• Title/Summary/Keyword: 신뢰성분석

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Financial Condition and the Determinants of Credit Ratings in Korean Small and Medium-Sized Business (중소상공인의 금융현황과 신용등급의 결정요인 관련 연구)

  • Kang, Hyoung-Goo;Binh, Ki Beom;Lee, Hong-Kyun;Koo, Bonha
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.6
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    • pp.135-154
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    • 2020
  • This paper analyzes the 5,521 samples of the small and medium-sized businesses(SMBs) obtained from the Korea Credit Guarantee Fund. From January 2014 to September 2019, 85% of the SMBs have 5 or fewer full-time employees. The proportion of SMBs is overwhelmed by the elderly men, and most founders are the CEO. Also, about 87% of the workplace types are rented, while 64% of the CEO's residence types are owner-occupation. 47% of the financial grade score is less than 10 points out of 100 and 80% of SMBs have less than 200 million won of the loan guarantee. In particular, the total guarantee loan amount or the days of net guarantee have significantly positive relations with the working period of the CEO in the same industry, the number of employees, the operation period of SMBs, and the corporate business type. In the case of the financial grading score which has the highest weight in overall credit rating gets higher with the higher number of employees, the longer the operation period, and the corporate business type. However, the quantified non-financial grading score has no significant relationship with other explanatory variables, except for the corporate business type. This implies that a non-financial grade score is measured by other determinants that are not observed by the Korea credit guarantee fund. The pure non-financial grade score has positive relations with the working period of the CEO. Overall, this paper would help Korean SMBs upgrade their credit ratings and expand the money supply when there is no standardized credit rating model or no publicly available evaluation criteria for SMBs. We expect this paper provides important insights for further research and policy-makers for SMBs. In particular, to address the financial needs of thin-filers such as SMBs, technology-based financial services (TechFin) would use alternative data to evaluate the financial capabilities of thin-filers and to develop new financial services.

A Practical Method to Quantify Very Low Fluxes of Nitrous Oxide from a Rice Paddy (벼논에서 미량 아산화질소 플럭스의 정량을 위한 실용적 방법)

  • Okjung, Ju;Namgoo, Kang;Hoseup, Soh;Jung-Soo, Park
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.24 no.4
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    • pp.285-294
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    • 2022
  • In order to accurately calculate greenhouse gas emissions in the agricultural field, Korea has been developing national-specific emission factors through direct measurement of gas fluxes using the closed-chamber method. In the rice paddy, only national-specific emission factors for methane (CH4) have been developed. It is thus necessary to develop those for nitrous oxide (N2O) affected by the application of nitrogen fertilizer. However, since the concentration of N2O emission from rice cultivation is very low, the QA/QC methods such as method detection and practical quantification limits are important. In this study, N2O emission from a rice paddy was evaluated affected by the amount of nitrogen fertilizer, by taking into account both method detection and practical quantification limits for N2O concentration. The N2O emission from a rice paddy soils affected by the nitrogen fertilizer application was estimated in the following order. The method detection limit (MDL) of N2O concentration was calculated at 95% confidence level based on the pooled standard deviation of concentration data sets using a standard gas with 98 nmol mol-1 N2O 10 times for 3 days. The practical quantification limit (PQL) of the N2O concentration is estimated by multiplying 10 to the pooled standard deviation. For the N2O flux data measured during the rice cultivation period in 2021, the MDL and PQL of N2O concentration were 18 nmol mol-1 and 87 nmol mol-1, respectively. The measured values above the PQL were merely about 12% of the total data. The cumulative N2O emission estimated based on the MDL and PQL was higher than the cumulative emission without nitrogen fertilizer application. This research would contribute to improving the reliability in quantification of the N2O flux data for accurate estimates of greenhouse gas emissions and uncertainties.

Dynamic response of segment lining due to train-induced vibration (세그먼트 라이닝의 열차 진동하중에 대한 동적 응답특성)

  • Gyeong-Ju Yi;Ki-Il Song
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.4
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    • pp.305-330
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    • 2023
  • Unlike NATM tunnels, Shield TBM tunnels have split linings. Therefore, the stress distribution of the lining is different even if the lining is under the same load. Representative methods for analyzing the stress generated in lining in Shield TBM tunnels include Non-joint Mode that does not consider connections and a 2-ring beam-spring model that considers ring-to-ring joints and segment connections. This study is an analysis method by Break-joint Mode. However, we do not consider the structural role of segment lining connections. The effectiveness of the modeling is verified by analyzing behavioral characteristics against vibration loads by modeling with segment connection interfaces to which vertical stiffness and shear stiffness, which are friction components, are applied. Unlike the Non-joint mode, where the greatest stress occurs on the crown for static loads such as earth pressure, the stress distribution caused by contact between segment lining and friction stiffness produced the smallest stress in the crown key segment where segment connections were concentrated. The stress distribution was clearly distinguished based on segment connections. The results of static analysis by earth pressure, etc., produced up to seven times the stress generated in Non-joint mode compared to the stress generated by Break-joint Mode. This result is consistent with the stress distribution pattern of the 2-ring beam-spring model. However, as for the stress value for the train vibration load, the stress of Break-joint Mode was greater than that of Non-joint mode. This is a different result from the static mechanics concept that a segment ring consisting of a combination of short members is integrated in the circumferential direction, resulting in a smaller stress than Non-joint mode with a relatively longer member length.

Development of a New Cardiac and Torso Phantom for Verifying the Accuracy of Myocardial Perfusion SPECT (심근관류 SPECT 검사의 정확도 검증을 위한 새로운 심장.흉부 팬텀의 개발)

  • Yamamoto, Tomoaki;Kim, Jung-Min;Lee, Ki-Sung;Takayama, Teruhiko;Kitahara, Tadashi
    • Journal of radiological science and technology
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    • v.31 no.4
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    • pp.389-399
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    • 2008
  • Corrections of attenuation, scatter and resolution are important in order to improve the accuracy of single photon emission computed tomography (SPECT) image reconstruction. Especially, the heart movement by respiration and beating cause the errors in the corrections. Myocardial phantom is used to verify the correction methods, but there are many different parts in the current phantoms in actual human body. Therefore the results using a phantom are often considered apart from the clinical data. We developed a new phantom that implements the human body structure around the thorax more faithfully. The new phantom has the small mediastinum which can simulate the structure in which the lung adjoins anterior, lateral and apex of myocardium. The container was made of acrylic and water-equivalent material was used for mediastinum. In addition, solidified polyurethane foam in epoxy resin was used for lung. Five different sizes of myocardium were developed for the quantitative gated SPECT (QGS). The septa of all different cardiac phantoms were designed so that they can be located at the same position. The proposed phantom was attached with liver and gallbladder, the adjustment was respectively possible for the height of them. The volumes of five cardiac ventricles were 150.0, 137.3, 83.1, 42.7 and 38.6ml respectively. The SPECT were performed for the new phantom, and the differences between the images were examined after the correction methods were applied. The three-dimensional tomography of myocardium was well reconstructed, and the subjective evaluations were done to show the difference among the various corrections. We developed the new cardiac and torso phantom, and the difference of various corrections was shown on SPECT images and QGS results.

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Packaging Technology for the Optical Fiber Bragg Grating Multiplexed Sensors (광섬유 브래그 격자 다중화 센서 패키징 기술에 관한 연구)

  • Lee, Sang Mae
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.4
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    • pp.23-29
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    • 2017
  • The packaged optical fiber Bragg grating sensors which were networked by multiplexing the Bragg grating sensors with WDM technology were investigated in application for the structural health monitoring of the marine trestle structure transporting the ship. The optical fiber Bragg grating sensor was packaged in a cylindrical shape made of aluminum tubes. Furthermore, after the packaged optical fiber sensor was inserted in polymeric tube, the epoxy was filled inside the tube so that the sensor has resistance and durability against sea water. The packaged optical fiber sensor component was investigated under 0.2 MPa of hydraulic pressure and was found to be robust. The number and location of Bragg gratings attached at the trestle were determined where the trestle was subject to high displacement obtained by the finite element simulation. Strain of the part in the trestle being subjected to the maximum load was analyzed to be ${\sim}1000{\mu}{\varepsilon}$ and thus shift in Bragg wavelength of the sensor caused by the maximum load of the trestle was found to be ~1,200 pm. According to results of the finite element analysis, the Bragg wavelength spacings of the sensors were determined to have 3~5 nm without overlapping of grating wavelengths between sensors when the trestle was under loads and thus 50 of the grating sensors with each module consisting of 5 sensors could be networked within 150 nm optical window at 1550 nm wavelength of the Bragg wavelength interrogator. Shifts in Bragg wavelength of the 5 packaged optical fiber sensors attached at the mock trestle unit were well interrogated by the grating interrogator which used the optical fiber loop mirror, and the maximum strain rate was measured to be about $235.650{\mu}{\varepsilon}$. The modelling result of the sensor packaging and networking was in good agreements with experimental result each other.

A STUDY ABOUT ALVEOLAR CREST BONE HEIGHT BEFORE AND AFTER ORTHODONTIC TREATMENT BY USING BITEWING FILM (교익사진을 이용한 교정치료 전후의 치조골 높이 변화에 관한 연구)

  • Hwang, Chung-Ju
    • The korean journal of orthodontics
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    • v.27 no.3 s.62
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    • pp.421-430
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    • 1997
  • Alveolar bone grows with development of tooth germs and roots; bone deposition occurs with tooth eruption. Bone components undergoes processes of resorption and deposition, and when the balance between them is disrupted, decrease in alveolar bone height or excessive bone deposition result. It has been hon that repositioning of teeth through orthodontic treatment can cause alveolar bone resorption which result in decreased alveolar bone height, and there have been many studies to evaluate such effects. X-ray films that could be replicated and standardized were chosen in clinical studies, and among them, bitewing films were used for objective evaluation of changes in alveolar bone level. Twenty subjects, 10 to 13-year- old (average 12.2) children with Cl I molar key, healthy oral condition, no congenital missing, no periodontal disease, and pre-and post-orthodontic bitewing films, were randomly selected for comparison of alveolar bone heights. Amounts of tooth and changes in alveolar bone heights were analyzed. The following results were obtained: 1. Amount of tooth movement in canine, premolar, and molar regions, changes in tooth axis, and changes in alveolar bone heights were measured, and the mean and median values were obtained. 2. When pre-and post-orthodontic alveolar bone levels were compared, larger changes were noticed in maxilla than mandible. 3. When mesio-distally compared, larger changes were observed in the distal sides of 3D3 and 4M3, mesial sides of 4M3 and 4D3, distal sides of 4D3 and 5M3, mesial sides of 5M3 and 5D3, md distal sides of 5D3 and 6M3. 4. When the amounts of tooth movements(TX, TY)and changes in tooth axis(A) were compared,34TX, 34TY, 34A of both sides in maxilla were greater, iud changes in alveolar bone level were greater than any other region.

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Recognition, purchase, and consumption of edible insects in Korean adults (한국 일부 성인의 식용곤충에 대한 인식, 구매 및 섭취 실태)

  • Park, Eun-Sun;Choi, Mi-Kyeong
    • Journal of Nutrition and Health
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    • v.53 no.2
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    • pp.190-202
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    • 2020
  • Purpose: This study aims to evaluate the recognition, purchase, and intake status of edible insects in adults, who are the main consumers of edible insects, and to provide the information necessary to expand the production and consumption of edible insects and related products in the future. Methods: A total of 453 adults (172 males and 281 females) aged 19 years and older were surveyed regarding their awareness of edible insects, purchase and consumption experience, and intention to purchase and consume, and the differences between them were analyzed according to gender and age groups. Data collection took place from December 2018 to January 2019. Results: Those who had knowledge of edible insects accounted for 87.0%, whereas those who had more than average knowledge were 75.9%, suggesting recognition was relatively high. Men had more experience than women in purchasing or consuming edible insects and related products (45.9% vs. 31.0%, p < 0.01). In terms of age, experience was 22.5% in 20-30s, 44.6% in 40-50s, and 63.1% in 60s and older, showing significant growth as age increased (p < 0.001). The satisfaction level of edible insects was highest in taste (3.4 points), and especially for shape and appearance, it decreased as age reduced (p < 0.001). The most common reason for not being willing to use edible insects was feeling repulsive (4.1 points), which was significantly more common in women than in men (4.3 vs. 3.9, p < 0.001), and lower with age (p < 0.001). The most needed information display for using edible insects was country of origin (63.8%), the main nutrient in edible insects was protein (93.6%), and the most preferred form of products was powder (39.5%). Conclusion: According to the above results, the recognition of edible insects was high, whereas experience of using edible insects and intention to use edible insects were low especially in women and younger groups. The reason for this is that consumers are dissatisfied with edible insects due to their appearance. This study is expected to be used as basic data for expanding the production and consumption of edible insects and related products in the future.

Effects on cooperative spirit of a cohort by instruction types of Taekwondo (태권도 지도자의 지도유형이 집단응집력에 미치는 영향)

  • Jeong, Chan-Sam
    • Korean Security Journal
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    • no.13
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    • pp.471-485
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    • 2007
  • This study is performed to find out what type instructions are produced to players by coaches and what effects are resulted in cooperative spirit of the concerned group. Furthermore the study has its aims at advancing instructors' skills by using finding of it. The study used 'SPSS 11.0 FOR WINDOW - Statistical Package' to analyze the collected samples and dealt with data of 174 individuals. Statistical analysis of the research for hypothesis verification was about frequency, trust level, mutual relationship, variables, and T-verification. The meaningful level for any result was ranged within 95%(p< .05), 99%(p<.01). The finding are as follows. Effects on pleasure, one of elements of team spirits taken by instructor's training style are analyzed as follows. It was proved to be meaningful in relation with a series of activities like training, democratic, social, compensatory aspects and showed also considerable relation with power based behaviors. That says, players are found to enjoy high pleasure when social and bureaucratic behaviors of instructors are very energetic. In addition to that, training, democratic, and compensatory activities didn't show any meaningful effect. Team spirit was found to play a main role between instructor's behaviors and training, democratic, social rewarding activities. Democratic and social acts influence on team spirit. Looking into the detailed aspects, team spirit was resulted very high in the individuals with low democratic mind and was shown high group spirit by groups with high sociable activities. Teamworks was found to be affected by relation between instructor's acts and training, democratic, social and compensatory aspects and it showed meaningful relations with training, social, bureaucratic behaviors. Low degree of training and bureaucratic activities are found to prefer for power team spirit, and high social activities led a strong teamworks. Group binding spirit was influenced by training, democratic, social compensatory, bureaucratic behaviors and it showed to give effects on democratic, social, and bureaucratic activities of instructors. Low degree of democratic and bureaucratic behaviors are found to produce strong team spirit. In contrast with that, strong social activities was found to be motive of powerful team spirit. Value of team spirit was found to play a main role between instructor's behaviors and training, democratic, social, rewarding activities. It didn't show any meaningful effect on behavior of instructors.

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A Study on the Accelerated Life Test for the Estimation of Licorice Durability in Cosmetics (화장품 중 유용성감초추출물의 유통기한 예측을 위한 가속수명 시험연구)

  • Lee, So-Mi;Joo, Kyeong-Mi;Park, Jong-Eun;Jeong, Hye-Jin;Chang, Ih-Seop
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.33 no.3
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    • pp.197-201
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    • 2007
  • Oil soluble licorice extract(licorice extract) is an officially approved cosmetic component as a whitening ingredient in Korea. The durability of licorice, during which the whitening effect can be maintained in optimum condition, must be accurately defined. Since the cosmetics durability under real condition is relatively longer than its development time. It is needed to predict the real durability interval from the experimental measurement under simulated operating conditions. We analyzed the relationship between the licorice lifetime and the high temperature condition by using Arrhenius equation. We have established the constant stress test with temperature of $50^{\circ}C$, $55^{\circ}C$, and $60^{\circ}C$ condition, within which no formulation change of licorice products is expected for the accelerated stress test. In this paper, the lifetime of licorice in cosmetics was defined as time period for its 10% contents reduction. We observed that the lifetime of licorice is 580 h at $50^{\circ}C$, 319 h at $55^{\circ}C$ and 166 h at $60^{\circ}C$. Using the above experimental data, we obtained the equation for the relationship between the licorice lifetime and temperature as follows; log(lifetime)=-35.0243 + 1.15322$\times$(11604.83/temperature). From this equation, the lifetime of licorice at $25^{\circ}C$ can be estimated as 26 months. The estimated result was verified by measuring full lifetime of licorice. In fact, there was no significant difference between the estimated lifetime and real measurement within 95 % significance level. This study can be applied to other useful cosmetic components for the fast estimation of the exact durability.

Site Characterization using Shear-Wave Velocities Inverted from Rayleigh-Wave Dispersion in Chuncheon, Korea (레일리파 분산을 역산하여 구한 횡파속도를 이용한 춘천시의 부지특성)

  • Jung, JinHoon;Kim, Ki Young
    • Geophysics and Geophysical Exploration
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    • v.17 no.1
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    • pp.1-10
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    • 2014
  • To reveal and classify site characteristics in densely populated areas in Chuncheon, Korea, Rayleigh-waves were recorded at 50 sites including four sites in the forest area using four 1-Hz velocity sensors and 24 4.5-Hz vertical geophones during the period of January 2011 to May 2013. Dispersion curves of the Rayleigh waves obtained by the extended spatial autocorrelation method were inverted to derive shear-wave velocity ($v_s$) models comprising 40 horizontal layers of 1-m thickness. Depths to weathered rocks ($D_b$), shear wave velocities of these basement rocks ($v_s^b$), average velocities of the overburden layer ($\bar{v}_s^s$), and the average velocity to a depth of 30 m ($v_s30$), were then derived from those models. The estimated values of $D_b$, $v_s^b$, $\bar{v}_s^s$, and $v_s30$ for 46 sites at lower altitudes were in the ranges of 5 to 29 m, 404 to 561 m/s, 208 to 375 ms/s, and 226 to 583 m/s, respectively. According to the Korean building code for seismic design, the estimated $v_s30$ indicates that the lower altitude areas in Chuncheon are classified as $S_C$ (very dense soil and soft rock) or $S_D$ (stiff soil). To determine adequate proxies for $v_s30$, we compared the computed values with land cover, lithology, topographic slope, and surface elevation at each of the measurement sites. Due to a weak correlation (r = 0.41) between $v_s30$ and elevation, the best proxy of them, applications of this proxy to Chuncheon of a relatively small area seem to be limited.