• Title/Summary/Keyword: Study design

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A Study on the Vegetation Landscape and Management Methods of Buyongdae on Hahoe Village, Andong (안동 하회마을 부용대(芙蓉臺) 일원의 식물상 및 관리방안)

  • Oh, Hyun-Kyung;Rho, Jae-Hyun;Choi, Yung-Hyun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.31 no.1
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    • pp.13-27
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    • 2013
  • This study investigated flora and vascular plants area around Buyongdae where include optimum view point Okyeonjeongsa and Gyeomamjeongsa in Hahoe Village, Andong. Based on the findings, the aim of results was attempted to suggest the management plan of the vegetation area around Buyongdae which designated UNESCO World cultural heritage and folk village in Korea. The results of the study is as the following. All flora of this site, Buyongdae in Andong, were 301 taxa; 89 families, 217 genera, 251 species, 1 subspecies, 38 varieties and 11 forms. Vegetation of each of areas in site was classified Pinus densiflora as representative forest around Buyongdae, Quercus variabilis forest around Gyeomamjjeongsa and Koelreuteria paniculata forest in river cliff of Buyongdae. The 14 taxa(Polygala tenuifolia, Koelreuteria paniculata, and others) as the rare plants and the 7 taxa(Weigela subsessilis, and others) as endemic species were recorded in the surveyed site among the whole flora. The specific plants which is categorized to degree by the Ministry of Environment appeared as 32 taxa; degree IV was 4 species; Polygala tenuifolia, etc. and degree III was 10 species; Hypodematium glandulosopilosum, Pyrrosia petiolosa, etc. and degree I was 13 species; Hemiptelea davidii, Zizyphus jujuba var. jujuba, etc. Also, the 11 taxa were recorded in limestone area as the chamaephyte; Hypodematium glandulosopilosum, Celtis koraiensis, Siphonostegia chinensis, Artemisia gmelini, and others. The naturalized plants recorded as 25 taxa; Viola arvensis, Erechtites hieracifolia, etc. and invasion of Sicyos angulatus which is ecosystem disturbing plants. The naturalization rate(NR) was 8.3% and the urbanization index(UI) was 7.8% by field survey. For recovery of indigenous to traditional vegetation landscape in Buyongdae, Pinus rigida of upper-growth and Alnus sibirica of middle-growth need thinning. In addition, the site demands both sustainable management through long-term monitering and gradual elimination method for the naturalized plants including Sicyos angulatus where found in Kyumamjeongsa. Particularly, intentional planting for decoration and cultivation around Hwachunseowon, Helianthus tuberosus must be substitute with the native plants. Meanwhile, Polygala tenuifolia is potently demanded preventing habitate, confirming additional habitate, seed securing and preservation of gene resource internally or externally. Koelreuteria paniculata; denoting feature of river cliff, including Hypodematium glandulosopilosum, Siphonostegia chinensis, Zizyphus jujuba var. jujuba, Pyrrosia petiolosa, and Celtis koraiensis, also need an assertive preservation. Futhermore, Wisteria floribunda for. floribunda, located around Galmo rock to Chunggil course, remained by colonizing form, need preservation and observation for a while. Beside that, the information boards are required to educate visiting user about safe regulations on the narrow way in rock hill.

Exploratory Case Study for Key Successful Factors of Producy Service System (Product-Service System(PSS) 성공과 실패요인에 관한 탐색적 사례 연구)

  • Park, A-Rum;Jin, Dong-Su;Lee, Kyoung-Jun
    • Journal of Intelligence and Information Systems
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    • v.17 no.4
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    • pp.255-277
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    • 2011
  • Product Service System(PSS), which is an integrated combination of product and service, provides new value to customer and makes companies sustainable as well. The objective of this paper draws Critical Successful Factors(CSF) of PSS through multiple case study. First, we review various concepts and types in PSS and Platform business literature currently available on this topic. Second, after investigating various cases with the characteristics of PSS and platform business, we select four cases of 'iPod of Apple', 'Kindle of Amazon', 'Zune of Microsoft', and 'e-book reader of Sony'. Then, the four cases are categorized as successful and failed cases according to criteria of case selection and PSS classification. We consider two methodologies for the case selection, i.e., 'Strategies for the Selection of Samples and Cases' proposed by Bent(2006) and the seven case selection procedures proposed by Jason and John(2008). For case selection, 'Stratified sample and Paradigmatic cases' is adopted as one of several options for sampling. Then, we use the seven case selection procedures such as 'typical', 'diverse', 'extreme', 'deviant', 'influential', 'most-similar', and 'mostdifferent' and among them only three procedures of 'diverse', 'most?similar', and 'most-different' are applied for the case selection. For PSS classification, the eight PSS types, suggested by Tukker(2004), of 'product related', 'advice and consulancy', 'product lease', 'product renting/sharing', 'product pooling', 'activity management', 'pay per service unit', 'functional result' are utilized. We categorize the four selected cases as a product oriented group because the cases not only sell a product, but also offer service needed during the use phase of the product. Then, we analyze the four cases by using cross-case pattern that Eisenhardt(1991) suggested. Eisenhardt(1991) argued that three processes are required for avoiding reaching premature or even false conclusion. The fist step includes selecting categories of dimensions and finding within-group similarities coupled with intergroup difference. In the second process, pairs of cases are selected and listed. The second step forces researchers to find the subtle similarities and differences between cases. The third process is to divide the data by data source. The result of cross-case pattern indicates that the similarities of iPod and Kindle as successful cases are convenient user interface, successful plarform strategy, and rich contents. The differences between the successful cases are that, wheares iPod has been recognized as the culture code, Kindle has implemented a low price as its main strategy. Meanwhile, the similarities of Zune and PRS series as failed cases are lack of sufficient applications and contents. The differences between the failed cases are that, wheares Zune adopted an undifferentiated strategy, PRS series conducted high-price strategy. From the analysis of the cases, we generate three hypotheses. The first hypothesis assumes that a successful PSS system requires convenient user interface. The second hypothesis assumes that a successful PSS system requires a reciprocal(win/win) business model. The third hypothesis assumes that a successful PSS system requires sufficient quantities of applications and contents. To verify the hypotheses, we uses the cross-matching (or pattern matching) methodology. The methodology matches three key words (user interface, reciprocal business model, contents) of the hypotheses to the previous papers related to PSS, digital contents, and Information System (IS). Finally, this paper suggests the three implications from analyzed results. A successful PSS system needs to provide differentiated value for customers such as convenient user interface, e.g., the simple design of iTunes (iPod) and the provision of connection to Kindle Store without any charge. A successful PSS system also requires a mutually benefitable business model as Apple and Amazon implement a policy that provides a reasonable proft sharing for third party. A successful PSS system requires sufficient quantities of applications and contents.

Development of Agent-based Platform for Coordinated Scheduling in Global Supply Chain (글로벌 공급사슬에서 경쟁협력 스케줄링을 위한 에이전트 기반 플랫폼 구축)

  • Lee, Jung-Seung;Choi, Seong-Woo
    • Journal of Intelligence and Information Systems
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    • v.17 no.4
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    • pp.213-226
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    • 2011
  • In global supply chain, the scheduling problems of large products such as ships, airplanes, space shuttles, assembled constructions, and/or automobiles are complicated by nature. New scheduling systems are often developed in order to reduce inherent computational complexity. As a result, a problem can be decomposed into small sub-problems, problems that contain independently small scheduling systems integrating into the initial problem. As one of the authors experienced, DAS (Daewoo Shipbuilding Scheduling System) has adopted a two-layered hierarchical architecture. In the hierarchical architecture, individual scheduling systems composed of a high-level dock scheduler, DAS-ERECT and low-level assembly plant schedulers, DAS-PBS, DAS-3DS, DAS-NPS, and DAS-A7 try to search the best schedules under their own constraints. Moreover, the steep growth of communication technology and logistics enables it to introduce distributed multi-nation production plants by which different parts are produced by designated plants. Therefore vertical and lateral coordination among decomposed scheduling systems is necessary. No standard coordination mechanism of multiple scheduling systems exists, even though there are various scheduling systems existing in the area of scheduling research. Previous research regarding the coordination mechanism has mainly focused on external conversation without capacity model. Prior research has heavily focuses on agent-based coordination in the area of agent research. Yet, no scheduling domain has been developed. Previous research regarding the agent-based scheduling has paid its ample attention to internal coordination of scheduling process, a process that has not been efficient. In this study, we suggest a general framework for agent-based coordination of multiple scheduling systems in global supply chain. The purpose of this study was to design a standard coordination mechanism. To do so, we first define an individual scheduling agent responsible for their own plants and a meta-level coordination agent involved with each individual scheduling agent. We then suggest variables and values describing the individual scheduling agent and meta-level coordination agent. These variables and values are represented by Backus-Naur Form. Second, we suggest scheduling agent communication protocols for each scheduling agent topology classified into the system architectures, existence or nonexistence of coordinator, and directions of coordination. If there was a coordinating agent, an individual scheduling agent could communicate with another individual agent indirectly through the coordinator. On the other hand, if there was not any coordinating agent existing, an individual scheduling agent should communicate with another individual agent directly. To apply agent communication language specifically to the scheduling coordination domain, we had to additionally define an inner language, a language that suitably expresses scheduling coordination. A scheduling agent communication language is devised for the communication among agents independent of domain. We adopt three message layers which are ACL layer, scheduling coordination layer, and industry-specific layer. The ACL layer is a domain independent outer language layer. The scheduling coordination layer has terms necessary for scheduling coordination. The industry-specific layer expresses the industry specification. Third, in order to improve the efficiency of communication among scheduling agents and avoid possible infinite loops, we suggest a look-ahead load balancing model which supports to monitor participating agents and to analyze the status of the agents. To build the look-ahead load balancing model, the status of participating agents should be monitored. Most of all, the amount of sharing information should be considered. If complete information is collected, updating and maintenance cost of sharing information will be increasing although the frequency of communication will be decreasing. Therefore the level of detail and updating period of sharing information should be decided contingently. By means of this standard coordination mechanism, we can easily model coordination processes of multiple scheduling systems into supply chain. Finally, we apply this mechanism to shipbuilding domain and develop a prototype system which consists of a dock-scheduling agent, four assembly- plant-scheduling agents, and a meta-level coordination agent. A series of experiments using the real world data are used to empirically examine this mechanism. The results of this study show that the effect of agent-based platform on coordinated scheduling is evident in terms of the number of tardy jobs, tardiness, and makespan.

Analysis of the Dose Distribution of Moving Organ using a Moving Phantom System (구동팬텀 시스템에 의한 움직이는 장기의 선량분포 분석)

  • Kim, Yon-Lae;Park, Byung-Moon;Bae, Yong-Ki;Kang, Min-Young;Lee, Gui-Won;Bang, Dong-Wan
    • The Journal of Korean Society for Radiation Therapy
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    • v.18 no.2
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    • pp.81-87
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    • 2006
  • Purpose: Few researches have been peformed on the dose distribution of the moving organ for radiotherapy so far. In order to simulate the organ motion caused by respiratory function, multipurpose phantom and moving device was used and dosimetric measurements for dose distribution of the moving organs were conducted in this study. The purpose of our study was to evaluate how dose distributions are changed due to respiratory motion. Materials and Methods: A multipurpose phantom and a moving device were developed for the measurement of the dose distribution of the moving organ due to respiratory function. Acryl chosen design of the phantom was considered the most obvious choice for phantom material. For construction of the phantom, we used acryl and cork with density of $1.14g/cm^3,\;0.32g/cm^3$ respectively. Acryl and cork slab in the phantom were used to simulate the normal organ and lung respectively. The moving phantom system was composed of moving device, moving control system, and acryl and cork phantom. Gafchromic film and EDR2 film were used to measure dose ditrbutions. The moving device system may be driven by two directional step motors and able to perform 2 dimensional movements (x, z axis), but only 1 dimensional movement(z axis) was used for this study. Results: Larger penumbra was shown in the cork phantom than in the acryl phantom. The dose profile and isodose curve of Gafchromic EBT film were not uniform since the film has small optical density responding to the dose. As the organ motion was increased, the blurrings in penumbra, flatness, and symmetry were increased. Most of measurements of dose distrbutions, Gafchromic EBT film has poor flatness and symmetry than EDR2 film, but both penumbra distributions were more or less comparable. Conclusion: The Gafchromic EBT film is more useful as it does not need development and more radiation dose could be exposed than EDR2 film without losing film characteristics. But as response of the optical density of Gafchromic EBT film to dose is low, beam profiles have more fluctuation at Gafchromic EBT. If the multipurpose phantom and moving device are used for treatment Q.A, and its corrections are made, treatment quality should be improved for the moving organs.

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A Study of Health Condion and Shift Service of the Nurse in (종합병원 간호사의 교대근무와 건강상태에 관한 연구)

  • Kim, Soon-Ok
    • Journal of Korean Academy of Nursing Administration
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    • v.3 no.1
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    • pp.119-133
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    • 1997
  • Continuing shift service of clinical nurses can be not only the cause of occupational dissatisfaction by being connected with the change of circadian rhythm and the burden of duties to be applicable to such changes. But also of inviting the lowering of nursing quality by being affected to the resignation of the nurses as the threat to the health of the nurses. This study has selected 500 nurses at random under non-probability sampling who have been serving by shift in 7 general hospitals which have over 400 sickbeds for the purpose of cross-sectional survey design from Sep. 7 through 20, 1996. Standardized modification of the CMI has been used which was designed for Koreans with Cornell Medical Index developed by Broadman and his fellow workers as the study device. The structure of the device was composed of 35 questions on physical appeal(Chronbach's ${\alpha}=8507$) and 22 questions of mental appeal(Cronbach's ${\alpha}=.8166$ totalling 57 questions. The collected data has been computerrized by using SPSS. General character, present symptom, perceived symptom and others are sought by practical number and percentage, and the health condition comparison followed by general characters was conducted by t-test and ANOVA. The post test was by Duncan's test by the level of p<.05. 1) The items of the answer that they have the physical symptom presently by 50% or over of the nurses were as "Do you often have spells of severe dizziness", "Are your eyes often red or inflamed", "Does press or pain in the head often make like miserable", "Are your ankles often badly swollen", "Do pains in the back make it hard for you to keep up with your work". 2) The items of the answer by over 50% of the nurses as the mental symptom at present were "do you fell bad when criticized?", "Do you get angry when everything is against your will?", "do you get angry when ordered to do this and that?", "do you feel uneasy by such a trifle thing?", "do you tremble or are you freightened by sudden sound?". The mental and physical symptoms which have appeared presently in connection with the shift service have been agreed with each other. But the physical condition has been worse than the mental one. 3) In the physical health conditions followed by demosociological character, there were the significant differences by sex, religion and place of residence(p<.05), and in the mental health conditions, there were the significant differences by age, marital status, residence place and the required time for attending hospital(p<.05). 4) There was significant difference by the degree of satisfaction about the duty in both the physical and mental health conditions. In short, the higher the degree of duty satisfaction, the better the health conditions. 5) There were the significant difference according to the times of night duty and whether they take the drug or not or the kinds of the drugs in the physical health conditions related with the characters of night shift. Mental health conditions in the night shift case showed significant differences according to their taking drug or not or the kinds of the drugs(p<.05). I can confirm that the nurses have been affected continuously by the shift service mentally and physically. The maintenance of the physical and mental health of the nurses and its promotion are very important problem to guarantee the quality nursing in the performance of the nursing service continuously and effectively, so the hospital should make every effort to improve the duty conditions by finding out the causes affecting to their health. In the nursing management viewpoint, I think that elevating the satisfaction degree about the duty would be a great help to the promotion of physical and mental health conditions. But what is most important is that the nurses themselves should take care of themselves in maintaining the good conditions in their service in the hospital.

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The Diagnosis of Work Connectivity between Local Government Departments -Focused on Busan Metropolitan City IT Project - (지자체 부서 간 업무연계성 진단 -부산광역시 정보화사업을 중심으로 -)

  • JI, Sang-Tae;NAM, Kwang-Woo
    • Journal of the Korean Association of Geographic Information Studies
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    • v.21 no.3
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    • pp.176-188
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    • 2018
  • Modern urban problems are increasingly becoming a market mix that can not be solved by the power of a single department and the necessity of establishing a cooperation system based on data communication between departments is increasing. Therefore, this study analyzed Busan metropolitan city's IT projects from 2014 to 2018 in order to understand the utilization and sharing status of departmental data from the viewpoint that cooperation between departments can start from the sharing of data with high common utilization. In addition, based on the results of the FGI(Focus Group Interview) conducted for the officials of the department responsible for the informatization project, we verified the results of data status analysis. At the same time, we figured out the necessity of data link between departments through SNA(Social Network Analysis) and presented data that should be shared first in the future. As a result, most of the information systems currently use limited data only within the department that produced the data. Most of the linked data was concentrated in the information department. Therefore, this study suggested the following solutions. First, in order to prevent overlapping investments caused by the operation of individual departments and share information, it is necessary to build a small platform to tie the departments, which have high connectivity with each other, into small blocks. Second, a local level process is needed to develop data standards as an extension of national standards in order to expand the information to be used in various fields. Third, as another solution, we proposed a system that can integrate various types of information based on address and location information through application of cloud-based GIS platform. The results of this study are expected to contribute to build a cooperation system between departments through expansion of information sharing with cost reduction.

Analysis on Tax Benefits of Tax Lease Scheme for Ships (선박 조세 리스제도의 세제혜택효과 분석)

  • Cho, Kyu-Yeol;Lee, Ki-Hwan
    • Journal of Korea Port Economic Association
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    • v.36 no.2
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    • pp.63-86
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    • 2020
  • The tax lease scheme for ships is an advanced ship financing tool that generates tax benefits through accelerated depreciation of capital allowances and transferring them to the ship operator (leasee) via reductions in rental payments. The scheme was introduced by Japan in 1978 and by France in 1998 to support their shipping and shipbuilding industries. The size of tax benefits varies by country depending on the depreciation rate for ships, corporate tax rate, and the tax system on profits from the sale of ship. This study uses a virtual model of the Korean tax lease scheme for ships based on the French tax lease scheme. The size of tax benefits is calculated and compared to those in the French and Japanese tax lease schemes. According to the analysis, the size of the tax benefit was approximately 19% for France, 14% for Japan, and 12% for Korea. This is differentiated by the country's depreciation rate and corporate tax rate, which have the greatest impact on the size of tax benefits. For the Korean virtual model, if the tax benefits are distributed by the operator and the investor at the rate of 75:25, the operator is expected to enjoy tax benefits equivalent to about 9% of the ship price and the investor to enjoy 3%. Despite limited information and data regarding the tax lease scheme for ships, this study was the first attempt in Korea to design a virtual model of the Korean tax lease scheme based on some predictable assumptions. Therefore, a group of shipping, financing, and legal experts will follow up on more professional and practical reviews of the model in the near future. Hence, this study will serve as a small contribution to the early introduction of the Korean tax lease scheme for ships.

The Effect of Visual Health Promotion Program in Elementary School-Age Children (초등학생 시력건강증진 프로그램 효과)

  • Oh, Jin-Joo;Shin, Hee-Sun
    • Research in Community and Public Health Nursing
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    • v.12 no.2
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    • pp.397-405
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    • 2001
  • The vision disturbances of school- age children has been recognized as and important school health problem. As the visual disturbances of the school-age children is recognized as the nation's health problem. the importance of the development of educational program for visual health should be emphasized. Recently, eyeball movement and other visual health management method has been introduced for prevention or recovery of decrease in visual acuity. But, the effect of eyeball movement was not confirmed yet. And, the controversy around the treatment effect is continued. The decrease of visual acuity is one of the important school health problem as well as it causes discomfort in daily life of the students. So, it should be considered as an important subject for school health and there is a need to develop an effective intervention program for visual health. The purpose of this study is to develop and evaluate the program with the recognition of the need of the intervention for visual health. The visual health promotion program was developed by the researcher and the program was initiated by the school. Nonequivalent control group pretest-posttest design was applied for study which examined the effect of the visual health promotion program. The subjects were 742 children (experimental group: 398; control group: 344). The experiment was composed of health education and eyeball movement. Health education was provided 5 times to the children in the class room. Children of experimental group exercised eyeball movement in the class, watching video for 10 minutes two times a day. The exercise was continued for 10 weeks. The result of the study were as follows. 1) change of visual acuity Before the intervention, mean of the visual acuity was .86 for the experimental group and .91 for control group. After the intervention, mean of visual acuity was .95 for the experimental group and. 90 for the control group. There was no significant difference in the change of visual acuity between experimental and control group. 2) change of refraction. In the experimental group, 327 eyes (41.08%) were normal vision and 469 eyes (58.98%) were eyes of refraction errors, 38.82 % of the total eyes were myopia. There was no significant change in the refraction in the children with myopia after the intervention. 3) Awareness of visual acuity, change of knowledge, behavior. and attitude (1) After the intervention, there was a significant difference in the awareness of visual acuity (experimental group: 70.10%. control group: 50.97%, p<.01). (2) After the intervention, there was a significant knowledge increase in the experimental group (pp<.01). (3) There was no significant difference in the visual health behavior after the intervention. (4) There was a significant positive change in the attitude related to visual health in the experimental group ( pp<.05). 4) There was a significant positive change in the subjective discomfort of the students. But, there was no significant change in the objective eye symptom after the intervention. Even though there was no effect in the visual acuity and the change of the refraction. subjective visual health as well as the attitude and knowledge' of the children and parents toward visual health was improved significantly. Also, there was an increase in the intention of change and the awareness for the visual health management. It is suggested that various educational strategies for visual health promotion should be developed and examined for the visual health promotion of the students.

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Effect of rhPMP-2 coated implants on alveolar ridge augmentation in dogs (성견에서 골형성단백질이 코팅된 임플란트가 치조골 증대에 미치는 영향)

  • Park, Chan-Kyung;Kim, Jong-Eun;Shin, Ju-Hee;Ryu, Jae-Jun;Huh, Jung-Bo;Shin, Sang-Wan
    • The Journal of Korean Academy of Prosthodontics
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    • v.48 no.3
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    • pp.202-208
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    • 2010
  • Purpose: This study was aimed to evaluate the effect of rhPMP-2 coated implants on alveolar ridge augmentation in dogs. Materials and methods: Six Beagle dogs were used in this study. Six 8.0 mm long anodized surface titanium implants were placed 5 mm into the mandibular alveolar ridge following 6 month of healing period after extraction. Each animal received three implants coated with rhBMP-2 and three uncoated control implants using the randomized split-mouth design. Radiographic examinations were undertaken immediately at implant placement (baseline), at weeks 4 and 8 after implant placement. The amount of bone augmentation was evaluated by measuring the distance from the uppermost point of the coverscrew to the marginal bone. Implant Stability Quotient (ISQ) values were measured immediately at implant placement and 8 weeks after implant placement. For the statistical analysis, Man-Whitney ranksum test and Wilcoxon signed rank test of SPSS 12.0 software were used (P=.05). Results: The BMP group exhibited radiographic vertical bone augmentation about $0.6{\pm}0.7$ mm at 8 weeks later while controls showed bone loss about $0.4{\pm}0.6$ mm. There was significant difference among the rhBMP-2 group and controls in bone level change (P<.05). The ISQ values were significantly higher in the BMP-2 group than the control group at 8 weeks later (P<.05), while there was no significant difference at surgery. Conclusion: Within the limitation of this study, the rhBMP-2 coated on anodized implant could stimulate vertical alveolar bone augmentation, which may increase implant stability significantly on completely healed alveolar ridge.

Study on the Heritabilities of Pinus densiflora S. et Z. (I) (소나무의 유전력(遺傳力)에 관(關)한 연구(硏究)(I))

  • Yim, Kyong Bin;Noh, Eui Rae
    • Journal of Korean Society of Forest Science
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    • v.42 no.1
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    • pp.74-82
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    • 1979
  • Pinus densiflora S. et Z. which has the widest distribution and highest stock at present in Korea and has used as materials for fuel, house construction, furniture and many other purposes for several hundred years, is considered as one of major species of economic importance, although there are a few epidemic insect injuries and silvicultural difficulties in regeneration. However, since disorderly cutting has been conducted for long time, the valuable local stands have disappeared. Therefore immediate attempts should be taken on the gene conservation and genetic studies including heritabilities and genetic gains of desirable characters. One hundred and twently five plus trees have so far been selected from the nationwide area and kept for the purpose of seed orchard establishment and other theoretical studies. In this study, the wind pollinated seeds of grafted stocks of 13 plus trees in clone bank located in Suweon and the seeds of 4 Japanese plus trees were collected and their progenies were used for heritability study. As indicated in figure 1, thirteen plus trees are from the middle part of Korea and two experimental plantations were laid out in ]972 (1-1 stock) by the randomized block design with five replications, consisting of 10 trees line plots of each family in each replication. Tree height, root collar diameter and branch diameter at 1cm apart from the main stem were measured. The results are summarized as follows 1. The rank of height growth of each plus tree progenies by age was greatly changed under age 3 and it was affected more in poor site than good site. 2. The heritabilities of height growth were estimated to be 7.2% at age 3, negative sign at age 4, 9.4% at age 5, 13.0% at age 6, 8.1% at age 7 and abrupt increase of 63.8% at age 8. The heritabilities were generally increased with increase of age. 3. The heritabilities of root collar diameter and branch diameter (average of the three biggest branches) was 3.2% and 11.8% at age 8 respectively. 4. The genetic gain was largest at age 8 and it was 46.6% when a selection intensity, 1/500 was taken. It, therefore, seems to be reasonable that selection should not be made under age 7.

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