• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.85-95
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• 2017

This study aimed at more precisely estimating the age of big old trees using dendrochronological method. Gesan-gun in Chungbuk (CBGS), Gurye-gun in Jeonnam (JNGR) and Uljin-gun in Gyeongbuk (GBUJ) were study areas and Zelkova serrata (ZS) and Pinus densiflora (PD) selected as protected trees therein were used as experimental tree species. The increment cores were extracted from 12, 8, and 6 ZSs and 10, 3, and 9 PDs in CBGS, JNGR, and GBUJ, respectively, using an increment borer (${\phi}5.2mm$). In order to clearly distinguish tree-ring boundary, the surface in the transverse section was cut for ZS using a sliding microtome and sanded for PD using a sand paper. Ring widths were measured in the resolution of 0.01 mm. Based on the measurement values, 203-year long (1813-2015) ZS local master tree-ring chronologies were successfully established and 175-year long (1841-2015) ZS local master tree-ring chronology for JNGR was also successfully established. In the case of PD, 154-, 175-, and 250-year long local master tree-ring chronologies for CBGS, JNGR, and GBUJ were successfully established, respectively. In the comparisons between local master tree-ring chronologies, they showed low t-values and Glks. According to the comparisons of the local master tree-ring chronologies with 50-year (1950~2000) average temperature and precipitation distribution maps, the annual variations of local master tree-ring chronologies seem to be determined by not temperature but precipitation. For such cross-dating therefore more local master tree-ring chronologies have to be established at the least based on the distribution map for precipitation.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.535-542
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• 2002

This paper show communication network scheme problem for the railway is solved which were electrical noise and line break in wayside using rerouting communication line, Considering the availability and the maintainability based on the reliability in design of communication networks. At first, Self-Healing Ring algorithm is suggested in that solution which is satisfied with above requirements. And also, in the advanced type, Dual Master scheme is suggested that the problem which is occurred in line break of both main and sub line at the same time can be solved using DMSHR(Dual Master Self Healing Ring). Therefore total reliability in railway system is going to be advanced using DMSHR scheme.

• Journal of the Korean Wood Science and Technology
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• v.47 no.6
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• pp.700-708
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• 2019

To verify the possibility of using resistograph to estimate the age of big old living trees, we selected three Zelkova serrata and seven Pinus densiflora in Goesan. The mean diameters at breast height of Z. serrata and P. densiflora were 102 (92-116) cm and 80 (65-110) cm, respectively. The heights measured from the ground using a resistograph ranged at 1.2-4.3 m and 0.6-1.1 m for Z. serrata and P. Densiflora, respectively. The most appropriate needle speed to determine tree-ring boundaries for measuring ring width was 1500 r/min for both tree species. Alternatively, the suitable feed speeds for Z. serrata and P. densiflora were 50 cm/min and 150 cm/min, respectively. From the measured data, the mean numbers of tree rings of Z. serrata and P. densiflora were 57 (43-68) and 104 (93-124), respectively, and the mean tree-ring widths were 4.27 mm (3.18-5.09 mm) and 2.93 mm (2.32-3.34 mm), respectively. A comparison between the time series of tree-ring widths by resistograph and that from the local master chronologies tallied for the heartwood part. Finally, this study showed that resistograph can be used to estimate tree ages when a local master chronology is available.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.2
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• pp.24-29
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• 2002

A study for the circularity of machine tool is classified into two ways. One is to measure the circularity of machine tool by a existing measuring device. The other is to measure the circularity by remodeling the existing measuring device. We will improve on measurement of circularity using circular test method by a two-dimensional probe and a master ring for machining tools and investigate influence of trigger method, acceleration data sampling.

• Journal of the Korea Furniture Society
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• v.23 no.1
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• pp.95-102
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• 2012

The objective of this study was to conduct the species identification and tree-ring dating of Lotus Pedestal of the Amitabha Statue at Ssangbong-Temple in Hwasun. The six wood blocks used for the Lotus Pedestal were hard pines (Pinus spp.; diploxilon) except one piece which was ginkgo (Ginkgo biloba L.). The lotus leaves surrounding the pedestal body were also made of ginkgo. Tree-ring patterns of 3 blocks were synchronized and a 133 years chronology was made. The chronology was crossdated well with the master chronology of Japanese red pine in South Korea. It dated back to A. D. 1551~1683, i.e. the last ring dated A. D. 1683. Through the estimation of the number of sapwood rings removed during carving, the felling year was calculated A. D. $1704{\pm}10$. The calligraphic writing on the Pedestal indicated that this statue was made in A. D. 1694. Therefore, the accuracy of the tree-ring dating has been proven.

• 한국문화재보존과학회:학술대회논문집
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• 2005.11a
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• pp.300-305
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• 2005

Tree-ring chronologies can be used to date historical buildings and furniture by matching them with the chronologies of living trees or previously dated samples. Tree-ring dating gives a calender year to each tree ring and produces the felling dates of logs or woods which had been used for buildings. In Korea, several chronologies of Japanese red pine(Pinus densiflora Sieb. et Zucc.,'sonamu' in Korean), a major species for the wooden building materials, have been developed and used for dating historical buildings. Daejojeon of Changduck Palace is known to be reconstructed in A.D. 1920 after burned-out in A.D. 1917. Instead of new woods, Daejojeon was reconstructed by reusing the woods of Kyotaejeon in Kyungbok Palace. We sampled total of 26 wood samples which were replaced during the repair process of Daejojeon in 1995. Felling dates of the samples were determined by the dendrochronological crossdating method. Crossdating method employs graphic comparison of the master patterns (ring-width plots of living trees or known dates) with those of the sample chronologies of unknown dates. The cutting dates of Daejojeon woods were divided in two groups. One was the late 1860s and the other 1880s. The results confirmed that Kyotaejeon was reconstruced first in the A.D 1860s and then in late 1880s after burning out in 1876.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2007.10b
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• pp.49-53
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• 2007

The purpose of this study is to consider the idea and the background of the establishment of master plans for parks and green spaces of metropolis in Japan, China and Korea after a careful comparative review of layout planning of green areas, plan objectives, future images and main measures. The method of study is the analysis of the control and plans in these three countries. The study reveals the characteristic of each plan as follows: 1) the conservation and revitalization of the shape of land and the river system in Tokyo; 2) the materialization of ideal green spaces in Beijing, the combination of the ring green and the radial layout of parks and green spaces; 3) the combination of cruciform greenery and the utilized existing public open spaces in Seoul. The result also shows that these cities have the different development of projects but face the common challenges.

• Journal of architectural history
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• v.12 no.3
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• pp.53-63
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• 2003

Tree-ring chronologies can be used to date historical buildings by matching them with the chronologies of living trees or previously dated samples. Tree-ring dating gives a calendar year to each tree ring and produces the felling dates of logs or woods which had been used for buildings. In Korea, several chronologies of Japanese red pine(Pinus densiflora Sieb. et Zucc., 'sonamu' in Korean), a major species for the wooden building materials, have been developed and used for dating historical buildings. In this study, Tongmyungjeon Hall of Changkyung Palace in Seoul was dated by tree rings. The present Tongmyungjeon Hall was known to be reconstructed in A.D. 1834 after burned-out in A.D. 1790. We sampled total of 122 wood samples which were replaced during the repair process in 2002-2003. Felling dates of the samples were determined by the dendrochronological crossdating method. Crossdating method employs graphic comparison of the master patterns (ring-width chronologies of known dates) with those of the sample chronologies of unknown dates. Tree-ring dates confirmed that the reconstruction of 1834 utilized second-handed timbers as well as fresh-cut ones. The felling dates of wooden floor frames were mostly A.D. 1913, indicating the 'Ondol' floors were changed to the wooden floors around 1914 when the Japanese rulers brutally destroyed the royal Korean Palaces and transformed palace buildings to their offices or exhibition halls after occupying Korea in 1910. This study proved that tree-ring dating was a useful and accurate method to identify the critical dates for the history of Korean traditional buildings.

• Journal of the Korean Wood Science and Technology
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• v.44 no.4
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• pp.515-525
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• 2016

The Palsangjeon Pagoda is a five-story wooden building in the Beopjusa Temple area in the Songnisan national park in Chungcheongbuk-do, Korea. According to historical records, it was constructed in either AD 1605 or AD 1626. To specify the construction year more precisely, we took 41 wood samples for tree-ring analysis during repair actions in 2013; 28 from red pine (Pinus densiflora S. et Z.), 12 from oak (Quercus spp.), and 1 from fir (Abies spp.). The tree-ring boundaries became clearly visible by smoothing their cross-sectional surface and the tree-ring widths were measured under a stereo microscope. All tree-ring series were compared with each other to establish mean chronologies, which we then compared with local master chronologies established using tree rings collected from wooden elements of the Daeungjeon Hall which is the main building in the Beopjusa Temple area. As a result, it was verified that the red pines were felled in AD 1624 and in AD 1851. Moreover, it was verified that the oaks were also felled in AD 1624 based on cross-dating with the red pine chronology. We concluded that the Palsangjeon Wooden Pagoda was constructed in AD 1626, as mentioned in the historical record (Daeungdaekwangmyeongjeonbulsangki, 1630) and the letters on a purlin on the $4^{th}$ story, using oak and red pine felled in AD 1624 and repaired later on using red pine felled in AD 1851.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2646-2653
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• 1993

A rotational torque calibration system is developed to measure rotational torque of power generating systems and to calibrate non-contact rotational torque measurement systems. The maximum capacity of the developed system is 4.5 N-m. It is composed of a DC motor, a DC generator, a control system, a master torque cell, a slip ling/brush set, supporters, a bed etc. The control system is characterized by the closed-loop control with differential intergrator. Rotational torque measurement test and unit response test are conducted to estimate the accuracy of the developed system. It is found that system maintain high consistency and accuracy with the maximum error of 0.25%, Therefore the developed system can be used to measure the rotational torque of power generating systems and to calibrate non-contact rotational torque measurement systems.