• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.102-109
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• 1986

Based on the Hartenberg-Denavit symbolic equation, which is one of equations for the kinematic analysis of three dimensional (3-D) linkage, a generalized kinematic motion equation is derived utilizing Euler angles and employing the coordinates transformation. The derived equation can feasibly be used for the motion analysis of any type of 3-D linkages as well as 2-D ones. In order to simulate the general motion of 3-D linkgages on digital computer, the generalized equation is programmed through the process of numerical analysis after converting the equation to the type of Newton-Raphson formula and denoting it in matrix form. The feasibility of theoretically derived equation is experimentally proved by comparing the results from the computer with those from experimental setup of three differrent but generally empolyed 3-D linkages.

• Tunnel and Underground Space
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• v.8 no.4
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• pp.321-331
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• 1998

A reliable analysis of tunnelling is needed to accomplish technically sound design and safe and economical construction. For the reliable analysis, a series of procedures of construction which include excavation and support stages must be considered. In this study, rock-support response behavior is studied and simulated in 2-D and 3-D finite element methods. Through the analysis of rock-support response behavior, the effects of the properties of shotcrete on the load distribution ratio can be quantified. The load distribution ratios for different rock types, different unsupported spans and various lateral earth pressure coefficients can be determined from the results of the 3-D finite element analysis. This load distribution ratios can be applied to a practical tunnel design through understanding of the trend of those various factors affecting the rock-support interaction.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.111-118
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• 2023

For the implementation of a smart factory, it is necessary to collect data by connecting various sensors and devices in the manufacturing environment and to diagnose or predict failures in production facilities through data analysis. In this paper, to predict the residual useful lifetime of milling insert used for machining products in CNC machine, weight k-NN algorithm, Decision Tree, SVR, XGBoost, Random forest, 1D-CNN, and frequency spectrum based on vibration signal are investigated. As the results of the paper, the frequency spectrum does not provide a reliable criterion for an accurate prediction of the residual useful lifetime of an insert. And the weighted k-nearest neighbor algorithm performed best with an MAE of 0.0013, MSE of 0.004, and RMSE of 0.0192. This is an error of 0.001 seconds of the remaining useful lifetime of the insert predicted by the weighted-nearest neighbor algorithm, and it is considered to be a level that can be applied to actual industrial sites.

• Economic and Environmental Geology
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• v.27 no.6
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• pp.557-561
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• 1994

Q estimates are made by direct measurements of energy loss per cycle from primary P and S waves, as a function of frequency. Assuming that intrinsic Q is frequency independent and scattering Q is frequency dependent over the frequencies of interest, the relative contributions of each, to a total observed Q, may be estimated. Test examples are produced by computing viscoelastic synthetic seismograms using a pseudo spectral solution with inclusion of relaxation mechanisms (for intrinsic Q) and a fractal distribution of scatterers (for scattering Q). The composite theory implies that when the total Q for S-waves is smaller than that for P-waves (the usual situation), intrinsic Q is dominating; when it is larger, scattering Q is dominating. In the inverse problem, performed by a global least squares search, intrinsic $Q_p$ and $Q_s$ estimates are reliable and unique when their absolute values are sufficiently low that their effects are measurable in the data. Large $Q_p$ and $Q_s$ have no measurable effect and hence are not resolvable. Standard deviation of velocity $({\sigma})$ and scatterer size (A) are less unique as they exhibit a tradeoff as predicted by Blair's equation. For the P-waves, intrinsic and scattering contributions are of approximately the same importance, for S-waves, the intrinsic contributions dominate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.259-270
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• 1985

Meteorological year variations for rice crop from 1973 to 1984 were compared by using air temperature and sunshine hour for nursery period, cooling index for reproductive stage and meteorological yield productivity index for ripening period. The most optimum transplanting date and heading date for crop yield based on real transplanting date-grain yield relationship or heading date-grain yield relationship, meteorological yield productivity index and actual results showed good agreement each other. Around May 26 for transplanting and August 10 for heading were the most optimum date in Indica/Japonica hybrid cultivars while these were about June 8 and August 23 for Japonica cultivars, respectively. On the other hand, theoretical late limiting heading date for safe ripening were August 20 for Indica/Japonica hybrid cultivars and August 30 for Japonica cultivars, respectively, for both methods, cumulative temperature method during ripening with 80% believable frequency and meteorological yield productive index method having 1000(kg/10a) yielding potential. Based on the yield forecast trial, the highest values of photosynthetic efficiency, 2.5%, and crop growth rate, 23g/㎡/day, were recorded during 30 days before rice heading. Considering the photosynthetic efficiency and solar radiation, the potential crop growth rate was more or less 30g/㎡/day and the biological grain yielding potential in a existing cultural practices was approximately 900-1000(kg/10a) in Milyang weather condition. To increase further yielding potential, either photosynthetic efficiency or harvest index or both should be improved by manipulating appropriate canopy architecture, plant spacing, fertilizer, chemical, etc.

• Journal of the Daesoon Academy of Sciences
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• v.41
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• pp.27-61
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• 2022

Documentation related to Mugeuk-do (Limitless Dao) is rare in comparison to other Korean new religions given that it has been open to the public and translated since the 1970s. Due to its rarity, the documentation has been used uncritically, without there being any comparative study or historical research. It is undeniable that distortions and fallacies are embedded in these documents, and this has resulted in quite a few problems in precisely understanding Mugeuk-do and Daesoon Jinrihoe (The Fellowship of Daesoon Truth), an order that has inherited the legacy of Mugeuk-do. In this regard, this study aims to critically define the characteristics and limitations of the major documents related to Mugeuk-do that were published by the colonial government in the 1920s~1930s and recorded by multiple orders in the 1970s-1980s through comparisons. An attempt to conduct this research allows for the discovery of a solution to the problem of uncritical usage of those materials. The documents produced by the colonial government that can be used as basic texts to study Mugeuk-do are The General Conditions of the Religion Mugeuk-do (無極大道敎槪況) and Unofficial Religions of the Korea (朝鮮の類似宗敎). These can be found through bibliography, comparison, and historical research. Chapters 6, 7, and 8 of The General Conditions of the Religion Mugeuk-do are a possible source on the order that reflects the circumstances of Mugeuk-do until 1925. In the case of Unofficial Religions of the Korea, if the descriptive perspective on unofficial religions is excluded, the articles written about the circumstances post 1925 have credibility. Another document that describes multiple orders and can be used as a basic text is chapter 2 of 'Progress of the Order' in Daesoon Jinrihoe's The Canonical Scripture. This is because its record precisely reflects the conditions of the era, with regard to the fact that it is the freest from distortions caused by changes in the belief system and it is less biased towards certain sects or denominations. Furthermore, the collection period of the articles is the earliest. Accordingly, as basic texts, Chapters 6, 7, and 8 of The General Conditions of the Religion Mugeuk-do and the articles from Unofficial Religions of the Korea after 1925, as well as chapter 2 of 'Progress of the Order' in The Canonical Scripture are appropriate for studying Mugeuk-do. In addition, Overview of Bocheonism, History of Jeungsan-gyo, and The True Scripture of the Great Ultimate can be utilized as references after removing distortions and fallacies through comparative study. Henceforth, relevant documents should be utilized to establish comprehensive data on Mugeuk-do through comparative and historical research.

• Korean Journal of Heritage: History & Science
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• v.57 no.2
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• pp.80-100
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• 2024

This paper investigated the major history and reality of iconological composition for Jagyeongjeon Hall's flowered wall in Gyeongbokgung Palace, which was controversial in terms of preservation and management of cultural heritage. While analyzing the moment and cause of the flowered wall's renovation as it is now, modified or disappeared patterns were identified, and meaningfully misinterpreted congratulatory phrases were reviewed. The research results can be used as meaningful basic data when discussions are made for the restoration of the wall in the future. Jagyeongjeon Hall's flowered wall has reached the present day with large and small changes, but the inflection point that had a significant impact was the Joseon Expo (朝鮮博覽會) held at Gyeongbokgung Palace in 1929. This is because the wall that remained in the Jagyeongjeon Hall area was demolished to build an exhibition hall while preparing for the expo, and it was restored after the end of the event. It is highly likely that the modification or disappearance of the patterns constituting Jagyeongjeon Hall's flowered wall was also due to the restoration process carried out after the expo. There is a view that was transformed into its current state in the process of repair work carried out after the Korean War, but it is difficult to find any meaningful circumstances and evidence. Currently, character patterns known as 'Seongnidori(聖人道理)' are arranged on the inner wall of the section from Gyeongdomun Gate(擎桃門) to Yeogangmun Gate(如岡門), but considering the design form and example, it can be read as 'Seongjasinson(聖子神孫)'. The inner wall of the section from Yeogangmun Gate to Yeonsumun Gate(燕壽門) was originally made in the form of a flowered wall, and the phrases presumed to be 'Gyegyeseungseung(繼繼繩繩)' and 'Cheonse(千世)' were arranged. In the case of the section from Yeonsumun Gate to Hamgyumun Gate(含奎門), the inner wall where the pattern has disappeared is originally composed of geometric and character patterns, and there were also phrases specified as 'Cheonsu(千壽)' and 'Mansemansu(萬世萬壽)'. On the outer wall of the section from Yeonsumun Gate to Hamgyumun Gate, there is a possibility that the phrase known as 'Nakgangmanse(樂彊萬歲)' can be read as 'Cheonsemanse(千歲萬歲)'. In addition, the current outer wall was composed of one drawing board, but in the past, two drawing boards were composed separately.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.30-35
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• 1996

It is well known that the improved methods of the estimation of the service power margin is necessary to design a optimum ship and to operate economically a ship. Unfortunately, most conventional methods of the predicting of the service power margin are not so accurate that attention should be payed to improve this. From this overview, it is importance with. the effects of waves, as recommended by the 15th and 16th International Towing Tank Conference in 1978 and l981. However the progress of research in this field is very slow mainly since it is taken so long time to take data about hull roughness according to ship ages. For instance, it would be taken 17 or 25 years to measure ideally the data for a ship. Moreover it would be also necessary to take data for many types of ships to lead a general solution. A relationship between roughness and ship age are studied in this paper considering full scale data. A comparison is also made between the effects of hull roughness and of weather at sea for the ship.

• Journal of the Korea Computer Graphics Society
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• v.23 no.2
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• pp.29-39
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• 2017

This paper presents a unified framework to efficiently and realistically simulate surface and wave foams. The framework is designed to first project 3D water particles from an underlying water solver onto 2D screen space in order to reduce the computational complexity of determining where foam particles should be generated. Because foam effects are often created primarily in fast and complicated water flows, we analyze the acceleration and curvature values to identify the areas exhibiting such flow patterns. Foam particles are emitted from the identified areas in 3D space, and each foam particle is advected according to its type, which is classified on the basis of velocity, thereby capturing the essential characteristics of foam wave motions. We improve the realism of the resulting foam by classifying it into two types: surface foam and wave foam. Wave foam is characterized by the sharp wave patterns of torrential flow s, and surface foam is characterized by a cloudy foam shape even in water with reduced motion. Based on these features, we propose a technique to correct the velocity and position of a foam particle. In addition, we propose a kernel technique using the screen space density to efficiently reduce redundant foam particles, resulting in improved overall memory efficiency without loss of visual detail in terms of foam effects. Experiments convincingly demonstrate that the proposed approach is efficient and easy to use while delivering high-quality results.

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.129-139
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• 1988

Vaginitis is one of the most common disease in gynecologic field in recent days. About 90% of these patients suffer from the infection of the vagina caused by Gardnerella vaginalis, Candida, or Trichomonas, either alone or in combination. For the effective diagnosis and management, it is essential to get an accurate identification of the causative agent. Applying simple and easy diagnostic methods such as pH of vaginal discharge, amine test and microscopic examination of wet mount preparation of normal saline and 10% KOH to 549 cases of randomly selected patients visiting Out-patient Department of Obstetrics and Gynecology of Yeung-nam University Hospital through May 1st to Sept. 31st, 1987, the following results were obtained. 1. In the Gardnerella vaginitis vaginal pH was more than 5.0 in 81.0% of total cases, positive amine test in 62.8%, decreased lactobacilli in 77.4% & decreased WBC counts in 70.1%, In the Trichomonas vaginitis vaginal pH more than 5.0 was noted in 93.3% of the cases, negative amine test in 90%, decreased lactobacilli in 90% & increased WBC counts in 93.3%, whereas Candida vaginitis and normal groups showed vaginal pH of 3.0~4.0 in 83.2%, negative amine test in 100%, normal distribution of lactobacilli in 89.7%, normal WBC counts in 72.4%. 2. The accuracy rates of physical diagnosis by wet mount preparation of normal saline and 10% KOH revealed 26.3%, 47.5% % 70,0% in Gardnerella vaginitis, Candida vaginitis, and Trichomonas vaginitis, respectively. The vaginal pH and amine test showed 83.2% of accuracy rate in Candida vaginitis group, 60.6% in Gardnerella vaginitis group and 83.3% III Trichomonas vaginitis group. 3. In 23 cases of Gardnerella vaginitis showing vaginal pH of 3.0 or 4.0 and positive amine test, the clue cells were observed in 10% or less in 12 cases, 30% in 5 cases, 50% in 4 cases and 50% or more in 2 cases. In summary vaginal pH and amine test could be useful in screening and differentiating the different types of infectious vaginitis. Furthermore by adding microscopic examination of normal saline and 10% KOH wet mount preparation to them, they not only could obtain higher diagnostic accuracy rate but would be more valuable in selecting the patients requiring cultures to confirm the diagnoses.