• 한국농공학회논문집
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• 제59권6호
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• pp.19-27
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• 2017

This study investigated to predict the compressive strength of unsaturated polyester resin based polymer concrete using the maturity method. The test results show that the development of the compressive strength increased exponentially until an age of 24 hours. After 24 hours, the development of the compressive strength just increased gradually. This test result shows that the strength of unsaturated polyester resin based polymer concrete was developed mainly at the early age. Estimated datum temperature of unsaturated polyester resin based polymer concrete was $-20.67^{\circ}C$ which was much lower than of datum temperature ($-10^{\circ}C$) of Portland cement concrete. Also, this study result shows that the existing maturity index associated with Portland cement concrete was not applicable for polymer concrete because curing time of Portland cement concrete is different clearly with curing time of polymer concrete. The cause of different curing time was that there were different curing mechanisms between Portland cement concrete and polymer concrete. In order to best apply the experimental data to a model, CurveExpert Professional, the commercial software, was used to determine the predictive model regarding the compressive strength of unsaturated polyester resin based polymer concrete. As a result, Gompertz Relation or Weibull Model was an appropriate model as a predictive model. The proposed model can be used to predict the compressive strength, especially, it is more useful when the maturity is in the range between $40^{\circ}C{\cdot}h^{0.4}$ and $900^{\circ}C{\cdot}h^{0.4}$.

• 한국전자거래학회지
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• 제24권2호
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• pp.165-178
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• 2019

스마트공장 등으로 변화하는 경쟁 환경 속에서 제조시스템의 현 수준을 측정하고 개선 목표와 과제를 도출, 추진하여 제조경쟁력의 수준을 높이는 것이 기업의 기본적 활동이 되고 있다. 그러나 기업의 미래 제조경쟁력을 갖추기 위한 구성요소 분석과 성숙도평가에 관한 연구는 부분적으로 진행되고 있고 초기단계에 있다. 본 연구는 제조시스템에 대한 다양한 관점의 모델, 개발프로세스, 프레임워크 등에 대한 기존 연구를 분석하였다. 또한 스마트공장 관련 성숙도평가 연구들을 통해 미래 제조시스템의 구성요소들을 도출하여 구조모델을 설계하였다. 평가모델, 변환모델까지 포함하는 메타모델을 설계하고 프레임워크 개발 프로세스를 도출하여 미래 제조시스템의 성숙도평가를 위한 통합적 프레임워크를 제안하였다. 또한 실제 스마트공장 평가에 적용하여 검증하였다. 제시된 프레임워크는 미래 제조시스템의 성숙도평가를 위한 기반 도구로 활용될 수 있을 것이다.

• 한국작물학회지
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• 제27권1호
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• pp.49-54
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• 1982

보리의 생리적 성숙기를 외시적 형질의 변이로서 판정할 수 있는 기준을 설정하여 효과적인 단기 등숙성 계통선발과 등숙유전 연구에 활용하고저 33 품종 및 계통을 4 출수군으로 분류하여 5개 형질에 대하여 검토하였다. 그 결과를 요약하면 다음과 같다. 1. 조기출수 품종일수록 등숙기간이 길어져 출수기와 등숙기간에는 고도의 부의 상관(r=0.656$^{**}$ )를 보였고, 품종간 등숙기간의 차이가 인정되었다. 2. 성숙기 결정에 이용된 각형질중 수분함량과 외영의 색도변화가 가장 유효하였다. 3. 생리적 성숙기를 외시적 측정에 의하여 결정할 때 외영의 색도가 가장 안정하고 민감하게 변화하여 유용한 형질이었다. 또한 지엽의 색도변화를 같이 고려한다면 더 정확한 숙기판단이 될 것으로 본다. 4. 이 시기에 외영의 색은 Grayish yellow (연회황색)이었고, 평균 수분함량은 약 33%이었다.

• 한국수산과학회지
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• 제38권4호
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• pp.232-238
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• 2005

This paper describes reproduction, population structure, growth and size at sexual maturity of a deep-water mud shrimp (Solenocera melantho) in the adjacent waters of Geomun Island, Korea. The shrimp was caught by a beam trawl from November 1998 to December 1999. Spawning period was estimated by gonadosomatic index to be from August to early November with a peak in October to early November. Female shrimps were $12\%$ matured at 16 mm in carapace length, $33\%$ matured at 18 mm and $75\%$ matured at 22 mm. The size at $50\%$ maturity for female was estimated to be 20.65 mm in carapace length. Breeding season was estimated to be from August to early November with a peak in October to early November. The size at $50\%$ inseminated was 19.81 mm CL. The fecundity was 87,500-405,200 and related exponentially to carapace length and total weight. This species survived between 25 and 26 months. The maximum carapace length of females and males were 48 mm and 34 mm respectively. Sex ratio was $51.3\%$, and the females were preponderant. Growth was estimated by modified von Bertalanffy growth function incorporating seasonal variation in growth in both years females (K=1.019/yr and $L_{\infty}$=51.731 mm CL) grew faster, reaching a larger size at a given age than males (K=1.848/yr, and $L_{\infty}$=27.499 mm CL). This is indicated by differences in growth performance indices $(\varphi')$ between females (3.291) and males (3.145).

• 한국패류학회지
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• 제16권1_2호
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• pp.35-41
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• 2000

1999년 4월부터 2000년 3월까지 서해 금강 하구인 내 초도에 서식하고 있는 가무락조개를 대상으로 자원증식 및 적정 관리를 위해 조직학적 방법에 의해 생식소지수, 생식 소발단단계에 따른 생식주기, 군성숙도를 조사하였다. 가무락조개는 자웅이체로서 난생이다. 가무락조개의 생식주기는 초기활성기(2-4월), 후기활성기(3-6월), 완숙기(4-8월), 부분산란기(7-10월초), 퇴화 및 비활성기(9-2월)의 연속적인 5단계로 구분할 수 있었다. 가무락조개의 산란기는 수온과 밀접한 관계를 가지며 수온이 24$^{\circ}C$이상인 7월부터 산란하기 시작하여 9월 중순까지로 산란성기는 7, 8월이었다. 고창산 가무락조개의 군성숙도는 각장 26.0-30.0 mm 사이에서 암, 수 공히 50% 이상이 재생산에 가담하였고, 각장 41.0 mm 이상에서는 100%가 산란에 참여하고 있다. 전 개체의 50%가 재생산에 가담하기 시작하는 개체들의 연령은 만 2세로 추정된다.

• Asian-Australasian Journal of Animal Sciences
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• 제2권4호
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• pp.565-570
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• 1989

The influence of age at first calving on the milk production of crossbred dairy cows produced under major dairy cattle crossbreeding projects in Pakistan was studied from the year 1974 to 1980. These animals were bred and raised at the Livestock Production Research Institute, Bahadarnagar (LPRI), Livestock Experiment Station, Karachi (LES) and the University of Agriculture, Faisalabad (UAF). Local Sahiwal (SWL) cattle were crossed with the European breeds, Holstein Friesian (HF) and Jersey (J) at LPRI and UAF. At LES, native Red Sindhi (RS) were crossed with the HF and J breeds. At LES and UAF, the crossbred progeny, thus, produced comprised of halfbreds only while at LPRI 3/4 HF, 3/4 J, 1/4 HF and 1/4 J groups were also available for this study. The average age at first calving was considerably higher among the native breeds. At LES, the RS calved for the first time at an age of approximately 56 months. Corresponding values for SWLs at LPRI and UAF were 44 and 64 months, respectively. The 1/2 HF and 1/2 J crossbreds calved first at the age of approximately 25, 26, 34, 36, 37 and 38 months at LPRI, LES and UAF respectively. For 3/4 HF, 3/4 K, 1/4 HF and 1/4 J groups of LPRI the average age at first calving was 29, 26, 34 and 33 months. Considerable differences in age at first calving between the crossbreds and native breeds were observed. Due to early maturity, the former attained the peak level of milk production in third lactation whereas the latter groups, because of late maturity, reached this level in their fourth lactation. This study suggested that early maturity in Zebu cattle (Box indicus) could be induced through crossbreeding with European cattle (Bos Taurus).

• 한국패류학회지
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• 제21권1호
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• pp.1-11
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• 2005

Reproductive cycle, first sexual maturity, spawning amount related with the size and spawning interval in female Ruditapes philippinarum were investigated by histological observation and the analysis of morphometric data during artificial spawning induction. Ruditapes philippinarum is dioecious and oviparous. The reproductive cycle of this species can be subdivided into five successive stages: early active stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (May to October), and spent/inactive stage (August to February). The spawning period was once a year between May and early October, and the main spawning occurred between July and August when seawater temperature was approximately $20^{\circ}C$. Percentages of first sexual maturity of female clam of 15.1-20.0 mm in shell length were 56.3%, and 100% for the clams > 25.1 mm. The mean number of the spawned eggs increased with the increase of size classes (shell length). In case of spawning induction by the same size class, the number of spawned eggs were gradually decreased with the increase of spawning frequencies (the first, second, and third spawnings). In the experiments of artificial spawning induction during the spawning season, the interval of each spawning was estimated to be 15-17 days (average 16.5 days).

• Asian-Australasian Journal of Animal Sciences
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• 제17권2호
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• pp.228-236
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• 2004

Two varieties of alfalfa (Medicago sativa L cv. Pioneer and Beaver) and timothy (Phleum pratense L cv. Climax and Joliette), grown at different locations in Saskatchewan (Canada), were cut at three stages [1=one week before commercial cut (early bud for alfalfa; joint for timothy); 2=at commercial cut (late bud for alfalfa; pre-bloom head for timothy); 3=one week after commercial cut (early bloom for alfalfa; full head for timothy)]. The energy values of forages were determined using three approaches, including chemical (NRC 2001 formula) and biological approaches (standard in vitro and in situ assay). The objectives of this study were to determine the effects of forage variety and stage of maturity on energy values under the climate conditions of western Canada, and to investigate relationship between chemical (NRC 2001 formula) approach and biological approaches (in vitro and in situ assay) on prediction of energy values. The results showed that, in general, forage species (alfalfa vs. timothy) and cutting stage had profound impacts, but the varieties within each species (Pioneer vs. Beaver in alfalfa; Climax vs. Joliette in timothy) had minimal effects on energy values. As forage maturity increased, the energy contents behaved in a quadratic fashion, increasing at stage 2 and then significantly decreasing at stage 3. However, the prediction methods-chemical approach (NRC 2001 formula) and biological approaches (in vitro and in situ assay) had great influences on energy values. The highest predicted energy values were found by using the in situ approach, the lowest prediction value by using the NRC 2001 formula, and the intermediate values by the in vitro approach. The in situ results may be most accurate because it is closest to simulate animal condition. The energy values measured by biological approaches are not predictable by the chemical approach in this study, indicating that a refinement is needed in accurately predicting energy values.

• 한국작물학회지
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• 제39권5호
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• pp.420-425
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• 1994

올콩의 수확시기에 따른 품질변화를 밝히고자, 대립종인 Yuhsuzumi와 소립종인 담양재내를 공시하여 수확시기별 종실의 수분함량, 입색, 발아율, 지방산 조성 등을 조사하여 다음과 같은 결과를 얻었다. 1. 협과 종실의 수분함량은 R7단계 전후까지는 협의 수분함량이 뚜렷이 높았으나, R8단계 이후에는 종실의 수분함량이 협보다 다소 높은 경향을 보였으며, 종실의 수분함량이 14%(종실 수분함량으로 본 수확적기) 내외가 되는 시점은 Yuhsuzumi에서는 생리적 성숙기(R7단계)로부터 24일, 담양재내는 8일이 소요되었다. 2. R8단계(고유 성숙협색기)에서 종실의 수분함량은 대립종인 Yuhsuzumi는 25.3%, 소립종인 담양재내는 14.5%를 나타내어 R8단계에 수확시 Yuhsuzumi는 철저한 건조과정이 필요하였다. 3. 수확기 지연에 의하여 Yuhsuzumi는 청색의 종실이 황변하고 입질이 저하되어 발아력이 낮아졌으나, 담양재내는 입질과 발아력의 차이가 없었다. 4. 수확기 지연에 의하여 Yuhsuzumi는 지방산 함량이 낮아졌고, 지방산 조성에 있어서는 Lino-lenic 산은 낮아지고 Oleic산은 증가되었다.

• 한국패류학회지
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• 제4권1호
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• pp.30-41
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• 1988

The gonadal development, the annual reproductive cycle and the first sexual maturity of surf clam, Mactra veneriformis Reeve were studied histologically. Speciemens were monthly collected at the intertidal zone of Naechodo, Chollabuk-do, Korea, for one year from March 1986 to February 1987. Sexuality of the clam is dioecious. The gonads were located between the subregion of mid-intestinal gland in the visceral cavity and the reticular connetive tissues of the foot, The ovary is composed of a number of ovarian sacs, and the testis comprise several testiculat lobules. The undifferentiated mesenchymal tissues and eosinophilic granular cells function as nutritive cells in the early stage. The ripe eggs were about 50-60${\mu}{\textrm}{m}$ in diameter, and they were wurroundedby the gelatinous membranes. The spawing period was from early June to September the main spawning occurred beetween July and August when the water temperature reached above 24$^{\circ}C$. The annual reproductive cycle of this species could be classified into five successive stages: multiplicative(January to March), growing(March to May), mature(April to August), spent(June to September), degenerative and resting(September to February). The monthly changes of fatness coefficient closely correlated with the annual reproductive cycle. Percentages of the first sexual maturity of female and male clams were over 50% among those individals ranging from 2.1 To 2.5cm, and 100% in those over 2.6cm in shell length.