• Proceedings of the KIEE Conference
• /
• 2002.06a
• /
• pp.161-165
• /
• 2002

The paper presents a diagnostic tool for analyzing the bit intermodulation in D/A converter. Bit intermodulation cause linearity errors which degrade the performance of the converter. A linear transformation of the Walsh transform of the integrated non-linearity diagram is shown to be sufficient to extract the bit intermodulation terms and their noise sensitivity. Practical applicability of the proposed method is shown by measurement.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.8 no.3
• /
• pp.107-120
• /
• 2005

In Korea, MOCT and KOWACO published a standard for lineament map drawings, "The Handbook for the Drawing and Management of Hydrogeologic Map" in 2003. According to this guideline, hydrogeologic and related thematic maps should include characteristics of groundwater quality and quantity. These maps are generally drawn with ArcView GIS 3.x software. The activities of well notation on groundwater level map and Stiff diagram drawings on groundwater quality map require a great deal of efforts because hundreds or thousands of well data, water level data and hydrogeochemical data are produced through many kinds of investigations. As well, lineament density map is very important to survey and explore groundwater in a deep aquifer. In this study we developed some modules for well notation, Stiff diagram drawings, and lineament density value calculation with Avenue$^{TM}$ script and it was revealed that they can be very useful and easy for drawing groundwater thematic maps.

• Journal of the Korean Electrochemical Society
• /
• v.18 no.2
• /
• pp.68-74
• /
• 2015

To compare the microstructure and electrochemical properties between two binary alloys (Cr-Si, Ni-Si), two composition of binary alloys with the same capacity were selected using phase-diagram and prepared by matrix-stabilization method to suppress the volume expansion of Si by inactive-matrix. Master alloys were made by Arc-melting followed by fine structured ribbon sample preparation by Rapid Solidification Process (RSP, Melt-spinning method) under the same conditions. Also powder samples were produced by wet grinding for X-Ray Diffraction (XRD) and electrochemical measurements. As predicted from the phase diagram, only active-Si and inactive-matrix ($CrSi_2$, $NiSi_2$) were detected. The results of Scanning Electron Microscope (SEM) and Transmission Electron Microscopy - Energy Dispersive X-ray Spectroscopy (TEM-EDS) show that Cr-Si alloy has finer microstructure than Ni-Si alloy, which was also predictable through phase diagram. The electrochemical properties related to microstructure were evaluated by coin type full- and half-cells. Separately, self-designed test-cells were used to measure the volume expansion of Si during reaction. Volume expansion of Cr-Si alloy electrode with finer microstructure was suppressed significantly and improved in cycle capability, in comparison Ni-Si alloy with coarse microstructure. From these, we could infer the correlation of microstructure, volume expansion and electrochemical degradation and these properties might be predicted by phase diagram.

• Journal of Korean Society of Forest Science
• /
• v.105 no.3
• /
• pp.342-350
• /
• 2016

This study aims to make the stand density management diagram which is very useful for establishing systematic management plan and obtaining management goal in Pinus densiflora forest. To estimate 5 models mainly composed of stand density management diagram, we used total of 1,886 sample plots having more than 75% of the total basal area of the pine trees in each stand. To test the goodness of fit, $X^2$ was computed with a significance level of 5%, and the acceptable error range as 20%. Also standard deviation of the model was $34.59m^3{\cdot}ha^{-1}$, minimum acceptable error range was 16.59% and coefficient of variation was 22.11%. If we use the stand density management diagram, it would be useful to establish the timber yield and thinning plan understanding the pathway of stand density management.

• Journal of The Korean Astronomical Society
• /
• v.28 no.2
• /
• pp.153-167
• /
• 1995

More than 22,300 stars in NGC 6752 were measured over the region of 5' < r < 23' in B and V AAT plates. The most of these are main sequence(MS) stars and about 130 blue horizontal branch(BHB) stars were detected. The C-M diagram of all measured stars shows gaps appearing at $V{\approx}15.^{m}2$ and $16.^{m}2$ along the red giant branch(RGB) and their appearance shown by Lee & Cannon(1980) is found to be independent of measured region. The bimodal distribution of BHB stars is confirmed again and a wide gap shown by Lee & Cannon(1980) at $V{\approx}16^m$ is clearly seen for stars in the outer part (8' < r < 13') in the cluster. It is noted, however, that this gap is occupied by about a dozen of BHB staIs located in the inner region (5' < r < 8'). The number ratio of bright BHB star (V < $15^m$) to faint BHB stars (V > $15^m$) decreases with increasing radial distance from the cluster center. Three faintest BHB stars were found, and two stars ($V{\approx}18.^{m}5$) of there are located in the inner region of $r{\approx}6'$ and the other faintest one ($V{\approx}19.^{m}3$) located in the outer part of $r{\approx}13'$. Also a bluest star of (B - V) $\approx$ -0.5 at $V{\approx}17.^{m}2$ is found but it is located at the outer part of $r{\approx}13'$ in NE region. Therefore, the membership of the faintest BHB star and bluest star is suspected. The luminosity function(LF) and mass function(MF) for NGC 6752 were derived for MS stars. The LF for stars of $M_v\;<\;6^m$ in the outer part of r > 8' shows a consistency with that derived by Penny & Dickens(1986).

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.8
• /
• pp.734-741
• /
• 2010

In this paper, an intake RCV system for low noise turbo engine was developed through optimization process of a geometric path of compressor housing and an open rate of recirculation valve. At first, the critical customer requirement from voice of customer was defined and quality function deployment of an intake RCV system was executed. And then, the renovative concept design using pugh matrix method was selected as final concept for satisfaction of requirement. Simultaneously, system analysis was carried by function diagram and fishbone diagram. Next, control factors and levels for the optimal design were performed. And, the optimal design of an intake RCV system was studied using design of experiment. Conclusively, we achieved not only cancellation tip-out noise at the driving condition but also improvement of NVH commodity through optimization process of an intake RCV system, which is optimal configuration of compressor housing and recirculation valve.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.2
• /
• pp.259-266
• /
• 2009

An experimental study was conducted to investigate the effects of forcing amplitude on the flow structure near the nozzle exit of forced jet diffusion flames. The jet was excited up to the blowout occurrence by a considerable large amplitude with a periodic velocity fluctuation at the tube resonating frequency. In the attached flame regime, we disclosed the very interesting result newly that adding of a moderate forcing amplitude caused the jet flame to become longer in spite of being forced. Particular attention is focused on the turnabout mechanism of vortex roll-up around the elongated flame, which has not been reported previously, and on the inner coherent structure of the forced jet in the attached flame regime. From the velocity and flow visualization results, it was ascertained that the surrounding air due to the occurrence of negative velocity parts was suck into the fuel nozzle. To aid in understanding the rotating phenomenon of coherent structure, we present a schematic diagram of the turnabout mechanism of vortex roll-up. The mechanism of vortex turnabout phenomenon can be easily understood by considering the positive and negative velocity amplitudes about the instantaneous velocity of the forcing flow, as shown in this diagram.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.31 no.12
• /
• pp.1214-1220
• /
• 2007

The vertical roller mill, which performs the grinding and partly blending of raw material, is the one of the important machine to produce ordinary portland cement. It has been reported that an unexpected fatigue failure occurred in a table liner in the course of grinding portland cement. The life of table liner is estimated to $4{\times}10^7$ cycles in the design stage, but at the field, when its operating time reaches to $2{\times}10^6{\sim}8{\times}10^6$ cycles, the fracture of table liner begins to be found. The fracture of table liner is initiated from the outside edge of grinding path contacting with the grinding roller. Its maintenance normally take 30 % of the total maintenance costs of the roller mill. Therefore, this study shows the clarification of the reasons occurring the fatal destruction of the table liner by fatigue fracture analysis utilizing fracture mechanics and by the finite element method. And, the results from Goodman diagram illustrate relationship of including information on the transition between tensile and bending fatigue strength in the fatigue characterization of table liner.

• The Korean Journal of Ecology
• /
• v.16 no.1
• /
• pp.75-91
• /
• 1993

Structure and dynamics of Abies koreana community in Mt. Gaya were studied to provide the basic data for conservation of Abies koreana community, an endemic species in Korea. A. koreana community of this study site was composed of tree layer (4~7m), subtree layer (2~4m), shrub layer (1~2m), and herb layer (below 1m). The heights of tree and subtree layers were low. Floristic composition showed that this study site was subalpine and dry site. In frequency distribution diagram of diameter classes of major species consisting of A. koreana community, those of both A. koreana and other species showed reverse J-shaped types. From these results, it was estimated that A. koreana community of this site might be maintained continuously as a stable climax state like present state. In the spatal distribution diagram of major species, saplings of A. koreana were established under the canopy of A. koreana and Pinus koraiensis and under the dead tree of A. koreana. From these results, it was known that A. koreana saplings were recruited before the community was disturbed and regeneration was accomplished by advance regeneration pattern, in which these saplings established before occurrence of disturbance fill with open site originated from death of mature tree. Growth of annual rings was variable among individuals, it was estimated that such variation was originated in that growth of each individual relates to microclimatic conditions rather than macroclimatic ones. Ecological longevity of A. koreana in this study site estimated by disturbance types and age of dead trees was about 120 years.

• Journal of Acupuncture Research
• /
• v.18 no.3
• /
• pp.171-183
• /
• 2001

Objective : To study the effects and merits of the Yanzhen Therapy(眼針療法), Method : We researched through studying 28 kinds of literature. Result : 1. The Division of Eye Region(眼區分劃), the Position of Yanxue(眼穴定位) and the mutual connection with Internal Organ(臟腑) during the Yanzhen Therapy(眼鍼療法) were made according to Huata's Thesis, and were made by combining Neijing(內經) Theory about eyes, Yinyang and Five Elements(陰陽五行) Theory, Meridian & Zang-Xiang Theory(經絡臟象學說), the Five Circles & Eight Regions(五輪八廓學說) Theory, and the Zhouyi Eight Diagrams(周易八卦) Theory. 2. The assignment between the Internal Organ and Eye-Division(眼區分劃) was formed on the basis of the Five-Circles and Eight-Regions Theory in Ophthalmology(眼科五輪八廓學說) of Zhengzhizhunsheng(證治準繩). 3. The Assignment(排列) & Position(方位) of the Congenital Eight Diagram(先天八卦) and the Acquired Eight Diagram(後天八卦) have influenced the Division of Eight Eye Region(眼鍼八區) and the Position of Yanxue(眼穴定位) significantly. 4. It showed no difference with the Map of Eye Position of Eight-Division(八廓眼位圖) like as Shenshiyaohan(審視瑤函), Yinhaizhinan(銀海指南) and Sanzijing of Ophthalmology(眼科三字經). Conclusion : While combining organically with other methods of acupuncture, the Yanzhen Therapy(眼鍼療法) may have better clinical effectiveness, and is also expect to expand the clinical indication.