towards democracy to us. Preservation and utilization of the documentary heritage constantly lead the memories of historical events to the present, and enable exchanges of experiences and ideas between the present and the future. This study, through the process of UNESCO's Memory of the World registration and post-registration process, beyond the value of archives, tries to examine how historical events are led to the present, through the archives and to discuss the other values of archives.

A Study on the need of the Conversion of Fire Services to State Affairs (소방사무의 국가사무로의 전환 필요성에 관한 연구)

  • Lee, Jae-Hak;Jang, Seong-Ho
    • The Journal of the Korea Contents Association
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    • v.21 no.7
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    • pp.281-290
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    • 2021
  • The scope of fire services has been expanded from local fire prevention to rescue and first aid services, and the fire services system has been converted from an autonomous fire services system to a wide-area fire services system, and the status of fire officers has been unified as a national public servant. However, the underlying problem remains unsolved. One is a problem related to the conversion of fire services to state affairs, and the other is that Fire officers converted to national public servants are in charge of fire services which are evaluated as local autonomous affairs. The controversy over the nature of fire service stems from uncertainty and redundancy in the coordination of office function and distribution between the State and Local governments, and incomplete legislation that fundamentally fails to achieve systematic unity of office work and status. The fire service has a national responsibility as an affair that includes the existence of the state and the welfare and order of the people along with the police affairs. That is, affairs related to the safety of the people that protect the lives, bodies and properties of the people should be understood as State affairs. 「The LOCAL AUTONOMY ACT」 stipulates that local governments cannot perform State affairs such as affairs necessary for the existence of the nation, affairs requiring performance in a uniform manner throughout the nation, and affairs of nationwide or similar scale unless otherwise provided by the law. Fire Service should be regarded as such affairs. Considering that the rights to the safety and life of the people and the duty to protect the people are the duty of the nation, it is necessary to keep in mind that the reason for the change fire officers to the national public servants was not basically just a matter of treatment and finance.

ICT Company Profiling Analysis and the Mechanism for Performance Creation Depending on the Type of Government Start-up Support Program (정부창업지원 프로그램 참여에 따른 ICT 기업 프로파일링과 성과창출 메커니즘)

  • Ha, Sangjip;Park, Do-Hyung
    • Journal of Intelligence and Information Systems
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    • v.28 no.3
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    • pp.237-258
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    • 2022
  • As the global market environment changes, the domestic ICT industry has a growing influence on the world economy. This industry is regarded as an important driving force in the national economy from a technological and social point of view. In particular, small and medium-sized enterprises (SMEs) in the ICT industry are regarded as essential actors of domestic economic development in terms of company diversity, technology development and job creation. However, since it is small compared to large-sized enterprises, it is difficult for SMEs to survive with a differentiated strategy in an incomplete and rapidly changing environment. Therefore, SMEs must make a lot of efforts to improve their own capabilities, and the government needs to provide the desirable help suitable for corporate internal resources so that they can continue to be competitive. This study classifies the types of ICT SMEs participating in government support programs, and analyzes the relationship between resources and performance creation of each type. The data from the "ICT Small and Medium Enterprises Survey" conducted annually by the Ministry of Science and ICT was used. In the first stage, ICT SMEs were clustered based on common factors according to their experiences with government support programs. Three clusters were meaningfully classified, and each cluster was named "active participation type," "initial support type," and "soloist type." As a second step, this study compared the characteristics of each cluster through profiling analysis for each cluster. The third step carried out in this study was to find out the mechanism of R&D performance creation for each cluster through regression analysis. Different factors affected performance creation for each cluster, and the magnitude of the influence was also different. Specifically, for "active participation type", "current manpower", "technology competitiveness", and "R&D investment in the previous year" were found to be important factors in creating R&D performance. "Initial support type" was identified as "whether or not a dedicated R&D organization exists", "R&D investment amount in the previous year", "Ratio of sales to large companies", and "Ratio of vendors supplied to large companies" contributed to the performance. Lastly, in the case of "soloist type", "current workforce" and "future recruitment plan", "technological competitiveness", "R&D investment", "large company sales ratio", and "overseas sales ratio" showed a significant relationship with the performance. This study has practical implications of showing what strategy should be established when supporting SMEs in the future according to the government's participation in the startup program and providing a guide on what kind of support should be provided.

Software Reliability Growth Modeling in the Testing Phase with an Outlier Stage (하나의 이상구간을 가지는 테스팅 단계에서의 소프트웨어 신뢰도 성장 모형화)

  • Park, Man-Gon;Jung, Eun-Yi
    • The Transactions of the Korea Information Processing Society
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    • v.5 no.10
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    • pp.2575-2583
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    • 1998
  • The productionof the highly relible softwae systems and theirs performance evaluation hae become important interests in the software industry. The software evaluation has been mainly carried out in ternns of both reliability and performance of software system. Software reliability is the probability that no software error occurs for a fixed time interval during software testing phase. These theoretical software reliability models are sometimes unsuitable for the practical testing phase in which a software error at a certain testing stage occurs by causes of the imperfect debugging, abnornal software correction, and so on. Such a certatin software testing stage needs to be considered as an outlying stage. And we can assume that the software reliability does not improve by means of muisance factor in this outlying testing stage. In this paper, we discuss Bavesian software reliability growth modeling and estimation procedure in the presence of an imidentitied outlying software testing stage by the modification of Jehnski Moranda. Also we derive the Bayes estimaters of the software reliability panmeters by the assumption of prior information under the squared error los function. In addition, we evaluate the proposed software reliability growth model with an unidentified outlying stage in an exchangeable model according to the values of nuisance paramether using the accuracy, bias, trend, noise metries as the quantilative evaluation criteria through the compater simulation.

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Study of Radiological Approach to Treat a Chronic Constipation (만성변비환자의 방사선학적 접근방법에 관한 고찰)

  • Yoon, Seok-Hwan
    • Journal of radiological science and technology
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    • v.27 no.3
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    • pp.5-12
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    • 2004
  • I. Introduction : The constipation is one of the common gastrointestinal symptoms seen in the clinical practice. When people come to the clinic complaining of the constipation, it is generally one of the cases of infrequent, painful or difficult evacuation as well as the hardened feces and unsatisfactory evacuation sense. Since the constipation is heavily influenced by dietary habit as well as the social and medical environment, the diagnostic radiology is useful to establish the objective and standardized definition in consideration of those various factors before diagnosis and treatment of the constipation patient. This paper describes the study of such diagnosis. II. Main Subject : Testing of CTT (colon transit time) is key study of the colon performance. CTT is very helpful in classifying the pathologic physiological types and defining the treatment plan for the chronic constipation. The study methods include using the radipaque marker, multiple marker technique and scintigraphic measurement. The defecography is the functional radiologic examination a that provides not only the anatomical information of anorectal but also performance of the pelvic floor and rectal change during evacuation. Study of dynamic movement of the anorectal during evacuation is helpful for diagnosis and treatment planning as well as follow-up testing for the constipation patient. One of the issues essential for the case history is the thorough observation of whether the patient shows the psychic psychological symptoms such as the behavior disorder or emotional disturbance. In that case, the decision must be made whether or which type of medication is needed for such psychiatric problem. III. Conclusion : The main causes of the constipation are insufficient intake of fiber or liquid. The key objective of such tests is to check etiology of the constipation. In general, the radiological examination does not provde the colon or anorectal performance information. It is envisaged that this study will provide the information to decide the testing and treatment plans and predict the prognosis of the patient by classifying the pathologic physiological types.

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