• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.292-304
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• 2011

The purpose of this study is to draw institutional implications for tree cutting permit system improvement in comparison with Korea and foreign countries (German, Japan). A survey about recognition of cutting system and cutting-invigorating factors for two groups in charge of work for cutting permit (forest-official) and cutting operation (forest owner, tree butcher, forestry association, and forestry corporation) was carried out. The survey provides basic information which is necessary to improve current cutting system. The result of analysis about both German and Japan's cutting system show that clear cutting area to hinder function of forests tends to decrease and flexible final age of maturity considering condition of regional forest not uniform cutting age were applied. As a result of German and Japan's cutting system review flexible cutting system on regional characteristics is used to manage for the purpose of forest regeneration. The survey result about awareness and invigorating factors of cutting system represents that only public official group said final age of pine tree (3.13) and cedar (3.05) was proper and final age of other species of trees should have shortened. In matters of cutover area, current standard is less than 5ha per a felling area and the largest total area limit is 30 ha, only tree butcher, forestry corporation said cutover area must expand. Invigorating factors of current cutting system are reinforcement of cutover area, facility support, enrichment of technical training, increase of equipment support, simplification of administrative procedures, and provision of various benefits. The reinforcement of technical training among them especially represents the statistical significance of the participants' differential recognition.

• Journal of Forest and Environmental Science
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• v.30 no.1
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• pp.107-112
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• 2014

The productivity and cost of clear cutting operations were examined to broaden our knowledge on the harvesting system in a Larix leptolepis stand of Korea. The harvesting system was divided into tree operations which were chainsaw (STIHL MS440) felling, tower yarder (Koller301-4) yarding and harvester (WOODY H50) processing. The average cycle time of felling, yarding and processing were 98 s/cycle, 245 s/cycle and 150 s/cycle. The total stump-to-pile operational productivity was 43.07 $m^3/hr$. The highest production activity was the felling 17.93 $m^3/hr$, followed by the productivity of processing 15.62 $m^3/hr$ and then by the productivity of yarding 9.52 $m^3/hr$. In addition the total stump-to-pile operational cost was 24,086 $won/m^3$. The highest cost activity was the yarding 14,557 $won/m^3$ (60.4% of the total cost), followed by the costs of processing 8,461 $won/m^3$ (35.2%) and then by the costs of felling 1,068 $won/m^3$.

• Structural Engineering and Mechanics
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• v.31 no.1
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• pp.57-74
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• 2009

Power signals resulting from spindle and feed motor, present a rich content of physical information, the appropriate analysis of which can lead to the clear identification of the nature of the tool wear. The partial least-squares regression (PLSR) method has been established as the tool wear analysis method for this purpose. Firstly, the results of the application of widely used techniques are given and their limitations of prior methods are delineated. Secondly, the application of PLSR is proposed. The singular value theory is used to noise reduction. According to grey relational degree analysis, sample variable is filtered as part sample variable and all sample variables as independent variables for modelling, and the tool wear is taken as dependent variable, thus PLSR model is built up through adapting to several experimental data of tool wear in different milling process. Finally, the prediction value of tool wear is compare with actual value, in order to test whether the model of the tool wear can adopt to new measuring data on the independent variable. In the new different cutting process, milling tool wear was predicted by the methods of PLSR and MLR (Multivariate Linear Regression) as well as BPNN (BP Neural Network) at the same time. Experimental results show that the methods can meet the needs of the engineering and PLSR is more suitable for monitoring tool wear.

• Korean Medical Education Review
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• v.11 no.1
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• pp.3-9
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• 2009

Outcome based education, a competence based approach at the cutting edge of curriculum development, offers a powerful and appealing way of reforming and managing medical education. The emphasis is on the product that is to say what sort of doctor will be producted rather than on the educational process. In outcome based education, the outcomes are clearly and unambiguously specified such as Tyler's curriculum design. The design of outcome based curriculum plans in the opposite direction, starting with the good doctor and working backwards. Outcome based curriculum offers many advantages as a way of achieving this. It emphasises relevance in the curriculum and accountability and can provide a clear and unambiguous framework for curriculum planning which has an intuitive appeal. It encourages the faculty and student to share responsibility for learning and it can guide the assessment.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.186-193
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• 1999

Sensor feedback for process control is one of the essential elements is an automated deburring procedure. This paper presents the implementation of acoustic emission (AE), which has been developed as a feedback sensing technique for precision (mechanical) deburring, in a precision laser deburring process. AE signals were sampled for laser machining/deburring under various experimental conditions and analyzed using several signal-processing methods including AErms and spectral analysis. The results, such as the sensitivity of AE signals for different laser cutting depths, edge detection capability and the frequency analysis show a clear correlation between physical process parameters and the AE signals. A subsequent control strategy for deburring automation is also briefly discussed.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.185-193
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• 2007

The object of this study is the development of a Method which is enable to review the preliminary feasibility for co-generation system in new apartment buildings. In Korea co-generation systems have been installed in most of large industrial plants and commercial buildings which consume a large quantity of electric and heat energy, for energy saving and cutting products cost, under positive governmental supports. However for apartment buildings which consume quite a large electric and heat energy, are still remained in conventional energy supply system, and are not popular to utilize useful co-generation system. One of the major reason for these is the lack of clear and easy justification tool. In this circumstance, this study can provide a tool to verify the feasibility of co-generation in apartment buildings with this handy tools for planners and designers beforehand.

• Progress in Medical Physics
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• v.31 no.3
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• pp.99-110
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• 2020

With hope and concern, the first Korean proton therapy facility was introduced to the National Cancer Center (NCC) in 2007. It added a new chapter to the history of Korean radiation therapy. There have been challenging clinical trials using proton beam therapy, which has seen many impressive results in cancer treatment. Compared to the rapidly increasing number of proton therapy facilities in the world, only one more proton therapy center has been added since 2007 in Korea. The Samsung Medical Center installed a proton therapy facility in 2015. Most radiation oncology practitioners would agree that the physical properties of the proton beam provide a clear advantage in radiation treatment. But the expensive cost of proton therapy facilities is still one of the main reasons that hospitals are reluctant to introduce them in Korea. I herein introduce the history of proton therapy and the cutting edge technology used in proton therapy. In addition, I will cover the role of a medical physicist in proton therapy and the future prospects of proton therapy, based on personal experience in participating in proton therapy programs from the beginning at the NCC.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.502-514
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• 2023

This study was conducted to understand the long-term changes in soil physiochemical properties and seedling growth in Larix kaempferi (larch) stands planted in clear-cut larch and Pinus rigida (pine) forest soils over an 11-year period after reforestation. Two-year-old bare-root larch seedlings were planted in 2009-2010 at a density of 3,000 seedlings ha^-1 in clear-cut areas that harvested larch (Chuncheon and Gimcheon) and pine (Wonju and Gapyeong) stands. We analyzed the physiochemical properties of the mineral soils sampled at 0-20 cm soil depths in the planting year, and the 3^rd, 7^thand 11^th years after planting, and we measured seedling height and root collar diameter in those years. We found significant differences in soil silt and clay content, total carbon and nitrogen concentration, available phosphorus, and cation exchangeable capacity between the two stands; however, seedling growth did not differ. The mineral soil was more fertile in Gimcheon than in the other plantations, while early seedling growth was greatest in Gapyeong. The seedling height and diameter at 11 years after planting were largest in Wonju (1,028 tree ha^-1) and Chuncheon (1,359 tree ha^-1) due to decreases in stand density after tending the young trees. The soil properties in all plantations were similar 11 years after larch planting. In particular, the high sand content and high available phosphorus levels (caused by soil disturbance during clear-cutting and planting) showed marked decreases, potentially due to soil organic matter input and nutrient uptake, respectively. Thus, early reforestation after clear-cutting could limit nutrient leaching and contribute to soil stabilization. These results provide useful information for nutrient management of larch plantations.

• Korean Journal of Environment and Ecology
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• v.16 no.2
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• pp.149-159
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• 2002

Dwarf bamboo(Sasa borealis) is a dominant understory species in the various forest types in Korea. The objective of this study was to investigate vegetation structure of Sasa borealis and effects of Sasa on the growth of overstory tree species along the forest development after clearcutting. Three representative stand types with and without S. borealis in Baekwoonsan, Chonnam province were selected in 1998 for this study: uncutting stands(natural deciduous forests with overstory vegetation), 1987-cutting stands (11 years after clearcutting), and 1993-cutting stands(5 years after clearcuting). Vegetation type was largely classified into Sasa borealis dominant type and Sasa borealis recessive or absent type. The former composed of four associations including Quercus serrata-Carpinus laxiflora / Sasa borealis community, Cornus controversa-Morus bombysis / Sasa borealis community, Styrax japonica-Styrax obassia / Sasa borealis association, Zelkova serrata / Sasa borealis community. The latter divided into six associations including Quercus serrata / Lindera erythrocarpa community, Cornus controversa / Lindera erythrocarpa community, Quercus serrata / Acer pseudosieboldianum / Deutzia glabrata community, Fraxinus rhynchophylla-Quercus serrata / Lindera erythrocarpa / Euonymus alataus community, Rubus crataegifolius-Hydrangea macrophylla community, Rubus crataegifolius-Lespedeza bicolor community. Distribution of Sasa, borealis by developmental stages of forests showed that in natural stands was dominant understory, but was various pattern in two cutting stands. Mean annual ring growth of Quercus serrata and Carpinus laxiflora during the last 35 years had not been affected by presence of Sasa, based on comparisons in annual ring growth between Sasa-present and Sasa-absent stands. In conclusion, dense crown of Sasa borealis suppressed the invasion of other shrubs or annuals and facilitated later stages of plant succession by promoting growth of shade-tolerant tree species after clear cutting.

• Journal of Forest and Environmental Science
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• v.9 no.1
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• pp.81-95
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• 1993

The purpose of this study is to analyze the historical development process on management plan and regulation in Japan in order to contribute to the systmatic management plan of national forest in Korea. Before the World War II, remarkable national forest management plan in Japan was introduction of the normal forest ideas by the management plan of the combination system of maximum forest rent and maximum soil rent, employing the clear-cutting of small area, simplified area-period method, and about 70-80 years rotation. After World War II, enterprise management was developed from the previous combination system. During the rapid economic development period, the original working system and normal forest ideas were not recognized, so that the destructions of forest and environment were resulted from the yield of future increment and clear-cutting of large area. During the slow economic development period, on the other hand, the reproduction of forest resources was difficult, as the result of the negligent management system and the depression of management. Future management system of national forest, therefore, should establish the working system and the management plan for the purpose of both forest resources reproduction and environment maintenance, simultaneously.