J-R 곡선에 대한 시편크기의 영향에 관한 연구

조연제,석창성,김영진,양원호,최용식 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

The objective of this paper is to investigate the constraint effect on fracture resistance curves. A series of fracture toughness tests with different specimen sizes taken from nuclear piping materials(SA312 TP347 SA516 Gr. 70) were performed. Test results show that fracture toughness is increased with increase in specimen size, probably due to the relaxation crack tip constraint. Elastic-plastic finite element analyses were also performed to investigate the constraint effect. Numerical results show that the stress triaxiality at the crack tip is the governing factor for fracture toughness.

Prediction of Retail Beef Yield Using Parameters Based on Korean Beef Carcass Grading Standards

Choy, Yun-Ho,Choi, Seong-Bok,Jeon, Gi-Jun,Kim, Hyeong-Cheol,Chung, Hak-Jae,Lee, Jong-Moon,Park, Beom-Young,Lee, Sun-Ho Korean Society for Food Science of Animal Resource 2010 한국축산식품학회지 Vol.30 No.6

Two sets of data on carcass traits and beef cut parameters were used to investigate the relationships between carcass and beef cut measurements, which can be used to make predictions of retail cut percentages. One set had a total of 1,141 measurements of Hanwoo cattle of three different sex origins, which were slaughtered in an abattoir located at the National Institute of Animal Science, RDA, Korea from 1996 to 2008. To develop prediction models for retail cut percentage with higher accuracies than the current model, another set consisting of a total of 13,389 records of carcass and beef cut traits were collected from 30 abattoirs and butcheries in Korea from 2008 to 2009. Bulls yielded heavier and leaner carcasses than steers. High correlation coefficients were estimated between amount of body fat and percent retail cut (-0.82) as well as between back fat thickness (BF) and percent retail cut (-0.62). The amount of retail cut, however, was highly correlated with body weight before slaughter (BW, 0.95) or with cold carcass weight (CWT, 0.94). Relationships between percent retail cut and measurable beef yield traits, BF, loin eye area (LEA) or CWT varied by sex class, which must be considered for development of a prediction model with high accuracy. Models of data for all breeds and sexes fit the effects of breed, sex, and interaction of abattoir by butchers, whereas models of data for each breed and sex fit the effect of interaction of abattoir by butcher only. Due to possible future changes in back fat control, we performed a log transformation of BF. Our new models fit better than the currently used model.

Breeding and Genetics : Estimation of Genetic Parameters for Economic Traits of Hanwoo Cows Using Ultrasound

( Yun Ho Choy ),( Jun Kyu Son ),( Hong Sik Kong ),( Hak Kyo Lee ),( Kyung Do Park ) 한국동물자원과학회(구 한국축산학회) 2011 한국축산학회지 Vol.53 No.6

This experiment was conducted to estimate the genetic parameters and breeding values of the economic traits measured from the cows(aged 15 months or older) using ultrasound and to use them as the information for the selection of stock animals at the farm level. The means and standard deviations of longissimus muscle area, backfat thickness and marbling score were 54.11cm2± 9.06, 3.57mm±2.45 and 2.65±2.88, respectively. While the linear regression coefficients of longissimus muscle area, backfat thickness and marbling score for age(in months) were all positive(0.3532, 0.0868 and 0.0833), the quadratic regression coefficients of them for age(in months) were all negative(-0.0023, -0.0005 and -0.0006), and as the body condition score increased longissimus muscle area, backfat thickness and marbling score increased collectively. The heritability estimates for the longissimus muscle area, backfat thickness and marbling score were 0.39, 0.48 and 0.13, respectively and the estimated annual genetic gains for the longissimus muscle area, backfat thickness and marbling score were 0.00334cm2, -0.0073mm and 0.0043 score, respectively, which were not significantly different from zero.

Estimation of Relative Economic Weights of Hanwoo Carcass Traits Based on Carcass Market Price

Choy, Yun-Ho,Park, Byoung-Ho,Choi, Tae-Jung,Choi, Jae-Gwan,Cho, Kwang-Hyun,Lee, Seung-Soo,Choi, You-Lim,Koh, Kyung-Chul,Kim, Hyo-Sun Asian Australasian Association of Animal Productio 2012 Animal Bioscience Vol.25 No.12

The objective of this study was to estimate economic weights of Hanwoo carcass traits that can be used to build economic selection indexes for selection of seedstocks. Data from carcass measures for determining beef yield and quality grades were collected and provided by the Korean Institute for Animal Products Quality Evaluation (KAPE). Out of 1,556,971 records, 476,430 records collected from 13 abattoirs from 2008 to 2010 after deletion of outlying observations were used to estimate relative economic weights of bid price per kg carcass weight on cold carcass weight (CW), eye muscle area (EMA), backfat thickness (BF) and marbling score (MS) and the phenotypic relationships among component traits. Price of carcass tended to increase linearly as yield grades or quality grades, in marginal or in combination, increased. Partial regression coefficients for MS, EMA, BF, and for CW in original scales were +948.5 won/score, +27.3 $won/cm^2$, -95.2 won/mm and +7.3 won/kg when all three sex categories were taken into account. Among four grade determining traits, relative economic weight of MS was the greatest. Variations in partial regression coefficients by sex categories were great but the trends in relative weights for each carcass measures were similar. Relative economic weights of four traits in integer values when standardized measures were fit into covariance model were +4:+1:-1:+1 for MS:EMA:BF:CW. Further research is required to account for the cost of production per unit carcass weight or per unit production under different economic situations.

Genetic Parameters of Pre-adjusted Body Weight Growth and Ultrasound Measures of Body Tissue Development in Three Seedstock Pig Breed Populations in Korea

Choy, Yun Ho,Mahboob, Alam,Cho, Chung Il,Choi, Jae Gwan,Choi, Im Soo,Choi, Tae Jeong,Cho, Kwang Hyun,Park, Byoung Ho Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.12

The objective of this study was to compare the effects of body weight growth adjustment methods on genetic parameters of body growth and tissue among three pig breeds. Data collected on 101,820 Landrace, 281,411 Yorkshire, and 78,068 Duroc pigs, born in Korean swine breeder farms since 2000, were analyzed. Records included body weights on test day and amplitude (A)-mode ultrasound carcass measures of backfat thickness (BF), eye muscle area (EMA), and retail cut percentage (RCP). Days to 90 kg body weight (DAYS90), through an adjustment of the age based on the body weight at the test day, were obtained. Ultrasound measures were also pre-adjusted (ABF, EMA, AEMA, ARCP) based on their test day measures. The (co)variance components were obtained with 3 multi-trait animal models using the REMLF90 software package. Model I included DAYS90 and ultrasound traits, whereas model II and III accounted DAYS90 and pre-adjusted ultrasound traits. Fixed factors were sex (sex) and contemporary groups (herd-year-month of birth) for all traits among the models. Additionally, model I and II considered a linear covariate of final weight on the ultrasound measure traits. Heritability ($h^2$) estimates for DAYS90, BF, EMA, and RCP ranged from 0.36 to 0.42, 0.34 to 0.43, 0.20 to 0.22, and 0.39 to 0.45, respectively, among the models. The $h^2$ estimates of DAYS90 from model II and III were also somewhat similar. The $h^2$ for ABF, AEMA, and ARCP were 0.35 to 0.44, 0.20 to 0.25, and 0.41 to 0.46, respectively. Our heritability estimates varied mostly among the breeds. The genetic correlations ($r_G$) were moderately negative between DAYS90 and BF (-0.29 to -0.38), and between DAYS90 and EMA (-0.16 to -0.26). BF had strong $r_G$ with RCP (-0.87 to -0.93). Moderately positive $r_G$ existed between DAYS90 and RCP (0.20 to 0.28) and between EMA and RCP (0.35 to 0.44) among the breeds. For DAYS90, model II and III, its correlations with ABF, AEMA, and ARCP were mostly low or negligible except the $r_G$ between DAYS90 and AEMA from model III (0.27 to 0.30). The $r_G$ between AEMA and ABF and between AEMA and ARCP were moderate but with negative and positive signs, respectively; also reflected influence of pre-adjustments. However, the $r_G$ between BF and RCP remained non-influential to trait pre-adjustments or covariable fits. Therefore, we conclude that ultrasound measures taken at a body weight of about 90 kg as the test final should be adjusted for body weight growth. Our adjustment formulas, particularly those for BF and EMA, should be revised further to accommodate the added variation due to different performance testing endpoints with regard to differential growth in body composition.

BEEF CATTLE BREEDING FOR THE LEAST COST

Choy, Yun Ho 한림대학교 한림과학원 부설 환경ㆍ생명과학연구소 1999 국제학술회의 Vol.1999 No.-

The purpose of this paper is to introduce ideas towards beef cattle breeding and management for maximal production efficiency. Several problems and general features of Korean beef cattle industry are discussed to help understanding the relationship between beef cattle breeding and cattle management. Beef cattle breeding objectives and methods to these are summarized. Due to the complexity in beef cattle business, breeding goals for beef cattle have somewhat different aspects from the other livestock species. A general conclusion from previous research works is that there is intermediate maxima in beef cattle in terms of economic efficiency.

Microsatellite marker를 활용한 칡소의 유전적 다양성 및 유연관계 분석

최연호(Yun Ho Choy),서주희(Joo Hee Seo),박병호(Byungho Park),이승수(Seung Soo Lee),최태정,조광현,최재원(Jae Won Choi),정경섭(Kyoung-sub Jung),공홍식(Hong Sik Kong) 한국생명과학회 2015 생명과학회지 Vol.25 No.6

본 연구는 microsatellite marker를 이용하여 국내에서 사육되고 있는 칡소 9지역 간의 유전적 거리 분석 및 계통 지도 작성 등의 계통유전학적 분석을 실시하였다. 11종의 MS 마커를 이용하여 대립유전자의 수(No. of allele)를 확인한 결과 8에서 24개로 확인되었으며, 기대이형접합율(expected heterozygosity, Hexp)은 0.672에서 0.834 범위 안에 나타났으며, 관측이형접합율(observed heterozygosity, Hobs)은 0.687에서 0.886, 다형성정보지수(Polymorphism information content, PIC)은 0.638에서 0.876로 확인되었다. 무작위 교배집단(Random)으로 가정하였을 경우 동일개체 출현빈도는 11개의 marker를 사용하였을 때, 5.24×10<SUP>-19</SUP> 빈도로 출현하는 것을 확인 할 수 있었으며, 반형매 교배집단(Half-sib)과 전형매 교배집단(sib)으로 가정했을 경우에는 2.63×10<SUP>-06</SUP>, 2.63×10<SUP>-06</SUP>으로 각각 확인되었다. 이러한 결과는 칡소의 개체식별 및 친지확인 marker로 11종의 MS marker가 충분히 활용 가능할 것으로 사료된다. Phylogenetic tree (Neighbor-Joining tree), Principle Component Analysis (PCA) 그리고 Factorial Component Analysis (FCA) 분석을 통해 9 지역의 칡소 집단 간의 유연관계를 확인하였다. 이러한 결과는 칡소 품종을 중요한 가축유전자원으로써 인식하고 국내 타 품종과의 유전적 차별화와 순수성 보존과 능력을 개량하는데 있어 기초 자료로 활용 가능할 것으로 사료된다. This study examined the genetic distance among Chikso (Korea native brindle cattle) in nine regional areas using allele frequencies and a genetic diversity analysis with microsatellite markers. The analysis of the genetic diversity and genetic relationships of 2068 Chikso (383 KW, 180 GG, 52 KN, 129 KB, 332 UL, 24 JN, 198 JB, 148 CN, 622 CB) was carried out using 11 microsatellite markers. The number of alleles, observed heterozygostiy (Hobs), expected heterozygosity (Hexp), and polymorphism information content (PIC) of the 11 microsatellite markers were 8?24, 0.672?0.834, 0.687?0.886, and 0.638?0.876, respectively. The expected probability of identity values in random individuals (PI), random half-sib (PIhalf-sibs), and random sibs (PIsibs) were estimated to be 5.24×10<SUP>-19</SUP>, 2.63×10<SUP>-06</SUP>, and 2.63× 10<SUP>-06</SUP>, respectively, indicating that these markers can be used for traceability systems in Chikso cattle. The results of a phylogenetic tree (neighbor-joining tree), principle component analysis (PCA), and factorial component analysis (FCA) revealed genetic distance among nine Chikso populations. In conclusion, this study provides useful basic data that can be utilized in Chikso breeding and development. In addition, we will have to manage and conserve as a valuable genetic resource, without losing diversity of Chikso.

치주인대의 응력 분포 양상에 관한 실험 연구

최광철,김경호,박영철,한정윤 대한치과교정학회 2001 대한치과교정학회지 Vol.31 No.1

원하는 형태의 치아이동을 얻기 위해서는 M/F(Moment/Force) ratio의 조절이 필요하며, 이를 위해서는 치아의 저항중심의 위치를 아는 것은 매우 중요한 일이다. 본 연구에서는 실제 치아주위 환경을 비교적 유사하게 재현할 수 있는 치조골상과 치아의 이동을 시뮬레이션하는 장치를 제작하고, LVDT를 이용한 3차원 운동을 실시간으로 측정할 수 있는 시스템을 사용하여, 힘에 대한 3차원 공간상에서의 치주인대 응력 분포 양상 및 치아 저항중심과 회전축의 위치변화를 계측한 결과 다음과 같은 결론을 얻었다. 1.상악 견치에 원심방향으로 힘을 가했을 때, 치아의 저항중심의 위치는 힘의 크기와는 무관하였으며, 치근의 치경부측 약 29% 부위에 위치하였다. 이는 2차원 모형(42%) 보다 치관 쪽에 위치한다. 2.모멘트만 가하는 경우 치아의 저항중심과 회전축은 일치하였다. 3.치아에 가해지는 모멘트가 증가하는 경우 방향에 관계없이 치아는 정출되는 경향을 보였다. 4.힘이 가해지는 위치, 저항중심, 회전축간에는 일정한 관계가 성립했다(a×b = 49.6mm2). 이 관계식을 통해서 수평력이 가해질 때 예상되는 치아운동 양상을 알 수 있다. 5.수평력이 가해질 때 회전축의 위치는 일직선으로 나타난다. In order to achieve a desirable tooth movement, it is of great importance to control the M/F ratio and to know the location of the center of resistance. The purpose of this study was to locate the center of resistance and the axis of rotation, and to estimate the stress distribution in the periodontal ligament with experimental model. After preparing a model of an upper canine with a simulated periodontal ligament and alveolar bone, the force and moment were applied. The tooth movement was traced using measuring device with LVDTs(Linear variable differential transformers) that can measure three dimensional tooth movement in real time. The results were as follows. 1.The location of center of resistance by transverse force was 29% of root length measured from alveolar crest to apex regardless of force magnitude. The position of the center of resistance is more coronal than that of two-dimensional model(42%). 2.The center of resistance and the axis of rotation coincide when couple moment was applied. 3.As the magnitude of moment increases, tooth tends to extrude irrespective of the direction of the moment. 4.The relationship between location of force and axis of rotation (a x b =49.6mm2) was obtained. A tooth movement can be predicted through this formula. 5.The centers of rotation by transverse force were plotted linearly.

Malocclusion with Congenital Missing of Lower Incisors

Kyung-Ho Kim(김경호),Kwang-Chul Choy(최광철),Kil-Yong Chung(정길용),Hee-Sun Yun(윤희선) 대한치과교정학회 1998 대한치과교정학회지 Vol.28 No.6

한국 성인 골격성 Ⅱ급 부정교합자의 측모두부규격 방사선 계측학적 연구

김경호,최광철,윤희선 대한치과교정학회 2002 대한치과교정학회지 Vol.32 No.4

교정치료의 목표는 좋은 안모 균형과 치열의 안정을 얻는 것이며 이를 위해서는 부정교합의 다양한 원인에 상응한 치료를 시행해야 한다. 본 연구에서는 성인 골격성 Ⅱ급 부정교합자의 측모두부규격 방사선학적 특징을 조사하기 위하여 성인 정상교합자 140명(남70명, 여자 70명)과 성인 골격성 Ⅱ급 부정교합자 120명(남60명, 여 60명)의 측모두부규격 방사선사진을 촬영하였으며 계측결과를 바탕으로 골격 및 치아, 연조직 59개 항목을 평가하여 다음과 같은 결론을 얻었다. 1. 수직적 거리 계측치 및 고경 비율은 골격 분석에서는 정상교합군과 Ⅱ급 부정교합군에서 차이가 없었으나 연조직분석에서는 다소 차이를 보였다. 2. Ⅱ급 부정교합군이 정상교합군에 비해 하악골 길이는 더 작았으며 더 후방에 위치하였다. 3. 상악골의 길이와 전후방적 위치는 Ⅱ급 부정교합굽과 정상교합군 간에 차이가 없었다. 4. 코, 상순, 상악 연조직 부위의 전후방적 위치와 Nasolabial angle은 정상교합군과 Ⅱ급 부정교합군 간에 차이가 없었으며 하악 연조직의 전후방적 위치에서 뚜렷한 차이를 보였다. 5. 상하악 전치의 수직적 길이(U1-HP, L1-MP)는 Ⅱ급 부정교합군이 정상교합군보다 더 켰으며 제1대구치에서는 주군간 차이가 없었다. 6. 상순에 대한 상악전치의 노출도(U1-Stms), 상악전치의 치축 각도(U1-HP)는 두 군간 차이가 없었으며 하악전치의 치축 각도(IMPA)는 Ⅱ급 부정교합군이 정상교합군보다 더 컸다. 7. Ⅱ급 부정교합군의 안모 유형 분류에서, 상악골은 정상 위치하고 하악골이 후방 위치하는 경우가 43.3%로 가장 많았으며, 상악골과 하악골이 모두 정상 위치하는 경우가 28.3%, 상악골과 하악골이 모두 후방 위치하는 경우가 20.0%였다. This study was performed to evaluate horizontal and vertical characteristics according to lateral cephalometry of adult Korean skeletal Class Ⅱ patients using a selected horizontal and vertical reference planes pf Koreans. 60 males and 60 females consisting of freshman of Yonsei University from 1996 to 1997 and patients with history of orthognatic surgery at the Dental Hospital of Yonsei University with a skeletal Class Ⅱ group had the following condition : 1. Profile composed of a retrognathic mandible or protrusive maxilla; 2. Class Ⅱ molar and canine key; 3. ANB-greater than 4˚; 4. Wits appraisal-greater than 1.0mm; Cephalometric analysis consisted of 22 skeletal, 25 soft tissue, 12 dental measurements. The results were as follows. 1. There was no considerable vertical measurement difference between the skeletal Class Ⅱ malocclusion group and the normal occlusion group in skeletal analysis. But, some variations were found between the two groups in soft tissue analysis 2. Mandibular length of the skeletal Class Ⅱ malocclusion group was smaller than that of the normal occlusion group. Mandible was more posteriorly positioned in the Class Ⅱ malocclusion group than in the normal occlusion group. 3. The length and antero-posterior position of the maxilla were not different between the Class Ⅱ malocclusion and the normal occlusion group. 4. The antero-posterior position of the nose, upper lip and maxillary soft tissue, and nasolabial angle were not different between the two groups. 5. Mandibular soft tissue of the Class Ⅱ malocclusion group was more posteriorly positioned than that of the normal. 6. The vertical measurements of the incisors(U1-HP, L1-MP) were bigger in the Class Ⅱ malocclusion group than in the normal, but those of the molars(U6-HP, L6-MP) showed no significant difference between the two groups. 7. Classifying the skeletal Class Ⅱ malocclusion group according to the antero-posterior position of both jaws, normally positioned maxilla and retruded mandible was 43.3%, both normally positioned maxilla and mandible 28.3%, both retruded maxilla and mandible 20.0%.