• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.4
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• pp.758-770
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• 1996

Discectomy is the oldest and most commonly performed operation for the painful temporomandibular joint with internal derangement. It is the one operation for which there are longest follow-up study, with Eriksson, Silver, and Tolvanen et al reporting good results in patients about 30 years after discectomy. About 80% to 90% of patients clinically experience relief from pain and dysfunction after discectomy, and interestingly, the results may improve with time. However such as Myrhaug found headache and Poswillo supposed pain and limitation of movement as postoperative complications, even though this operation had the longest follow-up term, several aspects of discectomy remain unclear. The controversies to discectomy for TMJ with pain and dysfunction have laid emphasis only upon clinical results, and then the histomorphological study was planned to evaluate the morphologic change of TMJ after discectomy. To clarify the nature of the change through an observation on the morphologic changes of articular cartilage and subchondral bone of the condyle resulting from experimental unilateral discectomy in rabbit, the author excised the left articular discs of 12 male rabbits(control 4 rabbits), weighing about 3kg, and at 1, 3, 6, 9 weeks following surgery, harvested both(left surgical site and right nonsurgical sits) TMJ. The specimens were examined with light microscope after H-E and MT stain and the obtained results were as follows. 1. Histopathological features showed thickening of articular zone and active proliferation of fibrocartilaginous zone associated with slight proliferative zone in surgical site than control group. Also replacement of chondrocytes in calcified cartilaginous zone into bone cells was observed. 2. There were thinning of thickness of each zone of articular cartilage except calcified cartilagnous zone was observed in nonsurgical site. 3. In MT stain of condylar trabeculae, there was increased calcification in nonsurgical site than control and surgical site and the degree of calcification was similar in surgical site and control group. 4. In both site of experimental group no features of degenerative changes were observed. From the above results, it is presumed that the morphologic changes of surgical site discectomy are compensatory remodeling process characterized by an hyperplastic reaction of the articular zone and fibrocartilaginous zone filling the void created by removing the disc, and the bone changes are secondary to changes in the cartilage. Increased degree of calcification seen in condylar trabeculae of nonsurgical site results from the excessive use of condyle of that site.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.4
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• pp.18-27
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• 2012

This paper proposes a management method for a coastal black pine forest landscape considering the parallax effect. For the study, 10 coastal black pine forests in Gangneung were investigated about the average width of the coastal forests, the average diameters, and the intervals of the pines. Categorizations were realized for the 3 types of scene(sea, field, mountain, residential area, commercial area), diameter(16cm, 22cm, 28cm) and interval(5m, 7m, 10m) to produce a total of 45 scenic simulations. An investigation was made on the scenic preferences using 45 simulation images with S.D, and Likert Scales. The results were as follows: According the comparison of scenic preferences, natural landscapes(sea, field, and mountain) ranked high among preferences, with fabricated landscapes(residential area, commercial area) ranked low. The highest scenic preferences were shown with the seascape and an interval of 7m between the trees. On the contrary, the interrelationship was very low between the visual quantity of the scenic's elements(green, sky, building, road etc.) and the scenic preferences. As the results of the factor analysis, the 3 sense factors of "Depth(78.0%)" "Diversity(l5.6%)" and "Spatiality(6.4%)" explained coastal scenic preferences. "Spatiality" showed significant differences at intervals of 5~7m, and 10m between trees. This shows coastal forest management based on the interval of 10m standard affecting scenic preference.

• Journal of Korean Society of Forest Science
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• v.99 no.1
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• pp.153-162
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• 2010

Abies holophylla Maxim. is a shade tolerant species that has potential to be used for continuous cover forestry system. Stand structure and natural regeneration of A. holophylla stands in Yong-In area located in the central part of Korea was investigated to estimate the self sustainability of A. holophylla plantation. Species composition, diameter at breast height (DBH) and height distribution of trees larger than 2 cm DBH were measured in ten stands in three study sites of Jeongsu-ri, Daedae-ri, and Hodong. Species and coverage of shrub layer, and A. holophylla seedlings were also investigated. While A. holophylla in non-managed stands (Jengsuri and Daedae-ri study sites) had the importance value of 40% and showed continuous diameter and age distribution, A. holophylla in Hodong site had narrow bell-shaped DBH distribution mostly concentrating between 25-35 cm DBH classes, and single canopy structure. Abies holophylla stands in Hodong have experienced occasional thinning and selective cutting. The correlation coefficient between age-DBH was significant but low ($R^2$=0.2, P=0.03), and similar aged A. holophylla had diverse DBH values. Continuos DBH distribution and multi-canopy structure of A. holophylla stands in Jeongsu-ri site show that natural regeneration of A. holophylla has been continuously occurred in this area. Seedling density of A. holophylla was between 2000 and 33000/ha, however, the number of trees in 2-5 cm DBH class was only 40-150 trees/ha, implying that the survival rate of seedlings is not high. Continuous natural regeneration and 0.6 cm/year of diameter growth rate of A. holophylla indicate that this area could be an appropriate habitat for this species, and A. holophylla plantation in this region seem to persist suggesting the possibility of managing the stands for continuous cover forestry system as well as selective harvesting practices.

• Journal of Korean Society of Forest Science
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• v.107 no.2
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• pp.174-183
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• 2018

This study aims to make the stand density management diagram which is useful for establishing stand density management system in Chamaecyparis obtusa forest. By using 216 sample plots to estimate Yield-Density relationship ($R^2=0.743$), the stand density management diagram was modeled by the estimated parameters. As a result of this diagram, after planting 3,000 trees per hectare the mortality rate of this unthinned C. obtusa stands over 80 years was estimated to be equal to $12.0{\sim}18.1trees{\cdot}ha^{-1}{\cdot}year^{-1}$, and stand volume was $463.1{\sim}695.4m^3{\cdot}ha^{-1}$, and stand density was $1,555{\sim}2,038trees{\cdot}ha^{-1}$. Developed stand density management diagram for C. obtusa is effective to establish the management criteria and production objective. Therefore, this study allowed us to make the optimal forest working plan.

• Journal of Mushroom
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• v.3 no.3
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• pp.95-99
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• 2005

Carbon dioxide($CO_2$) promotes development of primordia and depress differentiation of sporophore and gill containing basidia, have an effect on quality. This experiments were conducted to elucidate optimal level of $CO_2$ for king oyster mushroom(Pleurotus eryngii). King oyster mushroom was cultivated under 1,600, 2,400, and 3,200ppm $CO_2$. Harvest ratio in normal plot were 98.6, 99.3, and 93.8% at 1,600, 2,400, 3,200ppm, respectively, so 2,400ppm is optimal. The yield per bottle was 102.5g at 2,400ppm, better than 99.7g at 1,600ppm, The $CO_2$ concentration of 2,400ppm was also the best condition for quality, 6.1 at 2,400ppm was 115% of 1,600ppm's. In thinning treatment plot, quality at 2,400ppm was 9.5 better than 1,600ppm whose quality was 9.4. The yields per bottle were 90.7, 98.2, 77.3g at 1,600, 2,400, 3,200ppm respectively. These results show that 2,400ppm was optimal $CO_2$ concentration for quantity of King Oyster mushroom as well as quality.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.191-198
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• 2008

Flow accelerated corrosion (FAC) phenomenon of low alloy carbon steels in nuclear power plant has been known as one of major degradation mechanisms. It has a potential to cause nuclear pipe rupture accident which may directly impact on the plant reliability and safety. Recently, the equipotential switching direct current potential drop (ES-DCPD) method has been developed, by the present authors, as a method to monitor wall loss in a piping. This method can rapidly monitor the thinning of piping, utilizing either the wide range monitoring (WiRM) or the narrow range monitoring (NaRM) technique. WiRM is a method to monitor wide range of straight piping, whereas NaRM focuses significantly on a narrow range such as an elbow. WiRM and NaRM can improve the reliability of the current FAC screening method that is based on computer modeling on fluid flow conditions. In this paper, the measurements by ES-DCPD are performed with signal sensitivity analyses in the laboratory environment for extended period and showed the viability of ES-DCPD for real plant applications.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.560-567
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• 1991

Photosynthetic variation in field grown soybean [Glycine max (L.) Merr. cv Hodgson78］ was studied in relation to leaf anatomical variation. Variations in mesophyll morphology were accentuated by manipulating source and sink size. At R3 stage, two treatments were started: one was thinning and continu-ous debranching(6. 5 plants rather than 26 plants per m of row and remaining plants were debranched weekly), and the other was continuous partial depodding (allowing only one pod to develop at each mainstem node). Gas exchange characteristics, mesophyll cell volume and surface area per unit leaf surface, and microclimatic parameters were measured on the intact terminal leaflet at the 10th node. Observations were made 5 times with 3 to 4 day intervals starting R4 stage. Two models were used to compute leaf photosynthetic rates: one considered no effect of mesophyll morphology on photosynthesis, and the other considered potential effects of variations in mesophyll cell volume and surface area on diffusion and biochemical processes. Seventy nine percent of total photosynthetic variations observed in the experiment was explained by the latter, while 69% of the same variations was explained by the former model. By incorporating the mesophyll morphology concept, the predictability was improved by 14.6% in the field condition. Additional Index Words: photosynthesis model, leaf anatomy, Glycine max (L.) Merr., mesophyll surface area, mesophyll cell volume.

• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.121-130
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• 1998

This study was carried out to investigate working time, productivity, and heart rate during thinning using chain saw in Japanese larch(Larix leptolepis) plantation site for analysis of physical work load, and to investigate maximal oxygen uptake of worker for analysis of maximal work capacity. The real working time was 366 minutes in a day ; about 192 minutes in the a.m., 174 minutes in the p.m.. The ratio of real working time per total working time was approximately 90%. The rate of moving(Mo) to real working times was 26.3, which was the largest one of work elements. Average maximal oxygen uptake, as an asset of personnel performance, was $2.42{\ell}/min$($46.5m{\ell}/kg/min$). During the real working time, average productivity, the mean rate of increase of heart rate, and the mean work load index was $2.62m^3/hr$, 93.2%, and 41.9%, respectively.

• Journal of Korean Society of Forest Science
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• v.97 no.3
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• pp.274-284
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• 2008

For forest valuation, various input data were generally required: for example, slope, timber stocks, logging costs, hauling costs, market values of timber, afforestation costs, thinning costs, and so on. To enhance the efficiency of forest valuation process, it would be helpful to guide how and where to acquire such data sets. Moreover, to make an appraisal of timber assets through the Forestry Household Economy Survey, it would be inevitable to use standardized input data by region or tree species. Therefore, this research intended to develop a methodology of standardizing each input data, and to present its available data sources. Also, a guidance was presented to explain how to control input data within the appraisal process. Then, the appraisal process were analyzed and summarized in four types of information such as system flowchart, process flowcharts, detail flowcharts, and skimmer data, which are essential elements in developing an appraisal software, named EnVAST (Engine of Valuation System for Timber Assets). The software was designed to generate 'the standard forest valuation table' by species and province as the final output that is applicable for the forest valuation through the Forestry Household Economy Survey in Korea.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.1
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• pp.7-12
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• 2009

In this paper, we propose a directional feature extraction method for off-line handwritten numerals by using the morphological operations. Direction features are obtained from four directional line images, each of which contains horizontal, vertical, right-diagonal and left-diagonal lines in entire numeral lines. Conventional method for extracting directional features uses Kirsch masks which generate edge-shaped double line images for each direction, whereas our method uses directional erosion operations and generate single line images for each direction. To apply these directional erosion operations to the numeral image, preprocessing steps such as thinning and dilation are required, but resultant directional lines are more similar to numeral lines themselves. Our four [$4{\times}4$] directional features of a numeral are obtained from four directional line images through a zoning method. For obtaining the higher recognition rates of the handwrittern numerals, we use the multiple feature which is comprised of our proposed feature and the conventional features of a kirsch directional feature and a concavity feature. For recognition test with given features, we use a multi-layer perceptron neural network classifier which is trained with the back propagation algorithm. Through the experiments with the CENPARMI numeral database of Concordia University, we have achieved a recognition rate of 98.35%.