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STRAIN AND TEMPERATURE CHANGES DURING THE POLYMERIZATION OF AUTOPOLYMERIZING ACRYLIC RESINS

  • Ahn Hyung-Jun;Kim Chang-Whe;Kim Yung-Soo
    • The Journal of Korean Academy of Prosthodontics
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    • v.39 no.6
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    • pp.709-734
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    • 2001
  • The aims of this experiment were to investigate the strain and temperature changes simultaneously within autopolymerzing acrylic resin specimens. A computerized data acquisition system with an electrical resistance strain gauge and a thermocouple was used over time periods up to 180 minutes. The overall strain kinetics, the effects of stress relaxation and additional heat supply during the polymerization were evaluated. Stone mold replicas with an inner butt-joint rectangular cavity (40.0×25.0mm, 5.0mm in depth) were duplicated from a brass master mold. A strain gauge (AE-11-S50N-120-EC, CAS Inc., Korea) and a thermocouple were installed within the cavity, which had been connected to a personal computer and a precision signal conditioning amplifier (DA1600 Dynamic Strain Amplifier, CAS Inc., Korea) so that real-time recordings of both polymerization-induced strain and temperature changes were performed. After each of fresh resin mixture was poured into the mold replica, data recording was done up to 180 minutes with three-second interval. Each of two poly(methyl methacrylate) products (Duralay, Vertex) and a vinyl ethyl methacrylate product (Snap) was examined repeatedly ten times. Additionally, removal procedures were done after 15, 30 and 60 minutes from the start of mixing to evaluate the effect of stress relaxation after deflasking. Six specimens for each of nine conditions were examined. After removal from the mold, the specimen continued bench-curing up to 180 minutes. Using a waterbath (Hanau Junior Curing Unit, Model No.76-0, Teledyne Hanau, New York, U.S.A.) with its temperature control maintained at 50C, heat-soaking procedures with two different durations (15 and 45 minutes) were done to evaluate the effect of additional heat supply on the strain and temperature changes within the specimen during the polymerization. Five specimens for each of six conditions were examined. Within the parameters of this study the following results were drawn: 1. The mean shrinkage strains reached 3095μϵ,1796μϵ and 2959μϵ for Duralay, Snap and Vertex, respectively. The mean maximum temperature rise reached 56.7C,41.3C and 56.1C for Duralay, Snap, and Vertex, respectively. A vinyl ethyl methacrylate product (Snap) showed significantly less polymerization shrinkage strain (p<0.01) and significantly lower maximum temperature rise (p<0.01) than the other two poly(methyl methacrylate) products (Duralay, Vertex). 2. Mean maximum shrinkage rate for each resin was calculated to 31.8μϵ/sec,15.9μϵ/sec and 31.8μϵ/sec for Duralay, Snap and Vertex, respectively. Snap showed significantly lower maximum shrinkage rate than Duralay and Vertex (p<0.01). 3. From the second experiment, some expansion was observed immediately after removal of specimen from the mold, and the amount of expansion increased as the removal time was delayed. For each removal time, Snap showed significantly less strain changes than the other two poly(methyl methacrylate) products (p<0.05). 4. During the external heat supply for the resins, higher maximum temperature rises were found. Meanwhile, the maximum shrinkage rates were not different from those of room temperature polymerizations. 5. From the third experiment, the external heat supply for the resins during polymerization could temporarily decrease or even reverse shrinkage strains of each material. But, shrinkage re-occurred in the linear nature after completion of heat supply. 6. Linear thermal expansion coefficients obtained from the end of heat supply continuing for an additional 5 minutes, showed that Snap exhibited significantly lower values than the other two poly(methyl methacrylate) products (p<0.01). Moreover, little difference was found between the mean linear thermal expansion coefficients obtained from two different heating durations (p>0.05).

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Shade comparative analysis of natural tooth measured by visual and spectrophotometric methods (육안과 분광 측정기를 이용한 자연 치아의 색조비교분석)

  • Kim, Bum-Suk;Shin, Soo-Yeon;Lee, Jong-Hyuk
    • The Journal of Korean Academy of Prosthodontics
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    • v.46 no.5
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    • pp.443-454
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    • 2008
  • Statement of problem: A clinically successful color match is one of the important factor to get an esthetic dental restoration. Dental shade guides are commonly used to evaluate tooth color in restorative procedure. But numerous reports have indicated that common shade guides do not provide sufficient spectral coverage of the natural tooth colors. To address issues associated with the shade guide, distinct avenues have been pursued objective spectrophotometric / colorimetric assessment. Purpose: This study compared the accuracy of tooth color selection of spectrophotometer with that of human visual determination. Three main factors were investigated, namely, the effect of light, the individual variation and the experience of the observer. Material and methods: At the first experiment, on ten patients, one operator independently selected the best matching shade to the unrestored maxillary central incisor, using a Vita Classical Shade Guide in the morning, at noon and in the afternoon. The same teeth were measured by means of a reflectance spectrophotometer. At the second experiment, on ten patients, ten operators (5 experts, 5 novices) selected and measured by the same method above at noon. At the third experiment, the results of the second experiment were divided into two groups, expert and novice, and analyzed. Results: 1. There was significant difference between visual and spectrophotometric assessment (mean ΔE values) in experiment 1, 2, 3 (P < .05). 2. There was no significant difference between experts and novices group, when comparing with each visual and spectrophotometric assessment (mean ΔE values). Conclusion: Spectrophotometer could be used to analyze the shade of natural tooth objectively. Thereby, this method offers the potential tominimize considerably the need for corrections or even remakesafter intraoral try-in of restoration. Furthermore, to achieve its advantage, both the shade-matching environment and communication between dentist and technician should be optimized with use of visual and instrumental shade-matching systems.

Ecological Examinations of the Radial Growth of Pine Trees (Pinus densiflora S. et Z.) on Mt. Namsan and the Potential Effects of Current Level of Air Pollutants to the Growth of the Trees in Central Seoul, Korea.

  • Kim, Eun-Shik
    • Journal of Korean Society for Atmospheric Environment
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    • v.10 no.E
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    • pp.371-386
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    • 1994
  • Ecological examinations of the radial growth Patterns of pine trees(Pinus densiflora Sieb. et Zucc) growing on Mt. Namsan in central Seoul were made to test a Proposition that the pine trees decline due to the influence of air pollution and acid rain, which was proposed by some researchers in Korea, and the potential effects of current level of air pollutants to the growth of the Pine trees in central Seoul have been speculated. Tree-rings of 40 trees sampled at 3 sites of Mt. Namsan were prepared and examined using a Computer-aided Tree-Ring Measuring System at Kookmin University, Korea. Air Pollutant data collected by the Ministry of Environment( MOE ) and the Forestry Research Institute(FRI) were used to infer the general conditions of the environment. Correlation analysis was applied to the data set of tree growth and the other environmental factors. General information derived from the close examination of the tree-rings and the data on air pollution, drought and the other biological conditions suggested that the growth of the pine trees was severely affected by the occurrence of drought(climatic variation), the prevalence of the pine leaf gall midges(insects), and the suppression by the black locust trees(Robinia pseudo-acacia L.) (competition among trees). While the current condition of air pollution in Seoul cannot be categorized as good, the concentrations of air pollutants are not so high as to cause acute damages to the trees. In addition, while the data of rain acidity showed episodic low PHs of under 4.0, the average of them is far less acidic than those which were observed in either northeastern United States or central Europe, where the decline of trees were not solely attributed to any of the air pollutants. Considering the sequential facts that one of the most important environmental factors that affect the growth of trees is weather condition of the forest that the proposition of the decline of the pine trees was made without careful examination of the growth patterns and past growth history of them as well as the complex influences of many other factors including the weather conditions to the growth of trees, and that no objective explanation has been made on the causal relationships between the current condition of air pollution and the growth of the trees, such a proposition should be evaluated as invalid for the explanation of tree growth on Mt. Namsan in central Seoul, Korea. The author evaluates the factors of air pollution (including acid rain) as the predisposing factors, which may have the Potentials to chronically affect the tree growth at the forest ecosystem on Mt. Namsan for a long period of time. Ecosystem ecological studies should be further carried out to carefully explain both the functional and the structural aspects of the ecosystem processes, which include the biogeochemistry and the long-term changes of soil conditions as well as the growth of the other tree species on the mountain.

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Comparative Study on the Nurses' Job Satisfaction between the Oriental Medicine Ward and the General Ward (한방병동과 일반병동 간호사의 직무만족도의 비교연구)

  • Byun, Chang-Ja;Choi, Sang-Soon;Paik, Seung-Nam;Lee, Mi-Aie
    • Journal of Korean Academy of Nursing Administration
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    • v.1 no.1
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    • pp.97-111
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    • 1995
  • In our society today, a variety of medical caring system, along with a scientific development in the area of oriental medical science plus national demand, has increased the augmentation and the opening of oriental wards and hospitals (Han Bang), which has come to create an additional requirement of nursing activity at oriental medicine wards should be different from that of the general wards or the same as the other. In view of this, various studies need to be made in this connection. The purpose of this study is to comprehend the number of nurses who want to work at oriental medicine wards and measure job satisfaction in nursing as compared with those working at general wards so as to provide basic materials for future assignment and supplementary training for the nurses. An attempt was made to contribute toward nursing administration on the one hand improving nursing training course on the other hand. A total of 72 nurses currently working at two oriental medicine hospitals available in Seoul and 82 general nurses were selected for this study using the questionaire from December 1993 to January 1994. An instrument for the study was based on the measurement of work satisfaction developed by Paula L. Stamps including 37 questions complemented by Kim for revision (1993) and 14 questions regarding general characteristics and oriental medicine wards. The instrument to test dependability showed Cronbach's=0.7711. The collected data have been processed by computer package SPSS. General characteristics of the two groups and the matters involved in oriental medicine wards were calculated into real figure and percentage an similarities between the two groups were analyzed by t-test and F-test according to the characteristics of variables. The comparative test on work satisfaction among the two groups including general characteristics and work factors were conducted by t-test and F-test. The major findings as a result of the study are as follows : 1. As general characteristics, age group of 2630 years are more than any segment of age. As to marital status, the number of those in single status is slightly higher than the married. Approximately 80% of them are graduates of nursing schools and nursing colleges. They are mostly in service for one to three years. There is no significant difference between the two groups. 2. The number of those who want to work at oriental medicine wards represents 40.3% against 58.4%, being in favor of general wards. 3. The reason for service at oriental medicine wards is that "there is room for potential research" which happened to rank first, followed by "easy job," "good working atmosphere" and "growing interest in oriental medicine." 4. Work satisfactions among nurses who work at oriental medicine wards prove greater than that of nurses who work at general wards. 5. Work satisfaction between the two groups by work factors is reflected with significant difference statistically on task requirement, interaction and doctor-nurse relationships. 6. The general charcateristics and the work satisfaction by work factors prove that there are significant difference in age, marital status, education and the period of work. They tend to be more satisfied with the work as they grow in age. Significant differneces are found in the work factors such as autonomy, adiministration and professional job in the relationship with doctor-nurse. As to marital status, the married are more satisfied than the unmarried. There are significant differneces in the factors respecting administration and doctor-nurse college graduates are highly satisfied with task requirement. However, satisfaction with the professional level has proven the highest degree for those having master degree. The period of work and satisfaction : There are significant differneces in task requirement, administration, interactions, professional level and doctor-nurse relationships. As a general rule, the degree of satisfactions is in proportion to the lengrh of service. The following conclusions are drawn based on the fndings mentioned above. Even though the work satisfaction of the nurse who work at oriental medicine ward is relatively high, it is desired that personal consultation be given as to disposition of nurses when they are assigned to oriental medicine wards. It is also recommended that lectures on oriental medicine be conducted through supplementary training and/or basic nursing course in order that they may be motivated for ingenious activities with an increasing sense of self-esteem which will eventually enhance positive changes for the patients who are in need of oriental medicine nursing and for the medical teams. In addition, joint reseaches involvingclinical care and education should be in constant process for unique and scientific development for those who are subject to oriental medicine nursing care.

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A Study on Estimating Optimal Tonnage of Coastal Cargo Vessels in Korea (우리나라 연안화물선의 적정선복량 추정에 관한 연구)

  • 이청환;이철영
    • Journal of the Korean Institute of Navigation
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    • v.13 no.1
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    • pp.21-53
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    • 1989
  • In the past twenty years, there has been a rapid increase in the volume of traffic in Korea due to the Korean great growth of the Korean economy. Since transformation provides an infrastructure vital to economic growth, it becomes more and more an integral part of the Korea economy. The importance of coastal shipping stands out in particular, not only because of the expansion limit on the road network, but also because of saturation in the capacity of rail transportation. In spite of this increase and its importance, coastal shipping is falling behind partly because it is givenless emphasis than ocean-going shipping and other inland transportation systems and partly because of overcompetition due to excessive ship tonnage. Therefore, estimating and planning optimum ship tonnage is the first take to develop Korean coastal shipping. This paper aims to estimate the optimum coastal ship tonnage by computer simulation and finally to draw up plans for the ship tonnage balance according to supply and demand. The estimation of the optimum ship tonnage is peformed by the method of Origin -Destimation and time series analysis. The result are as follows : (1) The optimum ship tonnage in 1987 was 358, 680 DWT, which is 54% of the current ship tonnage (481 ships, 662, 664DWT) that is equal to the optimum ship tonnage in 1998. this overcapacity result is in excessive competition and financial difficulties in Korea coastal shipping. (2) The excessive ship tonnage can be broken down into ship types as follows : oil carrier 250, 926 DWT(350%), cement carrier 9, 977 DWT(119%), iron material/machinery carrier 25, 665 DWT(117%), general cargo carrier 17, 416DWT(112%). (3) the current total ship crew of 5, 079 is more than the verified optimally efficient figure of 3, 808 by 1271. (4) From the viewpoint of management strategy, it is necessary that excessive ship tonnage be reduced and uneconomic outdated vessels be broken up. And its found that the diversion into economically efficient fleets is urgently required in order to meet increasing annual rate in the amounts of cargo(23, 877DWT). (5) The plans for the ship tonnage balance according to supply and demand are as follows 1) The establishment of a legislative system for the arrangement of ship tonnage. This would involve; (a) The announcement of an optimum tonnage which guides the licensing of cargo vessels and ship tonnage supply. (b) The establishment of an organization that substantially arrangement tonnage in Korea coastal shipping. 2) The announcement of an optimum ship tonnage both per year and short-term that guides current tonnage supply plans. 3) The settlement of elastic tariffs resulting in the protect6ion of coastal shipping's share from other tonnage supply plans. 4) The settlement of elastic tariffs resulting in the protection of coastal shipping's share from other transportation systems. 4) Restriction of ocean-going vessels from participating in coastal shipping routes. 5) Business rationalization of coastal shipping company which reduces uneconomic outdated vessels and boosts the national economy. If we are to achieve these ends, the followings are prerequisites; I) Because many non-licensed vessels are actually operating and threatening the safe voyage of the others in Korea coastal routes, it is necessary that those ind of vessels be controlled and punished by the authorities. II) The supply of ship tonnage in Korean coastal routes should be predently monitored because most of the coastal vessels are to small to be diverted into ocean-going routes in case of excessive supply. III) Every ship type which is engaged in coastal shipping should be specialized according to the characteristics of its routes as soon possible.

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A Study on the animation music video production for the viral marketing purposes A case study of project (바이럴 마케팅용 애니메이션 뮤직비디오 제작 연구 : 월드컵 응원가 <일어나라 대한민국> 사례를 중심으로)

  • Han, Sang-Gyun;Kim, Tak-Hoon;Kim, Yu-Mi
    • Cartoon and Animation Studies
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    • s.22
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    • pp.47-63
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    • 2011
  • Recently, contemporary cultural contents have been shown its diversity changes followed by the birth of new media platforms with consumers' new needs in the global market. Also, developments of Internet and computer system networks are the main contributors of making this changes happened rapidly. This study aims to know that how to usefully use those new media platforms through the great example of stop-motion animation music video by analyzing its production and marketing process. The music video production had been focused to be completed with high quality by adjusting the production process economically in spite of the relatively short period(less than one month)from its crank-up to the deadline. Because the production was planned that main characters lead the whole story, the creative team had been tried to reduce the production hours by commonly use the same mold when they make original clay models by collecting the similarities of characters' appearances. By using CG technic, could overcome the visual monotonous from the similarities which inferred above. Also, the repeated rhythm in the music video, the similar scenes of backgrounds were commonly used by copy of the original scene. At the point of directing, the creative team considered both economical and art aspects for the quality work. In details, they divided the scenes into foreground and background, and removed unnecessary parts to save the production hours and budget but make depth of fields in the scenes. Except the viral marketing purposes, was searching for the methods to compensate the production cost. For this, the characters in the music video dressed the same T-shirts which are world-cup logo on, and those were designed for the sale after released the music video. Even the result of the sales was not enough to satisfied, it was estimated a great attempt to the domestic animation industry.

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VR media aesthetics due to the evolution of visual media (시각 미디어의 진화에 따른 VR 매체 미학)

  • Lee, Dong-Eun;Son, Chang-Min
    • Cartoon and Animation Studies
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    • s.49
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    • pp.633-649
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    • 2017
  • The purpose of this study is to conceptualize the changing aspects of human freedom of observation and viewing as the visual media evolves from film to 3D stereoscopic film and VR. The purpose of this study is to conceptualize the aspect of freedom and viewing aspect from the viewpoint of genealogy. In addition, I will identify the media aesthetic characteristics of VR and identify the identity and ontology of VR. Media has evolved around the most artificial sense of human being. There is a third visual space called screen at the center of all the reproduction devices centering on visual media such as painting, film, television, and computer. In particular, movies, television, and video screens, which are media that reproduce moving images, pursue perfect fantasy and visual satisfaction while controlling the movement of the audience. A mobilized virtual gaze was secured on the assumption of the floating nature of the so-called viewers. The audience sees a cinematic illusion with a view while seated in a fixed seat in a floating posture. They accept passive, passive, and passively without a doubt the fantasy world beyond the screen. But with the advent of digital paradigm, the evolution of visual media creates a big change in the tradition of reproduction media. 3D stereoscopic film predicted the extinction of the fourth wall, the fourth wall. The audience is no longer sitting in a fixed seat and only staring at the front. The Z-axis appearance of the 3D stereoscopic image reorganizes the space of the story. The viewer's gaze also extends from 'front' to 'top, bottom, left, right' and even 'front and back'. It also transforms the passive audience into an active, interactive, and experiential subject by placing viewers between images. Going one step further, the visual media, which entered the VR era, give freedom to the body of the captive audience. VR secures the possibility of movement of visitors and simultaneously coexists with virtual space and physical space. Therefore, the audience of the VR contents acquires an integrated identity on the premise of participation and movement. It is not a so-called representation but a perfection of the aesthetic system by reconstructing the space of fantasy while inheriting the simulation tradition of the screen.

Application of Modified Mupit for the Recurrent Vulva Cancer in Brachytherapy (재발한 Vulvar 종양의 근접치료 시 Modified Mupit Applicator의 적용)

  • Kim, Jong-Sik;Jung, Chun-Young;Oh, Dong-Gyoon;Song, Ki-Won;Park, Young-Hwan
    • The Journal of Korean Society for Radiation Therapy
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    • v.18 no.1
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    • pp.13-19
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    • 2006
  • Purpose: To evaluate whether modified MUPIT applicator can effectively eradicate recurrent tumor in uterine cervix cancer and reduce rectal complication after complete radiation treatment. Materials and Methods: Modified MUPIT applicator basically consists of an acrylic cylinder with flexible brain applicator, an acrylic template with a predrilled array of holes that serve as guides for interstitial needles and interstitial needles. CT scan was peformed to determine tumor volume and the position of interstitial needles. Modified MUPIT applicator was applied to patient in operation room and the accuracy for position of interstitial needles in tumor volume was confirmed by CTscan. Brachytherapy was delivered using modified MUPIT applicator and RALS(192-lr HDR) after calculated computer planning by orthogonal film. The daily dose was 600cGy and the total dose was delivered 3,000 cGy in tumor volume by BID. Rectal dose was measured by TLD at 5 points so that evaluated the risk of rectal complication. Results: The application of modified MUPIT applicator improved dramatically dose distributions in tumor volume and follow-up of 3 month for this patient was clinically partial response without normal tissue complication, Rectal dose was measured 34.1 cGy, 57.1 cGy, 103.8 cGy, 162.7 cGy, 165.7 cGy at each points, especially the rectal dose including previous EBRT and ICR was 34.1 cGy, 57.1 cGy. Conclusion: Patients with locally recurrent tumor in uterine cervix cancel treated with modified MUPIT applicator can expect reasonable rates of local control. The advantages of the system are the fixed geometry provided by the template and cylinders. and improved dose distributions in irregular tumor volume without rectal complication.

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A Study on Growth Acceleration in Korean as Indirected by the Maximum Growth Age in Body Height (한국인(韓國人) 신장(身長)의 최대발육연령(最大發育年齡)으로 본 발육촉진현상(發育促進現象)의 추이(推移)에 관(關)한 연구(硏究))

  • Shin, Hyung-Gyun;Park, Soon-Young;Park, Yang-Won
    • Journal of Preventive Medicine and Public Health
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    • v.17 no.1
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    • pp.173-192
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    • 1984
  • On the basis of the study intended to research by crosssectional study keeps pace with semilongitudinal study the growthaccelerating phenomena that Maximum Growth age in teenager's body-height. By the random sampling method, the subject of study are 12659 persons(male; 6355, female; 6304) that they are from 7 ages to 17 ages in the whole country including the rural community. The measurement period passed three month days, the statistical data became electronic data processing system with computer. The other side, body-height and MGA of Koreans who had been for during the period from 1925 to 1966 proved transition of the growth-accelerating phenomena by research data reported between 1913 and 1983. The results are as follows; 1. The Growth and Development-Value of Body-height An age bracket the growth and development-value of body-height were, respectively, male is 123.88±5.05cm and female is 123.29±5.54cm for 7 ages group. these indices increased with age. the top-value reach, respectively. 169.08±5.62cm and 157.57±6.13cm. The intersecting ages of male and female were the age 8.512.5, during these periods, female excelled male but after these periods, male excelled female again. In case of body-height, MGA's are 7.0cm for male between 12 and 13 ages, and 7.01cm for female between 8 and 9 ages. As a rule, body-height of male excelled female but intersection phenomena of male and female appeared between 8.5 and 12.5 ages. By reginal groups, it is most prevailing is Seoul, and medium size cities and rural community rome in order. By regional groups, intersection phenomena of male and female are. a region of Seoul; 8.511.5 ages a region of Daejeon; 7.59.5 ages rural community; 11.514.5 ages the whole country's average; 8.512.5 ages By regional groups, the rate of maximum increase in a year are a region of Seoul; male is 7.23cm as 13 ages female is 7.65cm as 9 ages. a region of Daejeon; male is 7.85cm as 11 ages. female is 8.39cm as 9 ages. rural community; male is 7.65cm as 14 ages. female is 6.25cm as 12 ages. the whole country's average; male is 7.0cm as 13 ages. female is 7.01 as 9 ages. 2. Maximum Growth Age (M.G.A.) By reginal groups, maximum Growth Age's are as below in a region of Seoul, MGA's are 12.63 for male and 9.01 for female, which shows that MGA for female appears about 3.5 years earlier than that for male. In a region of Daejeon, MGA's are 9.20 for male and 8.93 for female, which. show that they are all much the same in M.G.A. In rural community, MGA's are 14.00 for male and 11.89 for female, which shows that MGA for female apperars about 2 years earlier than that for male. In the whole average, MGA's are 13.01 for male and 8.97 for femal, which shows that for female appears about 4 years earlier than that for male. For boy, M.G.A. shows fastest-growing in Daejeon, and Seoul and rural commonly come in order. For girl, It shows equal growth in Seoul and Daejeon, rural community comes later. 3. The M.G.A's in body height of male are respectively the age 15.02 in 1913, 14.23 in 1956, 13.86 in 1967, 13.62 in 1975, and 12.82 in 1981, while those of female are the age 12.0 in 1940, 11.52 in 1965, 9.53 in 1975, and 11.16 in 1980; these data show that the MGA of the Koreans has been getting younger. 4. The equation of linear regression of all the MGA's in body height are as follow; Male: Y(M.G.A)=0.020× (the year)+15.19: female:Y(MGA)=0.028×(the year)+13.2549. 5. The corelation of all the MGA's in body height are as below; male; r=-0.329 female;r=-0.252 6. From the transition of the growth-accelating phenomena in 1980 we can capture the fact that the MGA's has been getting younger by 0.2 year per 10 years. 7. The MGA's in bodyheight are shown in table 4... 8. The future growth-accelating phenomena in body height are expected to show the similar tendency like that of the past, in 1910's but it should by more precisely reviewed after investigating the phenomena of the years directly ahead.

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An Alternative Approach for Setting Equilibrium Prices of Sericultural Products (잠사류의 균형 가격모색)

  • 이질현
    • Journal of Sericultural and Entomological Science
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    • no.12
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    • pp.47-50
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    • 1970
  • There are many factors affecting the development of sericultural industry in Korea. The setting of a rational pricing system for sericultural products is one of important activities of the Korean Government to improve the incentives to producers. The determination o: the prices for many years were based on the production costs including a certain level of profits. Some of cost items are in conflict both in cocoon producers and silk-reeling industries. Government officials have to evaluate these conflicting problems and estimate the consequences of their decisions. In this situation the final decision often became political decisions. This analysis is aimed at providing an alternative method of setting the prices of sericultural products. The criteria of the equilibrium employed in this analysis are based on economic principle which equilibrium condition is determined by the relationships between the marginal productivity of input factors and factor prices. In order to obtain the related information Cobb-Douglas'functions were fitted using KIST computer and data were obtained mostly from the Bank of Korea and the Ministry of Agriculture and Forestru, An important assumption is that "Opportunity Costs" of factors input in both cocoon production and silk-Peeling industries are same, The major finding s obtained are as followings. 1) The sum of coefficient of production elastisity in silk-reeling industries is greater than one. Silk-reeling industries are operating under the situation of increasing return to scale and it is, therefore, expected to develop the industries as the capital-intensive large scale. 2) The cocoon producing farmers are under the situations of the decreasing return to scale and it is expected to continue their cocoon farming as the labor-intensive small scale, assuming the present level of production technology. As the development of commercial farming, the resources input in cocoon production will be shifted to the production for higher profitable crops, 3) The price elastisity of production is higher in cocoon production than in silk-reeling industries. It is expected that the price changing effects on domestic production will be resulted from cocoon producers. 4) Based on analysis results of marginal productivities and the opportunity costs of resources, cocoon price for meeting equilibrium price condition is to be increased by 8-16 percent or standard price level of silk increased by 6-8 percent. There were the possibilities of over evaluation on opportunity cost of resources input in silk-reeling industries, or income transfered from the farmers to the industries. It is recommended that the prices for meeting equilibrium price conditions are to be determined by 72 percent for cocoon and 28 percent for silk-reeling costs, based on standard level of the exporting prices.

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