• 자원ㆍ환경경제연구
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• 제19권3호
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• pp.597-632
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• 2010

지구온난화의 주요 원인이 되는 온실가스 증가는 화석연료의 사용과 세계 각 지역에 분포된 산림의 벌채 및 파괴에 주로 기인하고 있다. 화석연료의 연소는 대기에 탄소를 증가시키는 반면에 산림자원과 더불어 화석연료 소비의 감소를 초래하는 연료용 목재의 사용은 대기의 탄소를 일정하게 유지하는 역할을 수행한다. 특히, 목조 주택과 목조구조물, 그리고 산림을 구성하는 나무는 지하에 매장된 화석연료처럼 대기로부터 탄소를 흡수하여 저장하는 기능을 한다. 따라서 본 연구는 지구온난화의 완화를 위해 산림자원이 기여하는 현안들을 논의하기 위해 목재시장, 화석연료시장, 탄소순환 과정을 결합한 통합모형을 개발하였다. 본 연구는 이산시간 적정제어이론을 사용하여 통합모형에 포함된 내생변수들의 적정시간경로와 운동방정식, 그리고 정상상태에서의 해를 도출하였다. 본 연구는 이 결과를 바탕으로 대기에 축적되는 탄소를 줄이기 위해 규제당국이 교부하거나 부과할 보조금 및 조세의 적정규모를 규명하였다. 아울러 본 연구는 대기에 축적되는 탄소로 인해 발생하는 사회적 비용의 증가가 내생변수들에 미치는 영향을 분석하기 위해 시뮬레이션을 시도하였다. 그 결과 본 연구는 기존연구들이 제안한 연구결과와는 달리 사회적 비용의 증가가 산림자원의 적정수확기간에 미치는 영향이 매우 미약하다는 사실을 발견하였다.

• Archives of Reconstructive Microsurgery
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• 제13권2호
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• pp.93-100
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• 2004

This study was designed to investigate the optimal period of pedicles implantation in the prefabricated periosteofascial flap with a vascular tissue transfer. The flap prefabrication was prepared with a transposition of left occipital pedicles on the calvarial fascia of male Sprague-Dawley rats. Thirty flaps were divided into five groups of six flaps, including control group (group I) of the conventional periosteofascial flap based on the lateral border of the rat calvarium. The prefabricated flap was elevated as an $1{\times}1cm$ sized island flap based on the implanted pedicle at 1, 2, 3, and 4 weeks after the pedicles transfer in groups II, III, IV, and V, respectively. After the completion of creating a critical-sized calvarial defect and implanting with hydroxyapatite granules, the flap was sutured back for covering the defect and kept isolated from surrounding tissues. Six weeks after flap repositioning, the osseous changes of the defect were examined with simple radiographic findings, radiodensitometric analysis, and histological studies. By simple radiographic findings, specimens of the control, groups IV and V showed homogeneous radioopacity within the defect. But in groups II and III, focal radiolucency was observed in the defect. In the radiodensitometric analysis, the control group and the group V showed significant increased radiodensites statistically. Histologically, the implanted hydroxyapatite was absorbed partly in the defect in groups II, III, and IV. In the defects of the control group and the group V, the implanted hydroxyapatite was kept in its volume and the deposition of the bone cells was observed sparsely. In conclusion, the prefabricated periosteofascial flap can be created with a vascular tissue transfer and the pedicles should be implanted at least for 4 weeks to bring out positive osseous changes in the calvarial defect.

• 한국응용곤충학회지
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• 제55권4호
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• pp.383-388
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• 2016

전북 부안지역에서 오디용 뽕나무에 발생하는 뽕나무이의 발생 양상과 친환경자재에 의한 방제 효과를 조사하였다. 뽕나무이 월동 성충은 3월 하순부터 5월 중순까지 뽕나무 포장으로 비래하였으며 발생최성기는 4월 중순이었다. 알은 4월 중순부터 관찰되었으며 약충은 5월 상순부터 부화하기 시작하여 5월 중순에 발생피크를 나타냈다. 신성충은 6월 상순부터 관찰되었으며 이후 비산하여 6월 중순 이후에는 뽕나무 포장에서 관찰되지 않았다. 따라서 뽕나무이의 발생소장에 의한 방제 적기로 월동 성충은 4월 중순, 약충은 5월 상순으로 판단되었다. 뽕나무이 약충 방제에 고삼 추출물과 데리스 추출물이 효과적이었으며, 뽕나무 포장에서 뽕나무이 약충 방제적기에 데리스 제제를 5일 간격으로 2~3회 처리한 결과 방제 효과가 높았다.

• Journal of Periodontal and Implant Science
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• 제53권4호
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• pp.259-268
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• 2023

Purpose: Hyaluronic acid (HA) affects angiogenesis and promotes the migration and differentiation of mesenchymal cells, thereby activating the osteogenic ability of osteoblasts. Although studies on the action of HA during bone regeneration are being actively conducted, the optimal dose of HA required for bone regeneration remains unclear. Therefore, the purpose of this study was to elucidate the most effective HA dose for bone formation using a rat critical-size defect model. Methods: Thirty rats were randomly divided into 5 groups, with 6 rats in each group. An absorbable collagen sponge soaked with HA or saline was used to fill an 8-mm defect, which was then covered with a collagen membrane. Different treatments were performed for each group as follows: (1) saline control, (2) 1 mg/mL HA, (3) 25 mg/mL HA, (4) 50 mg/mL HA, or (5) 75 mg/mL HA. After a healing period of 4 weeks, micro-computed tomography and histological analysis were performed. The obtained values were analyzed using analysis of variance and the Tukey test (P<0.05). Results: At week 4, the 75 mg/mL HA group had the highest bone volume/total volume ratio, new bone, and bone fill among the 5 groups, and these values were significantly different from those observed in the control group (P<0.01) and 1 mg/mL HA group (P<0.001). More active bone formation was observed in the higher-dose HA groups (25 mg/mL, 50 mg/mL, and 75 mg/mL HA), which included a large amount of woven bone. Conclusions: The 75 mg/mL HA group showed better bone formation than the other groups (1, 25, and 50 mg/mL HA and control).

• 한국환경농학회지
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• 제41권1호
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• pp.24-31
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• 2022

BACKGROUND: The most common litter materials used in South Korea are sawdust, rice husk, etc. Recently, the cost of litter has been steadily rising, and the maturity test has been strengthened. For this reason, new litter materials are needed for better water control ability to solve the problems. The object of this study was to evaluate the water absorption properties for litter materials. METHODS AND RESULTS: The volumetric water capacity according to the addition of cow manure was investigated to calculate the water absorption speed of litter materials (sawdust, peatmoss, cocopeat, and biochar). The water absorption speed constant (-K) in the first stage was high in the order of cocopeat (0.1190), sawdust (0.0961), biochar (0.0762), and peatmoss (0.0523). The optimal period of the litter use was in the following order: peatmoss (48d), biochar (42d), sawdust (30d), and cocopeat (24d). The water absorption rate (%) of the used litters was high in the order of biochar ≈ cocopeat, sawdust, and peatmoss, which was significantly correlated with the water absorption speed of the first stage. CONCLUSION(S): Considering the water absorption speed and water absorption rate, biochar and peatmoss were found to be the best and optimal litter materials among the tested materials. These litter materials can be used as water control agents in livestock facilities.

• 전기학회논문지
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• 제58권8호
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• pp.1504-1511
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• 2009

By development of renewable energies and high-efficient facilities and deregulated electricity market, the operation cost of distributed generation(DG) becomes more competitive. The amount of distributed resource is considerably increasing in the distribution network consequently. Also, international environmental regulations of the leaking carbon become effective to keep pace with the global efforts for low-carbon paradigm. It contributes to spread out the business of DG. Therefore, the operator of DG is able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, community energy system(CES) having DGs is recently a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to the transmission service charges and etc. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize the profit. If there is no regulation for carbon emission(CE), the generators which get higher production than generation cost will hold a prominent position in a competitive price. However, considering the international environment regulation, CE newly will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper will introduce the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES and Particle Swarm Optimization (PSO) will be used to solve this problem. The optimal operation of DG represented in this paper is to be resource to CES and system operator for determining the decision making criteria.

• KIEAE Journal
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• 제16권3호
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• pp.89-94
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• 2016

Purpose: This study aimed at developing an artificial neural network (ANN) model to predict the optimal start moment of the setback temperature during the normal occupied period of a building. Method: For achieving this objective, three major steps were conducted: the development of an initial ANN model, optimization of the initial model, and performance tests of the optimized model. The development and performance testing of the ANN model were conducted through numerical simulation methods using transient systems simulation (TRNSYS) and matrix laboratory (MATLAB) software. Result: The results analysis in the development and test processes revealed that the indoor temperature, outdoor temperature, and temperature difference from the setback temperature presented strong relationship with the optimal start moment of the setback temperature; thus, these variables were used as input neurons in the ANN model. The optimal values for the number of hidden layers, number of hidden neurons, learning rate, and moment were found to be 4, 9, 0.6, and 0.9, respectively, and these values were applied to the optimized ANN model. The optimized model proved its prediction accuracy with the very storing statistical correlation between the predicted values from the ANN model and the simulated values in the TRNSYS model. Thus, the optimized model showed its potential to be applied in the control algorithm.

• Structural Engineering and Mechanics
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• 제33권1호
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• pp.79-93
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• 2009

This paper investigates the possibility of controlling the response of typical portal frame structures to blast loading using a combination of semi-active and passive control devices. A one storey reinforced concrete portal frame is modelled using non-linear finite elements with each column discretised into multiple elements to capture the higher frequency modes of column vibration response that are typical features of blast responses. The model structure is subjected to blast loads of varying duration, magnitude and shape, and the critical aspects of the response are investigated over a range of structural periods in the form of blast load response spectra. It is found that the shape or length of the blast load is not a factor in the response, as long as the period is less than 25% of the fundamental structural period. Thus, blast load response can be expressed strictly as a function of the momentum applied to the structure by a blast load. The optimal device arrangements are found to be those that reduce the first peak of the structural displacement and also reduce the subsequent free vibration of the structure. Semi-active devices that do not increase base shear demands on the foundations in combination with a passive yielding tendon are found to provide the most effective control, particularly if base shear demand is an important consideration, as with older structures. The overall results are summarised as response spectra for eventual potential use within standard structural design paradigms.

• Asian-Australasian Journal of Animal Sciences
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• 제18권3호
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• pp.384-389
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• 2005

These experiments were conducted to evaluate the feeding value of rice protein concentrate (RPC) in weaning pigs. In expt. I, a 5-week feeding trial was conducted with 126 pigs (L${\times}$Y${\times}$D; 21 d-old; 5.32${\pm}$0.34 kg). Treatments were spray-dried plasma protein (SDPP; control), soy protein concentrate (SPC) and RPC (phase 1), and dried porcine soluble (DPS; control), SPC and RPC (phase 2). An ileal digestibility trial was also conducted to compare digestibility of amino acids in the tested protein sources. In expt. II, 160 weaning pigs (L${\times}$Y${\times}$D; 21 d-old; 5.65${\pm}$0.35 kg) were used in a 5-week feeding trial to determine the optimal inclusion level of RPC in the diet. Treatments were control (9% SPC), and three levels of RPC instead of SPC in the diets (3, 6 and 9%). During phase 1, pigs fed SDPP showed better (p<0.05) ADG and FCR compared with those fed SPC or RPC, while there was no difference in ADFI among treatments. During phase 2, however, pigs fed DPS showed lower (p<0.05) ADG than those fed SPC or RPC. During the total period, there were no significant differences in ADG, ADFI and FCR among treatments. The apparent ileal digestibilities of his, lys, phe, thr and met were not different among the tested protein sources. The apparent ileal digestibilities of arg, ile, leu and val were lower (p<0.05) in RPC than SDPP. The true ileal digestibilities of arg and leu were lower (p<0.05) in RPC than SDPP and SPC. However, that of met was higher (p<0.05) in RPC than SDPP. In expt. II, there were no significant differences in ADG and FCR when SPC was substituted with RPC up to 9% during the total period. In conclusion, based on our experimental results, RPC would replace SPC in the complex prestarter diet, which is somewhat cheaper than SPC.

• International Journal of Industrial Entomology and Biomaterials
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• 제32권1호
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• pp.41-48
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• 2016

Mealworms, Tenebrio molitor (Coleoptera: Tenebrionidae), are widely used as food sourcefor animal rearing as well as human diet. Conventionally, mealworms raised on wheat bran. In this study, we investigated the effects of brewer's spent grain (BSG) on the growth of mealworm larvae to reduce the rearing cost. We prepared five different diets with various BSG content, 0, 10, 30, 50, and 70% of heated air dried BSG with wheat bran. We compared survivorship, larval weight, developmental duration, pupation rate, and pupal weight of five different groups of T. molitor raised on these five diets. The larval survivorships were almost similar with the control group except a group with 70% of BSG. For the larval weight, groups with 30% and 50% of BSG gained more weight than that with control treatment, 0% of BSG. For the developmental period, the groups with 30% of BSG took less time compared to the control group. In all treatment groups, more than 90% of pupation rate were observed. Especially, the group with 30% of BSG showed highest pupation rate among the five groups. Wheat bran with 30~50% of BSG was the optimal diet for successive insect rearing among the five diet treatments. Based on this study, we concluded that adding BSG to wheat bran helps to improve the quality of T. molitor and to reduce the rearing period.