• 한국콘텐츠학회논문지
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• 제21권4호
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• pp.424-433
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• 2021

본 연구는 상업적인 목적으로 미꾸라지, 잉어, 메기 등의 어종을 활용한 아쿠아포닉스 시스템과 다르게 가정에서 반려어로 사육하는 열대 어종인 구피를 활용한 가정용 아쿠아포닉스의 적용 가능성을 탐색한 논문이다. 가정에서 아쿠아포닉스의 적용이 쉽도록 사물 인터넷 기술을 활용하여, 수조, 수초, 수경재배 화분, 식물생장용 LED, 아두이노 센서 등을 연결하여 시스템을 갖추었다. 수경재배 작물로는 가정에서 쉽게 구할 수 있고 소비할 수 있는 상추를 선택하였다. 열대어를 활용한 아쿠아포닉스의 적용 가능성을 확인하기 위해 동일한 환경의 수경재배 작물을 대조군으로 성장률을 비교하였다. 열대어를 활용한 아쿠아포닉스 작물의 성장률은 수경재배 작물의 성장률 대비 77.4% 정도였으며 이것은 향후 사육 열대어의 수, 성장에 적절한 산도(pH) 조절 등의 조건을 충족시킬 경우 수경재배와 동일한 효과를 낼 수 있다고 볼 수 있으며 향후 이를 활용하여 가정에서 적용 가능한 아쿠아포닉스 표준 시스템을 개발할 수 있다.

• 한국정보통신학회논문지
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• 제25권11호
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• pp.1559-1565
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• 2021

본 논문에서는 다중 사용자 거대 다중 안테나 시스템에서 안테나 선택 기법을 제안한다. 제안된 안테나 선택 기법은 심화 강화학습 네트워크를 활용함으로써 피드백 오버헤드를 획기적으로 낮추면서 기존 방식과 거의 같은 성능을 얻을 수 있다. 각 사용자는 기지국의 거대 안테나들과 형성된 채널의 이득 값을 L번째 큰 채널 이득과 비교하여 대소관계에 따라서 단일 비트의 이진수로 변환하여 피드백함으로써 기존 피드백 방식보다 오버헤드를 낮출 수 있다. 제안 방식에서는 감소한 피드백 정보로 인한 성능 저하를 방지하기 위해서 심화 강화학습 네트워크를 활용하였다. 제안 방식의 성능을 분석하기 위하여 다양한 환경에서 시뮬레이션을 수행하였으며, 제안 방식이 최적 방식에 가까운 기존 방식과 유사한 평균 전송률을 얻을 수 있음을 확인하였다.

• Membrane and Water Treatment
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• 제13권5호
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• pp.235-243
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• 2022

The paper presents the effect of operating temperatures and flow rates on the distillate flux that can be obtained from a hydrophobic membrane having the characteristics: pore size of 0.15 ㎛; thickness of 130 ㎛; and 85% porosity. That membrane in the present investigation could be the direct contact (DCMD) or the air-gap membrane distillation (AGMD). To model numerically the membrane distillation processes, the two-dimensional computational fluid dynamic (CFD) is used for the DCMD and AGMD cases here. In this work, DCMD and AGMD models have been validated with the experimental data using different flows (Parallel and Counter-current flows) in non-steady-state situations. A good agreement is obtained between the present results and those of the experimental data in the literature. The new approach in the present numerical modeling has allowed examining effects of the nature of materials (Polyvinylidene fluoride (PVDF) polymers, copolymers, and blends) used on thermal properties. Moreover, the effect of the area surface of the membrane (0.021 to 3.15 ㎡) is investigated to explore both the laminar and the turbulent flow regimes. The obtained results found that copolymer P(VDF-TrFE) (80/20) is more effective than the other materials of membrane distillation (MD). The mass flux and thermal efficiency reach 193.5 (g/㎡s), and 83.29 % using turbulent flow and an effective area of 3.1 ㎡, respectively. The increase of feed inlet temperatures and its flow rate, with the reduction of cold temperatures and its flow rate are very effective for increasing distillate water flow in MD applications.

• Journal of Animal Science and Technology
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• 제65권1호
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• pp.96-112
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• 2023

Rye (Secale cereale L.) is a valuable annual forage crop in Korea but there is limited information about the impact of chemical and biological additives on fermentation characteristics of the crop. This experiment was conducted to investigate fermentation dynamics of wilted forage rye treated with the following six additives; control (no additive), sodium diacetate applied at 3 g/kg wilted forage weight (SDA3), 6 g/kg wilted forage weight (SDA6), inoculations (10⁶ CFU/g wilted forage) of Lactobacillus plantarum (LP), L. buchneri (LB), or LP+LB. The ensiled rye sampled at 1, 2, 3, 5, 10, 20, 30, and 45 days indicated that the acidification occurred fast within five days of storage than the rest of the storage period. The microbial inoculants decline the pH of ensiled forage, more rapidly than the control or SDA treated, which accompanied by the decrease of water-soluble carbohydrates and increase of lactic acid. Compared with the control silage, all treatments suppressed ammonia-nitrogen formation below to 35 g/kg DM throughout the sampling period. Suppression of total microbial counting occurred in SDA6, LP, and LP + LB. The lactic acid production rates were generally higher in microbial inoculation treatments. Acetic acid concentration was lowest in the LP-treated silage and highest in the SDA- and LB-treated silages. The in vitro dry matter (DM) digestibility and total digestible nutrients were the highest in the silage treated with SDA (6 g/kg) at day 45 of ensiling. Based on lower ammonia-nitrogen concentrations and higher feed value, ensiling forage rye treated with SDA at 6 g/kg is promising through enhanced silage quality.

• International Journal of Industrial Entomology and Biomaterials
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• 제46권2호
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• pp.34-40
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• 2023

As agricultural production increases due to population growth, agricultural by-products that are generated at all production stages increase commensurately. Black soldier fly (BSF) (Hermetia illucens) treatment has potential as an environmentally friendly process to combat the environmental pollution caused by agricultural by-products. This study examined the utilization of BSF larvae in the decomposition of the by-products of apples and mandarins, fruits commonly produced in South Korea. The BSF test larvae were fed apple pomace or mandarin waste, and the control larvae were fed calf feed. Larval weight and size were measured at 4-day intervals until larvae reached the pre-pupal stage. Larval development time, survival rate, and BSF fecundity rate were calculated for all three substrates. Waste reduction and bioconversion ratios were also calculated. The developmental time of larvae fed with apple pomace and mandarin waste was greater than that of the control larvae. The average weight of larvae fed with the fruit by-products was less than that of the control. There was no significant difference in the survival rate of BSF larvae or the fecundity rate of BSF between the substrates used in this study. BSF larvae decomposed 48.0% and 61.5% of apple pomace and mandarin waste, respectively. The bioconversion efficiency rates of BSF larvae fed with apple pomace and mandarin waste were 9.1% and 12.1%, respectively. These results indicated that decomposition of single fruit by-products by BSF larvae is an environmentally friendly and effective bioconversion process.

• 현장농수산연구지
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• 제20권2호
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• pp.117-123
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• 2018

본 연구의 목적은 성숙한 당나귀의 큰잘록 창자 폐색 증례를 진단하여 보고하고자 한다. 당나귀(Equus africanus asinus; 암, 6세) 1마리가 제주경마공원 동물병원에 전날부터 시작된 식욕부진 증상으로 내원하였다. 장음소실, 탈수, 심한 복강 확장 등의 증상을 확인하였으나 호흡수 및 심박수는 정상이었고, 복통 증상은 없었다. 직장검사에서 폐색된 부분이 잘록 창자임을 확인하였다. 위세척, 수액요법 및 비스테로이드 계열의 진통제를 투여하였으나 다음날 새벽 갑자기 몸을 떨며 기립곤란과 같이 신체상태가 악화되기 시작한지 2시간 만에 폐사하였다. 부검에서 특히 왼배쪽 잘록 창자와 같은 큰잘록 창자에서 다량의 식괴를 발견하였고, 막창자와 곧창자는 정상이었다. 당나귀는 내원하기 11일 전에 새로 입사해서 사양 관리체계가 바뀌었다. 사료변경, 수분섭취 감소, 운동부족 등이 질병을 유발하였을 것으로 생각된다. 그러나 당나귀의 정확한 급사원인은 더 연구해야 할 과제로 남는다.

• 한국초지조사료학회지
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• 제43권4호
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• pp.199-205
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• 2023

Pasture formation and management are crucial to avoid yield reduction. This experiment aimed to examine the effects of tall fescue-centered mixed-seeding combinations on yield and vegetation changes in perennial pastures in the central region for two years, from September 2020 to October 2022. The treatments were arranged in three replications in a randomized block design: control (C), tall fescue-based mixture-1 (T-1), and tall fescue-based mixture-2 (T-2). The tall fescue (TF), orchard grass (OG), perennial ryegrass (PRG), Kentucky bluegrass (KBG), and white clover (WC) were used. The emergency rate of grasses (70.0 to 73.3%) did not differ among mixed seeding combinations. Overwintering rates (81.7 to 83.3%) were similar among treatments. The plant height of grasses was similar at each harvest date, with the highest height (86.2 cm) recorded in the second harvest of the first year, followed by that (58.4 cm) in the third harvest of the first year; it was least (38.9 cm) in the fourth harvest of the second year. There was no significant difference in the dry matter yield of grasses among the mixed seeding combination treatments in the first, third, or fourth harvests of the first year (p>0.05). For second-year grasses, dry matter yield was not significantly different in harvest date among the treatments (p>0.05). Based on mixed seeding ratio, orchard grass showed the highest yield at 70% in the C treatment, followed by tall fescue at 80% and 60% in the T-1 and T-2 treatments, respectively, in the first harvest after seeding. There was no significant difference in feed value between treatments (p>0.05), but a significant difference was observed between the third and fourth harvest (p<0.05). Therefore, it indicated that it is important to create perennial pastures in the central region through mixed seeding combinations centered on tall fescue.

• Animal Bioscience
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• 제36권12호
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• pp.1918-1925
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• 2023

Objective: The objective of this study was to evaluate the effect of biogas slurry application on biomass production and the silage quality of corn. Methods: A field experiment was conducted in which corn was grown using different biogas slurry application rates. The effect of 25% to 500% biogas slurry nitrogen replacement (T1 to T14) on the yield and quality indices of corn were studied by field plot experiments. Results: The results revealed that biogas slurry application improved the stem diameter and relative feed value of corn silage in treatments T13 and T11. Moreover, the fermentation quality of corn silage was improved due to an increase in lactic acid content; in comparison with the chemical synthetic fertilizer (CF) group. The crude protein contents of corn silage had no obvious change with increasing biogas slurry application. However, the forage quality index of acid detergent fiber was decreased (p<0.05) in the T11 group compared with the CF group. In addition, higher (p<0.05) 30 h in vitro dry matter digestibility and 30 h in vitro neutral detergent fiber digestibility were observed in the T11 and T13 groups than in the CF group. Conclusion: Based on these results, it was concluded that the optimum biogas slurry application rate for corn was approximately 350% to 450% biogas slurry nitrogen replacement under the present experimental conditions.

• Geomechanics and Engineering
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• 제36권5호
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• pp.489-509
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• 2024

Slope stability analysis and prediction are of critical importance to geotechnical engineers, given the severe consequences associated with slope failure. This research endeavors to forecast the factor of safety (FOS) for slopes through the implementation of six distinct ML techniques, including back propagation neural networks (BPNN), feed-forward neural networks (FFNN), Takagi-Sugeno fuzzy system (TSF), gene expression programming (GEP), and least-square support vector machine (Ls-SVM). 344 slope cases were analyzed, incorporating a variety of geometric and shear strength parameters measured through the PLAXIS software alongside several loss functions to assess the models' performance. The findings demonstrated that all models produced satisfactory results, with BPNN and GEP models proving to be the most precise, achieving an R² of 0.86 each and MAE and MAPE rates of 0.00012 and 0.00002 and 0.005 and 0.004, respectively. A Pearson correlation and residuals statistical analysis were carried out to examine the importance of each factor in the prediction, revealing that all considered geomechanical features are significantly relevant to slope stability. However, the parameters of friction angle and slope height were found to be the most and least significant, respectively. In addition, to aid in the FOS computation for engineering challenges, a graphical user interface (GUI) for the ML-based techniques was created.

• 한국초지조사료학회지
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• 제23권1호
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• pp.1-6
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• 2003

본 연구는 제주지역에서 인산시비량 차이에 따른(0, 40, 80, 120, 160, 200kg/ha) 청예팥의 생육반응, 수량성 및 사료가치를 검토하고, 적정 인산시비량을 구명하기 위하여 2002년 5월 부터 2002년 8월까지 시험하였다. 초장은 무인산구에서 80.7cm이었던 것이 인산시비량이 증가함에 따라 점차적으로 증가하여 160kg/ha 시비구와 200kgHa 시비구에서 각각 88.8cm, 88.9cm로 커졌으나 두 시비구 간에는 유의성이 없었다. 1주당 분지수, 엽수, 경직경, 엽중 및 경중은 초장의 반응과 비슷한 경향이었다. 생초, 건물, 단백질 및 TDN 수량은 무인산구에서 각각 23.8MT/ha, 3MT/ha, 0.5MT/ha, 1.8MT/ha이었으나 인산시비량이 증가함에 따라 점차적으로 증가되어 160kg, 200kg/ha 시비구에서 생초수랑은 47.2MT/ha에서 47.3MT/ha로, 건물수량은 7.IMT/ha에서 7.2MT/ha로, 단백질수량은 1.2MT/ha에서 1.3MT/ha로, TDN 수량은 4.6MT/ha에서 4.7MT/ha로 증수되었으나 이두 시비구 간의 유의성은 없었다. 인산시비량이 증가됨에 따라 단백질 함량은 15.2%에서 18.6%로 조지방 함량은 3.4%에서 4.5%로, 가용 무질소물은 41.1%에서 45.5%로, TDN 함량은 58.3％에서 65.5%로 증가되었으나 이와는 반대로 조섬유 함량은 31.5%에서 24.8%로, 조회분 함량은 8.5%에서 6.6%로 감소되는 경향을 보였다.