• Title/Summary/Keyword: Standard normal Distribution

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Study of surgical anatomy of portal vein of liver segments by cast method and its clinical implications

  • Shrikantaiah, Vidya C.;Basappa, Manjaunatha;Hazrika, Sangita;Ravindranath, Roopa
    • Anatomy and Cell Biology
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    • v.51 no.4
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    • pp.232-235
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    • 2018
  • Portal vein provides about three-fourths of liver's blood supply. Portal vein is formed behind the neck of pancreas, at the level of the second lumbar vertebra and formed from the convergence of superior mesenteric and splenic veins. The purpose of this study is to review the normal distribution and variation, morphometry of portal vein and its branches for their implication in liver surgery and preoperative portal vein embolization. It is also helpful for radiologists while performing radiological procedures. A total of fresh 40 livers with intact splenic and superior mesenteric vein were collected from the mortuary of Forensic Department, JSS Medical College and Mysuru Medical College. The silicone gel was injected into the portal vein and different segments were identified and portal vein variants were noted. The morphometry of portal vein was measured by using digital sliding calipers. The different types of portal vein segmental variants were observed. The present study showed predominant type I in 90% cases, type II 7.5% cases, and type III 2.5% cases. Mean and standard deviation (SD) of length of right portal vein among males and females were $2.096{\pm}0.602cm$ and $1.706{\pm}0.297cm$, respectively. Mean and SD of length of left portal vein among males and females were $3.450{\pm}0.661cm$ and $3.075{\pm}0.632cm$, respectively. The difference in the Mean among the males and females with respect to length of right portal vein and left portal vein was found to be statistically significant (P=0.010). Prior knowledge of variations regarding the formation, termination and tributaries of portal vein are very helpful and important for surgeons to perform liver surgeries like liver transplantation, segmentectomy and for Interventional Radiologists.

Data Acquisition and Statistical Processing of Insulation Resistance for High-Power Cables in Operation (운전 중 고전력 케이블의 절연저항 데이터의 취득과 통계적 처리 방법)

  • Park, Sung-Hee;Um, Kee-Hong
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.6
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    • pp.181-186
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    • 2018
  • With progress in industrialization, facilities for generating, delivering, and receiving high levels of electric power are in great demand. The scale of electric power equipment is increasing in both size and complexity. This has contributed to the development of our modern, high-tech and information-based society. However, if the generation of electric power is suspended due to unexpected accidents at power facilities or power stations, a range of equipment the operations of which are dependent on electric power can be damaged, causing substantial socioeconomic losses in an industrial society. A great deal of time and money would be expended to repair damaged facilities at a power station, causing enormous economic loss. In order to detect the deterioration processes of power cables, and to prevent the destruction of power cables, the operation status of power cables should be monitored on a regular basis. We studied the method in order to improve accuracy and reliability for diagnosising the junction where accident occurs frequently. We present the method of data acquisition and statistical processing.

A Risk Assessment of Asbestos Fiber Leaks to Environment during Asbestos Removal Activity in Buildings (건물 내 석면제거 작업과 공기 중 석면의 외부누출 위험성 평가)

  • Paik, Namwon;Lee, Soungcheoul;Byeon, Jaecheol;Lee, Donghee
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.30 no.4
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    • pp.405-411
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    • 2020
  • Objectives: The objectives of this study were to investigate whether airborne fibers were released to the outside air from the asbestos removal area in buildings, and to confirm the existence of asbestos fibers in samples using transmission electron microscopy(TEM). Methods: A total of 1,295 samples was collected from inside and outside 155 asbestos removal areas. To investigate the release of asbestos fibers from the removal area, samples were collected at three locations, such as an entrance to change room, an exit of negative pressure unit(NPU) and perimeter areas. Samples were also collected in the removal area prior to and after removal activity. All samples were analyzed by phase contrast microscopy(PCM) and one-tenth of the samples was analyzed using TEM to discriminate asbestos fibers. Results: During the asbestos removal activity, 27(4.1%) of 662 samples collected outside the removal area showed airborne fiber concentrations equal to or in excess of 0.01 f/cc, the permissible emission standard of the Korean Ministry of Environment. Further, 111 samples were analyzed using TEM. The distribution of asbestos fiber concentrations was log-normal. It was found that 51 of 111 samples(46%) contained asbestos fibers. Conclusions: There is a potential risk of asbestos exposure among neighbors and the public outside the asbestos removal areas. It is recommended that the asbestos removal work be conducted strictly following the specifications required by government and/or professional organizations.

Statistical Techniques to Derive Heavy Rain Impact Level Criteria Suitable for Use in Korea (통계적 기법을 활용한 한국형 호우영향도 기준 산정 연구)

  • Lee, Seung Woon;Kim, Byung Sik;Jung, Seung Kwon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.40 no.6
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    • pp.563-569
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    • 2020
  • Presenting the impact of meteorological disasters departs from the traditional weather forecasting approach for meteorological phenomena. It is important to provide impact forecasts so that precautions against disruption and damage can be taken. Countries such as the United States, the U.K., and France already conduct impact forecasting for heavy rain, heavy snow, and cold weather. This study improves and applies forecasts of the impact of heavy rain among various weather phenomena in accordance with domestic conditions. A total of 33 impact factors for heavy rain were constructed per 1 km grids, and four impact levels (minimal, minor, significant, and severe) were calculated using standard normal distribution. Estimated criteria were used as indicators to estimate heavy rain risk impacts for 6 categories (residential, commercial, utility, community, agriculture, and transport) centered on people, facilities, and traffic.

Evaluation of the accuracy of dental casts manufactured with 3D printing technique in the All-on-4 treatment concept

  • Hilin, Tas;Fatih, Demirci;Mesut, Tuzlali;Erkan, Bahce;Guler Yildirim, Avcu
    • The Journal of Advanced Prosthodontics
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    • v.14 no.6
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    • pp.379-387
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    • 2022
  • PURPOSE. The aim of this study is to compare the casts obtained by using conventional techniques and liquid crystal display (LCD) three-dimensional (3D) print techniques in the All-on-4 treatment concept of the edentulous mandibular jaw. MATERIALS AND METHODS. In this study, a completely edentulous mandibular acrylic cast (typodont) with bone-level implants placed with the Allon-4 technique served as a reference cast. In this typodont, impressions were taken with the conventional technique and dental stone casts were obtained. In addition, after scanning the acrylic cast in a dental laboratory scanner and obtaining the Standard Tessellation Language (STL) data, 3D printed casts were manufactured with a 3D printing device based on the design. The stone and 3D printed casts were scanned in the laboratory scanner and STL data were obtained, and then the interimplant distances were measured using Geomagic Control X v2020 (3D Systems, Rock Hill, SC, USA) analysis software (n = 60). The obtained data were statistically evaluated with one-way analysis of variance (ANOVA) and Tukey's pairwise comparison tests. RESULTS. As a result of the one-way ANOVA test, it was determined that the stone casts, 3D printed casts, and reference cast values in all distance intervals conformed to the normal distribution and these values had a significant difference among them in all distance intervals. In Tukey pairwise comparison test, significant differences were found between casts at all distance intervals. In all analyses, the level of significance was determined as .05. CONCLUSION. 3D printed casts obtained with a 3D LCD printing device can be an alternative to stone casts when implants are placed in edentulous jaws. [J Adv Prosthodont 2022;14:379-87]

Accessory infraorbital foramen location using cone-beam computed tomography

  • Daesung An;Kumar K C;Chakorn Vorakulpipat;Supak Ngamsom;Thongnard Kumchai;Sunya Ruangsitt;Teeranut Chaiyasamut;Natthamet Wongsirichat
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.23 no.5
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    • pp.257-264
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    • 2023
  • Background: Accessory infraorbital foramen (AIOF) can change the normal course of emerging branches of the infraorbital nerve and blood vessels exiting the infraorbital foramen (IOF). This study aimed to examine the AIOF, number of foramina, and their position in relation to IOF using cone-beam computed tomography (CBCT). Methods: We performed a retrospective CBCT assessment of hospital records between January 2018 and August 2022. The CBCT of 507 patients were examined to extract information on the prevalence, number, position, linear distance from the IOF, and diameter of AIOF in relation to demographic factors. Descriptive statistics were used to evaluate the prevalence of AIOF. Mean and standard deviation were used to calculate the linear distance and diameter of the AIOF, respectively. The AIOFs, its distribution, and number were compared between sexes and sides using the chi-square test. The independent t-test and Mann-Mann-Whitney test were used to compare the mean difference between the sexes and sides. Statistical significance was set at P < 0.05. Results: In this current study, the prevalence of AIOF was 7.1% (36 of the 507 patients). Additionally, the current study examined the number of foramina using a single foramen on each side and double foramina located bilaterally at a distance from the AIOF to the IOF. The mean AIOF diameter was also studied, and the AIOF position with respect to the IOF on CBCT was superomedial or inferomedial. There were no statistically significant associations between any of the parameters assessed in this study when comparing sex and sides. Conclusions: A greater number of patients with AIOF presented with a single foramen and unilateral occurrence, without a statistically significant difference. The AIOF was most commonly located superomedial to the IOF.

The Factors Associated with Weight Control Experiences among Adolescents - Based on Self-esteem, Body-cathexis, Attitudes toward the Body, Anthropometric Characteristics and Perceptions of Body Shape - (일부 청소년의 체중조절과 관련된 요인에 관한 연구 -자아존중감, 신체만족도 및 중요도, 신체적 특성과 체형에 대한 인식을 중심으로-)

  • 허은실;강현진;이경혜
    • Korean Journal of Community Nutrition
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    • v.8 no.5
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    • pp.658-666
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    • 2003
  • This study was carried out to investigate among adolescents (total=729) the relationship between their self-esteem, body-cathexis, their attitudes toward the importance of their bodies, their anthropometric characteristics, their perceptions of their body shapes and their experiences with weight control. The results are summarized as follows: The mean values for self-esteem and body-cathexis were generally low, but these values were significantly higher among boys than girls (p<0.01-0.001). However the mean values for their attitudes toward the importance of their bodies were relatively high and were significantly higher among girls than boys (p<0.01). The mean values for Percent Ideal Body Weight (PIBW) and Body Mass Index (BMI) were normal and no significant differences between the genders were observed. The distribution of the PIBW and the BMI values showed a higher rate for normal weights among the girls and a higher rate for underweightedness and obesity among the boys (p<0.01). With regard to their perception of their body image, among the boys, their current figures were almost identical with their idea of an ideal figure, but among the girls, their idea of an ideal figure was thinner than their current figure. The girls were more dissatisfied with their own body image than the boys (p<0.001). Fifty-four percent of the subjects had previous weight control experience, and the girls had significantly more experience than the boys (p<0.001). Their main reason for practising weight control was to lose weight (65.3%) Those who had more weight control experience had lower satisfaction with their body shapes, higher PIBW, higher BMIs or currently had fatter figures. Their standard image of their figures was influenced by TV (40.3%) and friends (36.9%). There was a weakly positive correlation between their self-esteem and their satisfaction with their body shapes, and a weakly negative correlation between their satisfaction with their body shapes and their attitudes toward the importance of their bodies. These results suggest the necessity for an educational program for adolescents as to foster a positive body image. Such a program should consider psychological factors such as self-esteem, satisfaction with body shape and attitudes toward the importance of the body.

Evaluation of Atopy and Its Possible Association with Indoor Bioaerosol Concentrations and Other Factors at the Residence of Children (초등학생 가정을 대상으로 한 바이오에어로졸 노출과 아토피와의 연관성 평가)

  • Ha, Jin-Sil;Jung, Hea-Jung;Byun, Hyae-Jeong;Yoon, Chung-Sik;Kim, Yang-Ho;Oh, In-Bo;Lee, Ji-Ho;Ha, Kwon-Chul
    • Journal of Environmental Health Sciences
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    • v.37 no.6
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    • pp.406-417
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    • 2011
  • Objectives: Exposure to bioaerosols in the indoor environment could be associated with a variety adverse health effects, including allergic disease such atopy. The objectives of this study were to assess children's exposure to bioaerosol in home indoor environments and to evaluate the association between atopy and bioaerosol, environmental, and social factors in Ulsan, Korea. Methods: Samples of viable airborne bacteria and fungi were collected by impaction onto agar plates using a Quick Take TM 30 and were counted as colony forming units per cubic meter of air (CFU/$m^3$). Bioaerosols were identified using standard microbial techniques by differential stains and/or microscopy. The environmental factors and possible causes of atopy based on ISAAC (International Study of Allergy and Asthma in Childhood) were collected by questionnaire. Results: The bioaerosol concentrations in indoor environments showed log-normal distribution (p < 0.01). Geometric mean (GM) and geometric standard deviation (GSD) of airborne bacteria and fungi in homes were 189.0 (2.5), 346.1(2.0) CFU/$m^3$, respectively. Indoor fungal levels were significantly higher than those of bacteria (p < 0.001). The concentration of airborne bacteria exceeded the limit recommended by the Korean Ministry of Environment, 800 CFU/$m^3$, in three out of 92 samples (3.3%) from 52 homes. The means of indoor to outdoor ratio (I/O) for airborne bacteria and fungi were 8.15 and 1.13, respectively. The source of airborne bacteria was not outdoors but indoors. GM of airborne bacteria and fungi were 217.6, 291.8 CFU/$m^3$ in the case's home and 162.0, 415.2 CFU/$m^3$ in the control's home respectively. The difference in fungal distributions between case and control were significant (p = 0.004) and the odds ratio was 0.996 (p = 0.027). Atopy was significantly associated with type of house (odds ratio = 1.723, p = 0.047) and income (odds ratio = 1.891, p = 0.041). Some of the potential allergic fungal genera isolated in homes were Cladosporium spp., Botrytis spp., Aspergillus spp., Penicillium spp., and Alternatia spp. Conclusions: These results suggest that there this should be either 'was little' meaning 'basically no significant association was found' or 'was a small negative' mean that an association was found but it was minor. It's a very improtant distinction. Association between airborne fungal concentrations and atopy and certain socioeconomic factors may affect the prevalence of childhood atopy.

The Mean-VaR Framework and the Optimal Portfolio Choice (평균-VaR 기준과 최적 포트폴리오 선택)

  • Ku, Bon-Il;Eom, Young-Ho;Choo, Youn-Wook
    • The Korean Journal of Financial Management
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    • v.26 no.1
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    • pp.165-188
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    • 2009
  • This paper has suggested the methodology for the frontier portfolios and the optimal portfolio under the mean-VaR framework, not assuming the normal distribution and considering the investor's preferences for the higher moments of return distributions. It suggested the grid and rank approach which did not need an assumption about return distributions to find the frontier portfolios. And the optimal portfolio was selected using the utility function that considered the 3rd and the 4th moments. For the application of the methodology, weekly returns of the developed countries index, the emerging market index and the KOSPI index were used. After the frontier portfolios of the mean-variance framework and the mean-VaR framework were selected, the optimal portfolios of each framework were compared. This application compared not only the difference of the standard deviation but also the difference of the utility level and the certainty equivalent expressed by weekly expected returns. In order to verify statistical significances about the differences between the mean-VaR and the mean-variance, this paper presented the statistics which were obtained by the historical simulation method using the bootstrapping. The results showed that an investor under the mean-VaR framework had a tendency to select the optimal portfolio which has bigger standard deviation, comparing to an investor under the mean-variance framework. In addition, the more risk averse an investor is, the bigger utility level and certainty equivalent he achieves under the mean-VaR framework. However, the difference between the two frameworks were not significant in statistical as well as economic criterion.

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A Study on the Properties Analysis of an Iron Fittings Type CSST Damaged by the PCITS (PCITS에 의해 소손된 강이음쇠형 CSST의 특성 해석에 관한 연구)

  • Lee, Jang-Woo;Choi, Chung-Seog
    • Fire Science and Engineering
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    • v.30 no.4
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    • pp.121-127
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    • 2016
  • This study analyzed the structural and electrical characteristics of an iron fittings type Corrugated Stainless Steel Tubing (CSST) damaged by the Primary Current Injection Test System (PCITS). CSST consists of cladding, tube, nuts, clamp ring, flare cap, socket, and ball valve. For an evaluation of the dielectric withstand voltage, the area between the live part and non-live part of the CCST shall withstand a voltage of 220 V AC for one minute. For an evaluation of the insulation performance by 500 V DC, it is required that the insulation exceed more than $1M{\Omega}$ before the temperature rise test, $0.3M{\Omega}$ after the test. Although the average resistance of the product was $11.5m{\Omega}$, that of the product damaged at a current of 130 A by the PCITS was $11.50m{\Omega}$. Furthermore, parts of the cladding were melted and black smoke appeared when a current of 130 A applied for 10 s. After 60 s, most parts were heated and turned red. At 120 s, the parts that turned red had widened. Although it did not form a normal distribution because the P value was 0.019 with a confidential interval of 95%, it revealed outstanding characteristics with an AD (Anderson-Darling) value of 0.896 and a standard deviation of 0.5573.