• Journal of the Korean Society of Environmental Restoration Technology
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• v.22 no.3
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• pp.1-14
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• 2019

With a view to developing a database of death years of Korean firs (Abies koreana) at Yeongsil in Mt. Halla and investigating their abrupt inter-annual growth reduction tree-ring analysis was employed. To this end, 10 living trees (YSL) were selected to establish a master chronology and 20 dead trees were used to date their dead years. To investigate the difference in death years by death types, 10 trees, which remained standing (YSSD) out of the 20 dead trees were selected. The rest 10 dead trees were already fallen (YSFD). Two increment cores per tree at breast height were extracted in contour direction using an increment borer. A 106-year master chronology (1911-2016) was successfully established from the 10 YSLs. Through cross-dating between individual YSSD time series and the master chronology, it was verified that 1 YSSD was dead in summer 1978, 1 YSSD between autumn 1999 and spring 2000, 2 YSSDs in summer 2007, 1 YSSD in summer 2010, 1 YSSD in summer 2012, and 1 YSSD in summer 2013. The youngest tree rings of 2 YSSDs having no bark were in 1977 and 2002. For the YSFDs, it was verified that 1 YSFD was dead between autumn 1997 and spring 1998, 1 YSFD between autumn 2001 and spring 2002, 2 YSFDs between autumn 2009 and spring 2010, 1 YSFD in summer 2010, and 2 YSFDs between autumn 2012 and spring 2013, while the youngest tree rings of 2 YSFDs having no bark were in 1989 and 2004. To note, the death years of two trees, one from each death type (YSSD and YSFD), could not be verified due to poor cross-dating with the master chronology. The inter-annual growth reductions of YSSD and YSFD occurred more frequently and intensively than YSL. Typically, the YSFD showed the most frequent and intensive inter-annual growth reduction. On comparing the inter-annual growth reductions with the corresponding records of typhoons however we could not find any reliable relationship. Finally, from prior reports and results of the current study it can be concluded that the death and abrupt growth reduction of korean fir at Yeongsil in Mt. Halla are not caused by only a certain environmental factor but various factors.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.54-65
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• 1993

The paper describes and alternative method based on a new idea to measure the circular movement of machining centers. ISO has employed three testing methods for the acceptance tests of machine tools; the first is a rotating one-dimensional probe method, the second is a two-dimensional probe and a master circular ring, and the third is a kinematic ball bar. The last two methods were proposed and introduced by W. Knapp and J. B. Bryan, respectively. The newly developed method is superior to above two methods; the rotating angle can be detected and the rotating radius is variable. Circular movement errors of machining centers were investigated by the analysis of data measured by R- .THETA. method. Followint observations are obtained 1) The errors which depend on positions, i.e., periodical errors by the pitch of ball screws, errors by compensation of backlash and errors by perpendicularity of X and Y-axis, were analyzed. 2) The errors which depend on NC control system, i.e., errors by the unbalance of position-loop-gaians, errors by velocity-loop-gains and errors by feed speeds, were quantiatively analyzed. 3) The method of extracting error information, which uses moving technique of averaging angle and fourier's analysis data mesured by the R- .THETA. method, was proposed.

• Journal of architectural history
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• v.15 no.2
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• pp.95-114
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• 2006

This study was conducted on the premise that plan types of the public residential houses proposed after the 1945 implicatively showed the developing process of the modern housing. The formal characteristics created through the developing process were analyzed in Micro-Historically. Moreover, by providing a new viewpoint on the changes of the residential houses that occurred around 1945, we tried to provide the fundamental research background for the research on the developing processes of the future housing cultures. The research pursued mainly on the major spaces that became the modern change indices of housing plan changes from the traditional housings in 1940s to the modern housings such as the master bedrooms(An-Bang), kitchen, the main floored-space(Maru), and the secondary bedroom (Kune-Bang). The major experimental subjects are the 87 public residential plan types designed and supplied by the Korea Housing Cooperation in between 1945 and 1970. The study synthesized the developing process of the public residential houses from the traditional residential houses in 1940s through modern situation and intrusion of foreign housing cultures. Following results were derived from the study: First, various and experimental housing plan types had been proposed as public residential houses since 1945. Among them, the plan having the main floored-space(Maru) were the representative type of public residential houses and various series of houses were constructed based on this type. Second, the main floored-space(Maru) type had continued building connection order of the R-M-R that were used in the traditional houses. On the other hand, with decomposition of connecting ring between the main floored-space(Maru) and the kitchen, rationalization of women circulations and introduction of family-centered spaces had been resolved the demands of modern society. It had greate effect on settlement of the current double-row Maru plan type. Third, in Korea most of plan types for the public residential houses were proposed in between 1945 and 1965. Forth, the location of kitchen and relation between Maru and the master bedroom were arranged visually on the corner and center of the rear row with the micro change characteristics of the public residential houses. In this process, the front row was similar with traditional residential houses but the rear row was differentiated and developed with expansion of Maru and Ondol rooms, increase of closet spaces, and introduction of kitchen that divided spaces for sleeping and eating.

• Journal of the Korean Magnetics Society
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• v.26 no.2
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• pp.62-66
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• 2016

We designed a model composed a ring type magnet, a yoke, and a sensing coil buried in a projectile for calculating the muzzle velocity based on the voltage induced from sensing coil by simulation. The muzzle velocity was calculated from the master curve obtained through the voltage induced from sensing coil by simulation. The induced voltage increased with increasing the diameter of sensing coil. The projectile's velocity was proportional to the induced voltage when the sensing coil was buried in projectile. The projectile will be surely exploded at the target region by inputting the information of muzzle velocity variation corrected the diameter effect of induced voltage of sensing coil.

• Fashion & Textile Research Journal
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• v.16 no.2
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• pp.185-195
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• 2014

This study is to develop marine fashion items for various marine leisure activities based on the identity of Busan. Motifs from the fireworks festival and image colors of Busan are introduced for the items. A prototype design to express uniqueness and characteristics of fireworks was produced with a line combination among design modeling factors and applied to T-shirt item for comfort use in the marine leisure activity and daily life. T-shirt is one of fashion items for a message communication due to a unique modeling which can be used an excellent advertising item for the culturel identity and image of Busan. Designs were produced with the characteristics of fireworks in which circular shapes of a chrysanthemum, ring, and peony designates as motif 1, 2, 3 as well as linear shape of Niagara, fan shape, and tiger-tail as motif 4, 5, and 6. These designs were located on the front, central chest, and left chest in the T-shirts then analyzed by major students in the course of master and doctor of clothing and textiles with statistical methods. A design with new coloring preferred than the design of a symbolic construction, and circular design on the front and linear design on the left chest were preferred in the results. Prototypes were produced with peony and tiger-tail design which show a high corelation between circular and linear shape, and coloring as well as high purchasing needs. This study results will expect to use for the development of advertising items for the various events of Busan based on the textile design and fashion items with the identity of Busan.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.131-134
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• 2005

This paper describes the efficient peer-to-peer migration method of Grid service agent on the mobile agent based P-Grid. The migration mechanism for transmitting service agent upon the service request is based on the peer's logic network topology. The network topologies that this system uses are organized as star topology, ring topology and tree topology, and agents are migrated by the master/slave method and serial/parallel method. The migration method of services is chosen based on the execution range and characteristic of the requested service. Also, the entire execution time of service is affected by the performance of peer that is a part of network topology, and the migration order, Therefore, the system monitors the performance of peers, and determines the migration priority based on analyzing and learning history. The system can reduce service execution time efficiently with decisions of migration method for service agent and priority of peers.

• The Journal of Korea Robotics Society
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• v.1 no.1
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• pp.17-24
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• 2006

Though the final goal of mobile robot navigation is to be autonomous, operators' intelligent and skillful decisions are necessary when there are many scattered obstacles. There are several limitations even in the camera-based tele-operation of a mobile robot, which is very popular for the mobile robot navigation. For examples, shadowed and curved areas cannot be viewed using a narrow view-angle camera, especially in bad weather such as on snowy or rainy days. Therefore, it is necessary to have other sensory information for reliable tele-operations. In this paper, sixteen ultrasonic sensors are attached around a mobile robot in a ring pattern to measure the distances to obstacles. A collision vector is introduced in this paper as a new tool for obstacle avoidance, which is defined as a normal vector from an obstacle to the mobile robot. Based on this collision vector, a virtual reflection force is generated to avoid the obstacles and then the reflection force is transferred to an operator who is holding a joystick to control the mobile robot. Relying on the reflection force, the operator can control the mobile robot more smoothly and safely. For this bi-directional tele-operation, a master joystick system using a hall sensor was designed to resolve the existence of nonlinear sections, which are usual for a general joystick with two motors and potentiometers. Finally, the efficiency of a force reflection joystick is verified through the comparison of two vision-based tele-operation experiments, with and without force reflection.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.443-447
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• 2019

Aryl hydrocarbon receptor (AhR) is the master regulator of xenobiotics metabolizing enzymes (XMEs). AhR is activated by aryl hydrocarbons upon binding then goes into the cell nucleus and acts as a transcription factor. Despite the role of AhR in human physiology has been investigated for a long while, it is yet to be understood mainly due to the lack of appropriate chemical agents. Furthermore, it has been reported that AhR is related to a wide range of pathogenesis. In addition, recent studies suggest that the study on the development of AhR antagonist may provide a valid therapeutic agent. Some known antagonists in current use are partially agonistic whereas a pure antagonist is still absent. In this study, two phenyl-ring structures of phenyldiazenylphenylpicolinamide has been modified into various structures and evaluated its impact on the AhR antagonistic activity to elucidate the structure-activity relationship.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.102-121
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• 2010

Three bronze bells excavated from the Hoeamsa temple site were investigated for their microstructures and chemical compositions in an effort to understand the technology applied in fabrication, which may represent the related industry established in the early Joseon period. The result shows that the bells were cast from alloys of approximately 85% copper-8% tin-7% lead. The chemical analysis for ten trace elements shows that they were all kept below 0.3 weight %, suggesting that the alloys were made of relatively well-refined copper, tin and lead. The presence of sulfur and iron indicates that chalcopyrite or chalcocite may have been used in the smelting of copper. Evidence has been found that the bells were cast by pouring the liquid metal from the top of the sand molds that were set up in an upright position. No additional treatments, thermal or mechanical, other than a little grinding were applied upon the completion of casting. After the shaping process, a balancing plate was attached to the top of the bell using a steel connection ring. The connection assembly was then fixed to the main body by using molten bronze as a solder. The surface inscription was found carved using different techniques. The differences in the order of strokes and the calligraphic style indicate that the carving was carried out by more than one master. In the absence of documentary evidence on past bronze technology, the present bronze bells with known chronology, provenance and the main agent of production, prove to be a rare and valuable archaeological material for the understanding of the related technology in use in the early Joseon period.

• The Korean Journal of Nuclear Medicine
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• v.38 no.5
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• pp.338-343
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• 2004

Purpose: The purpose of this study was to develop a small animal PET using dual layer phoswich detector to minimize parallax error that degrades spatial resolution at the outer part of field-of-view (FOV). Materials and Methods: A simulation tool GATE (Geant4 Application for Tomographic Emission) was used to derive optimal parameters of small PET, and PET was developed employing the parameters. Lutetium Oxyorthosilicate (LSO) and Lutetium-Yttrium Aluminate-Perovskite(LuYAP) was used to construct dual layer phoswitch crystal. $8{\times}8$ arrays of LSO and LuYAP pixels, $2mm{\times}2mm{\times}8mm$ in size, were coupled to a 64-channel position sensitive photomultiplier tube. The system consisted of 16 detector modules arranged to one ring configuration (ring inner diameter 10 cm, FOV of 8 cm). The data from phoswich detector modules were fed into an ADC board in the data acquisition and preprocessing PC via sockets, decoder block, FPGA board, and bus board. These were linked to the master PC that stored the events data on hard disk. Results: In a preliminary test of the system, reconstructed images were obtained by using a pair of detectors and sensitivity and spatial resolution were measured. Spatial resolution was 2.3 mm FWHM and sensitivity was 10.9 $cps/{\mu}Ci$ at the center of FOV. Conclusion: The radioactivity distribution patterns were accurately represented in sinograms and images obtained by PET with a pair of detectors. These preliminary results indicate that it is promising to develop a high performance small animal PET.